Rev.7.5_00 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER S-8520 / 8521 Series The S-8520 / 8521 Series consists of CMOS step-down switching regulator-controllers with PWM control (S-8520 Series) and PWM / PFM switching control (S-8521 Series). These devices contain a reference voltage source, oscillation circuit, error amplifier, and other components. The S-8520 Series provides low-ripple power, highefficiency, and excellent transient characteristics thanks to a PWM control circuit capable of varying the duty ratio linearly from 0% up to 100%. The series also contains an error amplifier circuit as well as a soft-start circuit that prevents overshoot at startup. The S-8521 Series works with either PWM control or PFM control, and can switch from one to the other. It normally operates using PWM control with a duty ratio of 25 to 100%, but under a light load, it automatically switches to PFM control with a duty ratio of 25%. This series ensures high efficiency over a wide range of conditions, from standby mode to operation of peripheral equipment. With the addition of an external Pch power MOS FET or PNP transistor, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOT-23-5 small package, providing such outstanding features as low current consumption. Since this series can accommodate an input voltage of up to 16 V, it is also ideal when operating via an AC adapter. Features * Low current consumption During operation: 60 A max. (A, B types) 21 A max. (C, D types) 100 A max. (E, F types) During shutdown: 0.5 A max. * Input voltage: 2.5 to 16 V (B, D, F types) 2.5 to 10 V (A, C, E types) * Output voltage: Selectable between 1.5 V and 6.0 V in 0.1 V step * Duty ratio: 0 to 100% PWM control (S-8520 Series) 25 to100% PWM / PFM switching control (S-8521 Series) * The only peripheral components that can be used with this IC are a Pch power MOS FET or PNP transistor, a coil, a diode, and capacitors (If a PNP transistor is used, a base resistance and a capacitor will also be required). * Oscillation frequency: 180 kHz typ. (A, B types) 60 kHz typ. (C, D types) 300 kHz typ. (E, F types) * Soft-start function: 8 ms. typ. (A, B types) 12 ms. typ. (C, D types) 4.5 ms. typ. (E, F types) * With a shutdown function * With a built-in overload protection circuit Overload detection time: 4 ms. typ. (A type) 14 ms. typ. (C type) 2.6 ms. typ. (E type) Seiko Instruments Inc. 1 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Applications * On-board power supplies of battery devices for portable telephones, electronic notebooks, PDAs. * Power supplies for audio equipment, including portable CD players and headphone stereo equipment. * Fixed voltage power supply for cameras, video equipment and communications equipment. * Power supplies for microcomputers. * Conversion from four NiH or NiCd cells or two lithium-ion cells to 3.3 V / 3 V. * Conversion of AC adapter input to 5 V / 3 V. Package Package Name SOT-23-5 2 Package MP005-A Drawing code Tape MP005-A Seiko Instruments Inc. Reel MP005-A STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Block Diagrams 1. S-8520 Series L Tr VIN Oscillation circuit EXT VIN + CIN Reference voltage source with soft-start + PWM control circuit SD VOUT + COUT - VON / OFF VSS ON / OFF Remark All the diodes in the figure are parasitic diodes. Figure 1 2. S-8521 Series L Tr VIN Oscillation circuit EXT VIN + CIN Reference voltage source with soft-start PWM/PFM switching control circuit SD VON / OFF VOUT + + COUT - VSS ON / OFF Remark All the diodes in the figure are parasitic diodes. Figure 2 Seiko Instruments Inc. 3 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Product Name Structure * The control types, product types, and output voltage for the S-8540 / 8541 series can be selected at the user's request. Please refer to the "1. Product name" for the definition of the product name and "2. Product Name List" for the full product names. 1. Product name S-852 x x xx MC - xxx - T2 IC direction in tape specifications*1 Product code*2 *1. *2. 4 Package code MC: SOT-23-5 Output voltage 15 to 60 (Ex. When the output voltage is 1.5 V, it is expressed as 15.) Product type A: Oscillation frequency of 180 kHz, With overload protection circuit. B: Oscillation frequency of 180 kHz, Without overload protection circuit. C: Oscillation frequency of 60 kHz, With overload protection circuit. D: Oscillation frequency of 60 kHz, Without overload protection circuit. E: Oscillation frequency of 300 kHz, With overload protection circuit. F: Oscillation frequency of 300 kHz, Without overload protection circuit. Control system 0: PWM control 1: PWM/PFM switching control Refer to the taping specifications at the end of this book. Refer to "2. Product name list". Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. Product name list 2. 1 S-8520 Series Table 1 (1 / 2) Series Output voltage [V] 1.8 2.1 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 4.3 5.0 5.3 S-8520AxxMC Series S-8520BxxMC Series S-8520CxxMC Series S-8520A21MC-AVG-T2 S-8520A25MC-AVK-T2 S-8520A26MC-AVL-T2 S-8520A27MC-AVM-T2 S-8520A28MC-AVN-T2 S-8520A29MC-AVO-T2 S-8520A30MC-AVP-T2 S-8520A31MC-AVQ-T2 S-8520A32MC-AVR-T2 S-8520A33MC-AVS-T2 S-8520A34MC-AVT-T2 S-8520A35MC-AVU-T2 S-8520A36MC-AVV-T2 S-8520A50MC-AWJ-T2 S-8520B18MC-ARD-T2 S-8520B24MC-ARJ-T2 S-8520B25MC-ARK-T2 S-8520B27MC-ARM-T2 S-8520B28MC-ARN-T2 S-8520B29MC-ARO-T2 S-8520B30MC-ARP-T2 S-8520B31MC-ARQ-T2 S-8520B32MC-ARR-T2 S-8520B33MC-ARS-T2 S-8520B34MC-ART-T2 S-8520B35MC-ARU-T2 S-8520B36MC-ARV-T2 S-8520B43MC-ASC-T2 S-8520B50MC-ASJ-T2 S-8520B53MC-ASM-T2 S-8520C25MC-BRK-T2 S-8520C27MC-BRM-T2 S-8520C28MC-BRN-T2 S-8520C29MC-BRO-T2 S-8520C30MC-BRP-T2 S-8520C31MC-BRQ-T2 S-8520C32MC-BRR-T2 S-8520C33MC-BRS-T2 S-8520C34MC-BRT-T2 S-8520C35MC-BRU-T2 S-8520C36MC-BRV-T2 S-8520C50MC-BSJ-T2 Table 1 (2 / 2) Series S-8520DxxMC Series S-8520ExxMC Series S-8520FxxMC Series Output voltage [V] 1.5 S-8520F15MC-BNA-T2 1.6 S-8520E16MC-BJB-T2 1.8 S-8520E18MC-BJD-T2 S-8520F18MC-BND-T2 2.0 S-8520F20MC-BNF-T2 2.5 S-8520D25MC-BVK-T2 S-8520E25MC-BJK-T2 S-8520F25MC-BNK-T2 2.6 S-8520F26MC-BNL-T2 2.7 S-8520D27MC-BVM-T2 S-8520F27MC-BNM-T2 2.8 S-8520D28MC-BVN-T2 2.9 S-8520D29MC-BVO-T2 3.0 S-8520D30MC-BVP-T2 S-8520E30MC-BJP-T2 S-8520F30MC-BNP-T2 3.1 S-8520D31MC-BVQ-T2 S-8520F31MC-BNQ-T2 3.2 S-8520D32MC-BVR-T2 3.3 S-8520D33MC-BVS-T2 S-8520E33MC-BJS-T2 S-8520F33MC-BNS-T2 3.4 S-8520D34MC-BVT-T2 S-8520F34MC-BNT-T2 3.5 S-8520D35MC-BVU-T2 3.6 S-8520D36MC-BVV-T2 5.0 S-8520D50MC-BWJ-T2 S-8520E50MC-BKJ-T2 S-8520F50MC-BOJ-T2 5.2 S-8520E52MC-BKL-T2 5.5 S-8520F55MC-BOO-T2 Remark Please contact the SII marketing department for the availability of product samples other than those specified above. Seiko Instruments Inc. 5 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2-2. S-8521 Series Table 2 (1 / 2) Series Output voltage [V] 1.5 1.6 1.8 1.9 2.0 2.1 2.3 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 4.0 4.4 5.0 S-8521AxxMC Series S-8521BxxMC Series S-8521CxxMC Series S-8521A25MC-AXK-T2 S-8521A27MC-AXM-T2 S-8521A28MC-AXN-T2 S-8521A29MC-AXO-T2 S-8521A30MC-AXP-T2 S-8521A31MC-AXQ-T2 S-8521A32MC-AXR-T2 S-8521A33MC-AXS-T2 S-8521A34MC-AXT-T2 S-8521A35MC-AXU-T2 S-8521A36MC-AXV-T2 S-8521A50MC-AYJ-T2 S-8521B15MC-ATA-T2 S-8521B18MC-ATD-T2 S-8521B19MC-ATE-T2 S-8521B20MC-ATF-T2 S-8521B21MC-ATG-T2 S-8521B23MC-ATI-T2 S-8521B25MC-ATK-T2 S-8521B26MC-ATL-T2 S-8521B27MC-ATM-T2 S-8521B28MC-ATN-T2 S-8521B29MC-ATO-T2 S-8521B30MC-ATP-T2 S-8521B31MC-ATQ-T2 S-8521B32MC-ATR-T2 S-8521B33MC-ATS-T2 S-8521B34MC-ATT-T2 S-8521B35MC-ATU-T2 S-8521B36MC-ATV-T2 S-8521B40MC-ATZ-T2 S-8521B44MC-AUD-T2 S-8521B50MC-AUJ-T2 S-8521C16MC-BTB-T2 S-8521C25MC-BTK-T2 S-8521C27MC-BTM-T2 S-8521C28MC-BTN-T2 S-8521C29MC-BTO-T2 S-8521C30MC-BTP-T2 S-8521C31MC-BTQ-T2 S-8521C32MC-BTR-T2 S-8521C33MC-BTS-T2 S-8521C34MC-BTT-T2 S-8521C35MC-BTU-T2 S-8521C36MC-BTV-T2 S-8521C50MC-BUJ-T2 Table 2 (2 / 2) Series S-8521DxxMC Series S-8521ExxMC Series S-8521FxxMC Series Output voltage [V] 1.5 S-8521E15MC-BLA-T2 S-8521F15MC-BPA-T2 1.6 S-8521D16MC-BXB-T2 S-8521E16MC-BLB-T2 1.7 S-8521E17MC-BLC-T2 1.8 S-8521E18MC-BLD-T2 S-8521F18MC-BPD-T2 1.9 S-8521E19MC-BLE-T2 S-8521F19MC-BPE-T2 2.0 S-8521D20MC-BXF-T2 S-8521E20MC-BLF-T2 2.5 S-8521D25MC-BXK-T2 S-8521E25MC-BLK-T2 S-8521F25MC-BPK-T2 2.7 S-8521D27MC-BXM-T2 2.8 S-8521D28MC-BXN-T2 2.9 S-8521D29MC-BXO-T2 3.0 S-8521D30MC-BXP-T2 S-8521E30MC-BLP-T2 S-8521F30MC-BPP-T2 3.1 S-8521D31MC-BXQ-T2 3.2 S-8521D32MC-BXR-T2 3.3 S-8521D33MC-BXS-T2 S-8521E33MC-BLS-T2 S-8521F33MC-BPS-T2 3.4 S-8521D34MC-BXT-T2 S-8521F34MC-BPT-T2 3.5 S-8521D35MC-BXU-T2 S-8521E35MC-BLU-T2 3.6 S-8521D36MC-BXV-T2 4.0 S-8521D40MC-BXZ-T2 5.0 S-8521D50MC-BYJ-T2 S-8521E50MC-BMJ-T2 S-8521F50MC-BQJ-T2 Remark Please contact the SII marketing department for the availability of product samples other than those specified above. 6 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Pin Configuration Table 3 SOT-23-5 Top view 5 Pin No. 1 4 Pin name Pin description Shutdown pin "H": Normal operation ON / OFF (Step-down operation) "L": Step-down operation stopped (All circuits deactivated) 1 2 2 3 4 5 3 VSS VOUT EXT VIN GND pin Output voltage monitoring pin Connection pin for external transistor IC power supply pin Figure 3 Absolute Maximum Ratings Table 4 Item VIN pin voltage VOUT pin voltage Symbol VIN A, C, E types B, D, F types VOUT A, C, E types B, D, F types VON / OFF A, C, E types (Ta=25 C unless otherwise specified) Absolute maximum ratings Unit V VSS-0.3 to VSS+12 VSS-0.3 to VSS+18 VSS-0.3 to VSS+12 VSS-0.3 to VSS+18 VSS-0.3 to VSS+12 B, D, F types VSS-0.3 to VSS+18 EXT pin voltage VEXT VSS -0.3 to VIN +0.3 EXT pin current IEXT mA 50 Power dissipation PD 250 mW Operating ambient temperature Topr -40 to +85 C Storage temperature Tstg -40 to +125 Caution The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Power dissipation (PD) [mW] ON / OFF pin voltage 300 200 100 0 0 Figure 4 50 100 150 Temperature (Ta) [C] Power dissipation of Package (Before mounting) Seiko Instruments Inc. 7 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Electrical Characteristics 1. A type, B type Table 5 Parameter Output voltage*1 Symbol Condition VOUT(E) Input voltage VIN Current consumption 1 Current consumption during shutdown EXT pin output current ISS1 VOUT=VOUT(S)x1.2 ISSS VON / OFF =0 V IEXTH VEXT=VIN-0.4 V IEXTL Line regulation VOUT1 Load regulation Output voltage temperature coefficient Oscillation frequency VOUT2 VOUT Ta fosc A type B type S-8520 / 8521x15 to 24 S-8520 / 8521x25 to 34 S-8520 / 8521x35 to 44 S-8520 / 8521x45 to 54 S-8520 / 8521x55 to 60 VEXT=0.4 V S-8520 / 8521x15 to 24 S-8520 / 8521x25 to 34 S-8520 / 8521x35 to 44 S-8520 / 8521x45 to 54 S-8520 / 8521x55 to 60 VOUT(S)2.0 V VIN=2.5 to 2.94 V VOUT(S)>2.0 V VIN=VOUT(S)x1.2 to 1.4 Load current=10 A to IOUT x1.25 (Ta=25 C unless otherwise specified) Measurement Min. Typ. Max. Unit circuit VOUT(S) VOUT(S) VOUT(S) 3 x0.976 x1.024 V 2.5 10.0 2.5 16.0 2 35 60 A 0.5 -2.3 -3.7 -5.3 -6.7 -8.0 +4.3 +7.0 +9.9 +12.6 +15.0 Ta=-40 to +85 C Measured waveform at EXT VOUT(S)2.4 V pin. VOUT(S)2.5 V 144 153 -4.5 -7.0 -9.3 -11.3 -13.3 +8.4 +13.2 +17.5 +21.4 +25.1 30 30 30 VOUT(S) x5E-5 180 180 60 60 60 mA mV V / C 216 207 kHz 3 PWM / PFM control switching duty ratio PFMDuty No load, Measured waveform at EXT pin. 15 25 40 % (S-8521 Series) VSH Judged oscillation at EXT pin 1.8 ON / OFF pin V 2 input voltage Judged oscillation stop at EXT pin 0.3 VSL ISH -0.1 0.1 ON / OFF pin A 1 input leakage current -0.1 0.1 ISL Soft start time tss 4.0 8.0 16.0 3 ms Overload detection time Duration from the time VOUT is reduced to tpro 2.0 4.0 8.0 2 (A type) 0 V to the time the EXT pin obtains VIN. Efficiency EFFI 93 % 3 External parts Coil: Sumida Corporation CD54 (47 H) Diode: Matsushita Electric Industrial Co., Ltd. MA720 (Shottky type) Capacitor: Matsushita Electric Industrial Co., Ltd. TE (16 V, 22F tantalum type) Transistor: Toshiba Corporation 2SA1213Y Base resistance (Rb): 0.68 k Base capacitor (Cb): 2200 pF (Ceramic type) The recommended components are connected to the IC, unless otherwise indicated. VIN=VOUT(S)x1.2 V (VIN=2.5 V if VOUT(S)2.0 V), IOUT=120 mA The ON / OFF pin is connected to VIN pin. *1. VOUT(S): Specified output voltage value, VOUT(E): Actual output voltage value 8 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. C type, D type Table 6 Parameter Output voltage*1 Symbol Condition VOUT(E) Input voltage VIN Current consumption 1 Current consumption during shutdown EXT pin output current ISS1 VOUT=VOUT(S)x1.2 ISSS VON / OFF =0 V IEXTH VEXT=VIN-0.4 V IEXTL C type D type (Ta=25 C unless otherwise specified) Measurement Min. Typ. Max. Unit circuit VOUT(S) VOUT(S) VOUT(S) 3 x0.976 x1.024 V 2.5 10.0 2.5 16.0 2 10 21 A 0.5 S-8520 / 8521x15 to 24 S-8520 / 8521x25 to 34 S-8520 / 8521x35 to 44 S-8520 / 8521x45 to 54 S-8520 / 8521x55 to 60 VEXT=0.4 V S-8520 / 8521x15 to 24 S-8520 / 8521x25 to 34 S-8520 / 8521x35 to 44 S-8520 / 8521x45 to 54 S-8520 / 8521x55 to 60 VOUT(S)2.0 V VIN=2.5 to 2.94 V VOUT(S)>2.0 V VIN=VOUT(S)x1.2 to 1.4 Load current=10 A to IOUT x1.25 Line regulation VOUT1 Load regulation Output voltage temperature coefficient Oscillation frequency VOUT2 VOUT Ta=-40 to +85 C Ta fosc Measured waveform at VOUT(S)2.4 V EXT pin. VOUT(S)2.5 V -2.3 -3.7 -5.3 -6.7 -8.0 +4.3 +7.0 +9.9 +12.6 +15.0 45 48 -4.5 -7.0 -9.3 -11.3 -13.3 +8.4 +13.2 +17.5 +21.4 +25.1 30 30 30 VOUT(S) x5E-5 60 60 60 60 60 mA mV V / C 75 72 kHz 3 PWM / PFM control switching duty ratio PFMDuty No load, Measured waveform at EXT pin 15 25 40 % (S-8521 Series) VSH Judged oscillation at EXT pin 1.8 ON / OFF pin input voltage V 2 Judged oscillation stop at EXT pin 0.3 VSL ISH -0.1 0.1 ON / OFF pin input A 1 leakage current -0.1 0.1 ISL Soft start time tss 6.0 12.0 24.0 3 ms Overload detection time Duration from the time VOUT is reduced to tpro 7.0 14.0 28.0 2 (C type) 0 V to the time the EXT pin obtains VIN. Efficiency EFFI 93 % 3 External parts Coil: Sumida Corporation CD54 (47 H) Diode: Matsushita Electric Industrial Co., Ltd. MA720 (Shottky type) Capacitor: Matsushita Electric Industrial Co., Ltd. TE (16 V, 22F tantalum type) Transistor: Toshiba Corporation 2SA1213Y Base resistance (Rb): 0.68 k Base capacitor (Cb): 2200 pF (Ceramic type) The recommended components are connected to the IC, unless otherwise indicated. VIN=VOUT(S)x1.2 V (VIN=2.5 V if VOUT(S)2.0 V), IOUT=120 mA The ON / OFF pin is connected to VIN pin. *1. VOUT(S): Specified output voltage value, VOUT(E): Actual output voltage value Seiko Instruments Inc. 9 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 3. E type, F type Table 7 Parameter Output voltage*1 Symbol Condition VOUT(E) Input voltage VIN Current consumption 1 Current consumption during shutdown EXT pin output current ISS1 VOUT=VOUT(S)x1.2 ISSS VON / OFF =0 V IEXTH VEXT=VIN-0.4 V VOUT(S)2.4 V VOUT(S)2.5 V 225 240 -4.5 -7.0 -9.3 -11.3 -13.3 +8.4 +13.2 +17.5 +21.4 +25.1 30 30 30 VOUT(S) x5E-5 300 300 PFMDuty No load, Measured waveform at EXT pin 15 25 IEXTL Line regulation Load regulation Output voltage temperature coefficient Oscillation frequency PWM / PFM control switching duty ratio (S-8521 Series) ON / OFF pin input voltage E type F type (Ta=25 C unless otherwise specified) Measurement Min. Typ. Max. Unit circuit VOUT(S) VOUT(S) VOUT(S) 3 x0.976 x1.024 V 2.5 10.0 2.5 16.0 2 60 100 A 0.5 VOUT1 S-8520 / 8521x15 to 24 S-8520 / 8521x25 to 34 S-8520 / 8521x35 to 44 S-8520 / 8521x45 to 54 S-8520 / 8521x55 to 60 VEXT=0.4 V S-8520 / 8521x15 to 24 S-8520 / 8521x25 to 34 S-8520 / 8521x35 to 44 S-8520 / 8521x45 to 54 S-8520 / 8521x55 to 60 VOUT(S)2.0 V VIN=2.5 to 2.94 V VOUT(S)>2.0 V VIN=VOUT(S)x1.2 to 1.4 Load current=10 A to IOUT x1.25 VOUT2 VOUT Ta=-40 to +85 C Ta fosc Measured waveform at EXT pin. -2.3 -3.7 -5.3 -6.7 -8.0 +4.3 +7.0 +9.9 +12.6 +15.0 60 60 60 mA mV V / C 375 360 kHz 40 % 3 Judged oscillation at EXT pin 1.8 V 2 Judged oscillation stop at EXT pin 0.3 -0.1 0.1 ON / OFF pin input leakage A 1 current -0.1 0.1 Soft start time 2.0 4.5 9.2 3 ms Overload detection time Duration from the time VOUT is reduced to tpro 1.3 2.6 4.5 2 (E type) 0 V to the time the EXT pin obtains VIN. Efficiency EFFI 90 % 3 External parts Coil: Sumida Corporation CD54 (47 H) Diode: Matsushita Electric Industrial Co., Ltd. MA720 (Shottky type) Capacitor: Matsushita Electric Industrial Co., Ltd. TE (16 V, 22F tantalum type) Transistor: Toshiba Corporation 2SA1213Y Base resistance (Rb): 0.68 k Base capacitor (Cb): 2200 pF (Ceramic type) The recommended components are connected to the IC, unless otherwise indicated. VIN=VOUT(S)x1.2 V (VIN=2.5 V if VOUT(S)2.0 V), IOUT=120 mA VSH VSL ISH ISL tss The ON / OFF pin is connected to VIN pin. *1. VOUT(S): Specified output voltage value, VOUT(E): Actual output voltage value 10 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Measurement Circuits 1. open EXT VIN A VOUT open ON / OFF VSS Figure 5 2. Oscilloscope A VIN EXT VOUT + ON / OFF VSS - Figure 6 3. 0.68 k VIN 2200 pF EXT VOUT + - + ON / OFF VSS - V Figure 7 Seiko Instruments Inc. 11 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Operation 1. Switching control method 1. 1 PWM control (S-8520 Series) The S-8520 Series consists of DC-DC converters that employ a pulse-width modulation (PWM) system. This series is characterized by its low current consumption. In conventional PFM system DC-DC converters, pulses are skipped when they are operated with a low output load current, causing variations in the ripple frequency of the output voltage and an increase in the ripple voltage. Both of these effects constitute inherent drawbacks to those converters. In the S-8520 series the pulse width varies in the range from 0 to 100% according to the load current, yet ripple voltage produced by the switching can easily be removed by a filter since the switching frequency is always constant. These converters thus provide a low-ripple voltage over wide range of input voltage and load current. And it will be skippped to be low current consumption when the pulse width is 0% or it is no load, input current voltage is high. 1. 2 PWM / PFM switching control (S-8521 Series) The S-8521 series is a DC-DC converter that automatically switches between a pulse width modulation method (PWM) and a pulse frequency modulation method (PFM), depending on the load current, and features low current consumption. The S-8521 series operates under PWM control with the pulse width duty changing from 25 to 100% when the output load current is high. On the other hand, when the output current is low, the S-8541 series operates under PFM control with the pulse width duty fixed at 25%, and pulses are skipped according to the load current. The oscillator thus oscillates intermittently so that the resultant lower current consumption prevents a reduction in the efficiency when the load current is low. The switching point from PWM control to PFM control depends on the external devices (coil, diode, etc.), input voltage, and output voltage. This series is an especially efficient DC-DC converter at an output current of around 100 A. 12 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. Soft start function The S-8520 / 8521 Series comes with a built-in soft start circuit. This circuit enables the output voltage (VOUT) to rise gradually over the specified soft start time (t), when the power is switched on or when the ON / OFF pin remains at the "H" level. This prevents the output voltage from overshooting. However, the soft start function of this IC is not able to perfectly prevent a rush current from flowing to the load (Refer to Figure 8). Since this rush current depends on the input voltage and load conditions, we recommend that you evaluate it by testing performance with the actual equipment. S-8520A33MC (VIN: 04.0 V) 3V Power switched on VOUT [1 V/div] 0V 1.5 A Rush current [0.5 A/div] 0A t [1 ms/div] Figure 8 3. Waveforms of output voltage and rush current at soft start ON/ OFF pin (Shutdown pin) This pin deactivates or activates the step-down operation. When the ON / OFF pin is set to "L", the VIN voltage appears through the EXT pin, prodding the switching transistor to go off. All the internal circuits stop working, and substantial savings in current consumption are thus achieved. The ON / OFF pin is configured as shown in Figure 9. Since pull-up or pull-down is not performed internally, please avoid operating the pin in a floating state. Also, try to refrain from applying a voltage of 0.3 to 1.8 V to the pin, lest the current consumption increase. When this ON / OFF pin is not used, leave it coupled to the VIN pin. ON / OFF pin "H" "L" Table 8 CR Oscillation Circuit Activated Deactivated Output Voltage Set value VSS VIN ON / OFF VSS Figure 9 Seiko Instruments Inc. 13 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 4. Overload protection circuit (A, C, E types) The A, C and E types of the S-8520 / 8521 Series come with a built-in overload protection circuit. If the output voltage falls because of an overload, the maximum duty state (100%) will continue. If this 100% duty state lasts longer than the prescribed overload detection time (tpro), the overload protection circuit will hold the EXT pin at "H," thereby protecting the switching transistor and inductor. When the overload protection circuit is functioning, the reference voltage circuit will be activated by means of a soft start in the IC, and the reference voltage will rise slowly from 0 V. The reference voltage and the feedback voltage obtained by dividing the output voltage are compared to each other. So long as the reference voltage is lower, the EXT pin will be held at "H" to keep the oscillation inactive. If the reference voltage keeps rising and exceeds the feedback voltage, the oscillation will resume. If the load is heavy when the oscillation is restarted, and the EXT pin holds the "L" level longer than the specified overload detection time (tpro), the overload protection circuit will operate again, and the IC will enter intermittent operation mode, in which it repeats the actions described above. Once the overload state is eliminated, the IC resumes normal operation. Waveforms at EXT pin Overload detection time (tpro) Protection circuit ON [tssx0.3] Figure 10 5. Waveforms appearing at EXT pin as the overload protection circuit operates 100% duty cycle The S-8520 / 8521 Series operates with a maximum duty cycle of 100%. When a B, D and F types products not provided with an overload protection circuit is used, the switching transistor can be kept ON to supply current to the load continually, even in cases where the input voltage falls below the preset output voltage value. The output voltage delivered under these circumstances is one that results from subtracting, from the input voltage, the voltage drop caused by the DC resistance of the inductance and the on-resistance of the switching transistor. If an A, C and E types products provided with an overload protection circuit is used, this protection circuit will function when the 100% duty state has lasted longer than the preset overload detection time (tpro), causing the IC to enter intermittent operation mode. Under these conditions, the IC will not be able to supply current to the load continually, unlike the case described in the preceding paragraph. 14 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Selection of Series Products and Associated External Components 1. Method for selecting series products The S-8520 / 8521 Series is classified into 12 types, according to the way the control systems (PWM control and PWM / PFM Switching control), the different oscillation frequencies, and the inclusion or exclusion of an overload protection circuit are combined one with another. Please select the type that best suits your needs by taking advantage of the features of each type described below. 1. 1 Control systems Two different control systems are available: PWM control system (S-8520 Series) and PWM / PFM switching control system (S-8521 Series). If particular importance is attached to the operation efficiency while the load is on standby -- for example, in an application where the load current heavily varies from that in standby state as the load starts operating -- a high efficiency will be obtained in standby mode by selecting the PWM / PFM switching control system (S-8521 Series). Moreover, for applications where switching noise poses a serious problem, the PWM control system (S-8520 Series), in which the switching frequency does not vary with the load current, is preferable because it can eliminate ripple voltages easily using a filter. 1. 2 Oscillation frequencies The oscillation frequencies are selectable in 180 kHz (A and B types), 60 kHz (C, D types), and 300 kHz (E, F types). Because of their high oscillation frequency and low ripple voltage the A, B, E and F types offer excellent transient response characteristics. The products in these series allow the use of smallsized inductors since the peak current remains smaller in the same load current than with products of the other series. In addition, they can also be used with small output capacitors. These outstanding features make the A, B, E and F types ideal products for downsizing the associated equipment. On the other hand, the C and D types, having a lower oscillation frequency, are characterized by a small self-consumption of current and excellent efficiency under light loads. In particular, the D type, which employs a PWM / PFM switching control system, enables the operation efficiency to be improved drastically when the output load current is approximately 100 A (Refer to "Reference Data"). Seiko Instruments Inc. 15 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 1. 3 Overload protection circuit Products can be chosen either with an overload protection circuit (A, C, E types) or without one (B, D, F types). Products with an overload protection circuit (A, C, E types) enter intermittent operation mode when the overload protection circuit operates to accommodate overloads or load short-circuiting. This protects the switching elements and inductors. Nonetheless, in an application where the load needs to be fed continually with a current by taking advantage of the 100 % duty cycle state, even if the input voltage falls below the output voltage value, a B, D, F types product will have to be used. Choose whichever product best handles the conditions of your application. In making the selection, please keep in mind that the upper limit of the operating voltage range is either 10 V (A, C, E types) or 16 V (B, D, F types), depending on whether the product comes with an overload protection circuit built in. Table 9 provides a rough guide for selecting a product type depending on the requirements of the application. Choose the product that gives you the largest number of circles ( ). Table 9 S-8520 Series B C D E A An overload protection circuit is required The input voltage range exceeds 10 V The efficiency under light loads (load current1 mA) is an important factor To be operated with a medium load current (200 mA class) To be operated with a high load current (1 A class) It is important to have a low-ripple voltage Importance is attached to the downsizing of external components Remark : Indispensable condition : Superiority of requirement : Particularly superiority of requirement 16 Seiko Instruments Inc. F A S-8521 Series B C D E F STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. Inductor The inductance value (L) greatly affects the maximum output current (IOUT) and the efficiency (). The peak current (IPK) increases by decreasing L and the stability of the circuit improves and IOUT increases. If L is made even smaller, the efficiency falls causing a decline in the current drive capacity for the switching transistor, and IOUT decreases. The loss of IPK by the switching transistor decreases by increasing L and the efficiency becomes maximum at a certain L value. Increasing L further decreases the efficiency due to the loss of coil DC resistance. IOUT also decreases. When the inductance is large in an S-8520 / 8521 series product, the output voltage may grow unstable in some cases, depending on the conditions of the input voltage, output voltage, and the load current. Perform sufficient evaluation under the actual condition and decide an optimum inductance. The recommended inductances are 47 H for A, B, C, D types and 22 H for E, F types. When choosing an inductor, attention to its allowable current should be paid since the current over the allowable value will cause magnetic saturation in the inductor, leading to a marked decline in efficiency. An inductor should therefore be selected so as not IPK to surpass its allowable current. The peak current (IPK) is represented by the following equation in non-continuous operation mode: ( VOUT + VF) x ( VIN - VOUT ) 2 x fosc x L x ( VIN + VF) Where fosc is the oscillation frequency, and VF the forward voltage of the diode. IPK = IOUT + 3. Diode The diode to be externally coupled to the IC should be a type that meets the following conditions: * Its forward voltage is low (Schottky barrier diode recommended). * Its switching speed is high (50 ns max.). * Its reverse direction voltage is higher than VIN. * Its current rating is higher than IPK. 4. Capacitors (CIN, COUT) The capacitor inserted on the input side (CIN) serves to lower the power impedance and to average the input current for better efficiency. Select the CIN value according to the impedance of the power supplied. As a rough rule of thumb, you should use a value of 47 to 100 F, although the actual value will depend on the impedance of the power in use and the load current value. For the output side capacitor (COUT), select one of large capacitance with low ESR (Equivalent Series Resistance) for smoothing the ripple voltage. However, notice that a capacitor with extremely low ESR (say, below 0.3 ), such as a ceramic capacitor, could make the output voltage unstable, depending on the input voltage and load current conditions. Instead, a tantalum electrolytic capacitor is recommended. A capacitance value from 47 to 100 F can serve as a rough yardstick for this selection. Seiko Instruments Inc. 17 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 5. External transistor The external transistor of the enhancement (Pch) MOS FET type or bipolar (PNP) typ. 5. 1 Enhancement (Pch) MOS FET type The EXT pin is capable of directly driving a Pch MOS FET with a gate capacity of some 1000 pF. When a Pch MOS FET is chosen, because it has a higher switching speed than a PNP type bipolar transistor and because power losses due to the presence of a base current are avoided, efficiency will be 2 to 3 % higher than when other types of transistor are employed. The important parameters to be kept in mind in selecting a MOS FET include the threshold voltage, breakdown voltage between gate and source, breakdown voltage between drain and source, total gate capacity, on-resistance, and the current rating. The EXT pin swings from voltage VIN over to voltage VSS. If the input voltage is low, a MOS FET with a low threshold voltage has to be used so that the MOS FET will come on as required. If, conversely, the input voltage is high, select a MOS FET whose gate-source breakdown voltage is higher than the input voltage by at least several volts. Immediately after the power is turned on, or when the power is turned off (that is, when the step-down operation is terminated), the input voltage will be imposed across the drain and the source of the MOS FET. Therefore, the transistor needs to have a drain-source breakdown voltage that is also several volts higher than the input voltage. The total gate capacity and the on-resistance affect the efficiency. The power loss for charging and discharging the gate capacity by switching operation will increase, when the total gate capacity becomes larger and the input voltage rises higher. Therefore the gate capacity affects the efficiency of power in a low load current region. If the efficiency under light loads is a matter of particular concern, select a MOS FET with a small total gate capacity. In regions where the load current is high, the efficiency is affected by power losses caused due to the on-resistance of the MOS FET. Therefore, if the efficiency under heavy loads is particularly important for your application, choose a MOS FET with as low an on-resistance as possible. As for the current rating, select a MOS FET whose maximum continuous drain current rating is higher than IPK. For reference purpose, some efficiency data has been included in this document. For applications with an input voltage range of 10 V or less, data was obtained by using TM6201 of Toyoda Industries Corporation. IRF7606, a standard of International Rectifier Corporation, was used for applications with an input voltage range over 10 V (Refer to "Reference Data"). 18 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 5. 2 Bipolar PNP type Figure 11 shows a sample circuit diagram using Toshiba Corporation 2SA1213-Y for the bipolar transistor (PNP). The driving capacity for increasing the output current by means of a bipolar transistor is determined by the hFE value and the Rb value of that bipolar transistor. Toshiba Corporation 2SA1213-Y VIN Rb Cb EXT VIN Figure 11 The Rb-value is given by the following equation: VIN - 0.7 0 .4 Rb = - Ib IEXTL Find the necessary base current (Ib) using the (hFE) value of bipolar transistor by the equation, IPK , and select a smaller Rb value. Ib = hFE A small Rb value will certainly contribute to increasing the output current, but it will also adversely affect the efficiency. Moreover, in practice, a current may flow as the pulses or a voltage drop may take place due to the wiring resistance or some other reason. Determine an optimum value through experimentation. In addition, if speed-up capacitor (Cb) is inserted in parallel with resistance Rb, as shown in Figure 11, the switching loss will be reduced, leading to a higher efficiency. Select a Cb value by using the following equation as a guide: 1 Cb 2 x Rb x fosc x 0.7 Select a Cb value after performing sufficient evaluation since the optimum Cb value differs depending upon the characteristics of the bipolar transistor. Seiko Instruments Inc. 19 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Standard Circuits 1. Using a bipolar transistor L Tr VIN Cb Rb EXT VIN Reference voltage source with soft start Oscillation circuit + CIN SD PWM control or PWM/PFM switching cotrol circuit VOUT + + COUT - VON / OFF ON / OFF VSS Figure 12 2. Using a Pch MOS FET transistor L Tr VIN EXT VIN + CIN SD Oscillation circuit Reference voltage source with soft start PWM control or PWM/PFM switching control circuit ON / OFF + - VOUT + COUT VON / OFF VSS Figure 13 Caution 20 The above connection diagram and constant will not guarantees successful operation. Perform through evaluation using the actual application to set the constant. Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Precautions * Mount the external capacitors, the diode and the coil as close as possible to the IC, and secure grounding at a single location. * Characteristics ripple voltage and spike noise occur in IC containing switching regulators. Moreover, rush current flows at the time of a power supply injection. Because these largely depend on the coil, the capacitor and impedance of power supply used, fully check them using an actually mounted model. * The overload protection circuit of this IC performs the protective function by detecting the maximum duty time (100 %). In choosing the components, make sure that over currents generated by short-circuits in the load, etc., will not surpass the allowable dissipation of the switching transistor and inductor. * Make sure that dissipation of the switching transistor (especially at a high temperature) does not exceed the allowable dissipation of the package. * Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in electrostatic protection circuit. * SII claims no responsibility for any and all disputes arising out of or in connection with any infringement of the products including this IC upon patents owned by a third party. Seiko Instruments Inc. 21 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Application Circuits 1. External adjustment of output voltage The S-8520 / 8521 Series allows you to adjust the output voltage or to set the output voltage to a value over the preset output voltage range (6 V) of the products of this series, when external resistances (RA and RB), and capacitor (CC) are added, as illustrated in Figure 14. Moreover, a temperature gradient can be obtained by inserting a thermistor or other element in series with RA and RB. OUT CC EXT S-8520/8521Series VIN + PWM control or PWM/PFM switching control circuit - ON / OFF Oscillation circuit + - Reference voltage source with soft start RA VOUT R1 D1 R2 RB + - VSS Caution Figure 14 The above connection diagram and constant will not guarantees successful operation. Perform through evaluation using the actual application to set the constant. The S-8520 / 8521 Series have an internal impedance of R1 and R2 between the VOUT pin and the VSS pin, as shown in Figure 14. Therefore, OUT (the output voltage) is determined by the output voltage value (VOUT) of the S-8520 / 8521 Series, and the ratio of the parallel resistance value of external resistance (RB) and internal resistances (R1+R2) of the IC, to external resistance (RA). The output voltage is expressed by the following equation: OUT=VOUT+VOUTxRA/(RB//*1(R1 + R2)) The voltage accuracy of the OUT set by resistances (RA and RB) is not only affected by the IC's output voltage accuracy (VOUT 2.4 %), but also by the absolute precision of external resistances (RA and RB) in use and the absolute value deviations of internal resistances (R1 and R2) in the IC. Let us designate the maximum deviations of the absolute value of RA and RB by RAmax and RBmax, respectively, the minimum deviations by RAmin and RBmin, respectively, and the maximum and minimum deviations of the absolute value of R1 and R2 in the IC by (R1+R2) max and (R1+R2) min, respectively. Then, the minimum deviation value OUTmin and the maximum deviation value OUTmax of the OUT are expressed by the following equations: OUT min.=VOUTx0.976+VOUTx0.976xRAmin./(RBmax//(R1+R2) max.) OUT max.=VOUTx1.024+VOUTx1.024xRAmax./(RBmin//(R1+R2) min.) The voltage accuracy of the OUT cannot be made higher than the output voltage accuracy (VOUT 2.4 %) of the IC itself, without adjusting the RA and RB involved. The closer the voltage value of the output OUT and the output voltage value (VOUT) of the IC are brought to one other, the more the output voltage remains immune to deviations in the absolute accuracy of RA and RB and the absolute value of R1 and R2 in the IC. In particular, to suppress the influence of deviations in R1 and R2 in the IC, a major contributor to deviations in the OUT, the RA and RB must be limited to a much smaller value than that of R1 and R2 in the IC. 22 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series On the other hand, a reactive current flows through RA and RB. This reactive current must be reduced to a negligible value with respect to the load current in the actual use of the IC so that the efficiency characteristics will not be degraded. This requires that the value of RA and RB be made sufficiently large. However, too large a value (more than 1 M) for the RA and RB would make the IC vulnerable to external noise. Check the influence of this value on actual equipment. There is a tradeoff between the voltage accuracy of the OUT and the reactive current. This should be taken into consideration based on the requirements of the intended application. Deviations in the absolute value of the internal resistances (R1 and R2) in the IC vary with the output voltage of the S-8520 / 8521 Series, and are broadly classified as follows: Output voltage 1.5 V to 2.0 V 2.1 V to 2.5 V 2.6 V to 3.3 V 3.4 V to 4.9 V 5.0 V to 6.0 V Table 10 Deviations in the absolute value of R1 and R2 in the IC 5.16 M to 28.9 M 4.44 M to 27.0 M 3.60 M to 23.3 M 2.44 M to 19.5 M 2.45 M to 15.6 M When a value of R1+R2 given by the equation indicated below is taken in calculating the voltage value of the output OUT, a median voltage deviation will be obtained for the OUT. R1+R2=2/(1/maximum deviation in absolute value of R1 and R2+1/minimum deviation in absolute value of R1 and R2) Moreover, add a capacitor (CC) in parallel to the external resistance (RA) in order to avoid output oscillations and other types of instability. (Refer to Figure 14.) Make sure that CC is larger than the value given by the following equation: CC (F)1/(2xxRA ()x7.5 kHz) If a large CC value is selected, a longer soft start time than the one set up in the IC will be set. * SII is equipped with a tool that allows you to automatically calculate the necessary resistance values of RA and RB from the required voltage accuracy of the OUT. SII will be pleased to assist its customers in determining the RA and RB values. Should such assistance be desired, please inquire. * Moreover, SII also has ample information on which peripheral components are suitable for use with this IC and data concerning the deviations in the IC's characteristics. We are ready to help our customers with the design of application circuits. Please contact the SII Components Sales Dept. *1. // shows the combined resistance in parallel. Caution The above connection diagram and constant will not guarantees successful operation. Perform through evaluation using the actual application to set the constant. Seiko Instruments Inc. 23 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Typical Characteristics 1. Examples of major parameters characteristics (1) Current consumption (ISS1)-Input voltage (VIN) (fosc=60 kHz) 20 ISS1 [A] ISS1 [A] 15 Ta=25C 10 Ta=85C 5 0 4 6 8 10 VIN [V] 12 30 Ta=25C 20 Ta=85C Ta=-40C 10 Ta=-40C 2 (fosc=180 kHz) 40 14 0 16 2 4 6 8 10 VIN [V] 12 14 16 (fosc=300 kHz) 60 50 Ta=85C ISS1 [A] 40 30 Ta=25 20 Ta=-40C 10 0 2 4 6 8 10 VIN [V] 12 14 16 (2) Oscillation frequency (fosc)-Input voltage (VIN) (fosc=60 kHz) 80 210 75 70 200 fosc [kHz] fosc [kHz] Ta=25C 65 Ta=85C 60 55 Ta=-40C 50 45 40 (fosc=180 kHz) 220 2 4 6 8 10 VIN [V] 360 12 14 16 190 180 170 160 150 140 Ta=25C Ta=85C 2 4 (fosc=300 kHz) fosc [kHz] 340 320 300 Ta=25C 280 Ta=-40 260 240 24 Ta=85C 2 4 6 8 10 VIN [V] 12 14 16 Seiko Instruments Inc. 6 8 10 VIN [V] Ta=-40C 12 14 16 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series -60 60 -50 50 -40 40 Ta=-40C Ta=25C -30 IEXTL [mA] IEXTH [mA] (3) EXT pin output current "H" (IEXTH)-Input voltage (VIN)(4) EXT pin output current "L" (IEXTL)-Input voltage (VIN) -20 -10 0 4 6 8 10 VIN [V] 12 14 Ta=25C 30 Ta=85C 20 10 Ta=85C 2 Ta=-40C 0 16 2 4 6 8 10 VIN [V] 12 14 16 (5) Soft start time (tSS)-Input voltage (VIN) (fosc=60 kHz) 25 Ta=-40C 20 Ta=25C 15 10 tSS [ms] tSS [ms] 20 Ta=85C 5 0 2 Ta=-40C 15 Ta=25C 10 5 4 6 8 10 VIN [V] 12 14 16 0 Ta=85C 2 4 6 8 10 VIN [V] 12 14 16 (fosc=300 kHz) 10 8 tSS [ms] (fosc=180 kHz) 25 Ta=-40C Ta=85C 6 4 Ta=25C 2 0 2 4 6 8 10 VIN [V] 12 14 16 Seiko Instruments Inc. 25 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series (6) Overload detection time (tpro)- Input voltage (VIN) (fosc=60 kHz) 26 7 22 6 Ta=85C 18 14 Ta=-40C 10 6 4 6 tpro [ms] Ta=-40C 5 Ta=25C 4 12 14 2 16 2 4 6 8 10 VIN [V] 12 14 16 (fosc=300 kHz) 4 Ta=85C 3 Ta=25C Ta=-40C 2 1 8 10 VIN [V] Ta=85C 3 Ta=25C 2 (fosc=180 kHz) 8 tpro [ms] tpro [ms] 30 2 4 6 8 10 VIN [V] 12 14 16 (7) ON/ OFF pin input voltage "H" (VSH)-Input voltage (8) ON/ OFF pin input voltage "L" (VSL)-Input voltage (VIN) (VIN) 1.8 1.7 1.6 1.2 VSL [V] VSH [V] 1.3 Ta=25C 1.0 0.8 0.4 2 4 6 8 10 VIN [V] 1.1 Ta=-40C Ta=25C 0.9 0.7 Ta=85C 0.6 26 1.5 Ta=-40C 1.4 0.5 12 14 16 0.3 Ta=85C 2 4 Seiko Instruments Inc. 6 8 10 VIN [V] 12 14 16 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series (9) Output voltage (VOUT)-Input voltage(VIN) 3.08 3.07 3.06 3.05 3.04 3.03 3.02 3.01 3.00 2.99 2.98 S-8521B50MC (Ta=25C) IOUT=0.1 mA IOUT=500 mA VOUT [V] VOUT [V] S-8521B30MC IOUT=100 mA 2 4 6 8 10 VIN [V] 12 14 16 3.38 3.37 3.36 3.35 3.34 3.33 3.32 3.31 3.30 3.29 3.28 IOUT=0.1 mA IOUT=100 mA IOUT=500 mA 2 (Ta=25C) IOUT=0.1 mA IOUT=500 mA IOUT=100 mA 2 4 6 8 10 VIN [V] 12 14 16 S-8521F50MC (Ta=25C) VOUT [V] VOUT [V] S-8521F33MC 5.08 5.07 5.06 5.05 5.04 5.03 5.02 5.01 5.00 4.99 4.98 4 6 8 10 VIN [V] 12 14 16 5.07 5.06 5.05 5.04 5.03 5.02 5.01 5.00 4.99 4.98 4.97 (Ta=25C) IOUT=0.1 mA IOUT=100 mA IOUT=500 mA 2 4 Seiko Instruments Inc. 6 8 10 VIN [V] 12 14 16 27 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. Transient Response Characteristics 2. 1 Power-on (IOUT: no load) (1) S-8520 / 8521C30MC (VIN=03.6 V) (VIN=09.0 V) 10 V 10 V VIN [2.5 V/div] VIN [2.5 V/div] 0V 0V 3V 3V VOUT [1 V/div] 0V VOUT [1 V/div] 0V t [2 ms/div] t [2 ms/div] (2) S-8520 / 8521A30MC (VIN=03.6 V) (VIN=09.0 V) 10 V 10 V VIN [2.5 V/div] VIN [2.5 V/div] 0V 0V 3V 3V VOUT [1 V/div] VOUT [1 V/div)] 0V 0V t [1 ms/div] t [1 ms/div] (3) S-8520 / 8521E33MC (VIN=04.0 V) (VIN=09.0 V) 10 V 10 V VIN [2.5 V/div] VIN [2.5 V/div] 0V 0V 3V 3V VOUT [1 V/div] VOUT [1 V/div] 0V 0V t [1 ms/div] 28 t [1 ms/div] Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. 2 Shutdown pin response ( VON/ OFF =01.8 V, IOUT=No load) (1) S-8520 / 8521C30MC (VIN=3.6 V) 3V (VIN=9.0 V) 3V VON / OFF VON / OFF [1 V/div] [1 V/div] 0V 0V 3V 3V VOUT [1 V/div] VOUT [1 V/div] 0V 0V t [2 ms/div] t [2 ms/div] (2) S-8520 / 8521A30MC (VIN=3.6 V) (VIN=9.0 V) 3V 3V VON / OFF VON / OFF [1 V/div] [1 V/div] 0V 0V 3V 3V VOUT [1 V/div] VOUT [1 V/div] 0V 0V t [1 ms/div] t [1 ms/div] (3) S-8520 / 8521E33MC (VIN=4.0 V) 3V (VIN=9.0 V) 3V VON / OFF VON / OFF [1 V/div] 0V [1 V/div] 0V 3V 3V VOUT [1 V/div] 0V VOUT [1 V/div] 0V t [1 ms/div] t [1 ms/div] Seiko Instruments Inc. 29 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. 3 Supply voltage variation (VIN=49 V, 94 V) (1) S-8520 / 8521C30MC (IOUT=10 mA) (IOUT=500 mA) 10 V 10 V VIN [2.5 V/div] VIN [2.5 V/div] 0V 0V VOUT [0.2 V/div] VOUT [0.2 V/div] t [0.5 ms/div] t [0.5 ms/div] (2) S-8520 / 8521A30MC (IOUT=10mA) 10 V (IOUT=500 mA) 10 V VIN [2.5 V/div] VIN [2.5 V/div] 0V 0V VOUT [0.2 V/div] VOUT [0.2 V/div] t [0.5 ms/div] t [0.5 ms/div] (3) S-8520 / 8521E33MC (IOUT=10 mA) (IOUT=500 mA) 10 V 10 V VIN [2.5 V/div] VIN [2.5 V/div] 0V 0V VOUT [0.2 V/div] VOUT [0.2 V/div] t [0.5 ms/div] t [0.5 ms/div] 30 Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. 4 Load variation (1) S-8520 / 8521C30MC (VIN=3.6 V, IOUT=5000.1 mA) (VIN=3.6 V, IOUT=0.1500 mA) 500 mA 500 mA IOUT 0.1 mA IOUT 0.1 mA VOUT [0.1 V/div] VOUT [0.1 V/div] t [5 ms/div] t [0.1 ms/div] (2) S-8520 / 8521A30MC (VIN=3.6 V, IOUT=0.1500 mA) (VIN=3.6 V, IOUT=5000.1 mA) 500 mA 500 mA IOUT 0.1 mA IOUT 0.1 mA VOUT [0.1 V/div] VOUT [0.1 V/div] t [0.1 ms/div] t [10 ms/div] (3) S-8520 / 8521E33MC (VIN=4.0 V, IOUT=5000.1 mA) (VIN=4.0 V, IOUT=0.1500 mA) 500 mA 500 mA IOUT 0.1 mA IOUT 0.1 mA VOUT [0.1 V/div] VOUT [0.1 V/div] t [5 ms/div] t [0.1 ms/div) Seiko Instruments Inc. 31 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Reference Data This reference data is intended to help you select peripheral components to be externally connected to the IC. Therefore, this information provides recommendations on external components selected with a view to accommodating a wide variety of IC applications. Characteristic data is duly indicated in the table below. Product name S-8520B30MC S-8520F33MC S-8520F33MC Output voltage 3.0 V 3.3 V S-8521D30MC S-8521D30MC 3.0 V S-8521B30MC S-8521B30MC S-8521F33MC 3.3 V S-8521F33MC S-8520B50MC S-8520B50MC S-8520F50MC S-8520F50MC S-8521D50MC S-8521D50MC S-8521B50MC S-8521B50MC S-8521F50MC S-8521F50MC 32 5.0 V Table 11 External parts for efficiency data Output Inductor Transistor Diode Application capacitor MA737 47 F IOUT1 A, VIN10 V CD105 / 47 H TM6201 MA720 IOUT0.5 A, VIN10 V D62F / 22 H 22 F CDH113 / 22 IRF7606 MA737 IOUT1 A, VIN16 V H IOUT0.5 A, VIN10 V, TM6201 With equipment standby mode MA720 47 Fx2 CD54 / 47 F IOUT0.5 A, VIN16 V, IRF7606 With equipment standby mode IOUT1 A, VIN10 V, TM6201 With equipment standby mode MA737 47 F CD105 / 47 H IOUT1 A, VIN16 V, IRF7606 With equipment standby mode IOUT0.5 A, VIN10 V, TM6201 MA720 D62F / 22 H With equipment standby mode 22 F CDH113 / 22 IOUT1 A, VIN16 V, IRF7606 MA737 With equipment standby mode H TM6201 MA720 IOUT0.5 A, VIN10 V CD54 / 47 F 47 F IRF7606 MA737 IOUT1 A, VIN16 V CD105 / 47 H TM6201 MA720 IOUT0.5 A, VIN10 V D62F / 22 H 22 F CDH113 / 22 IRF7606 MA737 IOUT1 A, VIN16 V H IOUT0.5 A, VIN10 V, TM6201 MA720 CD54 / 47 F With equipment standby mode 47 Fx2 IOUT1 A, VIN16 V, IRF7606 MA737 CD105 / 47 H With equipment standby mode IOUT0.5 A, VIN10 V, TM6201 MA720 CD54 / 47 F With equipment standby mode 47 F IOUT1 A, VIN16 V, IRF7606 MA737 CD105 / 47 H With equipment standby mode IOUT0.5 A, VIN10 V, TM6201 MA720 D62F / 22 H With equipment standby mode 22 F CDH113 / 22 IOUT1 A, VIN16 V, IRF7606 MA737 With equipment standby mode H Seiko Instruments Inc. STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series Table 12 External parts for Ripple data Product name S-8520D30MC S-8521D30MC S-8520B30MC S-8521B30MC S-8520F33MC S-8521F33MC S-8520D50MC S-8521D50MC S-8520B50MC S-8521B50MC S-8520F50MC S-8521F50MC Output voltage Inductor Transistor Rb Cb Diode 3.0 V CD105 / 47 H 2SA1213Y 680 2200 pF MA720 CDH113 / 22 H IRF7606 MA737 CD105 / 47 H 2SA1213Y 680 2200 pF MA720 CDH113 / 22 H IRF7606 3.3 V Component Inductor Diode Output capacity 22 Fx2 22 F 47 Fx2 22 Fx2 MA737 CD54 CD105 CDH113 D62F MA720 MA737 F93 2SA1213Y 22 F Performance Data Maximum allowable Diameter current 0.72 A 5.8 mm 0.37 47 H 1.28 A 10.0 mm 0.17 1.44 A 11.0 mm 0.09 22 H 0.70 A 6.0 mm 0.25 Forward current 500 mA (at VF=0.55 V) Forward current 1.5 A (at VF=0.5 V) Product name Manufacturer name "L" value DC resistance TE External transistor (Bipolar PNP) External transistor (MOS FET) 47 Fx2 5.0 V Table 13 Output capacitor Sumida Corporation Toko Ink. Matsushita Electric Industrial Co., Ltd. Nichicon Corporation Matsushita Electric Industrial Co., Ltd. Height 4.5 mm 5.4 mm 3.7 mm 2.7 mm VCEO 50 V max., IC -2 A max., hFE 120 to 240, SOT-89-3 package Toshiba Corporation TM6201 Toyota Industries Corporation IRF7606 International Rectifier Corporation VGS 12 V max., ID -2 A max., Vth -0.7 V min., Ciss 320 pF typ., Ron 0.25 max. (VGS=-4.5 V), SOT-89-3 package VGS 20 V max., ID -2.4 A max., Vth -1 V min., Ciss 470 pF typ., Ron 0.15 max. (VGS=-4.5 V), Micro 8 package Seiko Instruments Inc. 33 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 1. Efficiency Characteristics: Output current (IOUT)-Efficiency (EFFI) (1) S-8520B30MC (CD105/47 H, TM6201) 100 90 EFFI [%] 80 70 VIN=3.6 V VIN=9.0 V 60 50 0.01 0.1 1 10 IOUT [mA] 100 1000 (2) S-8520F33MC (D62F/22 H, TM6201) 100 80 VIN=9 V VIN=6 V VIN=4 V 90 EFFI [%] EFFI [%] 90 100 70 60 50 0.01 80 (CDH113/22 H, IRF7606) VIN=14 V VIN=9 V VIN=6 V VIN=4 V 70 60 0.1 1 10 IOUT [mA] 100 50 0.01 1000 0.1 1 10 IOUT [mA] 100 1000 (3) S-8521D30MC (CD54/47 H, TM6201) 90 90 80 80 70 VIN=3.6 V VIN=9.0 V 60 50 0.01 0.1 1 10 IOUT [mA] 100 (CD54/47 H, IRF7606) 100 EFFI [%] EFFI [%] 100 70 VIN=3.6 V VIN=9.0 V 60 1000 50 0.01 0.1 1 10 IOUT [mA] 100 1000 (4) S-8521B30MC (CD105/47 H, TM6201) 90 90 80 80 70 VIN=3.6 V VIN=9.0 V 60 50 0.01 34 0.1 1 10 IOUT [mA] 100 1000 (CD105/47 H, IFR7606) 100 EFFI [%] EFFI [%] 100 70 VIN=3.6 V VIN=9.0 V 60 50 0.01 0.1 Seiko Instruments Inc. 1 10 IOUT [mA] 100 1000 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series (5) S-8521F33MC (D62F/22 H, TM6201) 100 80 VIN=9 V VIN=6 V VIN=4 V 90 EFFI [%] EFFI [%] 90 100 70 80 VIN=14 V VIN=9 V VIN=6 V VIN=4 V 70 60 60 50 0.01 (CDH113/22 H, IRF7606) 0.1 1 10 IOUT [mA] 100 50 0.01 1000 0.1 1 10 IOUT [mA] 100 1000 (6) S-8520B50MC (CD54/47 H, TM6201) 90 90 80 80 70 50 0.01 0.1 1 10 IOUT [mA] 100 VIN=14 V VIN=9 V VIN=6 V 70 60 VIN=6.0 V VIN=9.0 V 60 (CD105/47 H, IRF7606) 100 EFFI [%] EFFI [%] 100 50 0.01 1000 0.1 1 10 IOUT [mA] 100 1000 (7) S-8520F50MC (D62F/22 H, TM6201) 100 VIN=9 V VIN=6 V 90 EFFI [%] 90 EFFI [%] 80 70 60 50 0.01 (CDH113/22 H, IRF7606) 100 80 VIN=14 V VIN=9 V VIN=6 V 70 60 0.1 1 10 IOUT [mA] 100 50 0.01 1000 0.1 1 10 IOUT [mA] 100 1000 (8) S-8521D50MC (CD54/47 H, TM6201) 100 90 EFFI [%] EFFI [%] 90 80 70 VIN=6.0 V VIN=9.0 V 60 50 0.01 (CD105/47 H, IRF7606) 100 0.1 1 10 IOUT [mA] 100 1000 80 70 VIN=14 V VIN=9 V VIN=6 V 60 50 0.01 0.1 Seiko Instruments Inc. 1 10 IOUT [mA] 100 1000 35 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series (9) S-8521B50MC (CD54/47 H, TM6201) 100 100 90 EFFI [%] EFFI [%] 90 80 70 50 0.01 0.1 1 10 IOUT [mA] 100 VIN=14 V VIN=9 V VIN=6 V 70 60 VIN=6.0 V VIN=9.0 V 60 80 (CD105/47 H, IRF7606) 50 0.01 1000 0.1 1 10 IOUT [mA] 100 1000 (10) S-8521F50MC (D62F/22 H, TM6201) 100 VIN=9 V VIN=6 V 90 EFFI [%] EFFI [%] 90 100 80 70 60 50 0.01 36 80 (CDH113/22 H, IRF7606) VIN=14 V VIN=9 V VIN=6 V 70 60 0.1 1 10 IOUT [mA] 100 1000 50 0.01 0.1 Seiko Instruments Inc. 1 10 IOUT [mA] 100 1000 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 2. Ripple Voltage Characteristics: Ripple voltage (Vrip)-Input voltage (VIN) (L: CD105 / 47 F, Tr: 2SA1213, SBD: MA720) (1) S-8520D30MC (2) S-8521D30MC (COUT=47 Fx2) 240 200 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 160 120 Vrip [mV] Vrip [mV] 200 80 0 2 4 6 8 10 VIN [V] 12 14 Vrip [mV] Vrip [mV] 4 6 8 10 VIN [V] 12 14 16 (COUT=22 Fx2) 200 IOUT=500 mA 160 IOUT=100 mA IOUT=0.1 mA 120 80 160 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 120 80 40 40 2 4 6 8 10 VIN [V] 12 14 0 16 (5) S-8520F33MC 2 4 6 200 Vrip [mV] IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 120 120 80 40 40 4 6 8 10 VIN [V] 12 14 0 16 (7) S-8520D50MC 240 4 6 8 10 VIN [V] 12 14 16 (COUT=47 Fx2) 240 Vrip [mV] 120 2 200 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 160 16 (8) S-8521D50MC (COUT=47 Fx2) 200 14 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 160 80 2 12 (COUT=22 F) 240 200 160 8 10 VIN [V] (6) S-8521F33MC (COUT=22 F) 240 80 IOUT =500 mA IOUT =100 mA IOUT =0.1 mA 160 120 80 40 40 0 2 240 200 Vrip [mV] 80 (4) S-8521B30MC (COUT=22 Fx2) 240 Vrip [mV] 120 0 16 (3) S-8520B30MC 0 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 160 40 40 0 (COUT=47 Fx2) 240 2 4 6 8 10 VIN [V] 12 14 16 0 2 4 Seiko Instruments Inc. 6 8 10 VIN [V] 12 14 16 37 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series (9) S-8520B50MC (10) S-8521B50MC (COUT=22 Fx2) 240 200 IOUT =500 mA IOUT =100 mA IOUT =0.1 mA 160 120 Vrip [mV] Vrip [mV] 200 40 40 2 4 6 8 10 VIN [V] 12 14 200 4 6 8 10 VIN [V] 12 14 16 200 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 160 120 (COUT=22 F) 240 Vrip [mV] Vrip [mV] 2 (12) S-8521F50MC (COUT=22 F) 240 80 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 160 120 80 40 40 0 0 16 IOUT=500 mA IOUT=100 mA IOUT=0.1 mA 120 80 (11) S-8520F50MC 38 160 80 0 (COUT=22 Fx2) 240 2 4 6 8 10 VIN [V] 12 14 16 0 2 4 Seiko Instruments Inc. 6 8 10 VIN [V] 12 14 16 STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR Rev.7.5_00 S-8520 / 8521 Series 3. PWM / PFM switching characteristics: Input voltage (VIN)-Output current (IOUT) (1) S-8521D30MC (2) S-8521B30MC 14 VIN [V] VIN [V] 14 10 6 6 2 1 10 IOUT [mA] 100 2 1 1000 (3) S-8521F33MC VIN [V] VIN [V] 100 1000 10 6 6 1 10 IOUT [mA] 100 2 1000 (5) S-8521B50MC 1 10 IOUT [mA] 100 1000 100 1000 (6) S-8521F50MC 14 VIN [V] 14 VIN [V] IOUT [mA] 14 10 10 10 6 6 2 10 (4) S-8521D510MC 14 2 10 1 10 IOUT [mA] 100 1000 2 1 Seiko Instruments Inc. 10 IOUT [mA] 39 2.90.2 1.90.2 4 5 1 2 +0.1 0.16 -0.06 3 0.950.1 0.40.1 No. MP005-A-P-SD-1.2 TITLE No. SOT235-A-PKG Dimensions MP005-A-P-SD-1.2 SCALE UNIT mm Seiko Instruments Inc. 4.00.1(10 pitches:40.00.2) +0.1 o1.5 -0 2.00.05 +0.2 o1.0 -0 0.250.1 4.00.1 1.40.2 3.20.2 3 2 1 4 5 Feed direction No. MP005-A-C-SD-2.1 TITLE SOT235-A-Carrier Tape No. MP005-A-C-SD-2.1 SCALE UNIT mm Seiko Instruments Inc. 12.5max. 9.00.3 Enlarged drawing in the central part o130.2 (60) (60) No. MP005-A-R-SD-1.1 SOT235-A-Reel TITLE No. MP005-A-R-SD-1.1 SCALE QTY. UNIT mm Seiko Instruments Inc. 3,000 * * * * * * The information described herein is subject to change without notice. Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein whose related industrial properties, patents, or other rights belong to third parties. The application circuit examples explain typical applications of the products, and do not guarantee the success of any specific mass-production design. When the products described herein are regulated products subject to the Wassenaar Arrangement or other agreements, they may not be exported without authorization from the appropriate governmental authority. Use of the information described herein for other purposes and/or reproduction or copying without the express permission of Seiko Instruments Inc. is strictly prohibited. The products described herein cannot be used as part of any device or equipment affecting the human body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc. Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the failure or malfunction of semiconductor products may occur. The user of these products should therefore give thorough consideration to safety design, including redundancy, fire-prevention measures, and malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.