SI-8008TM DC-to-DC Step-Down Converter Features and Benefits Description 1.5 A output current supplied in a small power surface mount package High efficiency: 81% at VIN = 15 V, IO = 0.5 A,VO = 5 V Requires only six external components (optional soft start requires an additional capacitor) Oscillation circuit built-in (frequency 300 kHz typical Constant current type overcurrent protection circuit and an overheating protection circuit built in Soft start function built-in (can be implemented as an ON/OFF function, output OFF state at low level) Low consumption current during output OFF state The SI-8008TM DC voltage regulator is a DC-to-DC buck convertor that attains an oscillation frequency of 300 kHz, and has an integrated miniaturized choke coil, allowing it to serve as a small, high efficiency power supply in a compact TO252-5 (SC-63) package. The switching regulator function realizes a high efficiency switching regulator operation without adjustment, requiring only six external support components, and an optional capacitor for soft start operation and an optional transistor for on/off control. The SI-8008TM includes overcurrent and overheating protection circuits. Applications include: DVD recorder FPD TV Telecommunications equipment Office automation equipment, such as printers On-board local power supply Output voltage regulator for second stage of SMPS (switched mode power supply) Package: TO252-5 (SC-63) Not to scale Functional Block Diagram with Typical Application SI -8008TM VIN 1 C1 C3 SS L 2 Di PReg 5 SW IN VO C2 Overcurrent Protection ON/ OFF Soft Start Reset Latch & Driver R1 Comparator Thermal ADJ Protection Component C1 C2 C3 Di L1 Oscillator 4 Error Amp Rating 220 F 470 F 1 F (for soft start function) SJPB-H6 (Sanken) 47 H R2 Reference Voltage GND 3 Figure 1. Application implementing soft start, without implementation of on/off control. 27469.054 SI-8008TM DC-to-DC Step-Down Converter Selection Guide Part Number Output Voltage (V) Efficiency (Typical) (%) Input Voltage (V) Output Current (A) Packing SI-8008TM-TL (Adjustable Type) 0.8 (VADJ) 81 (5 V Set-up) 43 0 to 1.5 3000 pieces per reel Absolute Maximum Ratings Characteristic DC Input Voltage Symbol Remarks Rating Units 43 V 1.06 W 1.65 W -30 to 150 C -40 to 150 C VIN Power Dissipation 1 PD1 Glass-epoxy board mounting in 900 Tj 125C Power Dissipation 2 PD2 Glass-epoxy board mounting in 900 mm2, copper area 50% Tj 125C Junction Temperature TJ Storage Temperature Tstg Thermal Resistance (Junction-case) Rj-c Thermal Resistance (Junction-ambient air) Rj-a mm2, copper area 4.3%, The thermal protection circuit is built-in and may enable when junction temperature rises to 130C or higher. Recommended maximum junction temperature during product operation is 125C. Glass-epoxy board mounting in 900 mm2, copper area 4.3% 6 C/W 95 C/W Recommended Operating Conditions Characteristic Symbol Range1 VIN DC Input Voltage DC Output Voltage Range DC Output Current Range2 Remarks IO = 0 to 1.5 A VO IO VIN VO + 3 V Min. Max. Units VO + 3 40 V 0.8 24 V 0 1.5 A Operating Junction Temperature Range TJOP -20 100 C Operating Temperature Range2 TOP -20 85 C 1The minimum value of the input voltage, VIN (min) is the larger of either 4.5 V or VO+3 V. In the case in which VIN is in the range VO + 2 V to VO + 3 V, VIN(min) is set so that IO = 1 A (maximum). 2To be used within the allowable package power dissipation characteristics (refer to Power Dissipation chart). All performance characteristics given are typical values for circuit or system baseline design only and are at the nominal operating voltage and an ambient temperature, TA, of 25C, unless otherwise stated. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 SI-8008TM DC-to-DC Step-Down Converter ELECTRICAL CHARACTERISTICS, valid at TA = 25C, VO = 5 V (adjusted), R1 = 4.2 k, R1 = 0.8 k Characteristic Symbol Reference Voltage VADJ Reference Voltage Temperature Coefficient Test Conditions VIN = 15 V, IO = 0.1 A Min. Typ. Max. Units 0.784 0.8 0.816 V - 0.1 - mV/C - 81 - % VREF /T VIN = 15 V, IO = 0.1 A, TOP = 0 to 100 C Efficiency* Operating Frequency VIN = 15 V, IO = 0.5 A fO VIN = 15 V, IO = 0.5 A - 300 - kHz Line Regulation VLine VIN = 10 to 30 V, IO = 0.5 A - 60 80 mV Load Regulation VLoad VIN = 15 V, IO = 0.2 to 1.5 A - 10 40 mV 1.6 - - A Overcurrent Protection Threshold Current IS VIN = 15 V SS Terminal On/Off Operation Threshold Voltage VSSL SS Terminal On/Off Operation Outflow Current ISSL Quiescent Current 1 Iq Quiescent Current 2 Iq(off) - - 0.5 V VSSL = 0 V - 10 40 A VIN = 15 V, IO = 0 A - 6 - mA VIN = 15 V, VSS = 0 V - 200 400 A *Efficiency is calculated by the following equation. (%) = VO IO VIN IIN Pin-out Diagram 100 Terminal List Table Name Number IN 1 Supply voltage SW 2 Regulated supply output GND 3 Ground terminal ADJ 4 Terminal for resistor bridge feedback SS 1 2 3 4 Function 5 The SS terminal is used to enable soft start and to control on/off operation of the IC output, VO (see figure 2). To enable soft start, connect a capacitor between SS and ground. To control on/off operation, connect an NPN bipolar transistor, in a TTL open collector output configuration, between the SS terminal and GND. Turn off is done by decreasing VSSL below its rated level. When both soft start and VO on/off are used, a protection measure such as current limiting is required because, if the capacitance of C3 large, the discharge current of C3 flows across the transistor for on/off operation. Because a pull-up type resistor is provided inside the IC, no external voltage can be applied. 5 SI-8008TM SI-8008TM SI-8008TM SS 5 SS 5 SS 5 System TTL C3 System TTL (a) VO on/off control only (b) Soft start only C3 (c) VO on/off and soft start control Figure 2. Alternative configurations for SS pin. If neither soft start nor VO on/off is required, the SS pin is left open. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 SI-8008TM DC-to-DC Step-Down Converter SI-8008TM Performance Characteristics at TA = 25C 85 8V 5.06 10 V 15 V 5.04 80 4.98 40 V Load Regulation: Output Voltage versus Output Current 70 65 VIN VO (V) (%) 40 V 5.00 30 V 75 Efficiency versus Output Current VO= 5 V (Adjusted) R1 = 4.2 k R2 = 0.8 k VIN 5.02 20 V 30 V 20 V 15 V 4.96 4.94 10 V 4.92 8V 4.90 4.88 60 4.86 55 0 0.5 1 4.84 1.5 0 0.2 0.4 IO (A) 1.2 20 VIN (V) 30 1.4 1.6 8 Quiescent Current versus Supply Voltage IO = 0 A 200 Iq (mA) 300 6 4 100 0 0.8 1.0 IO (A) 10 2 0 10 20 VIN (V) 30 0 40 0 10 40 6 5 Low Voltage Behavior Output Voltage versus Supply Voltage 0A 0.1 A 0.5 A 4 VO (V) Circuit Current at Output Off versus Supply Voltage VSS = 0 V I O(0ff)(A) 400 0.6 1.0 A 1.5 A 3 2 IO 1 0 0 2 4 VIN (V) 6 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 10 4 SI-8008TM DC-to-DC Step-Down Converter SI-8008TM Thermal Performance Characteristics 6 TSD On Thermal Protection: Output Voltage versus Junction Temperature 5 VIN = 8 V, IO = 0.01 A VO (V) 4 Junction temperature, TJ, can be calculated as: TJ = PD x RJC + TC 3 where RJC = 6C/W, and TC is the temperature taken by a thermocouple mounted adjacent to the case on the tab at the location indicated: 2 1 TSD Off Thermocouple mount at tab center 0 0 20 40 60 80 100 TJ (C) 120 140 160 180 2.0 Power Dissipation versus Ambient Temperature 1.8 TJ(max) = 125C Mounted on glass-epoxy PCB (30 mm x 30 mm), with varying exposed copper areas 1.6 100 V - 1 - VF I O 1 - O PD = VO I O Hx VIN Cu Area: 625 mm2 RJA = 58.9C/W Cu Area: 450 mm2 RJA = 60.4C/W 1.4 Cu Area: 270 mm2 RJA = 65.1C/W PD (W) 1.2 where: VO is output voltage in V, VIN is input supply voltage in V, IO is output current in A, X is IC efficiency in percent (varies with VIN and IO; refer to efficiency curve for value), and VF is forward voltage for the input diode, Di. In these tests, the Sanken SJPB-H6 was used, at 0.5 V and IO = 1.5 A. For application design, obtain thermal data from the datasheet for the diode. Cu Area: 180 mm2 RJA = 71.4C/W 1.0 Cu Area: 90 mm2 RJA = 80.3C/W 0.8 Cu Area: 39 mm2 RJA = 93.7C/W 0.6 0.4 0.2 0 -25 0 25 50 75 100 125 TA (C) 100 Glass-epoxy PCB, 30 mm2 RJA(C/W) 90 Device Thermal Resistance versus Exposed Copper Area on PCB 80 70 60 50 40 10 100 Copper Area (mm2) 1000 Device Power Dissipation versus Exposed Copper Area on PCB 2 Glass-epoxy PCB, 30 mm PD(W) 1.5 1.0 25C TA 40C 60C 0.5 85C 0 10 100 1000 2 Copper Area (mm ) Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 SI-8008TM DC-to-DC Step-Down Converter Component Selection Diode Di A Schottky-barrier diode must be used for Di. If other diode types are used, such as fast recovery diodes, the IC may be destroyed because of the reverse voltage applied by the recovery voltage or ON voltage. neither OS capacitors nor tantalum capacitors which cause an abnormal oscillation for C2. Choke Coil L1 If the winding resistance of the choke coil is too high, the efficiency may go down to the extent that it is out of the rating. Because the overcurrent protection start current is approximately 2.5 A, attention must be paid to the heating of the choke coil by the magnetic saturation due to overload or short-circulated load. Resistor R1 and R2 R1, R2 is a resistor bridge to the output voltage. IADJ should be set to 1 mA. To do so, calculate R1, R2 by the following expressions: Capacitor C1,C2, and C3 As large ripple currents flow across C1 and C2, capacitors with high frequency and low impedance for SMPS must be used. Especially when the impedance of C2 is high, the switching waveform may not be normal at low temperature. Please use C3 is a capacitor for soft start. In case soft start function is not used, please keep the SS terminal open. A pull-up resistor is provided inside the IC. R1 = (VO - VADJ ) (VO - 0.8) ( ), R 2 = VADJ = 0.8 -3 = 0.8k ( ) = I ADJ 1 x 10- 3 I ADJ 1 x 10 R2 should always be connected for stable operation, even if output voltage, VO, is set to 0.8 V. It is recommended that VO be set at VIN+ 8% or greater. Typical Application Circuit 1 IN VIN L 47 H 2 SW VO SI-8008TM SS C1 220 F ADJ GND 5 R1 4 Di 3 R2 IADJ C2 470 F Component C1 C2 C3 Di L1 Rating 220 F 470 F 1 F (for soft start function) SJPB-H6 (Sanken) 47 H C3 GND GND Recommended PCB Layout Recommended Solder Pad Layout GND 8008TM C1 C2 C3 + + R1 IN SW R2 Di Vo L All external components should be mounted as close as possible to the SI-8008TM. The ground of all components should be connected at one point. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 SI-8008TM DC-to-DC Step-Down Converter 6.60 0.20 5.34 0.20 2.3 0.20 (5.04) 0.5 0.10 (1.50) 2 3 0.70 MAX 4 5 +0.254 R0 .25 + 1.524 -0.127 1 Seating Plane 0.00-0.127 (0.89) XXXXXXXX XXXXXXXX 9.90 0.30 Branding 2.70 0.20 6.10 0.20 + (4.41) 1.10 0.2 PACKAGE OUTLINE DRAWING, TO252-5 0.5 0.10 (1.00) 0.5 0.10 (5x) 0-8 5X 0.01 4xP1.27 TYP Terminal dimension at lead tips Terminal core material: Cu Terminal treatment: Ni plating and solder dip Heat sink core material: Cu Heat sink treatment: Ni plating Approximate weight: 0.33 g Dimensions in millimeters Branding codes (exact appearance at manufacturer discretion): 1st line, type: 8008TM 2nd line, lot: YM W Where: Y is the last digit of the year of manufacture M is the month (1 to 9, O, N, D) W is the week 3rd line, Tracking number (four digits) Device is lead (Pb) free. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 SI-8008TM DC-to-DC Step-Down Converter PACKING SPECIFICATION Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 SI-8008TM DC-to-DC Step-Down Converter WARNING -- These devices are designed to be operated at lethal voltages and energy levels. Circuit designs that embody these components must conform with applicable safety requirements. Precautions must be taken to prevent accidental contact with power-line potentials. Do not connect grounded test equipment. The use of an isolation transformer is recommended during circuit development and breadboarding. Because reliability can be affected adversely by improper storage environments and handling methods, please observe the following cautions. Cautions for Storage * Ensure that storage conditions comply with the standard temperature (5C to 35C) and the standard relative humidity (around 40 to 75%); avoid storage locations that experience extreme changes in temperature or humidity. * Avoid locations where dust or harmful gases are present and avoid direct sunlight. * Reinspect for rust on leads and solderability of products that have been stored for a long time. Cautions for Testing and Handling When tests are carried out during inspection testing and other standard test periods, protect the products from power surges from the testing device, shorts between adjacent products, and shorts to the heatsink. Soldering * When soldering the products, please be sure to minimize the working time, within the following limits: 2605C 10 s 3505C 3 s * Soldering iron should be at a distance of at least 1.5 mm from the body of the products Electrostatic Discharge * When handling the products, operator must be grounded. Grounded wrist straps worn should have at least 1 M of resistance to ground to prevent shock hazard. * Workbenches where the products are handled should be grounded and be provided with conductive table and floor mats. * When using measuring equipment such as a curve tracer, the equipment should be grounded. * When soldering the products, the head of soldering irons or the solder bath must be grounded in other to prevent leak voltages generated by them from being applied to the products. * The products should always be stored and transported in our shipping containers or conductive containers, or be wrapped in aluminum foil. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 SI-8008TM DC-to-DC Step-Down Converter The products described herein are manufactured in Japan by Sanken Electric Co., Ltd. for sale by Allegro MicroSystems, Inc. Sanken and Allegro reserve the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Therefore, the user is cautioned to verify that the information in this publication is current before placing any order. When using the products described herein, the applicability and suitability of such products for the intended purpose shall be reviewed at the users responsibility. Although Sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and defect of semiconductor products at a certain rate is inevitable. Users of Sanken products are requested to take, at their own risk, preventative measures including safety design of the equipment or systems against any possible injury, death, fires or damages to society due to device failure or malfunction. Sanken products listed in this publication are designed and intended for use as components in general-purpose electronic equipment or apparatus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.). Their use in any application requiring radiation hardness assurance (e.g., aerospace equipment) is not supported. When considering the use of Sanken products in applications where higher reliability is required (transportation equipment and its control systems or equipment, fire- or burglar-alarm systems, various safety devices, etc.), contact a company sales representative to discuss and obtain written confirmation of your specifications. The use of Sanken products without the written consent of Sanken in applications where extremely high reliability is required (aerospace equipment, nuclear power-control stations, life-support systems, etc.) is strictly prohibited. The information included herein is believed to be accurate and reliable. Application and operation examples described in this publication are given for reference only and Sanken and Allegro assume no responsibility for any infringement of industrial property rights, intellectual property rights, or any other rights of Sanken or Allegro or any third party that may result from its use. Copyright (c) 2007 Allegro MicroSystems, Inc. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10