(R) SP4446 PRELIMINARY High Output Voltage Boost Regulator LCD Bias Regulator FEATURES High Output Voltage: Up to 30V High Efficiency Low Quiescent Current: ~20uA Miniature Package: (5-lead SOT-23) Single Battery Cell Operation Programmable Output Voltage 1 Switch (150mV at 150mA) VIN SHDN 5 4 SP4446 5 Pin SOT-23 APPLICATIONS LCD Bias Tuner Pin Voltage White LED Driver High Voltage Bias Digital Cameras Cell Phone Battery Backup Handheld Computers 1 2 3 SW GND FB Now Available in Lead Free Packaging DESCRIPTION The SP4446 is a micro power Boost Regualtor in a 5-lead SOT-23 package. It is a current limited, fixed off time regulator configured for use in boost mode applications. The operating voltage can be less than 3V and is capable of generating voltages as high as 30 Volts. The SP4446 is to be supplied in a SOT-23-5 and permits the construction of complete regulators that occupy < 0.2 square inches of board space. TYPICAL APPLICATION SCHEMATIC L1 VIN 2 to 7V D1 High Voltage Output 10H VIN R1 SW C2 SP4446 SHDN GND 2.2 F FB C1 R2 4.7F Rev. 7/14/03 SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 1 (c) Copyright 2003 Sipex Corporation ABSOLUTE MAXIMUM RATINGS Lead Temperature (Soldering, 10 sec) ............ 300C ESD Rating ................................................. 2kV HBM VIN ....................................................................... 15V SW Voltage .............................................. -0.4 to 34V FB Voltage .......................................................... 2.5V All other pins .................................. -0.3 to VCC + 0.3V Current into FB ................................................. 1mA TJ Max ............................................................. 125C Operating Temperature Range ............ -40C to 85C Peak Output Current < 10us SW .................... 500mA Storage Temperature ...................... -65C to +150C Power Dissipation. ......................................... 200mW These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. ELECTRICAL CHARACTERISTICS Specifications are at VIN = 3.3V, VSHDN = VIN, TA = 25C, denotes the specifications which apply over the full operating temperature range, unless otherwise specified. PARAMETER SYMBOL MIN Input voltage VIN Supply Current IQ Reference Voltage VFB FB Hysteresis TYP 1.0 1.17 MAX UNITS 8.0 V 20 30 A 0.01 1 A 1.22 1.27 V HYST 8 IFB 15 Line Regulation Vo/VI 0.04 %/V Switch Off Time TOFF 300 nS VFB Input Bias Current Switch Saturation Voltage VCESAT Switch Current Limit ILIM SHDN Bias Current ISHDN SHDN High Threshold (on) VIH SHDN Low Threshold (off) Switch Leakage Current 100 Switch Current Limit = 150mA No Switching SHDN = 0V mV 80 nA 1200 nS 50 mV 150 mV VFB = 1.22V 1.2 VIN 8V VFB > 1V VFB < 0.3V ISW = 50mA ISW = 150mA 150 200 mA 5 12 A VSHDN = 5V Switch Off, VSW = 5V 0.9 V VIL ISWLK CONDITIONS 2 0.25 V 5 A PIN DESCRIPTION PIN NUMBER PIN NAME 1 SW 2 GND Rev. 7/14/03 3 FB 4 SHDN 5 VIN DESCRIPTION Switch input to the internal power switch. Ground Feedback Shutdown. Pull high (on) to enable. Pull low (off) for shutdown. Input Voltage. Bypass this pin with a capacitor as close to the device as possible. SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 2 (c) Copyright 2003 Sipex Corporation FUNCTIONAL DIAGRAM L1 VOUT D1 VI VIN 5 C1 SW 1 C2 (EXTERNAL) R6 R5 R1 X1 DISABLE + Q1 POWER TRANSISTOR SET Q2 300ns ONE-SHOT 3 FB (EXTERNAL) CLEAR R3 X2 R2 DRIVER + - R4 SHDN 4 52.5mV 0.35 GND Shutdown Logic 2 THEORY OF OPERATION General Overview: At the end of the 0.3s time period, driver transistor is again allowed to turn on which ramps the current back up to the 150mA level. Comparator X2 clears the latch, it's output turns off the driver transistor, and this allows delivery of L1's stored kinetic energy to C2. This switching action continues until the output capacitor voltage is charged to the point where FB is at band gap (1.22V). When this condition is reached, X1 turns off the internal circuitry and the cycle repeats. The SP4446 contains circuitry to provide protection during start-up and while in short-circuit conditions. When FB pin voltage is less than approximately 300mV, the switch off time is increased to about 1.2s and the current limit is reduced to about 70% of its normal value. While in this mode, the average inductor current is reduced and helps minimize power dissipation in the SP4446, the external inductor and diode. Operation can be best understood by referring to the above block diagram. Q1 and Q2 along with R3 and R4 form a band gap reference. The input to this circuit completes a feedback path from the high voltage output through a voltage divider, and is used as the regulation control input. When the voltage at the FB pin is slightly above 1.22V, comparator X1 disables most of the internal circuitry. Current is then provided by capacitor C2, which slowly discharges until the voltage at the FB pin drops below the lower hysteresis point of X1, about 6mV. X1 then enables the internal circuitry, turns on chip power, and the current in the inductor begins to ramp up. When the current through the driver transistor reaches about 150mA, comparator X2 clears the latch, which turns off the driver transistor for a preset 0.3s. At the instant of shutoff, inductor current is diverted to the output through diode D1. During this 0.3s time limit, inductor current decreases while its energy charges C2. Rev. 7/14/03 SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 3 (c) Copyright 2003 Sipex Corporation APPLICATION INFORMAMTION Inductor Selection Capacitor Selection For SP4446, the internal switch will be turned off only after the inductor current reaches the typical dc current limit (ILIM=150mA). However, there is typically propagation delay of 200nS between the time when the current limit is reached and when the switch is actually turned off. During this 200nS delay, the peak inductor current will increase, exceeding the current limit by a small amount. The peak inductor current can be estimated by: V IPK = ILIM + IN(MAX) * 200nS L The larger the input voltage and the lower the inductor value, the greater the peak current. In selecting an inductor, the saturation current specified for the inductor needs to be greater than the SP4446 peak current to avoid saturating the inductor, which would result in a loss in efficiency and could damage the inductor. Choosing an inductor with low DCR decreases power losses and increase efficiency. Refer to Table 1 for some suggested low ESR inductors. Ceramic capacitors are recommended for their inherently low ESR, which will help produce low peak to peak output ripple, and reduce high frequency spikes. For the typical application, 4.7F input capacitor and 2.2F output capacitor are sufficient. The input and output ripple could be further reduced by increasing the value of the input and output capacitors. Place all the capacitors as close to the SP4446 as possible for layout. For use as a voltage source, to reduce the output ripple, a small feedforward (47pF) across the top feedback resistor can be used to provide sufficient overdrive for the error comparator, thus reduce the output ripple. Refer to Table 2 for some suggested low ESR capacitors. Table 2. Suggested Low ESR Capacitor Table 1. Suggested Low ESR inductor MANUF. PART NUMBER DCR () Current Rating (mA) MURATA 770-436-1300 LQH32CN100K21 (10H) 0.44 300 MURATA 770-436-1300 LQH32CN220K21 (22H) 0.71 250 TDK 847-803-6100 NLFC453232T-100K (10H) 0.273 250 TDK 847-803-6100 NLC453232T-100K (22H) MANUF. PART NUMBER CAP/ VOLTAGE SIZE/ TYPE MURATA 770-436-1300 GRM32RR71E 225KC01B 2.2F/25V 1210/X5R MURATA 770-436-1300 GRM31CR61A 475KA01B 4.7F/10V 1206/X5R TDK 847-803-6100 C3225X7R1E 225M 2.2F/25V 1206/X7R TDK 847-803-6100 C3216X5R1A 475K 4.7F/10V 1206/X5R Output Voltage Program 0.9 The SP4446 can be programmed as voltage source, the SP4446 requires 2 feedback resistors R1 & R2 to control the output voltage. As shown in Fig. 19. 370 VIN D1 L1 VOUT Diode Selection C2 R1 C1 U1 A schottky diode with a low forward drop and fast switching speed is ideally used here to achieve high efficiency. In selecting a Schottky diode, the current rating of the schottky diode should be larger than the peak inductor current. Moreover, the reverse breakdown voltage of the schottky diode should be larger than the output voltage. 5 VI N 4 1 SW SP4446 SHDN FB G ND 3 1.22V R2 2 Figure 19. Using SP4446 as Voltage Source Rev. 7/14/03 SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 4 (c) Copyright 2003 Sipex Corporation APPLICATION INFORMAMTION: Continued will be slightly sacrificed because of the saturation voltage and base current of the PNP transistor. The formula and table for the resistor selection are shown below: R3 R 1 =( VOUT 1.22 - 1 ) * R2 154K L1 10uH VIN C1 4.7uF Table 3. Divider Resistor Selection U1 VOUT (V) R1 () R2 () 12 1M 113K 15 1M 88.7K 18 1M 73.2K 20 1M 64.9K 30 1M 42.2K SP4446 SHDN FB VOUT R1 1 SW 5 VIN 4 Q1 MMBT2907A DS C2 47pF 1M C3 2.2uF 3 1.22V GND 20V R2 64.9K 2 Fig. 20. Load Disconnect in Shutdown PIN Diode Driver Layout Consideration The SP4446 can be used as PIN diode driver as shown in Fig. 21. Two Resistors (R1=1M, R2=42.2K) are used to program the output voltage to be 30V. When input voltage is 3.3V or 5V, it can supply a maximum current of 3mA and 5mA to the load. Both the input capacitor and the output capacitor should be placed as close as possible to the IC. This can reduce the copper trace resistance which directly effects the input and output ripples. The feedback resistor network should be kept close to the FB pin to minimize copper trace connections that can inject noise into the system. The ground connection for the feedback resistor network should connect directly to the GND pin or to an analog ground plane that is tied directly to the GND pin. The inductor and the schottky diode should be placed as close as possible to the switch pin to minimize the noise coupling to the other circuits, especially the feedback network. Murata LQH32CN100K21 3.3V or 5V 3 to 5 mA MBR0530 C2 47pF C1 4.7uF 4 C3 2.2uF 1 SW SP4446 SHDN FB 2 Load Disconnect in Shutdown When SP4446 was shut down, the load is still connected to the input. In applications that require output isolation during shutdown, an external PNP transistor (for example MMBT2907A) can be added as shown in Figure 20. When the SP4446 is active, the voltage set at the emitter of the transistor exceeds the input voltage, forcing the transistor into the saturation region. When the SP4446 is shut down, the input voltage exceeds the emitter voltage, thus the transistor becomes inactive and provides high-impedance isolation between the input and load. Efficiency R1 1M U1 5 VIN GND Rev. 7/14/03 30V VOUT DS L1 10uH 0.3A VIN 3 1.22V R2 42.2K Fig. 21. Pin Diode Driver SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 5 (c) Copyright 2003 Sipex Corporation PERFORMANCE CHARACTERISTICS Refer to the typical application circuit, TAMB = 25C, unless otherwise specified. Vin=3.3V;Vout =12V Efficiency Vin=5.0V;Vout =12V Efficiency 85 85 80 80 75 Efficiency (%) 75 Efficiency (%) 70 65 60 70 65 60 55 10 uH 10 uH 55 22 uH 22 uH 50 50 0 3 6 9 Iout (mA) 12 15 18 0 5 10 Figure 1. 12V Output Efficiency (VIN=3.3V) 20 25 Vin=5.0V;Vout =15V Efficiency 80 75 75 70 70 Efficiency (%) 80 65 60 65 60 55 55 10 uH 10 uH 22 uH 22 uH 50 0 2 4 6 Iout (mA) 8 10 50 12 0 Figure 3. 15V Output Efficiency (VIN=3.3V) 3 6 9 Iout (mA) 12 15 18 Figure 4. 15V Output Efficiency (VIN=5V) Vin=3.3V; Vout = 18V Efficiency Vin=5.0V; Vout = 18V Efficiency 80 80 75 75 70 70 65 Efficiency (%) Efficiency (%) 30 Figure 2. 12V Output Efficiency (VIN=5V) Vin=3.3V;Vout =15V Efficiency Efficiency (%) 15 Iout (mA) 60 55 50 65 60 55 50 10 uH 45 10 uH 45 22 uH 40 22 uH 40 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 0.0 2.0 Iout (mA) Figure 5. 18V Output Efficiency (VIN=3.3V) Rev. 7/14/03 4.0 6.0 8.0 Iout (mA) 10.0 12.0 14.0 Figure 6. 18V Output Efficiency (VIN=5V) SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 6 (c) Copyright 2003 Sipex Corporation PERFORMANCE CHARACTERISTICS: Continued Refer to the typical application circuit, TAMB = 25C, unless otherwise specified. Vin=3.3V;Vout = 20V Efficiency Vin=5V;Vout = 20V Efficiency 75 75 70 70 65 65 Efficiency (%) Efficiency (%) 60 55 50 60 55 50 45 45 40 10 uH 10 uH 40 35 22 uH 22 uH 35 30 0 1 2 3 4 5 6 0 7 2 4 6 Figure 7. 20V Output Efficiency (VIN=3.3V) 10 12 Figure 8. 20V Output Efficiency (VIN=5V) 12 6 10uH 10 10uH 22uH 5 Maximum Output Current (mA) Maximum Output Current (mA) 8 Iout (mA) Iout (mA) 8 6 4 22uH 4 3 2 2 1 0 2.7 3 3.3 3.6 3.9 4.2 4.5 4.8 0 2.7 5.1 3 3.3 3.6 Input Voltage (V) Figure 9. Maximum Output Current vs. VIN (VOUT=20V) 4.2 4.5 4.8 5.1 Figure 10. Maximum Output Current vs. VIN (VOUT=30V) 10 30 25 8 Shutdown Pin Current (uA) Quiescent Current (uA) 3.9 Input Voltage (V) 20 15 10 Tamb=-40C 5 6 4 2 Tamb=25C Tamb=85C 0 0 1 2 3 4 5 6 7 1 8 2 Input Voltage (V) 4 5 6 7 8 Input Voltage (V) Figure 11. Quiescent Current IQ vs. VIN Rev. 7/14/03 3 Figure 12. Shutdown Pin Current vs. VIN SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 7 (c) Copyright 2003 Sipex Corporation PERFORMANCE CHARACTERISTICS: Continued Refer to the typical application circuit, TAMB = 25C, unless otherwise specified. 250 1.25 1.24 200 Feedback Voltage (V) Ipk Current Limit (mA) 1.23 150 100 1.22 1.21 1.20 50 1.19 0 1 2 3 4 5 6 7 1.18 -40 8 -15 10 35 60 85 Temperature (C) Input Voltage (V) Figure 13. IPK Current Limit vs. VIN Figure 14. Feedback Voltage vs. Temperature 60 Switch Saturation Voltage (mV) 50 VIN 40 30 20 VOUT 10 0 -40 IIN (100mA/DIV) -15 10 35 60 85 Temperature (C) Figure 16. Startup Waveform (VIN=3.3V, VOUT=20V, IOUT=2mA) Figure 15. Switch Saturation Voltage VCESAT vs. Temperature (ISW=50mA) VSW IOUT (5mA/DIV) VOUT (AC) IL (0.1A/DIV) VOUT (AC) VSW Figure 18. Load Step Transient (VIN=3.3V, VOUT=20V, 1O=100A5mA) Figure 17. Typical Switching Waveforms (VIN=3.3V, VOUT=20V, IOUT=5mA) Rev. 7/14/03 SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 8 (c) Copyright 2003 Sipex Corporation PACKAGE: 5 PIN SOT-23 D e1 N N/2 +1 E/2 E1/2 B E E1 B SEE VIEW C VIEW A-A 1 2 N/2 e O1 b Gauge Plane L2 5 PIN SOT-23 JEDEC MO-178 (AA) Variation Dimensions in (mm) Seating Plane O1 L O L1 MIN NOM MAX A - - 1.45 A1 0 - 0.15 A2 0.90 b 0.30 - 0.50 c 0.08 - 0.22 1.15 VIEW C 1.30 A2 A Seating Plane A1 D E 2.80 BSC E1 1.60 BSC e 0.95 BSC b WITH PLATING 1.90 BSC e1 L SIDE VIEW 2.90 BSC 0.30 L1 0.45 0.60 c 0.60 REF L2 0.25 BSC O 0 4 8 O1 5 10 15 BASE METAL SECTION B-B 5 PIN SOT-23 Rev. 7/14/03 SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 9 (c) Copyright 2003 Sipex Corporation ORDERING INFORMATION Part Number Operating Temperature Range Package Type SP4446EK .................................................. -40C to +85C ........................................................ 5 Pin SOT-23 SP4446EK/TR ............................................ -40C to +85C ........................................................ 5 Pin SOT-23 Available in lead free packaging. To order add "-L" suffix to part number. Example: SP4446EK/TR = standard; SP4446EK-L/TR = lead free /TR = Tape and Reel Pack quantity is 2,500 for SOT-23. Corporation ANALOG EXCELLENCE Sipex Corporation Headquarters and Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600 Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others. Rev. 7/14/03 SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator 10 (c) Copyright 2003 Sipex Corporation