1 AIC1896. 1. 4 MHz thin Package Current-Mode Step-Up DC/DC Converter FEATURES DESCRIPTION. Fixed Frequency Current-Mode PWM AIC1896 is a Current-Mode pulse-width modulation Operation. (PWM), Step-Up DC/DC Converter. The built-in high Adjustable Output Voltage up to 30V. voltage N-channel MOSFET allows AIC1896 for Guaranteed 13V/ 200mA Output with 5V Input. Step-Up applications with up to 30V output voltage, to 10V Input Range. as well as for Single Ended Primary Inductance Maximum A Shutdown current . Converter (SEPIC) and other low-side switching Programmable Soft-Start. DC/DC converter. Tiny Inductor and Capacitors are allowed. Space-Saving SOT-23-6 and TSOT-23-6 The high switching frequency ( ) allows the Package . use of small external components. The Soft-Start function is programmable with an external capacitor, APPLICATIONS which sets the input current ramp rate. White LED Backlight. OLED Driver.
2 The AIC1896 is available in a space-saving LCD Bias SOT-23-6 and TSOT-23-6 Package . TYPICAL APPLICATION CIRCUIT. L D1. VIN. or 86. CH521S-30 C3. C1 84. ZD1. F 1 F. BZV55-B12 82. ~ Efficiency (%). AIC1896 80. 6 1 78 VIN= IN LX. 4. SHDN FB. 3. 76 VIN= OFF ON R2. SS GND. 1K ILED 74. 5 2. R1 72. C2 62 L: GTSK-51-150M (15 H). 70 L: GTSK-51-100M (10 H). F. 68. 2 4 6 8 10 12 14 16 18 20. LED current (mA). Fig. 1 Li-Ion Powered Driver for three white LEDs Analog Integrations Corporation Si-Soft Research Center DS-1896G-01 121208. 3A1, , Li-Hsin Rd. I, Science Park, Hsinchu 300, Taiwan, TEL: 886-3-5772500 FAX: 886-3-5772510 1. AIC1896. L D1. VIN 80. or CH521S-30 C3 78. C1. ZD1 76. F 1 F. BZV55-B24. 74. Efficiency (%). ~ AIC1896 72. 6 1. 70 VIN= IN LX. OFF ON. 4. SHDN FB. 3. 68. VIN= R2. SS GND ILED. 1K 66. 5 2. 64. R1 L: GTSK-51-150M (15 H). C2 62. 62 L: GTSK-51-100M (10 H). F. 60. 2 4 6 8 10 12 14 16 18 20.
3 LED current (mA). Fig. 2 Li-Ion Powered Driver for six white LEDs ORDERING INFORMATION. AIC1896 XXXX PIN CONFIGURATION. PACKING TYPE SOT-23-6 / TSOT-23-6. TR: TAPE & REEL FRONT VIEW 6 5 4. BG: BAG 1: LX. 2: GND. Package TYPE 3: FB 1896/1896P. G: SOT-23-6 4: SHDN. K: TSOT-23-6 5: SS. 6: IN 1 2 3. P: LEAD FREE COMMERCIAL. G: GREEN Package Note: Pin1 is determined by orienting Example: AIC1896 PKTR the Package marking as shown. in Lead Free TSOT-23-6 Package & Tape & Reel Packing Type AIC1896 PGTR. in Lead Free SOT-23-6 Package & Tape & Reel Packing Type TSOT-23-6 Marking Part No. Marking AIC1896PK 896PK. AIC1896GK 896GK. SOT-23-6 Marking Part No. Marking AIC1896PG 1896P. AIC1896GG 1896G. 2. AIC1896. ABSOLUTE MAXIMUM RATINGS. LX to GND to +33V. FB to GND to +6V. IN, SHDN to +11V. SS to GND to +6V. LX Pin RMS current Continuous Power Dissipation 727mW. Operating Temperature Range -40 C to 85 C. Junction Temperature 125 C.
4 Storage Temperature Range -65 C to 150 C. Lead Temperature (soldering, 10s) 260 C. Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. TEST CIRCUIT. L1 D1. VIN VOUT. to 10V + GTSK-51-100M(10uH) +. SS14. C1 R1 C5. U1 AIC1896 C3 C4. 10 F/16V 1 F. 6 1 10 F. IN LX. 4 3. SHDN FB. SHDN SS GND. 5 2 R2. C2 62. F. 3. AIC1896. ELECTRICAL CHARACTERISTICS. (VIN=V SHDN =3V, FB=GND, SS=Open, TA=25 C, unless otherwise specified) (Note 1). PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS. Input Supply Range VIN 10 V. Output Voltage Adjust Range VOUT 30 V. VIN Undervoltage Lockout UVLO VIN rising, 50mV hysteresis V. VFB = , not switching Quiescent current IIN mA. VFB = , switching 1 5. V SHDN = 0, TA = +25 C A. Shutdown Supply current V SHDN = 0 10 A. ERROR AMPLIFIER. Feedback Regulation Set Point VFB V. FB Input Bias current IFB VFB = 21 80 nA. Line Regulation < VIN < %/V. OSCILLATOR.
5 Frequency fOSC 1000 1400 1800 KHz Maximum Duty Cycle DC 82 86 %. POWER SWITCH. Steady State Output current Io Refer to Fig. 13 A. On-Resistance RDS(ON) Vin = 5V 1 . VLX = 30V, TA = +25 C 1. Leakage current ILX(OFF) A. VLX = 30V 10. SOFT-START. Reset Switch Resistance Guaranteed By Design 100 . Charge current VSS = 4 A. CONTROL INPUT. Input Low Voltage VIL V SHDN , VIN = to 10V V. Input High Voltage VIH V SHDN , VIN = to 10V V. V SHDN = 25 50. SHDN Input current I SHDN A. V SHDN = 0 Note 1: Specifications are production tested at TA=25 C. Specifications over the -40 C to 85 C operating temperature range are assured by design, characterization and correlation with Statistical Quality Controls (SQC). 4. AIC1896. TYPICAL PERFORMANCE CHARACTERISTICS. Switching Frequency (MHz). TA=25 C. VIN= Frequency (MHz). -40 -20 0 20 40 60 80 100 2 3 4 5 6 7 8 9 10 11. Supply Voltage (V). Temperature ( C). Fig. 3 Switching Frequency vs.
6 Temperature Fig. 4 Frequency vs. Supply Voltage VIN= Output Voltage (V). RDS(ON) ( ). 2 3 4 5 6 7 8 9 10 11 1 10 100. Supply Voltage (V) Output current (mA). Fig. 5 RDSON vs. Supply Voltage Fig. 6 Load Regulation (L1=10 H). VIN= FB= SHDN= Output Voltage (V). Supply current (mA). 1 10 100. 2 3 4 5 6 7 8 9 10 11. Output current (mA) Supply Voltage (V). Fig. 7 Load Regulation (L1=22 H) Fig. 8 Switching current 5. AIC1896. TYPICAL PERFORMANCE CHARACTERISTICS (Continued). 90. Feedback Voltage (V). A). 85. Supply current (. FB= 80 SHDN= 75. 70 VIN= 65 2 3 4 5 6 7 8 9 10 11 -50 -25 0 25 50 75 100. Supply Voltage (V) Temperature ( C). Fig. 9 Non-Switching current Fig. 10 Feedback Pin Voltage 90 90. VIN= 85 85. VIN= VIN= VIN= VIN= VIN= Efficiency (%). Efficiency (%). 80 80 VIN= VIN= 75 75. VIN= 70 70. 65 VOUT= 65 VOUT=12V. L1: GTSK-51-100M L1: SLF6025-220MR. 60 60. 0 100 200 300 400 500 600 0 50 100 150 200.
7 Output current (mA) Output current (mA). Fig. 11 Efficiency vs. Output current Fig. 12 Efficiency vs. output current (L1=10 H, test circuit refer to ) (L1=22 H, test circuit refer to ). 800 350. Maximum Output current (mA). Maximum Output current (mA). 700 300 VOUT=20V. VOUT=5V VOUT=13V. 600 250. VOUT=9V VOUT=25V. 500. VOUT=15V 200. 400. 150. 300. 100 VOUT=30V. 200. Maximum output current Maximum output current 50. 100 defined at 90% of no load defined at 90% of no load output voltage 0 output voltage 3 4 5 6 7 8 9 10 11. 2 3 4 5 6 7 8 9 10. Supply Voltage (V) Supply Voltage (V). Fig. 13(a) Maximum Output current vs. Supply Voltage Fig. 13(b) Maximum Output current vs. Supply Voltage (L1: 10 H, test circuit refer to ) (L1:22 H, test circuit refer to ). 6. AIC1896. TYPICAL PERFORMANCE CHARACTERISTICS (Continued). VLX. VSW. VOUT. VOUT. ILX ILX. Fig. 14 Operation Wave Form Fig. 15 Operation Wave Form (VIN=5V; VOUT=12V, L1=22 H; R1=105K; (VIN=3V;VOUT=5V;L1=10 H;R1=36K;R2=12K.))
8 R2=12K;C3=1nF;IOUT=200mA, test circuit refer to ) C3=39pF;IOUT=200mA, test circuit refer to ). VOUT VOUT. ILX ILX. Fig. 16 Load step Response Fig. 17 Load step Response (VIN= ; VOUT=5V;L1=10 H;IOUT=5mA to 200mA, (VIN=5V ; VOUT=12V ;L1=22 H;IOUT=5mA to 150mA, test circuit refer to ) test circuit refer to ). SHDN. VOUT. ILX. Fig. 18 Start-Up from Shutdown (VIN= ;VOUT=13V ;RLOAD=300 , test circuit refer to ). 7. AIC1896. BLOCK DIAGRAM. VIN. Control PWM/PFM I9. R3 Soft Start SS. R4 PWM 4 A. Error Amp Comparator - SHDN. + Control Driver +. Q1 - Logic FB Q2. RC. 1 8. R1 CC. LX. Oscillator x1. R2 Slope Compensation x20. current AMP x 5. + RS. - GND. PIN DESCRIPTIONS. PIN 1: LX - Power Switching Connection. SHDN with a slew rate of Connect LX to inductor and s or greater. Do not leave output rectifier. Keep the SHDN unconnected. SHDN. distance between the draws up to 50 A. components as close to LX as PIN 5: SS - Soft-Start Input.
9 Connect a possible. soft-start capacitor from SS to PIN 2: GND - Ground. GND in order to soft-start the converter. Leave SS open to PIN 3: FB - Feedback Input. Connect a disable the soft-start function. resistive voltage-divider from the output to FB to set the output PIN 6: IN - Internal Bias Voltage Input. voltage. Connect IN to the input voltage source. Bypass IN to GND with PIN 4: SHDN - Shutdown Input. Drive SHDN. a capacitor sitting as close to IN. low to turn off the converter. To as possible. automatically start the converter, connect SHDN to IN. Drive 8. AIC1896. APPLICATION INFORMATION. Inductor Selection accurate LED current , precision resistors are A 15 H inductor is recommended for most preferred (1% recommended). The formula for R1. AIC1896 applications. Although small size and selection is shown below. high efficiency are major concerns, the inductor R1 = (1). should have low core losses at and low DCR (copper wire resistance).
10 Open-Circuit Protection In the cases of output open circuit, when the LEDs Capacitor Selection are disconnected from the circuit or the LEDs fail, The small size of ceramic capacitors makes them the feedback voltage will be zero. AIC1896 will ideal for AIC1896 applications. X5R and X7R then switch to a high duty cycle resulting in a high types are recommended because they retain their output voltage, which may cause SW pin voltage capacitance over wider ranges of voltage and to exceed its maximum 30V rating. A zener diode temperature than other types, such as Y5V or can be used at the output to limit the voltage on Z5U. A F input capacitor and a 1 F output SW pin (Fig. 20). The zener voltage should be capacitor are sufficient for most AIC1896 larger than the maximum forward voltage of the applications. LED string. The current rating of the zener should be larger than Diode Selection Schottky diodes, with their low forward voltage Dimming Control drop and fast reverse recovery, are the ideal There are three different types of dimming control choices for AIC1896 applications.