Datasheet Boost 1channel white LED driver For large LCDs BD9488F General Description Key Specifications BD9488F is a high efficiency driver for white LEDs and Input voltage range: 9.0V to 18.0V designed for large LCDs. This IC is built-in a boost DCDC oscillation frequency: 150kHz (RT=100k) DCDC converters that employ an array of LEDs as the Active current consumption: 1.2mA(Typ.) light source. BD9488F has some protect function against Operating temperature range: -40 to +85 fault conditions, such as the over-voltage protection (OVP), the over current limit protection of DCDC (OCP), Package(s) W(Typ.) x D(Typ.) x H(Max.) LED over current protection (LEDOCP), the open SOP18 11.20mm x 7.80mm x 2.01mm detection of LED string. Therefore BD9488F is available Pin pitch 1.27mm for the fail-safe design over a wide range output voltage. Features Current mode DCDC converter Vout discharge circuit as shutdown LED protection circuit (OPEN protection, LED OCP protection) LED protect detection as small PWM dimming signal Over-voltage protection (OVP) for the output voltage. Adjustable soft start time constant The wide range of analog dimming 0.2V-3.5V The built-in transformation circuit from pulse to DC 2 PWM dimming signal The UVLO detection for the input voltage of the power Figure 1. SOP18 stage FAIL logic output Applications TV, PC display and other LCD backlight system. Typical Application Circuit(s) VCC VIN VCC UVLO OVP TC54 STB GATE RT CS Css SS FAILB DIMOUT PWM1 PWM2 ISENSE ADIM P FB ADIM GND Figure 2. Typical application circuit Product structureSilicon monolithic integrated circuit This product is not designed protection against radioactive rays .w ww.rohm.com TSZ02201-0F1F0C100040-1-2 2012 ROHM Co., Ltd. All rights reserved. 1/36 TSZ2211114001 11.Jul.2012 Rev.001Datasheet BD9488F Absolute Maximum Ratings (Ta=25) Ratings Unit Parameter Symbol Input voltage Vccmax 20 V STB pin voltage STB 20 V OVP, UVLO, SS, RT, OVP, UVLO, SS, RT, ISENSE, FB, CS, TC54 7 V ISENSE, FB, CS, TC54 pin voltage PWM1, PWM2, FAILB, PWM1, PWM2, FAILB, 20 V ADIM, ADIM P pin voltage ADIM, ADIM P DIMOUT, GATE pin voltage DIMOUT, GATE VCC V Power Dissipation Pd 687 (*1) mW Operating Temperature Range Topr -40 to +85 Junction Temperature Tjmax 150 Storage Temperature Range Tstg -55 to +150 *1 Pd derated at 5.5 mW/ for temperature above Ta=25, mounted on 70mm70mm1.6mm 1 layer glass-epoxy PCB. Operation range Parameter Symbol Range Unit VCC Power source voltage VCC 9.0 to 18.0 V DC/DC oscillation frequency fsw 50 to 800 kHz The effective range of ADIM signal VADIM 0.2 to 3.5 V PWM input frequency range FPWM 90 to 100k Hz Pin Configuration Package dimension, marking diagram OVP 1 18 TC54 UVLO 2 17 CS BB DD 99 44 88 88 FF BB DD 99 44 88 88 FF SS 3 16 FB RT 4 15 ISENSE PWM1 5 14 VCC Lot No. 6 13 PWM2 STB 7 12 FAILB GATE 8 11 ADIM DIMOUT ADIM P 9 10 GND Figure 3-1. Pin configuration Figure 3-2. Package dimension www.rohm.com TSZ02201-0F1F0C100040-1-2 2012 ROHM Co., Ltd. All rights reserved. 2/36 TSZ2211115001 11.Jul.2012 Rev.001