NXP 500 mA, dual-LED flash drivers SSL3250A/SSL3252 Maximum flash/torch efficiency and light from a small footprint These highly integrated devices deliver the right combination of features – high efficiency, maximum light, and a small footprint – for LED flash drivers in mobile devices. They extend battery life, improve pictures, reduce application size, and enhance system reliability. Key benefis } High efficiency for longer battery life } Maximum light for brighter pictures } High integration for a smaller application } Comprehensive protection circuits for enhanced reliability Key features } High-power, single- or dual-LED output current - Flash: up to 500 mA - Torch: up to 200 mA (SSL3250A) or 160 mA (SSL3252) } Integrated up to 20 mA (SSL3250A) or 10 mA (SSL3252) LED indicator } Greater than 85% efficiency at optimum output current } Soft start in torch and flash modes to avoid battery overload } Synchronous boost without external diode (SSL3252) } High-side drive simplifies thermal design (SSL3252) } Built-in broken-coil detect function (SSL3252) } Internally timed flash operation up to 820 ms } Strobe signal to avoid I2C-bus latency } Discrete enable signals for standalone operation } Optional configurable output currents via external resistors (SSL3250A) } Low device shut-down current (<1 μA) } Wide input voltage range (2.7 to 5.5 V) } Programmable, 400-kHz I2C-bus Key applications } Camera-equipped mobile phone } PDA } Digital camera } White LED driver for battery-operated device These highly integrated, highly efficiency LED flash drivers are ideal for driving up to two high-brightness LED. Their small size and high internal switching frequencies minimize the design footprint, and are ideal for space constrained mobile applications. The SSL3250A is a low-side asynchronous boost converter that has optional external resistors to configure the output current, while the SSL3252 is a high-side synchronous boost converter that has resistors built-in. Both devices use an inductive boost DC/DC converter to ensure maximum light generation in a battery-operated system. They are programmable for three modes of operation: Flash, Torch, or Indicator/Video-on. When driving two LEDs in series at up to 500 mA, they achieve at least 85% efficiency. A separate linear current source (10 or 20 mA) can be used to drive a single indicator LED. SSL3250A and SSL3252 comparison table Dual-LED power efficiency graph (flash mode) Feature SSL3250A SSL3252 Number of LEDs driven in series 1 or 2 1 or 2 LED power efficiency (PLED/PIN) vs VBAT and ILED Flash/torch/indicator current (mA) 500 / 200 / 20 400* / 160 / 10 Assist light No Yes LED output type Low-side drive High-side drive 90% 85% Fixed switching frequency (MHz) 1.2 2.0 80% Integrated diode and resistors No Yes 75% Interface type I2C-bus or direct I2C-bus or direct VIN range (V) 2.7 to 5.5 2.5 to 5.5 Inductor broken coil detect No Yes 70% 65% 50 125 200 * For single LED mode, SSL3252 drives a maximum of 500 mA flash current ILED, [mA] 60% 55% 275 50% 350 425 Ordering information Type number Package SSL3250AHN/C1 HVQFN-16 (3 x 3 x 0.8mm) SSL3252UK WLCSP-12 (1.5 x 2 x 0.6mm) LED power efficiency, [%] 5 4 5 .1 .4 V 4.24.5 V.8 V V 3 . V 3 . 3 3 .6 V 9 V 500 2 . 7 3 .0 V V VBAT, [V] V Dual-LED, in series, inductor boost results in higher efficiency because the driver always operate in boost mode SSL3250A application SSL3252 application L 2.2 MH battery PGND Cin 4.7 MF PGND LX VIN VO IF_SEL Flash LEDs ACT control signals Cout 4.7 MF STRB SCL/EN2 PGND LED SDA/EN1 INT current settings (optional) PGND R_TR PGND R_FL Vbat R_IND GND I_IND brb140 www.nxp.com/i2clogic www.nxp.com © 2009 NXP B.V. All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. Date of release: February 2009 The information presented in this document does not form part of any quotation or contract, is believed to be accurate and Document order number : 9397 750 16672 reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Printed in the Netherlands Publication thereof does not convey nor imply any license under patent- or other industrial or intellectual property rights.