LTC3217 600mA Low Noise Multi-LED Camera Light Charge Pumps FEATURES DESCRIPTION n Charge Pump Provides High Ef ciency with The LTC 3217 is a low noise charge pump DC/DC converter Automatic Mode Switching designed to power four high current LEDs. The LTC3217 n Multimode Operation: 1x, 1.5x, 2x requires only four small ceramic capacitors and two cur- n Four Low Dropout LED Outputs rent set resistors to form a complete LED power supply n Up to 600mA Total Output Current and current controller. n Independent Torch and Flash I and Enable Pins SET Built-in soft-start circuitry prevents excessive inrush cur- n Low Noise Constant Frequency Operation* rent during start-up and mode changes. High switching n PWM Brightness Control via the EN2 Pin frequency enables the use of small external capacitors. n Low Shutdown Current: 4A Independent high and low current settings are programmed n Internal Soft-Start Limits Inrush Current During by two external resistors. Shutdown mode and current Start-Up and Mode Switching output levels are selected via two logic inputs. n Open/Short LED Protection n The current through the LEDs is programmed via I No Inductors SET1 n and I . In addition, the brightness can be controlled (3mm x 3mm) 16-Lead QFN Plastic Package SET2 by pulse width modulation of the EN2 pin. APPLICATIONS The charge pump optimizes ef ciency based on the volt- age across the LED current sources. The part powers up n Multi-LED Camera Light Supply for Cellphones/ in 1x mode and will automatically switch to boost mode DSCs/PDAs whenever any enabled LED current source begins to enter L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other dropout. The rst dropout switches the part into 1.5x trademarks are the property of their respective owners. *Protected by U.S. Patents including 6411531. mode and a subsequent dropout switches the part into 2x mode. The LTC3217 resets to 1x mode whenever the part is shut down. The LTC3217 is available in a low profile 16-lead (3mm 3mm 0.75mm) QFN package. TYPICAL APPLICATION C2 C3 Ef ciency vs V 2.2F 2.2F BAT 100 100mA 200mA 90 C1P C1M C2P C2M 400mA 80 V V CPO BAT BAT C1 C4 70 2.2F 2.2F LTC3217 AOT-2015HPW-1751B 60 LED1 50 LED2 40 EN1 (TORCH) EN1 LED3 30 EN2 (FLASH) EN2 LED4 20 I I TOTAL OUTPUT CURRENT SET1 SET2 GND EN1 EN2 I 10 P /PIN LED LED LED = 2015 HPW AOT 0 0 0 (SHUTDOWN) 0 19.6k 6.49k 1 0 25mA/LED 3 3.2 3.4 3.6 3.8 4 4.2 4.4 1% 1% 0 1 75mA/LED V (V) BAT 1 1 100mA/LED 3217 TA01b 3217 TA01 3217fa 1 EFFICIENCY (P /PIN) (%) LEDLTC3217 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , CPO to GND ......................................... 0.3V to 6V BAT EN1, EN2 ......................................0.3V to (V + 0.3V) BAT 16 15 14 13 I (Note 2) ........................................................600mA CPO C1P 1 12 C2M I (Note 3) ...................................................150mA ILED1-4 CPO 2 11 EN2 17 CPO Short-Circuit Duration .............................. Inde nite EN1 3 10 I SET2 LED1 I Operating Temperature Range (Note 4)....40C to 85C 4 9 SET1 5 6 7 8 Storage Temperature Range ................... 65C to 125C UD PACKAGE 16-LEAD (3mm 3mm) PLASTIC QFNs T = 125C, = 68C/W JMAX JA EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3217EUD PBF LTC3217EUD TRPBF LBTQ 40C to 85C 16-Lead (3mm 3mm) Plastic QFN Consult LTC Marketing for parts speci ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: