LTC3202 Low Noise, High Efficiency Charge Pump for White LEDs FEATURES DESCRIPTIO n Low Noise Constant Frequency Operation The LTC 3202 is a low noise, constant frequency charge n 25% Less Input Current Than Doubler Charge Pump pump DC/DC converter that uses fractional conversion to n High Output Current: Up To 125mA increase efficiency in white LED applications. The part can n Small Application Circuit be used to produce a regulated voltage or current of up to n Regulated Output Voltage or Current 125mA from a 2.7V to 4.5V input. Low external parts count n Automatic Soft-Start (two flying capacitors and two small bypass capacitors at n V Range: 2.7V to 4.5V V and V ) make the LTC3202 ideally suited for small, IN IN OUT n No Inductors battery-powered applications. n 1.5MHz Switching Frequency An internal 2-bit DAC allows LED current to be adjusted for n I < 1m A in Shutdown CC LED brightness control. The LTC3202 also has thermal n Available in 10-Pin MSOP and 3mm 3mm shutdown protection and can survive a continuous short- DFN Packages circuit from V to GND. Built-in soft-start circuitry OUT U prevents excessive inrush current during start-up. High APPLICATIO S switching frequency enables the use of small external n White LED Backlighting capacitors. A low current shutdown feature disconnects n Programmable Boost Current Source the load from V and reduces quiescent current to less IN than1m A. The LTC3202 is available in the 10-pin MSOP and 3mm 3mm DFN packages. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO Programmable White LED Power Supply C2 C3 Input and Output Ripple 1F 1F V IN 7 8 96 (AC COUPLED) 0mA TO 125mA + + 20mV/DIV C1 C1 C2 C2 TOTAL CURRENT 3 10 D0 V OUT CURRENT PROGRAMMING 1 D1 LTC3202 2 V 4 V IN OUT V FB IN 3V TO 4.5V (AC COUPLED) GND 20mV/DIV C1 C4 36 36 36 36 36 36 1F 1F 5, 11 3202 G09 V = 3.6V 500ns/DIV IN C = C = 1F C1, C2, C3, C4 = MURATA GRM 39X5R105K6.3 OR TAIYO YUDEN JMK107BJ105MA IN OUT I = 60mA OUT 3202 TA01 3202fa 1 U ULTC3202 ABSOLUTE AXI U RATI GS (Note 1) V , V to GND ......................................... 0.3V to 6V Operating Temperature Range (Note 3) ...40 C to 85 C IN OUT D0, D1 .............................................0.3V to V + 0.3V Storage Temperature Range ..................65 C to 150 C IN V Short-Circuit Duration............................. Indefinite Lead Temperature (Soldering, 10 sec).................. 300 C OUT I (Note 2)....................................................... 150mA OUT UUW PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART ORDER PART NUMBER NUMBER TOP VIEW D1 1 10 D0 + D1 1 10 D0 FB 2 9 C2 + LTC3202EMS LTC3202EDD FB 2 9 C2 + 11 V 3 8 C1 + OUT V 3 8 C1 OUT V 4 7 C1 V 4 7 C1 IN IN GND 5 6 C2 SGND 5 6 C2 MS PACKAGE MS PART MARKING DD PART MARKING 10-LEAD PLASTIC MSOP DD PACKAGE 10-LEAD (3mm 3mm) PLASTIC DFN T = 150 C, q = 120 C/W JMAX JA LTWL LABB T = 150 C, q = 44 C/W, q = 3 C/W JMAX JA JC EXPOSED PAD IS PGND (PIN 11) MUST BE CONNECTED TO GROUND PLANE Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 3.3V unless otherwise noted. A IN PARAMETER CONDITIONS MIN TYP MAX UNITS Input Power Supply V Operating Voltage l 2.7 4.5 V IN I Operating Current I = 0mA, V = 3.6V, V = D0 = D1 = 4.5V l 2.5 5 mA CC OUT OUT IN I Shutdown Current V = 0V l 1 m A SHDN OUT Feedback Pin Set Points 0.2V Setting Feedback Voltage D0 = 1, D1 = 0, I = 0mA, V = 3.6V l 188 200 212 mV OUT IN 0.4V Setting Feedback Voltage D0 = 0, D1 = 1, I = 0mA, V = 3.6V l 380 400 420 mV OUT IN 0.6V Setting Feedback Voltage D0 = 1, D1 = 1, I = 0mA, V = 3.6V l 570 600 630 mV OUT IN I V = 0.8V l 50 50 nA FB FB Charge Pump R Open Loop Output Impedance (1.5V V )/I V = 3.3V, V = 4.4V, V = 0 l 4.5 6 W OL IN OUT OUT IN OUT FB V Load Regulation (D V /D I)I = 10mA to 90mA, D V /D V = 1 0.35 mV/mA OUT OUT OUT OUT FB OUT CLK Frequency 1.5 MHz D0, D1 High Level Input Voltage (V ) l 1.3 V IH Low Level Input Voltage (V ) l 0.4 V IL Input Current (I ) DO, D1 = V l 1 1 m A IH IN Input Current (I ) DO, D1 = 0V l 1 1 m A IL Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: The LTC3202E is guaranteed to meet performance specifications of a device may be impaired. from 0 C to 70 C. Specifications over the 40 C to 85 C operating temperature range are assured by design, characterization and correlation Note 2: Based on long-term current density limitations. with statistical process controls. 3202fa 2 U WWW