LTC3201 100mA Ultralow Noise Charge Pump LED Supply with Output Current Adjust FEATURES DESCRIPTIO n Input Noise Filter Minimizes Supply Noise The LTC 3201 is an ultralow noise, constant frequency, n Constant Frequency Operation charge pump DC/DC converter specifically designed for n 3-Bit LED Current Control powering white LEDs. The part produces a low noise n No Inductors boosted supply capable of supplying 100mA of output n Low Shutdown Current: I < 1m A current. LED current is regulated for accurate and stable IN n Output Current: 100mA backlighting. A 3-bit DAC provides output current adjust n V Range: 2.7V to 4.5V for brightness control. IN n 1.8MHz Switching Frequency Low external parts count (one small flying capacitor and n Soft-Start Limits Inrush Current at Turn-On three small bypass capacitors) and small MSOP-10 pack- n Short-Circuit and Overtemperature Protected age size make the LTC3201 ideally suited for space con- n Available in 10-Pin MSOP Package strained applications. An input noise filter further reduces input noise, thus enabling direct connection to the battery. U High switching frequency enables the use of small external APPLICATIO S capacitors. n White LED Backlighting The LTC3201 contains overtemperature protection and n Programmable Boost Current Source can survive an indefinite output short to GND. Internal soft-start circuitry also prevents excessive inrush current on start-up. A low current shutdown feature disconnects the load from V and reduces quiescent current to less IN , LTC and LT are registered trademarks of Linear Technology Corporation. than 1m A. TYPICAL APPLICATIO Ultralow Noise White LED Driver Input Current Ripple with Adjustable Current Control I = 100mA OUT 0.22F I = 205mA IN V = 3.6V IN CM CP UP TO V IN 6-WHITE LEDs + 50mA/DIV 1F Li ION V OUT FILTER 1F 0.22F LTC3201 LED 3 D0-D2 CURRENT ADJUST GND FB 56 56 56 3201 TA01b 100ns/DIV 3201 TA01a 3201f 1 U ULTC3201 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART TOP VIEW V , V , V , CP, CM to GND .............. 0.3V to 6V IN FILTER OUT NUMBER V 1 10 FB OUT D0, D1, D2, FB to GND ................. 0.3V to (V + 0.3V) IN CP 2 9 V IN FILTER 3 8 D2 V Short-Circuit Duration............................. Indefinite OUT LTC3201EMS CM 4 7 D1 I ...................................................................................... 150mA GND 5 6 D0 OUT Operating Temperature Range (Note 2) ...40 C to 85 C MS PACKAGE MS PART 10-LEAD PLASTIC MSOP Storage Temperature Range ................. 65 C to 150 C MARKING T = 150 C JMAX Lead Temperature (Soldering, 10 sec).................. 300 C q = 130 C/W (1 LAYER BOARD) JA q = 100 C/W (4 LAYER BOARD) JA LTVB 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 = 3.6V, C = C = 0.22m F, C = C = 1m F, A IN FILTER FLY IN OUT t to t unless otherwise noted. MIN MAX PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage l 2.7 4.5 V IN V Operating Current I = 0mA l 4 6.5 mA IN OUT V Shutdown Current D0, D1, D2 = 0V, V = 0V l 1 m A IN OUT Open-Loop Output Impedance I = 100mA 8 W OUT Input Current Ripple I = 200mA 30 mA IN P-P Output Ripple I = 100mA, C = 1mF30mV OUT OUT P-P V Regulation Voltage D0 = D1 = D2 = V l 0.57 0.63 0.66 V FB IN V DAC Step Size 90 mV FB Switching Frequency Oscillator Free Running 1.4 1.8 MHz D0 to D2 Input Threshold l 0.4 1.1 V D0 to D2 Input Current l 1 1 m A V Short-Circuit Current V = 0V 150 mA OUT OUT V Turn-On Time I = 0mA 1 ms OUT OUT Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC3201E is guaranteed to meet performance specifications from 0 C to 70 C. Specifications over the 40 C to 85 C operating temperature range are assured by design, characterization and correlation with statistical process controls. 3201f 2 U WWW