LT1946A Datasheet | Linear Technology

LT1946A 2.7MHz Boost DC/DC Converter with 1.5A Switch and Soft-Start Features s s s s s s s DESCRIPTIO 1.5A, 36V Internal Switch 2.7MHz Switching Frequency Integrated Soft-Start Function Adjustable Output from VIN to 35V Low VCESAT Switch: 300m V at 1.5A (Typical) 12V at 430m A from a 5V Input Small Thermally Enhanced 8-Lead MSOP Package U APPLICATIO S s s s s TFT-LCD Bias Supplies GPS Receivers DSL Modems Local Power Supply The LT®1946A is a fixed frequency step-up DC/DC converter containing an internal 1.5A, 36V switch. Capable of generating 12V at 430m A from a 5V input, the LT1946A is ideal for powering large TFT-LCD panels. The LT1946A switches at 2.7MHz, allowing the use of tiny, low profile inductors and low value ceramic capacitors. Loop pensation can be either internal or external, giving the user flexibility in setting loop pensation and allowing optimized transient response with low ESR ceramic output capacitors. Soft-start is controlled with an external capacitor which determines the input current ramp rate during start up. The 8-lead MSOP package and high switching frequency ensure a low profile overall solution less than 1.1mm high. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO VIN 5V 3 1 L1 2.2µH 6 VIN SHDN VC SS CSS 100n F 8 OFF ON C1 2.2µF RC 27.4k CC 270p F 5 SW D1 VOUT 12V 430m A R1 182k EFFICIENCY (%) 90 85 80 2 LT1946A FB 7 P GND- 4 R2 21k C2 2.2µF 75 70 65 60 C1: 2.2µF, X5R or X7R, 6.3V C2: 2.2µF, X5R or X7R, 16V D1: MICROSEMI UPS120 OR EQUIVALENT L1: SUMIDA CR43-2R2 - EXPOSED PAD MUST ALSO BE GROUNDED 1946A TA01 55 50 0 100 200 300 400 LOAD CURRENT (m A) 500 1946A TA01 Figure 1. 5V to 12V, 430m A Step-Up DC/DC Converter Efficiency sn1946a 1946afs ABSOLUTE (Note 1) AXI U RATI GS U U W PACKAGE/ORDER I FOR ATIO TOP VIEW VC FB SHDN GND 1 2 3 4 8 7 6 5 SS P VIN SW VIN Voltage .............................................................. 16V SW Voltage...