LM2705 Datasheet | National Semiconductor

LM2705 Micropower Step-up DC/DC Converter with 150m A Peak Current Limit April 2003 LM2705 Micropower Step-up DC/DC Converter with 150m A Peak Current Limit General Description The LM2705 is a micropower step-up DC/DC in a small 5-lead SOT-23 package. A current limited, fixed off-time control scheme conserves operating current resulting in high efficiency over a wide range of load conditions. The 21V switch allows for output voltages as high as 20V. The low 400ns off-time permits the use of tiny, low profile inductors and capacitors to minimize footprint and cost in spaceconscious portable applications. The LM2705 is ideal for LCD panels requiring low current and high efficiency as well as white LED applications for cellular phone back-lighting. The LM2705 can drive up to 3 white LEDs from a single Li-Ion battery. The low peak inductor current of the LM2705 makes it ideal for USB applications. Features n n n n n n n 150m A, 0.7Ω, internal switch Uses small surface mount ponents Adjustable output voltage up to 20V 2.2V to 7V input range Input undervoltage lockout 0.01µA shutdown current Small 5-Lead SOT-23 package Applications n n n n n LCD Bias Supplies White LED Back-Lighting Handheld Devices Digital Cameras Portable Applications Typical Application Circuit FIGURE 1. Typical 20V Application © 2003 National Semiconductor Corporation DS200397 .national. Connection Diagram Top View TJmax SOT23-5 = 125˚C, θJA = 220˚C/W (Note 2) Ordering Information Order Number LM2705MF-ADJ LM2705MFX-ADJ Package Type SOT23-5 SOT23-5 NSC Package Drawing MA05B MA05B Top Mark S59B S59B Supplied As 1000 Units, Tape and Reel 3000 Units, Tape and Reel Pin Description/Functions Pin 1 2 3 4 5 Name SW GND FB SHDN VIN Power Switch input. Ground. Output voltage feedback input. Shutdown control input, active low. Analog and Power input. Connect the ground of the feedback network to an AGND plane which should be tied directly to the GND pin....