LM2787 Datasheet | National Semiconductor

Description The LM2787 CMOS Negative Regulated Switched Capacitor Voltage Inverter delivers a very low noise adjustable output for an input voltage in the range of +2.7V to +5.5V. Four low cost capacitors are used in this circuit to provide up to 10m A of output current. The regulated output for the LM2787 is adjustable between - 1.5V and - 5.2V. The LM2787 operates at 260 k Hz (typical) switching frequency to reduce output resistance and voltage ripple. With an operating current of only 400 µA (charge pump power efficiency greater than 90% with most loads) and 0.05 µA typical shutdown current, the LM2787 provides ideal performance for cellular phone power amplifier bias and other low current, low noise negative voltage needs. The device es in a small 8-Bump micro SMD package. Features n n n n n Inverts and regulates the input supply voltage Small 8-Bump micro SMD package 91% typical charge pump power efficiency at 10m A Low output ripple Shutdown lowers Quiescent current to 0.05 µA (typical) Applications n n n n n Wireless munication Systems Cellular Phone Power Amplifier Biasing Interface Power Supplies Handheld Instrumentation Laptop puters and PDA’s Typical Application Circuit and Connection Diagram 8-Bump micro SMD (Top View) © 2002 National Semiconductor Corporation DS101313 .national. Ordering Information Device Order Number LM2787BP LM2787BPX Package Number BPA08CCB BPA08CCB Package Marking- S8 S8 .. Supplies As Tape and Reel (250 units/reel) Tape and Reel (3000 units/reel) Note: - The small physical size of the micro SMD package does not allow for the full part number marking. Devices will be marked with the designation shown in the column Package Marking. Pin Descriptions Pin No. A1 B1 C1 C2 C3 B3 A3 A2 Name Cap+ VIN VOUT VFB SD VNEG Cap- GND Positive terminal for C1. Positive power supply input. Regulated negative output voltage. Feedback input. Connect VFB to an external resistor divider between VOUT and a positive...