LM2787 Datasheet, PDF (1/8 Pages) National Semiconductor (TI) – Low Noise Regulated Switched Capacitor Voltage

August 2002
LM2787
Low Noise Regulated Switched Capacitor Voltage
Inverter in micro SMD
General 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 10mA
of output current. The regulated output for the LM2787 is
adjustable between −1.5V and −5.2V. The LM2787 operates
at 260 kHz (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 nega-
tive voltage needs. The device comes in a small 8-Bump
micro SMD package.
Features
n Inverts and regulates the input supply voltage
n Small 8-Bump micro SMD package
n 91% typical charge pump power efficiency at 10mA
n Low output ripple
n Shutdown lowers Quiescent current to 0.05 µA (typical)
Applications
n Wireless Communication Systems
n Cellular Phone Power Amplifier Biasing
n Interface Power Supplies
n Handheld Instrumentation
n Laptop Computers and PDA’s
Typical Application Circuit and Connection Diagram
8-Bump micro SMD (Top View)
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© 2002 National Semiconductor Corporation DS101313
10131302
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