Description
The LM27762DSST provides low-noise positive and negative outputs that can be adjusted between ±1.5 and ±5 volts. The input voltage ranges from 2.7 to 5.5 V, with a maximum output current of ±250 mA. The LM27762DSST delivers outstanding performance for power amplifier and DAC bias, as well as other high-current, low-noise negative voltage needs, with an operating current of just 390 μA and a typical shutdown current of 0.5 μA. With only a few external components, the gadget provides a tiny solution size.
A regulated inverting charge pump is used to generate negative voltage, which is then followed by a low-noise negative LDO. The LM27762DSST device's inverting charge pump runs at a 2-MHz (typical) switching frequency to reduce output resistance and voltage ripple. A low-noise positive LDO generates positive voltage from the input.
The LM27762DSST has separate enable inputs for positive and negative outputs. For unique system power-sequence needs, these outputs provide independent timing for the positive and negative rails. Enable inputs can also be connected to the input voltage by shorting them together. The LM27762DSST features a Power Good feature that may be turned on or off.
Features
? 390-μA Quiescent Current (Typical)
? Shutdown Quiescent Current to 0.5 μA (Typical)
? Current Limit and Thermal Protection
? Power Good Pin (Active Low)
? Create a Custom Design Using the LM27762 With the WEBENCH? Power Designer
? 2-MHz Low-Noise Fixed-Frequency Operation
? 2.5-? Inverter Output Impedance, VIN = 5 V
? Negative LDO Dropout Voltage 30 mV at 100 mA, VOUT = –5 V
? Positive LDO with 45-mV Dropout Voltage at 100 mA, VOUT = 5 V
? Generates Low-Noise Adjustable Positive Supply Voltage Between 1.5 V and 5 V and Negative Supply Voltage Between –1.5 V and –5 V
? Input Voltage Range 2.7 V to 5.5 V
? ±250-mA Output Current
? Inverting Charge Pump Followed by Negative LDO
Applications
? Wireless Communication Systems
? Interface Power Supplies
? Handheld Instrumentation
? Hi-Fi Audio Headphone Amplifiers
? Operational Amplifier Power Biasing
? Powering Data Converters
