LM27762DSST.A中文资料德州仪器数据手册PDF规格书

1 Features

1• 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

• 2-MHz Low-Noise Fixed-Frequency Operation

• 2.5-Ω 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

• 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 Applications

• Hi-Fi Audio Headphone Amplifiers

• Operational Amplifier Power Biasing

• Powering Data Converters

• Wireless Communication Systems

• Interface Power Supplies

• Handheld Instrumentation

3 Description

The LM27762 delivers very low-noise positive and

negative outputs that are adjustable between ±1.5 V

and ±5 V. Input-voltage range is from 2.7 V to 5.5 V,

and output current goes up to ±250 mA. With an

operating current of only 390 μA and 0.5-μA typical

shutdown current, the LM27762 provides ideal

performance for power amplifier and DAC bias and

other high-current, low-noise negative voltage needs.

The device provides a small solution size with few

external components.

Negative voltage is generated by a regulated

inverting charge pump followed by a low-noise

negative LDO. The inverting charge pump of the

LM27762 device operates at 2-MHz (typical)

switching frequency to reduce output resistance and

voltage ripple. Positive voltage is generated from the

input by a low-noise positive LDO.

Positive and negative outputs of LM27762 have

dedicated enable inputs. These outputs support

independent timing for the positive and negative rails

for specific system power-sequence needs. Enable

inputs can be also shorted together and connected to

the input voltage. The LM27762 has an optional

Power Good feature.