VIN

EN

LM27761

C1+

C1-

VOUT

VFB

CPOUT

GND

C1

1 µF

C3

4.7 µF

C4

2.2 µF

C2

4.7 µF

R1

R2

11

LM27761

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SNVSA85B – OCTOBER 2015 – REVISED FEBRUARY 2016

Product Folder Links: LM27761

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM27761 low-noise charge-pump voltage converter inverts a positive voltage in the range of 2.7 V to 5.5 V

to a negative output voltage configurable with external gain setting resistors. The device uses four low-cost

capacitors to provide up to 250 mA of output current. The LM27761 operates at a 2-MHz oscillator frequency to

reduce charge-pump output resistance and voltage ripple under heavy loads. With an operating current of only

370 µA and 7-µA typical shutdown current, the LM27761 provides ideal performance for battery-powered

systems.

8.2 Typical Application - Regulated Voltage Inverter

Figure 16. LM27761 Typical Application

8.2.1 Design Requirements

Example requirements for typical applications using the LM27761 device are listed in Table 1:

Table 1. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Input voltage

2.7 V to 5.5 V

Output voltage

–1.5 V to –5 V

Output current

0 mA to 250 mA

Boost switching frequency

2 MHz