General Description

The MAX680/MAX681 are monolithic, CMOS, dual charge-pump voltage converters that provide ±10V outputs from a +5V input voltage. The MAX680/MAX681 provide both a positive step-up charge pump to develop +10V from +5V input and an inverting charge pump to generate the -10V output. Both parts have an on-chip, 8kHz oscillator. The MAX681 has the capacitors internal to the package, and the MAX680 requires four external capacitors to produce both positive and negative voltages from a single supply.

The output source impedances are typically 150Ω, providing useful output currents up to 10mA. The low quiescent current and high efficiency make this device suitable for a variety of applications that need both positive and negative voltages generated from a single supply.

The MAX864/MAX865 are also recommended for new designs. The MAX864 operates at up to 200kHz and uses smaller capacitors. The MAX865 comes in the smaller µMAX package.

Features

♦ 95% Voltage-Conversion Efficiency

♦ 85% Power-Conversion Efficiency

♦ +2V to +6V Voltage Range

♦ Only Four External Capacitors Required (MAX680)

♦ No Capacitors Required (MAX681)

♦ 500µA Supply Current

♦ Monolithic CMOS Design

Applications

The MAX680/MAX681 can be used wherever a singlepositive supply is available and where positive and negative voltages are required. Common applications include generating ±6V from a 3V battery and generating ±10V from the standard +5V logic supply (for use with analog circuitry). Typical applications include:

±6V from 3V Lithium Cell

Hand-Held Instruments

Data-Acquisition Systems

Panel Meters

±10V from +5V Logic Supply

Battery-Operated Equipment

Operational Amplifier Power Supplies