描述 Description

The MAX722 and MAX723 CMOS power-supply ICs create dual regulated DC outputs for small, battery-operated microprocessor systems. Each device generates a main output (3V or 5V, selectable) and a negative auxiliary output that is adjustable for LCDs. Each device accepts two input voltages. Power can come from a main battery (two or three alkaline or NiCAD), or an unregulated DC source such as an AC-DC wall adapter.
The MAX722/MAX723 provide three improvements over prior-art devices. Physical size is reduced; the high switching frequencies (up to 0.5MHz), made possible by MOSFET power transistors, allow for tiny (< 5mm diameter) surface-mount magnetics. Efficiency is also improved to 87% (10% better than with low-voltage regulators made in bipolar technology). And supply current is reduced to 60μA by CMOS construction and a unique constant-off-time pulse-frequency modulation (PFM) control scheme.
The MAX722 and MAX723 differ only in the lower fixed output voltage of the main regulator, with a 3.3V output for the MAX722 and a 3.0V output for the MAX723.
For flash memory or PCMCIA applications that require a +12V output voltage, refer to the MAX717–721 data sheet.

特性 Features

? Low 0.9V to 5.5V Battery Input Range
? Unregulated 7V to 20V DC Input Range
? Dual Regulated Outputs
? Main Output: 3.3V/5V
? Auxiliary Output: 0V to -100V
? 87% Efficiency at 200mA
? Efficient PRAM Keep-Alive: 80% at 1mA
? 8W/in3 Power Density
? 60μA Quiescent Current
? 20μA Shutdown Mode with VREF Alive
? 500kHz Maximum Switching Frequency
? ±1.5% VREF Tolerance (Over Temp.)
? Detect Output Power Failures
? 16-Pin Narrow SO Packages

應(yīng)用 Application

? 條碼掃描儀
? LCD對比度調(diào)節(jié)
? 醫(yī)療儀表
? 掌上電腦
? 便攜式數(shù)據(jù)通信
? 便攜式數(shù)據(jù)收集設(shè)備

簡介

MAX722屬于集成電路（IC）的顯示驅(qū)動器。由制造生產(chǎn)的MAX722顯示驅(qū)動器顯示驅(qū)動器是一種集成電路 (IC)，可在微處理器 (MPU)、微控制器 (MCU) 或其他電路系統(tǒng)之間提供轉(zhuǎn)換、接口和控制，用于 LCD、LED、OLED、DLP、真空熒光和 AMOLED 等顯示器。可能的通信接口和協(xié)議包括模擬、BCD、I2C、并行、串行、SMBus、SPI 和 QSPI。