General Description

The MAX1747 triple charge-pump DC-DC converter provides the regulated voltages required by active matrix thin-film transistor (TFT) liquid-crystal displays (LCDs) in a low-profile TSSOP package. One high power and two low-power charge pumps convert the +2.7V to +4.5V input supply voltage into three independent output voltages.

The primary high-power charge pump generates an output voltage (VOUT) between 4.5V and 5.5V that is regulated within ±1. The low-power BiCMOS control circuitry and the low on-resistance (RON) power MOSFETs maximize efficiency. The adjustable switching frequency (200kHz to 2MHz) provides fast transient response and allows the use of small low-profile ceramic capacitors.

Features

♦ Adjustable Outputs

   Up to +5.5V Main High-Power Output

   Up to +35V Positive Charge-Pump Output

   Down to -35V Negative Charge-Pump Output

♦ 200kHz to 2MHz Adjustable Switching Frequency

♦ +2.7V to +4.5V Input Supply

♦ Internal Power MOSFETs

♦ 0.1µA Shutdown Current

♦ Internal Soft-Start

♦ Power-Ready Output

♦ Internal Supply Sequencing

♦ Fast Transient Response

♦ Ultra-Thin Solution (No Inductors)

♦ Thin TSSOP Package (1.1mm max)

Applications

   TFT Active-Matrix LCDs

   Passive-Matrix Displays

   Personal Digital Assistants (PDAs)