The MAX3325 integrates a two-transmitter, two-receiver RS-232 transceiver with an LCD supply plus temperature-compensated contrast control. It is intended for small 3V instruments requiring a 5V supply for either logic or an LCD display, an adjustable bias signal for contrast, LCD temperature compensation, and an RS-232 interface for serial communications. The 5V supply is a regulated charge pump followed by a low-dropout (LDO) linear regulator capable of supplying 11mA for the 5V LCD power. The MAX3325 has an internal 6-bit digital-to-analog converter (DAC) providing 64 contrast levels, plus an internal temperature sensor that compensates the LCD's contrast for changes in ambient temperature. The LCD contrast can be designed for any voltage range from -5V to +2V.