Description

The DAC-8228 is a dual 8-bit, voltage output, CMOS, D/A converter in a single chip. It was designed to drop into AD7528 / AD7628 sockets eliminating two external op amps in applications such as hard diskdrives. These applications generally operate the AD7528 / AD7628 with zero volts applied to VREF and offset AGND to +2.5 or +5 volts. The DAC-8228 is tested under both these conditions.The DAC-8228 can also be used in those applications requiring a unipolar output voltage. It can deliver an output voltage between 0V and +10V with VDD = +14V (maximum output voltage is VDD -4V). The DAC-8228's reference input can accept a negative voltage from 0V to -10V (the DAC's internal unity-gain inverting amplifier inverts the input signal). Choose the DAC-8229 for bipolar operation.The DAC8228 offers CerDIP and plastic packaged devices in the extended industrial temperature range of -40° to +85°C. Applications requiring the military temperature range should use the DAC-8229. To make the DAC-8229 pin and functionally compatible with the DAC-8228, AGND A and AGND B should be tied together to function as VZ, and VSS connected to GND.The DAC-8228 consists of two CMOS voltage output amplifiers, two high-accuracy R-2R resistor ladder networks, interface control logic, and two 8-bit registers. An internal regulator maintains TTL logic compatibility and fast microprocessor interface timing over the full VDD range.The DAC-8228 dissipates only 90mW in the space saving 20-pin 0.3' DIP or the 20-lead SO surface mount package. Its compact size, low power, and economical cost per channel, makes it attractive for applications requiring multiple D/A converters without sacrificing circuit-board space. Reduced parts count also improves system reliability.Using PMI's advanced oxide-isolated, silicon-gate CMOS process, coupled with its highly-stable thin-film resistor ladder, allows the DAC-8228 to offer superior matching and temperature tracking between DACs.APPLICATIONS Disk Drive Systems Automatic Test Equipment Process/Industrial Controls Energy Controls Programmable Instrumentation Multi-Channel Microprocessor-Controlled Systems Servo Control Systems