CMOS 12-Bit Successive Approximation A/D Converter

The AD7582 is a medium speed, 4-channel 12-bit CMOS A/D converter which uses the successive approximation technique to provide a conversion time of 100 µs per channel. An auto-zero cycle occurs at the start of each conversion resulting in very low system offset voltages, typically less than 100 µV. The devices is designed for easy microprocessor interface using standard control signals; CS (decoded device address), RD (READ) and WR, (WRITE). The 4-channel multiplexer is controlled via address inputs A0 and A1.

Conversion results are available in two bytes, 8LSB's and 4MSB's, over an 8-bit three state output bus. Either byte can be read first. Two converters busy flags are available to facilitate polling of the converter's status.

The analog input voltage range is 0V to +5V when using a reference voltage of +5V. The four analog inputs are all high impedance inputs with tight channel-to-channel matching—typically 0.1LSBs.

PRODUCT HIGHLIGHTS

* The AD7582 is a complete 4 channel 12-bit A/D converter in either a 28-pin DIP or 28-terminal surface mount package requiring only a few passive components and a voltage reference.

* Autozero cycle realizes very low offset voltages, typically 100 μV.

* The four channel input multiplexer (user addressable) features high input impedance and excellent channel-to-channel matching.

* Standard microprocessor control signals to allow easy interfacing to most popular 8- and 16-bit microprocessors.

* 12-Bit Successive Approximation ADC

* Four High Impedance Input Channels

* Analog Input Voltage Range of 0 to +5 V with Positive Reference of +5 V

* Conversion Time of 100 µs Per Channel