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GENERAL DESCRIPTION

The AD7237A/AD7247A is an enhanced version of the industry standard AD7237/AD7247. Improvements include operation from 12 V to 15 V supplies, faster interface times and better reference variations with VDD. Additional features include faster settling times.

The AD7237A/AD7247A is a complete, dual, 12-bit, voltage output digital-to-analog converter with output amplifiers and Zener voltage reference on a monolithic CMOS chip. No external user trims are required to achieve full specified performance.

Both parts are microprocessor compatible, with high speed data latches and interface logic. The AD7247A accepts 12-bit parallel data which is loaded into the respective DAC latch using the WR input and a separate Chip Select input for each DAC. The AD7237A has a double buffered interface structure and an 8-bit wide data bus with data loaded to the respective input latch in two write operations. An asynchronous LDAC signal on the AD7237A updates the DAC latches and analog outputs.

A REF OUT/REF IN function is provided which allows either the on-chip 5 V reference or an external reference to be used as a reference voltage for the part. For single supply operation, two output ranges of 0 V to +5 V and 0 V to +10 V are available, while these two ranges plus an additional ±5 V range are available with dual supplies. The output amplifiers are capable of developing +10 V across a 2 k? load to GND.

The AD7237A/AD7247A is fabricated in Linear Compatible CMOS (LC2MOS), an advanced, mixed technology process that combines precision bipolar circuits with low power CMOS logic. Both parts are available in a 24-pin, 0.3 wide plastic and hermetic dual-in-line package (DIP) and are also packaged in a 24-lead small outline (SOIC) package.

FEATURES

Complete Dual 12-Bit DAC Comprising

Two 12-Bit CMOS DACs

On-Chip Voltage Reference

Output Amplifiers

Reference Buffer Amplifiers

Improved AD7237/AD7247:

12 V to 15 V Operation

Faster Interface –30 ns typ Data Setup Time

Parallel Loading Structure: AD7247A

(8+4) Loading Structure: AD7237A

Single or Dual Supply Operation

Low Power—165 mW typ in Single Supply