AD779:  14-Bit 128 kSPS Complete Sampling ADC

The AD779 is a complete, multipurpose 14-bit monolithic analog-to-digital converter, consisting of a sample-hold amplifier (SHA), a microprocessor compatible bus interface, a voltage reference and clock generation circuitry.

The AD779 is specified for ac (or “dynamic”) parameters such as S/N+D ratio, THD and IMD which are important in signal processing applications. In addition, the AD779K, B and T grades are fully specified for dc parameters which are important in measurement applications.

The 14 data bits are accessed by a 16-bit bus in a single read operation. Data format is straight binary for unipolar mode and twos complement binary for bipolar mode. The input has a fullscale range of 10 V with a full power bandwidth of 1 MHz and a full linear bandwidth of 500 kHz. High input impedance (10 MW) allows direct connection to unbuffered sources without signal degradation.

This product is fabricated on Analog Devices’ BiMOS process, combining low power CMOS logic with high precision, low noise bipolar circuits; laser-trimmed thin-film resistors provide high accuracy. The converter utilizes a recursive subranging algorithm which includes error correction and flash converter circuitry to achieve high speed and resolution.

The AD779 operates from +5 V and ±12 V supplies and dissipates 560 mW (typ). Twenty-eight-pin plastic DIP and ceramic DIP packages are available.

1. COMPLETE INTEGRATION: The AD779 minimizes
   external component requirements by combining a high speed
   sample-hold amplifier (SHA), ADC, 5 V reference, clock
   and digital interface on a single chip. This provides a fully
   specified sampling A/D function unattainable with discrete designs.
2. SPECIFICATIONS: The AD779K, B and T grades provide
   fully specified and tested ac and dc parameters. The AD779J,
   A and S grades are specified and tested for ac parameters; dc
   accuracy specifications are shown as typicals. DC specifications
   (such as INL, gain and offset) are important in control
   and measurement applications. AC specifications (such as
   S/N+D ratio, THD and IMD) are of value in signal processing applications.
3. EASE OF USE: The pinout is designed for easy board layout,
   and the single cycle read output provides compatibility
   with 16-bit buses. Factory trimming eliminates the need for
   calibration modes or external trimming to achieve rated performance.
4. RELIABILITY: The AD779 utilizes Analog Devices’
   monolithic BiMOS technology. This ensures long term
   reliability compared to multichip and hybrid designs.
   
5. The AD779 is available in versions compliant with MIL-STD-883.
   Refer to the Analog Devices Military Products Databook or current
   AD779/883B data sheet for detailed specifications.