The design and layout of the AD7669AR have been optimized for ac performance and are responsible for its guaranteed and tested 94 dB signal-to-noise ratio to 20 kHz and 79 dB SNR to 250 kHz. Laser-trimming the AD766's silicon chromium thin-film resistors reduces total harmonic distortion below -81 dB (at 1 kHz), a specification also production tested. An optional linearity trim pin allows elimination of midscale differential linearity error for even lower THD with small signals.
The AD766's output amplifier provides a ±3 V signal with a high slew rate, small glitch, and fast settling. The output amplifier is short circuit protected and can withstand indefinite shorts to ground.
The serial interface consists of bit clock, data, and latch enable inputs. The twos-complement data word is clocked MSB first on falling clock edges into the serial-to-parallel converter, consistent with the serial protocols of popular DSP processors. The input clock can support data transfers up to 12.5 MHz. The falling edge of latch enable updates the internal DAC input register at the sample rate with the sixteen bits most recently clocked into the serial input register.
The AD7669AR operates over a ±5 V to ±12 V power supply range. The digital supplies, +VL and -VL, can be separated from the analog signal supplies, +VS and -VS, for reduced digital crosstalk. Separate analog and digital ground pins are also provided. An internal bandgap reference provides a precision voltage source to the output amp that is stable over temperature and time.
Power dissipation is typically 120 mW with ±5 V supplies and 300 mW with ±12 V. The AD7669AR is available in commercial (0°C to +70°C), industrial (-40°C to +85°C), and military (-55°C to +125°C) grades. Commercial and industrial grade parts are available in a 16-pin plastic DIP; military parts processed to MIL-STD-883B are packaged in a 16-pin ceramic DIP. See Analog Devices' Military Products Databook or current military data sheet for specifications for the military version.
Feature
- Zero-Chip Interface to Digital Signal Processors
- Complete DACPORTx
- On-Chip Voltage Reference
- Voltage and Current Outputs
- Serial, Twos-Complement Input
- ±3 V Output
- Sample Rates to 390 kSPS
- 94 dB Minimum Signal-to-Noise Ratio
- -81 dB Maximum Total Harmonic Distortion
- 15-Bit Monotonicity
- ±5 V to ±12 V Operation
- 16-Pin Plastic and Ceramic Packages
- Available in Comercial, Industrial and Military Temperature Ranges
Applications
- Digital Signal Processing
- Noise Cancellation
- Radar Jamming
- Automatic Test Equipment
- Precision Industrial Equipment
- Waveform Generation
