Protocol converter DAC7718

digitaldigital-analogDAC

Overview
The DAC7718 is a low-power octal 12-bit digital-to-analog converter (DAC) with buffered voltage outputs. Using a 5 V reference the outputs can be bipolar or unipolar depending on supply rails: bipolar ±15 V from dual ±15.5 V supplies or unipolar 0 V to +30 V from a +30.5 V supply. With a 5.5 V reference outputs extend to bipolar ±16.5 V or unipolar 0 V to +33 V with appropriate higher supplies. The device is factory trimmed for very low zero-code and gain error and supports system-level calibration. Output range can be offset via the DAC offset register.

Functional description
The DAC7718 features a high-speed SPI serial interface up to 50 MHz, compatible with 1.8 V, 3 V and 5 V logic. Input data are double-buffered. An asynchronous LDAC transfers data from the data register to the DAC latch. An asynchronous CLR sets all eight DAC outputs to AGND. A VMON monitor output routes selected internal signals and two external inputs through a multiplexer. The device is pin-to-pin and function-compatible with related family members (DAC8718, DAC8218). Available packages include QFN-48 (7×7 mm) and TQFP-64 (10×10 mm).

Key features

• 8 channels, 12-bit resolution
• Bipolar output ranges: ±2 V to ±16.5 V (depending on VREF and supplies)
• Unipolar output ranges: 0 V to +33 V (depending on VREF and supplies)
• Low power: ~14.4 mW per channel (bipolar supply condition)
• Relative accuracy (INL): 1 LSB max
• Low zero/full-scale error: ±1 LSB max
• Flexible system-level calibration (on-chip offset and gain calibration)
• Low glitch energy: ~4 nV·s
• Settling time: 15 µs
• Channel monitor output (VMON)
• Programmable gain: ×4 / ×6 and programmable offset
• SPI up to 50 MHz; 1.8 V / 3 V / 5 V logic compatible
• Schmitt-trigger inputs; daisy-chain with sleep mode enhancement

Applications

• Automatic test equipment and instrumentation
• PLC and industrial process control
• Communications and signal generation

Evaluation and development
An evaluation module (DAC7718EVM) is available to verify functionality and performance; evaluation kits include an evaluation board and GUI software for bench testing and development.

Technical specifications

• Resolution: 12 bits
• Number of channels: 8
• Interface: SPI, up to 50 MHz (1.8 V / 3 V / 5 V compatible)
• Output type: Buffered voltage outputs
• Output range: bipolar up to ±16.5 V; unipolar up to 0–+33 V (depending on VREF and supplies)
• INL (max): 1 LSB
• Settling time: 15 µs
• Reference: external (supports 5 V or 5.5 V reference options)
• Typical power consumption: ~115 mW total; ~14.4 mW per channel (bipolar condition)
• Glitch energy: ~4 nV·s
• Operating temperature: −40 °C to +85 °C (device specified)