DAC Family Features Precision DC & 1us Settling Time

16th October 2007

ES Admin

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Linear Technology has introduced a complete family of low-power, precision 16-/14-/12-bit unbuffered voltage output digital-to-analog converters. Both the unipolar LTC2641 and bipolar LTC2642 draw only 120uA of supply current while settling to within 0.5LSB for a full-scale step in only 1us. These voltage output DACs feature a 0.5nV•s glitch impulse, which is key for AC applications such as waveform generation. Low glitch reduces the transient voltages between code changes in the DAC. Fast settling and low glitch reduce harmonic distortion, making it possible to produce higher frequency, lower noise output waveforms.

The LTC2641-16 and LTC2642-16 also offer accurate DC specifications, including 16-bit monotonic resolution, ±2LSB(max) INL, ±2LSB(max) unipolar offset error, and ±5LSB(max) gain error. Additionally, these DACs have extremely low drift of 0.1ppm/°C over the -40°C to +85°C industrial temperature range. With their low offset and drift specifications, the LTC2641/LTC2642 can be used in precision DC positioning systems, gain and offset adjustment applications, automatic test equipment and data acquisition systems.

For bipolar operation, the LTC2642 includes matched scaling resistors for use with a precision external amplifier such as the LT1678, generating a ±5V output swing. Operating from a 2.7V to 5.5V supply voltage, these DACs each feature power-on reset circuitry that resets the LTC2642 to mid-scale and the LTC2641 to zero-scale at power-up. Communicating via a 3-wire SPI/QSPI/Microwire-compatible serial interface at clock rates up to 50MHz, these DACs can interface directly with optocouplers for applications requiring isolation.

The LTC2641 and LTC2642 are both available in pin-compatible 16-bit, 14-bit, and 12-bit versions. The LTC2641 is available in tiny 3mm x 3mm DFN-8 and MSOP-8 packages and the LTC2642 is available in 3mm x 3mm DFN-10 and MSOP-10 packages. All of the LTC2642 and LTC2641 DACs are software-compatible, making it easy to transition between bipolar or unipolar outputs at different resolutions for performance/cost optimization. Pricing begins at $2.95 for the LTC2642-12 and LTC2641-12 in 1,000-piece quantities.