16-channel, 16-bit, ±10V DAC drives 10 mA & 1000 pF

June 18, 2014 // By Graham Prophet
LTC2668-16 is a 16-channel, 16-bit voltage-output digital-to-analogue converter (DAC) with SoftSpan outputs, each of which can be independently configured for one of five selectable unipolar and bipolar output ranges up to ±10V.

Each rail-to-rail DAC output is capable of sourcing or sinking 10 mA with guaranteed load regulation and is stable driving capacitive loads as large as 1000 pF. This makes the LTC2668 suitable for driving a variety of demanding loads in applications such as optical modules, programmable logic controllers (PLCs), MRI and X-ray imaging, automatic test equipment, laser etch equipment, spectrum analysers and oscilloscopes.

The LTC2668 offers space-saving features in a 6 x 6-mm QFN package, nearly 50% smaller footprint than alternative 16-channel DACs and can be operated from a single 5V supply, or from dual bipolar supplies depending on the output voltage range requirement. The device includes a precision 2.5V 10 ppm/°C max reference to generate the five SoftSpan output ranges, or it can be driven with an external reference. A 16:1 high-voltage analogue multiplexer enables the user to monitor circuit integrity or perform in-circuit calibration, saving significant board real estate. The LTC2668 also supports an A/B toggle function for generating an AC bias or for applying dither to a system. Configuration of the LTC2668 is handled via an SPI-compatible serial interface which can be powered from an independent 1.8V to 5V digital supply.

The LTC2668, in both 16-bit and 12-bit versions, is available in commercial, industrial and automotive (-40°C to 125°C) temperature grades. Pricing begins at $31.25 each for the LTC2668-16 and $25.75 each for the LTC2668-12 (both 1000). An evaluation board, DC2025A, is available, and is supported by the Linduino firmware development system , using the DC2026A.

Linear Technology; www.linear.com/product/LTC2668