National’s new DAC: Bit on bits, low on power
A DAC’s a DAC, right? Well, maybe not. National Semiconductor’s latest 16-bit digital-to-analog converter, the DAC161S055, has some interesting features up its sleeve, er, SPI. This precision DAC is available over a wide -40 °C to +105 °C temperature range, so it’s ideal for high-rel applications. More importantly, the four-wire double-buffer SPI interface operates at 20 MHz and can be daisy-chained so multiple DACs in series can be connected via a single SPI I/F. This is but one aspect of the device’s flexibility that might save the designer some board space.
Designed for industrial I/O, automated test equipment, and other data acquisition, the fast, buffered output will settle in only 5 microseconds. As well, DC specs show off the device’s precision: +1LSB INL (max) and +1LSB DNL (max). The DAC161S055 has selectable power up to either 0 V or midscale, and the rail-to-rail buffered output has a very low noise of 120 nv/?Hz. There’s read-back on the SPI, an asynchronous load capability, reset pins, and a wide reference voltage of +2.5 V to VA. The analog supply is 2.7 to 5.25 V and supports digital interfaces down to 1.7 V. Oh, and the best part? The little 16-pinner sips only 5.5 mW at 5.25 V (max).