10-Bit ADCs Are Current Misers

Operating from a single 2.7V to 5.25V supply, a pair of very-low-power analog-to-digital converters (ADCs) are well suited for small, battery-powered devices and portable data-acquisition systems such as remote sensors or pen digitizers. The AS1528 single-channel fully differential ADC and the AS1529 dual-channel single-ended ADC both feature 10-bit resolution and consume less that 350 µA running at 3V and at their 150 ksample/s maximum sampling rate. Consumption drops to 245 µA at 100 ksamples/s and 2.5 µA at 1 ksamples/s. During shutdown, current consumption is 200 nA. An advanced automatic shutdown feature places the device into sleep mode between conversions. The AS1528/29 deliver dc performance of ±0.275 LSB (maximum) for INL and DNL, as well as a very low offset and gain error of ±0.25 LSB, combined with a total harmonic distortion of –79.5 dB. SPI, QSPI, and a Microwire-compatible interface enable high-speed data access to the AS1528/29 while minimizing board space. Both devices generate an internal clock but also support an external clock. AUSTRIAMICROSYSTEMS USA INC., Raleigh, NC. (919) 676-5292.