24 Bit ADC Is Fully Differential

Operating from a single 2.7V to 5.5V supply, the LTC2412 24-bit, no-latency delta-sigma a/d converter provides two fully differential input channels and a differential reference input. The device has a noise specification of 800 nVRMS and generates 22.5 effective number of bits (ENOBs) over a ±2.5V span and 16.9 ENOBs over a ±50mV span, eliminating the need for PGAs. Power consumption is 200 µA in operation and 4 µA in automatic shutdown between conversions. Accepting two differential inputs, full-scale input span is –0.5VREF to 0.5VREF where the reference voltage can be anywhere between 0.1V and VCC. Other features include an on chip oscillator with a selectable notch filter of 50Hz or 60Hz and a rejection better than 110 dB. An external clock source can be used for other rejection frequencies. The device communicates through a three-wire digital interface and is compatible with the SPI protocol. Available in a 16-pin SSOP, pricing starts at $4.75 each/1,000. LINEAR TECHNOLOGY CORP., Milpitas, CA. (800) 454-6327.