AD1555

a FEATURES AD1555 Fourth Order ⌺- ⌬ Modulator Large Dynamic Range 116 dB Min, 120 dB Typical @ 1 ms 117 dB Typical @ 0.5 ms Low Input Noise: 80 nV rms @ 4 ms with Gain of 34,128 Low Distortion: –111 dB Max, –120 dB Typical Low Intermodulation: 122 dB Sampling Rate at 256 kSPS Very High Jitter Tolerance No External Antialias Filter Required Programmable Gain Front End Input Range: ؎2.25 V Robust Inputs Gain Settings: 1, 2.5, 8.5, 34, 128 Common-Mode Rejection (DC to 1 kHz) 93 dB Min, 101 dB Typical @ Gain of 1 77 mW Typical Low Power Dissipation Standby Modes AD1556 FIR Digital Filter/Decimator Serial or Parallel Selection of Configuration Output Word Rates: 250 SPS to 16 kSPS 6.2 mW Typ Low Power Dissipation 70 ␮W in Standby Mode Reference Design and Evaluation Board with Software Available APPLICATIONS Seismic Data Acquisition Systems Chromatography Automatic Test Equipment GENERAL DESCRIPTION 24-Bit ⌺-⌬ ADC with Low Noise PGA AD1555/AD1556 high dynamic range measurement applications. The AD1555 outputs a ones-density bitstream proportional to the analog input. When used in conjunction with the AD1556 digital filter/ decimator, a high performance ADC is realized. The continuous-time analog modulator input architecture avoids the need for an external antialias filter. The programmable gain front end simplifies system design, extends the dynamic range, and reduces the system board area. Low operating power and standby modes makes the AD1555 ideal for remote battery-powered da...