描述The ADS7890 is a 14-bit 1.25-MSPS A-to-D converter with 2.5-V internal reference. The device includes acapacitor based SAR A/D converter with inherent sample and hold. The device offers a 14-bit serial SPI or DSPcompatible interface. The device has a pseudo-differential input stage. The ?IN swing of ±200 mV is useful to compensate for ground voltage mismatch between the ADC and sensorand also to cancel common-mode noise. The device operates at lower power when used at lower conversionrates because of the nap feature. The device is available in a 48-pin TQFP package.特性1.25 MHz Sample Rate, 14-Bit Resolution Zero Latency Unipolar, Pseudo Differential Input, Range: 0 V to 2.5 V SPI? Compatible Serial Interface 77.5 dB SNR and ?95 dB THD at 0.5 MHz I/P Power Dissipation 45 mW at 1.25 MSPS Nap Mode (10 mW Power Dissipation) Power Down (10 μW) Internal Reference Internal Reference Buffer 48-Pin TQFP Package APPLICATIONS Optical Networking (DWDM, MEMS Based Switching) Spectrum Analyzers High Speed Data Acquisition Systems High Speed Close-Loop Systems TelecommunicationSPI is a trademark of Motorola, Inc.