ADS7891

ADS7891 SLAS410 − DECEMBER 2003 14ĆBIT, 3ĆMSPS LOW POWER SAR ANALOGĆTOĆDIGITAL CONVERTER FEATURES D 3 MHz Sample Rate, 14-Bit Resolution D Zero Latency D Unipolar, Pseudo Differential Input, Range: D D D D D D D D D − 0 V to 2.5 V High Speed Parallel Interface 78 dB SNR and 88.5 dB THD at 3 MSPS Power Dissipation 85 mW at 3 MSPS Nap Mode (10 mW Power Dissipation) Power Down (10 mW) Internal Reference Internal Reference Buffer 8-/14-Bit Bus Transfer 48-Pin TQFP Package APPLICATIONS D Optical Networking (DWDM, MEMS Based D D D High Speed Close-Loop Systems D Telecommunication D Ultra-Sound Detection Switching) Spectrum Analyzers High Speed Data Acquisition Systems DESCRIPTION The ADS7891 is a 14-bit 3-MSPS A-to-D converter with 2.5-V internal reference. The device includes a capacitor based SAR A/D converter with inherent sample and hold. The device offers a 14-bit parallel interface with an additional byte mode that provides easy interface with 8-bit processors. 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 sensor and also to cancel common-mode noise. With nap mode enabled, the device operates at lower power when used at lower conversion rates. The device is available in a 48-pin TQFP package. SAR Output Latches and 3-State Drivers Comparator REFIN CLOCK REFOUT 2.5 V Internal Reference Conversion and Control Logic PWD/RST A_PWD BYTE +IN −IN + _ CDAC 14/8-Bit Parallel D...