ADS7890_15 Datasheet, PDF (1/29 Pages) Texas Instruments – 14-BIT, 1.25-MSPS LOW POWER SAR ANALOG-TO-DIGITAL CONVERTER

ADS7890
SLAS409 − DECEMBER 2003
14ĆBIT, 1.25ĆMSPS
LOW POWER SAR ANALOGĆTOĆDIGITAL CONVERTER
FEATURES
D 1.25 MHz Sample Rate, 14-Bit Resolution
D Zero Latency
D Unipolar, Pseudo Differential Input, Range:
− 0 V to 2.5 V
D SPIE Compatible Serial Interface
D 77.5 dB SNR and −95 dB THD at 0.5 MHz I/P
D Power Dissipation 45 mW at 1.25 MSPS
D Nap Mode (10 mW Power Dissipation)
D Power Down (10 mW)
D Internal Reference
D Internal Reference Buffer
D 48-Pin TQFP Package
APPLICATIONS
D Optical Networking (DWDM, MEMS Based
Switching)
D Spectrum Analyzers
D High Speed Data Acquisition Systems
D High Speed Close-Loop Systems
D Telecommunication
DESCRIPTION
The ADS7890 is a 14-bit 1.25-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 serial SPI or DSP
compatible 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 sensor
and also to cancel common-mode noise. The device operates at lower power when used at lower conversion
rates because of the nap feature. The device is available in a 48-pin TQFP package.
+IN
+
−IN
_
REFIN
REFOUT
SAR
CDAC
Comparator
Output
Latches
and
3-State
Drivers
CLOCK
2.5 V
Internal
Reference
Conversion
and
Control Logic
PWD/RST
SDO
SCLK
BUSY
CS
FS
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
SPI is a trademark of Motorola, Inc.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Copyright  2003, Texas Instruments Incorporated