Document
ADS7808
ADS7808
SBAS018A – JANUARY 1992 – REVISED SEPTEMBER 2003
12-Bit 10µs Serial CMOS Sampling ANALOG-to-DIGITAL CONVERTER
FEATURES
q 100kHz SAMPLING RATE q 72dB SINAD WITH 45kHz INPUT q ±1/2 LSB INL AND DNL q SIX SPECIFIED INPUT RANGES q SERIAL OUTPUT q SINGLE +5V SUPPLY OPERATION q PIN-COMPATIBLE WITH 16-BIT ADS7809 q USES INTERNAL OR EXTERNAL
REFERENCE q 100mW MAX POWER DISSIPATION q 0.3" SO-20 q SIMPLE DSP INTERFACE
DESCRIPTION
The ADS7808 is a complete 12-bit sampling analog-to-digital using state-of-the-art CMOS structures. It contains a 12-bit capacitor-based SAR A/D with S/H, reference, clock, and a serial data interface. Data can be output using the internal clock, or can be synchronized to an external data clock. The ADS7808 also provides an output synchronization pulse for ease of use with standard DSP processors.
The ADS7808 is specified at a 100kHz sampling rate, and specified over the full temperature range. Laser-trimmed scaling resistors provide various input ranges including ±10V and 0V to 5V, while an innovative design operates from a single +5V supply, with power dissipation under 100mW.
The ADS7808 is available in a 0.3" SO-20, fully specified for operation over the industrial –40°C to +85°C range.
R1IN R2IN R3IN CAP
20kΩ
10kΩ
20kΩ 5kΩ
REF
R/C
CS
Power Down
Successive Approximation Register and Control Logic
CDAC
Buffer 4kΩ
Internal +2.5V Ref
Comparator
Clock
Serial Data Out
BUSY Data Clock Serial Data
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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.
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ABSOLUTE MAXIMUM RATINGS(1)
Analog Inputs: R1IN .......................................................................... ±25V R2IN .......................................................................... ±25V R3IN .......................................................................... ±25V CAP ..................................... VANA+0.3V to AGND2 –0.3V REF ....................................... Indefinite Short to AGND2, Momentary Short to VANA
Ground Voltage Differences: DGND, AGND2 ................................. ±0.3V VANA ...................................................................................................... 7V VDIG to VANA ....................................................................................... +0.3 VDIG ....................................................................................................... 7V Digital Inputs ............................................................. –0..