12-Bit, 20MHz Sampling
ANALOG-TO-DIGITAL CONVERTER
FEATURES
● HIGH SFDR: 74dB at 9.8MHz f
IN
● HIGH SNR: 68dB
● LOW POWER: 300mW
● LOW DLE: 0.25LSB
● FLEXIBLE INPUT RANGE
● OVER-RANGE INDICATOR
APPLICATIONS
● STUDIO CAMERAS
● IF AND BASEBAND DIGITIZATION
● COPIERS
● TEST INSTRUMENTATION
DESCRIPTION
The ADS805 is a 20MHz, high dynamic range, 12-bit, pipelined
Analog-to-Digital Converter ADC. This converter includes a
high-bandwidth track-and-hold that gives excellent spurious
performance up to and beyond the Nyquist rate. This high-
bandwidth, linear track-and-hold minimizes harmonics and
has low jitter, leading to excellent Signal-to-Noise Ratio
(SNR) performance. The ADS805 is also pin-compatible with
the 10MHz ADS804 and the 5MHz ADS803.
The ADS805 provides an internal reference or an external
reference can be used. The ADS805 can be programmed for
a 2Vp-p input range which is the easiest to drive with a single
op amp and provides the best spurious performance. Alter-
natively, the 5Vp-p input range can be used for the lowest
input-referred noise of 0.09LSBs rms giving superior imaging
performance. There is also the capability to set the input
range between 2Vp-p and 5Vp-p, either single-ended or
differential. The ADS805 also provides an over-range flag
that indicates when the input signal has exceeded the
converter’s full-scale range. This flag can also be used to
reduce the gain of the front end signal conditioning circuitry.
The ADS805 employs digital error techniques to provide
excellent differential linearity for demanding imaging applica-
tions. Its low distortion and high SNR give the extra margin
needed for communications, medical imaging, video, and
test instrumentation applications. The ADS805 is available in
an SSOP-28 package.
12-Bit
Pipelined
ADC Core
Reference and
Mode Select
Reference Ladder
and Driver
Timing Circuitry
Error
Correction
Logic
3-State
Outputs
T&H
D0
D11
•
•
•
CLK
+V
S
ADS805
VDRV
OE
SEL REFBV
REF
REFT
INV
IN
IN
CM
OVR
ADS805
SBAS073B – JANUARY 1997 – REVISED NOVEMBER 2002
www.ti.com
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 © 1997, Texas Instruments Incorporated
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.
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