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ADC12DL080_14 Datasheet, PDF (4/35 Pages) Texas Instruments – Dual 12-Bit, 80 MSPS, A/D Converter for IF Sampling
ADC12DL080
SNAS345 – FEBRUARY 2006
Pin No.
15
2
Symbol
VINA+
VINB+
16
VINA−
1
VINB−
7
VREF
11
REFSEL/DCS
13
5
14
4
12
6
DIGITAL I/O
VRPA
VRPB
VRMA
VRMB
VRNA
VRNB
Equivalent Circuit
Description
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VA
AGND
Differential analog input pins. With a 1.0V reference voltage the
differential full-scale input signal level is 2.0 VP-P with each input pin
voltage centered on a common mode voltage, VCM. The negative
input pins may be connected to VCM for single-ended operation, but
a differential input signal is required for best performance.
VA
AGND
(1)
This pin is used in conjunction with REFSEL/DCS (pin 11) to select
the internal 1.0V reference, or as the external reference input.
If VREF is tied HIGH, the internal 1.0V reference is selected.
REFSEL/DCS must be LOW or tied to VRMA or VRMB.
If a voltage in the range of 0.8V to 1.2V is applied to this pin, that
voltage is used as the reference. VREF should be bypassed to AGND
with a 0.1 µF low ESL capacitor when an external reference is used.
The nominal external reference voltage is 1.0V but values in the
range of 0.8V to 1.2V may be used. REFSEL/DCS must be HIGH or
REFSEL/DCStied to VRMA or VRMB.
See Table 4 in for more information.
This pin is used in conjunction with VREF (pin 7) to select the
reference source and turn the Duty Cycle Stabilizer (DCS) on or off.
When REFSEL/DCS is LOW and VREF is HIGH, the internal 1.0V
(2)
reference is selected and DCS is On.
When REFSEL/DCS is HIGH, an external reference voltage in the
range of 0.8V to 1.2V should be applied to the VREF input. DCS is
On.
With this pin connected to VRMA or VRMB, DCS is Off.
See Table 4 in REFSEL/DCS for more information.
VA
VA
VA
VA
AGND
AGND
These are reference bypass pins. These pins should each be
bypassed to ground with a 0.1 µF capacitor. A 10 µF capacitor
should be placed between the VRPA and VRNA pins and between the
VRPB and VRNB pins.
These pins should not be loaded.
(3)
60
CLK
21
OF/DOEN
4
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VD
VA
AGND
DGND
Digital clock input. The range of frequencies for this input is as
specified in the electrical tables with guaranteed performance at 80
MHz. The inputs are sampled on the rising edge.
VA
AGND
(4)
OF/DOEN selects the output format (OF) or enables the DRDY
output (DOEN). The state of this pin also controls the function of pins
22 and 41.
When OF/DOEN is tied to VRMA or VRMB, DRDY is enabled. Pin 41
is used as the DRDY output strobe, and pin 22 is used to select the
output format. Output Enable for channels A and B are not available
in this mode.
When OF/DOEN is LOW, the output data format is offset binary.
With OF/DOEN tied HIGH, the output format is 2's complement.
See Table 5 in OF/DOEN, OEA/OF, and OEB/DRDY for more
information.
(5)
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Copyright © 2006, Texas Instruments Incorporated