ADC14L020 Datasheet, PDF (4/23 Pages) National Semiconductor (TI) – 14-Bit, 20 MSPS, 150 mW A/D Converter

Pin Descriptions and Equivalent Circuits (Continued)
Pin No.
Symbol
12-19
22-27
D0–D13
Equivalent Circuit
Description
Digital data output pins that make up the 14-bit conversion
result. D0 (pin 12) is the LSB, while D13 (pin 27) is the MSB of
the output word. Output levels are TTL/CMOS compatible.
Optimum loading is < 10pF.
ANALOG POWER
5, 29
V_A
4, 7
AGND
DIGITAL POWER
6
V_D
9
DGND
21
V_DR
20
DR GND
Positive analog supply pins. These pins should be connected
to a quiet +3.3V source and bypassed to AGND with 0.1 µF
capacitors located close to these power pins, and with a 10 µF
capacitor.
The ground return for the analog supply.
Positive digital supply pin. This pin should be connected to the
same quiet +3.3V source as is V_A and be bypassed to DGND
with a 0.1 µF capacitor located close to the power pin and with
a 10 µF capacitor.
The ground return for the digital supply.
Positive driver supply pin for the ADC14L020’s output drivers.
This pin should be connected to a voltage source of +2.4V to
V_D and be bypassed to DR GND with a 0.1 µF capacitor. If the
supply for this pin is different from the supply used for V_A and
V_D, it should also be bypassed with a 10 µF capacitor. V_DR
should never exceed the voltage on V_D. All 0.1 µF bypass
capacitors should be located close to the supply pin.
The ground return for the digital supply for the ADC’s output
drivers. These pins should be connected to the system digital
ground, but not be connected in close proximity to the ADC’s
DGND or AGND pins. See Section 5 (Layout and Grounding)
for more details.
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