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AS1545
Datasheet - Pinout
4 Pinout
Pin Assignment
Figure 2. Pin Assignments (Top View)
Pin Description
Table 1. Pin Description
Pin Number
Pin Name
Description
1, 29
DGND
Digital Ground.
Ground reference point for the digital portion of the
AS1545.
Reference select pin.
Internal/External Reference Selection. Logic input. If
this pin is tied to DGND, the on-chip 2.5V reference is used as the reference
source for both ADC A and ADC B. In addition, Pin REFA and Pin REFB
must be tied to decoupling capacitors. If the REF SELECT pin is tied to a
logic high, an external reference can be supplied to the AS1545 through the
REF
A
or REF
B
pins.
2
REF_SELECT
3
AV
DD
Analog Supply Voltage.
2.7V to 5.25V.
4, 20
REF
A
, REF
B
Reference Input/Output.
These pins are connected to the internal
reference through a series resistor and is the reference source for the
AS1545. The nominal reference voltage is 2.5V and appears at the pin. This
pin can be over-driven by an external reference or can be taken as high as
AV
DD
. Decoupling capacitors (4.7 uF recommended) are connected to
these pins to decouple the reference buffer for each respective ADC.
Analog Ground.
Decouple point for AV
DD
. Ground reference for track/hold,
reference, and DAC circuits.
Analog Ground.
Decouple point for V
REF
capacitors and analog input
filters. Pin 6 is the decoupling point for REFA, pin 19 for REFB. Ground
reference for track/hold, reference, and DAC circuits.
Analog Inputs of ADC A.
These may be programmed as six single-ended
channels, three pseudo-differential or three true-differential analog input
channel pairs.
5
AGND
6, 19
AGND
7 to 12
AIN0 to AIN5
AS1545
2
A2
1
S
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
AIN 0
AIN 1
A
A
A
A
B
B
B
B
BIN 1
BIN 0
AGND
REFB
RANGE
SGL/DIFF
A1
A
C
D
D
D
V
D
AGND
AGND
REFA
AVDD
REF_SELECT
DGND
33 Exp. Pad