Datasheet
AD5231 Data Sheet
Rev. D | Page 8 of 28
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
16
15
14
13
12
11
10
9
RDY
V
DD
A
W
TOP VIEW
(Not to Scale)
AD5231
1
2
3
4
5
6
7
8
CLK
SDI
SDO
V
SS
GND
T
O1
B
O2
CS
PR
WP
02739-005
Figure 5. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 O1 Nonvolatile Digital Output 1. ADDR = 0x1, data bit position D0. For example, to store O1 high, the data bit
format is 0x310001.
2 CLK Serial Input Register Clock Pin. Shifts in one bit at a time on positive clock edges.
3 SDI Serial Data Input Pin. Shifts in one bit at a time on positive clock CLK edges. MSB loaded first.
4 SDO Serial Data Output Pin. Serves readback and daisy-chain functions.
Command 9 and Command 10 activate the SDO output for the readback function, delayed by 24 or 25 clock
pulses, depending on the clock polarity before and after the data-word (see Figure 3, Figure 4, and Table 7).
In other commands, the SDO shifts out the previously loaded SDI bit pattern, delayed by 24 or 25 clock pulses
depending on the clock polarity (see Figure 3 and Figure 4). This previously shifted-out SDI can be used for
daisy-chaining multiple devices.
Whenever SDO is used, a pull-up resistor in the range of 1 kΩ to 10 kΩ is needed.
5 GND Ground Pin. Logic ground reference.
6 V
SS
Negative Supply. Connect to 0 V for single-supply applications. If V
SS
is used in dual-supply applications, it must be
able to sink 40 mA for 25 ms when storing data to EEMEM.
7
T
Reserved for factory testing. Connect to V
DD
or V
SS
.
8 B Terminal B of RDAC.
9 W Wiper Terminal of RDAC. ADDR (RDAC) = 0x0.
10 A Terminal A of RDAC.
11 V
DD
Positive Power Supply Pin.
12
WP
Optional Write Protect Pin. When active low,
WP
prevents any changes to the present contents, except
PR
and
Instruction 1 and Instruction 8 and refreshes the RDAC register from EEMEM. Execute a NOP instruction before
returning to
WP
high. Tie
WP
to V
DD
, if not used.
13
PR
Optional Hardware Override Preset Pin. Refreshes the scratchpad register with current contents of the EEMEM
register. Factory default loads midscale 512
10
until EEMEM is loaded with a new value by the user.
PR
is activated
at the logic high transition. Tie
PR
to V
DD
, if not used.
14
CS
Serial Register Chip Select Active Low. Serial register operation takes place when
CS
returns to logic high.
15 RDY Ready. Active-high open-drain output. Identifies completion of Instructions 2, 3, 8, 9, 10, and
PR
.
16 O2 Nonvolatile Digital Output 2. ADDR = 0x1, data bit position D1. For example, to store O2 high, the data bit
format is 0x310002.