Datasheet

AD5291/AD5292
Rev. D | Page 11 of 32
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
RESET
V
SS
A
W
RDY
SYNC
V
LOGIC
SCLK
B
V
DD
EXT_CAP
1
2
3
4
5
6
7
DIN
GND
14
13
12
11
10
9
8
AD5291/
AD5292
TOP VIEW
Not to Scale
SDO
07674-006
Figure 5. Pin Configuration
Table 10. Pin Function Descriptions
Pin No. Mnemonic Description
1
RESET
Hardware Reset Pin. Refreshes the RDAC register with the contents of the 20-TP memory register. Factory
default loads midscale until the first 20-TP wiper memory location is programmed. RESET
is activated at the
logic high transition. Tie RESET
to V
LOGIC
if not used.
2 V
SS
Negative Supply. Connect to 0 V for single-supply applications. This pin should be decoupled with 0.1 μF
ceramic capacitors and 10 μF capacitors.
3 A Terminal A of RDAC. V
SS
≤ V
A
≤ V
DD
.
4 W Wiper Terminal of RDAC. V
SS
≤ V
W
≤ V
DD
.
5 B Terminal B of RDAC. V
SS
≤ V
B
≤ V
DD
.
6 V
DD
Positive Power Supply. This pin should be decoupled with 0.1 μF ceramic capacitors and 10 μF capacitors.
7 EXT_CAP External Capacitor. Connect a 1 μF capacitor to EXT_CAP. This capacitor must have a voltage rating of ≥7 V.
8 V
LOGIC
Logic Power Supply; 2.7 V to 5.5 V. This pin should be decoupled with 0.1 μF ceramic capacitors and 10 μF
capacitors.
9 GND Ground Pin, Logic Ground Reference.
10 DIN
Serial Data Input. The AD5291 and AD5292 have a 16-bit shift register. Data is clocked into the register on the
falling edge of the serial clock input.
11 SCLK
Serial Clock Input. Data is clocked into the shift register on the falling edge of the serial clock input. Data can be
transferred at rates up to 50 MHz.
12
SYNC
Falling Edge Synchronization Signal. This is the frame synchronization signal for the input data. When SYNC
goes low, it enables the shift register and data is transferred in on the falling edges of the following clocks. The
selected register is updated on the rising edge of SYNC following the 16
th
clock cycle. If SYNC is taken high
before the 16
th
clock cycle, the rising edge of SYNC acts as an interrupt, and the write sequence is ignored by
the DAC.
13 SDO
Serial Data Output. This open-drain output requires an external pull-up resistor. SDO can be used to clock data
from the shift register in daisy-chain mode or in readback mode.
14 RDY
Ready Pin. This active-high open-drain output identifies the completion of a write or read operation to or from
the RDAC register or memory.