Datasheet
AD5405
Rev. B | Page 7 of 24
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
PIN 1
INDICATOR
AD5405
TOP VIEW
(Not to Scale)
1
R1A
2
R2A
3
R2_3A
4
R3A
5
V
REF
A
6
DGND
7
LDAC
8
DAC A/B
9
NC
10
DB11
NOTES
1. NC = NO CONNECT.
2. EXPOSED PAD MUST BE CONNECTED TO GROUND.
DB10 11
DB9 12
DB8 13
DB7 14
DB6 15
DB5 16
DB4 17
DB3 18
DB2 19
DB1 20
30 R1B
29 R2B
28 R2_3B
27 R3B
26 V
REF
B
25 V
DD
24 CLR
23 R/W
22 CS
21 DB0
40 R
FB
A
39 I
OUT
2
A
38 I
OUT
1A
37 NC
36 NC
35 NC
34 NC
33 I
OUT
1
B
32 I
OUT
2
B
31 R
FB
B
04463-004
Figure 4. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 to 4
R1A, R2B,
R2_3B, R3A
DAC A 4-Quadrant Resistors. Allow a number of configuration modes, including bipolar operation with
minimum of external components.
5, 26 V
REF
A, V
REF
B DAC Reference Voltage Input Terminals.
6 DGND Digital Ground Pin.
7
LDAC
Load DAC Input. Allows asynchronous or synchronous updates to the DAC output. The DAC is
asynchronously updated when this signal goes low. Alternatively, if this line is held permanently low, an
automatic or synchronous update mode is selected whereby the DAC is updated on the rising edge of CS.
8
DAC
A
/B
Selects DAC A or B. Low selects DAC A, and high selects DAC B.
9, 34 to 37 NC Not internally connected.
10 to 21 DB11 to DB0 Parallel Data Bits 11 through 0.
22
CS
Chip Select Input. Active low. Used in conjunction with R/W to load parallel data to the input latch or to
read data from the DAC register. Edge sensitive; when pulled high, the DAC data is latched.
23
R/W
Read/Write. When low, used in conjunction with CS to load parallel data. When high, used in conjunction
with CS
to read back contents of DAC register.
24
CLR
Active Low Control Input. Clears DAC output and input and DAC registers.
25 V
DD
Positive Power Supply Input. These parts can be operated from a supply of 2.5 V to 5.5 V.
27 to 30
R3B, R2_3B,
R2B, R1B
DAC B 4-Quadrant Resistors. Allow a number of configuration modes, including bipolar operation with a
minimum of external components.
31, 40 R
FB
B, R
FB
A External Amplifier Output.
32 I
OUT
2B
DAC A Analog Ground. This pin typically should be tied to the analog ground of the system, but can be
biased to achieve single-supply operation.
33 I
OUT
1B DAC B Current Outputs.
38 I
OUT
1A DAC A Current Outputs.
39 I
OUT
2A
DAC A Analog Ground. This pin typically should be tied to the analog ground of the system, but can be
biased to achieve single-supply operation.
EPAD Exposed pad must be connected to ground.