Data Sheet

AD5405

Rev. D | Page 7 of 24

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

AD5405

TOP VIEW

(Not to Scale)

1

R1A

2

R2A

3

R2_3A

4

R3A

5

6

DGND

7

LDAC

8

DAC A/B

9

NIC

10

DB11

NOTES

1. NIC = NOT INTERNALLY CONNECTED.

2. EXPOSED PAD MUST BE CONNECTED TO GROUND.

30 R1B

29 R2B

28 R2_3B

27 R3B

24 CLR

23 R/W

22 CS

21 DB0

Figure 4. Pin Configuration

Table 4. Pin Function Descriptions

Pin No.

Mnemonic

Description

1 to 4

R1A, R2A,

R2_3A, R3A

DAC A 4-Quadrant Resistors. Allow a number of configuration modes, including bipolar operation with

minimum of external components.

5, 26

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

NIC

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

Positive Power Supply Input. These devices 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

External Amplifier Output.

32

DAC A Analog Ground. This pin typically ties to the analog ground of the system, but can be biased to

achieve single-supply operation.

33

DAC B Current Outputs.

38

DAC A Current Outputs.

39

DAC A Analog Ground. This pin typically ties to the analog ground of the system, but can be biased to

achieve single-supply operation.

EPAD

Exposed pad must be connected to ground.