AD5405

Rev. 0 | Page 7 of 24

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

PIN 1

INDICATOR

AD5405

TOP VIEW

1

R1A

2

R2A

3

R2_3A

4

R3A

5

6

DGND

7

LDAC

8

DAC A/B

9

NC

10

DB11

NC = NO CONNECT

30 R1B

29 R2B

28 R2_3B

27 R3B

25 VDD

24 CLR

23 R/W

22 CS

21 DB0

Figure 4. Pin Configuration

Table 4. Pin Function Descriptions

Pin No.

Mnemonic

Function

1 to 4

R1A to 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, while high selects DAC B.

9, 34, 35,

36, 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

Positive Power Supply Input. These parts can be operated from a supply of 2.5 V to 5.5 V.

26 to 30

R3B to R1B

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

minimum of external components.

32

DAC A Analog Ground. This pin typically should be tied to the analog ground of the system, but may 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 should be tied to the analog ground of the system, but may be biased

to achieve single-supply operation.

31, 40

External Amplifier Output.