AD7398/AD7399

Rev. C | Page 7 of 24

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

1

16

2

15

3

14

4

13

5

12

6

GND

11

SDI

7

LDAC

10

CLK

8

RS

9

CS

AD7398/

AD7399

TOP VIEW

(Not to Scale)

Figure 5. Pin Configuration

Table 4. Pin Function Descriptions

Table 5. Control Logic Truth Table

CS

CLK

LDAC

Serial Shift Register Function

Input Register Function

DAC Register

H

X

H

No effect

No effect

No effect

L

L

H

No effect

No effect

No effect

L

↑+

H

Shift register data advanced one bit

Latched

No effect

L

H

H

No effect

Latched

No effect

↑+

L/H

H

No effect

Updated with shift register contents

No effect

H

X

L

No effect

Latched

Transparent

H

X

↑+

No effect

Latched

Latched

NOTES

1.

↑+ = Positive logic transition; ↓– = Negative logic transition; X = Don’t Care.

2. At power-on, both the input register and the DAC register are loaded with all zeros.

3. During power shutdown, reprogramming of any internal registers can take place, but the output amplifiers do not produce the new values until the part is taken out

of shutdown mode.

4. The LDAC input is a level-sensitive input that controls the four DAC registers.

Pin No.

Mnemonic

Description

1

DAC B Voltage Output.

2

DAC A Voltage Output.

3

Negative Power Supply Input. Specified range of operation 0 V to −5.5 V.

4

5

6

GND

Ground Pin.

7

LDAC

Load DAC Register Strobe. Level sensitive active low. Transfers all input register data to DAC registers.

Asynchronous active low input. See Table 5 for operation.

8

RS

Resets Input and DAC Registers to All Zero Codes. Shift register contents unchanged.

9

CS

Chip Select. Active low input. Disables shift register loading when high. Transfers serial register data to the input

register when CS returns high. Does not effect LDAC operation.

10

CLK

Schmitt Triggered Clock Input. Positive edge clocks data into shift register.

11

SDI

Serial Data Input. Input data loads directly into the shift register.

12

13

14

Positive Power Supply Input. Specified range of operation 3 V to 5 V ± 10%.

15

DAC D Voltage Output.

16

DAC C Voltage Output.