DAC8420

REV. 0

–6–

PIN CONFIGURATIONS

PIN FUNCTION DESCRIPTION

Power Supplies

VDD: Positive Supply, +5 V to +15 V.

VSS: Negative Supply, 0 V to –15 V.

GND: Digital Ground.

Clock

CLK: System Serial Data Clock Input, TTL/CMOS levels. Data presented to the input SDI is shifted into

the internal serial-parallel input register on the rising edge of clock. This input is logically ORed with CS.

Control Inputs

(All are CMOS/TTL compatible.)

CLR

: Asynchronous Clear, active low. Sets internal data registers A-D to zero or midscale, depending on cur-

rent state of CLSEL. The data in the serial input shift register is unaffected by this control.

CLSEL: Determines action of CLR. If HIGH, a Clear command will set the internal DAC registers A-D to

CS

: Device Chip Select, active low. This input is logically ORed with the clock and disables the serial data

register input when HIGH. When LOW, data input clocking is enabled, see the Control Function Table.

LD

: Asynchronous DAC Register Load Control, active low. The data currently contained in the serial input

shift register is shifted out to the DAC data registers on the falling edge of LD, independent of CS. Input data

must remain stable while LD is LOW.

Data Input

(All are CMOS/TTL compatible.)

SDI: Serial Data Input. Data presented to this pin is loaded into the internal serial-parallel shift register, which

shifts data in beginning with DAC address Bit A1. This input is ignored when CS is HIGH.

The format of the 16-bit serial word is:

(FIRST)

(LAST)

B0

B1

B2

B3

B4

B5

B6

B7

B8

B9

B10

B11

B12

B13

B14

B15

A1

A0

NC

NC

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

—Address Word—

(MSB)

—DAC Data Word—

(LSB)

NC = Don’t Care.

Reference Inputs

Analog Outputs

VOUTA through VOUTD: Four buffered DAC voltage outputs.

DIP

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

TOP VIEW

(Not to Scale)

DAC8420

VDD

VOUTD

VOUTC

VREFLO

VREFHI

VOUTB

VOUTA

VSS

CLSEL

NC

CLK

SDI

GND

CLR

LD

CS

NC = NO CONNECT

SOL

1

2

3

4

8

7

6

5

TOP VIEW

(Not to Scale)

DAC-8420

TOP VIEW

(Not to Scale)

DAC-8420

9

16

15

14

13

12

11

10

NC = NO CONNECT

VDD

VOUTD

VOUTC

VREFLO

VREFHI

VOUTB

VOUTA

VSS

CLSEL

NC

CLK

SDI

GND

CLR

LD

CS

TOP VIEW

(Not to Scale)

DAC8420