REV. A

AD7390/AD7391

–5–

DAC REGISTER LOAD

CLK

CLR

LD

CLK

SDI

AD7391

AD7390

t

LD1

D11

t

LD1

D10

D9

D7

D5

D4

D3

D2

D1

D0

t

LD2

t

DS

t

DH

t

CL

t

CH

t

LDW

t

S

t

CLRW

t

S

0.1% FS

ERROR BAND

SDI

LD

FS

ZS

Figure 4. Timing Diagram

Table I. Control-Logic Truth Table

CLK

CLR

LD

Serial Shift Register Function

DAC Register Function

↑

H

H

Shift-Register-Data Advanced One-Bit

Latched

X

H

L

Disables

Updated with Current Shift Register Contents

X

L

X

No Effect

Loaded with all Zeros

X

↑

H

No Effect

Latched with all Zeros

X

↑

L

Disabled

Previous SR Contents Loaded (Avoid usage of

CLR

when

LD is logic low, since SR data could be corrupted

if a clock edge takes place, while

CLR returns high.)

↑ = Positive logic transition.

X = Don’t care.

Table II. AD7390 Serial Input Register Data Format, Data is Loaded in the MSB-First Format

MSB

LSB

B11

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

AD7390

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Table III. AD7391 Serial Input Register Data Format, Data is Loaded in the MSB-First Format

MSB

LSB

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

AD7391

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0