SWITCHING CHARACTERISTICS

1, 2

Limit at 25

°C

Parameters

All Grades

(B, C Versions)

(T, U Versions)

Units

Conditions/Comments

0

0

0

ns min

Address to WR Setup Time

0

0

0

ns min

Address to WR Hold Time

70

90

100

ns min

Data Valid to WR Setup Time

10

10

10

ns min

Data Valid to WR Hold Time

95

120

150

ns min

Write Pulse Width

NOTES

°C to ensure compliance. All input rise and fall times measured from 10% to 90% of +5 V, t

V

2

INTERFACE LOGIC INFORMATION

Address lines A0, A1 and A2 select which DAC accepts data

from the input port. Table I shows the selection table for the

eight DACs with Figure 1 showing the input control logic.

When the WR signal is low, the input latch of the selected DAC

is transparent, and its output responds to activity on the data

bus. The data is latched into the addressed DAC latch on the

rising edge of WR. While WR is high, the analog outputs remain

at the value corresponding to the data held in their respective

latches.

Table I. AD7228A Truth Table

AD7228A Control Inputs

AD7228A

WR

A2

A1

A0

Operation

H

X

X

X

No Operation

Device Not Selected

LLLL

DAC 1 Transparent

g

L

L

L

DAC 1 Latched

LLLH

DAC 2 Transparent

L

L

H

L

DAC 3 Transparent

L

L

H

H

DAC 4 Transparent

L

H

L

L

DAC 5 Transparent

L

H

L

H

DAC 6 Transparent

L

H

H

L

DAC 7 Transparent

L

H

H

H

DAC 8 Transparent

H = High State

L = Low State

X = Don’t Care

+5 V SUPPLY OPERATION

BC

T

U

Parameter

Version

Version

Version

Version

Units

Conditions/Comments

STATIC PERFORMANCE

Resolution

8888

Bits

Relative Accuracy

± 2

± 2

± 2

± 2

LSB max

Differential Nonlinearity

± 1

± 1

± 1

± 1

LSB max

Guaranteed Monotonic

Full-Scale Error

± 4

± 2

± 4

± 2

LSB max

Zero Code Error

@ 25

°C

± 30

± 20

± 30

± 20

mV max

± 40

± 30

± 40

± 30

mV max

REFERENCE INPUT

Reference Input Range

1.2

1.2

1.2

1.2

V min

1.3

1.3

1.3

1.3

V max

Reference Input Resistance

2222k

Ω min

Reference Input Capacitance

500

500

500

500

pF max

POWER REQUIREMENTS

Positive Supply Range

4.75/5.25

4.75/5.25

4.75/5.25

4.75/5.25

V min/V max

For Specified Performance

Positive Supply Current

@ 25

°C

16161616

µA max

20

20

22

22

µA max

Negative Supply Current

@ 25

°C

14141414

µA max

18

18

20

20

µA max

NOTES

Specifications subject to change without notice.

10%)

Figure 1. Input Control Logic

Figure 2. Write Cycle Timing Diagram

AD7228A

REV. A

–3–