REV. E

AD7701

–7–

1.6mA

200µA

100pF

TO

OUTPUT

PIN

IOH

2.1V

+

Figure 1. Load Circuit for Access

Time and Bus Relinquish Time

DATA

VALID

t

10

HI-Z

SDATA

CS

Figure 3. SSC Mode Data

Hold Time

CAL

SC1, SC2

SC1, SC2 VALID

t

1

t

2

Figure 2a. Calibration Control Timing

DATA

VALID

t

15

HI-Z

SDATA

CS

Figure 4a. SEC Mode Data Hold Time

CLKIN

SLEEP

t

3

Figure 2b.

SLEEP Mode Timing

HI-Z

DB15 DB14

DB1

DB0

HI-Z

SDATA

DRDY

CS

t

12

t

11

t

13

t

14

SCLK

t

16

Figure 4b. SEC Mode Timing Diagram

HI-Z

DB15

DB14

DB1

DB0

HI-Z

SCLK

SDATA

CLKIN

CS

HI-Z

t

7

t

6

t

5

t

4

t

8

t

5

Figure 5. SSC Mode Timing Diagram

HI-Z

START

DB8

DB9

DB7

STOP 1

STOP 2

HI-Z

HIGH BYTE

LOW BYTE

SDATA

SCLK

DRDY

CS

t

17

t

18

t

19

Figure 6. AC Mode Timing Diagram

DEFINITION OF TERMS

Linearity Error

This is the maximum deviation of any code from a straight line

passing through the endpoints of the transfer function. The

endpoints of the transfer function are zero scale (not to be

confused with bipolar zero), a point 0.5 LSB below the first

code transition (000 . . . 000 to 000 . . . 001) and full scale, a

point 1.5 LSB above the last code transition (111 . . . 110 to

111 . . . 111). The error is expressed as a percentage of full scale.

Differential Linearity Error

This is the difference between any code’s actual width and the

ideal (1 LSB) width. Differential linearity error is expressed in

LSBs. A differential linearity specification of

± 1 LSB or less

guarantees monotonicity.

Positive Full-Scale Error

Positive full-scale error is the deviation of the last code transition

±3/2 LSBs).

It applies to both positive and negative analog input ranges and

is expressed in microvolts.

Unipolar Offset Error

Unipolar offset error is the deviation of the first code transition

from the ideal (AGND + 0.5 LSB) when operating in the Uni-

polar mode. It is expressed in microvolts.

Bipolar Zero Error

This is the deviation of the midscale transition (0111 . . . 111 to

1000 . . . 000) from the ideal (AGND – 0.5 LSB) when operating

in the Bipolar mode. It is expressed in microvolts.

Bipolar Negative Full-Scale Error

This is the deviation of the first code transition from the ideal

expressed in microvolts.

Positive Full-Scale Overrange

Positive full-scale overrange is the amount of overhead available

peaks or excess voltages due to system gain errors in system

calibration routines) without introducing errors due to overloading

the analog modulator or overflowing the digital filter. It is

expressed in millivolts.

Negative Full-Scale Overrange

This is the amount of overhead available to handle voltages below

the digital filter. Note that the analog input will accept negative

voltage peaks even in the Unipolar mode. The overhead is

expressed in millivolts.