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TYPICAL CHARACTERISTICS

68

14024

13025

93

234937

0

50000

100000

150000

200000

250000

FFFD

FFFE

FFFF

0000

0001

Code-Hex

+VA =5V,

+VAREG=3V,

+VBD=3V,

IntREFIN=4.096V,

262144Points,

Sigma=0.325,

78

13793

235679

12575

19

0

50000

100000

150000

200000

250000

FFFD

FFFE

FFFF

0000

0001

Code-Hex

+VA =5V,

+VAREG=3V,

+VBD=3V,

ExtREFIN=4.096V,

262144Points,

Sigma=0.319,

4.094

4.095

4.096

4.097

4.098

-40

-25

-10

5

20

35

50

65

80

T -Free-AirTemperature- C

A

º

D1

D3

D2

+VA =5V,

+VAREG=3V,

+VBD=3V

ADS8422

SLAS512B – JUNE 2006 – REVISED DECEMBER 2006

TERMINAL FUNCTIONS (continued)

NAME

NO

I/O

DESCRIPTION

DB9

22

O

D9

D1

D9

DB8

23

O

D8

D0 (LSB)

D8

DB7

26

O

D7

All ones

D7

DB6

27

O

D6

All ones

D6

DB5

28

O

D5

All ones

D5

DB4

29

O

D4

All ones

D4

DB3

30

O

D3

All ones

D3

DB2

31

O

D2

All ones

D2

DB1

32

O

D1

All ones

D1

DB0

33

O

D0 (LSB)

All ones

D0 (LSB)

–IN

7

I

Inverting input channel

+IN

6

I

Noninverting input channel

NC

11

–

No connection

Low true signal. A logic low longer than 1.5

µs applied to this pin powers down only the analog outputs that include

PD2

37

I

REFOUT and COMMOUT. (NOTE: The combination PD1 = 1, PD2 = 0 is reserved. Do not use this combination.)

REFIN

1

I

Reference input. Add 0.1-

µF decoupling capacitor between REFIN and REFM.

REFOUT

2

O

Reference output. Add 1-

µF capacitor between the REFOUT pin and REFM pin when internal reference is used.

REFM

47, 48

I

Reference ground

Low true signal. A low pulse applied to this pin resets the ADC; the ongoing conversion is aborted. A low pulse shorter

RESET/PD1

38

I

than 0.5

µs only resets, and one longer than 1.5 µs resets and also powers down the ADC. Note that analog outputs

REFOUT and COMMOUT can be powered down by PD2, if necessary.

RD

41

I

Synchronization pulse for the parallel output.

+VA

4, 46

–

Analog power supplies, 4.75 V to 5.25 VDC

+VAREG

10

–

Regulator supply, 2.85 V to 5.25 VDC

+VBD

24, 34

–

Digital power supply for bus

INTERNAL REFERENCE VOLTAGE

HISTOGRAM OF 262144

HISTOGRAM OF 262144

vs

CONVERSIONS OF DC INPUT AT

CONVERSIONS OF DC INPUT AT

FREE-AIR TEMPERATURE

CENTER CODE (Internal Reference)

CENTER CODE (External Reference)

(Three Devices Shown)

Figure 1.

Figure 2.

Figure 3.

8

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