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PIN ASSIGNMENTS

+VBD

BUS18/16

BYTE

CONVST

RD

CS

+VA

AGND

AGND

+VA

REFM

REFM

RGZ PACKAGE

(TOP VIEW)

1

2

3

4

5

6

7

8

9

10

11

12

36

35

34

33

32

31

30

29

28

27

26

25

48 47 46 45 44 43 42 41 40 39 38 37

13 14 15 16 17 18 19 20 21 22 23 24

+VBD

DB10

DB11

DB12

DB13

DB14

DB15

DB16

DB17

AGND

AGND

+VA

NC − No internal connection

NOTE: The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.

ADS8484

SLAS511 – NOVEMBER 2007

TERMINAL FUNCTIONS

NAME

NO

I/O

DESCRIPTION

8, 9, 17, 20,

AGND

23, 24, 26,

–

Analog ground

27

BDGND

37

–

Digital ground for bus interface digital supply

BUSY

48

O

Status output. High when a conversion is in progress.

Bus size select input. Used for selecting 18-bit or 16-bit wide bus transfer.

0: Data bits output on the 18-bit data bus pins DB[17:0].

BUS18/16

2

I

1: Last two data bits D[1:0] from 18-bit wide bus output on:

a) the low byte pins DB[9:2] if BYTE = 0

b) the high byte pins DB[17:10] if BYTE = 1

Byte select input. Used for 8-bit bus reading.

BYTE

3

I

0: No fold back

1: Low byte D[9:2] of the 16 most significant bits is folded back to high byte of the 16 most significant pins DB[17:10].

CONVST

4

I

Convert start. The falling edge of this input ends the acquisition period and starts the hold period.

CS

6

I

Chip select. The falling edge of this input starts the acquisition period.

8-BIT BUS

16-BIT BUS

18-BIT BUS

Data Bus

BYTE = 0

BYTE = 1

BYTE = 1

BYTE = 0

BYTE = 0

BYTE = 0

BUS18/16 = 0

BUS18/16 = 0

BUS18/16 = 1

BUS18/16 = 0

BUS18/16 = 1

BUS18/16 = 0

DB17

28

O

D17 (MSB)

D9

All ones

D17 (MSB)

All ones

D17 (MSB)

DB16

29

O

D16

D8

All ones

D16

All ones

D16

DB15

30

O

D15

D7

All ones

D15

All ones

D15

DB14

31

O

D14

D6

All ones

D14

All ones

D14

DB13

32

O

D13

D5

All ones

D13

All ones

D13

DB12

33

O

D12

D4

All ones

D12

All ones

D12

DB11

34

O

D11

D3

D1

D11

All ones

D11

DB10

35

O

D10

D2

D0 (LSB)

D10

All ones

D10

8

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Product Folder Link(s): ADS8484