Datasheet

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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
REFIN
REFOUT
NC
+VA
AGND
+IN
−IN
+VA
+VA
AGND
AGND
AGND
+VBD
DB10
DB11
DB12
DB13
DB14
DB15
DB16
DB17
AGND
AGND
+VA
BUSY
DB0
DB1
DB2
DB3
DB4
DB5
DB6
DB7
DB9
BDGND
NC − No internal connection
NOTE: The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.
DB8
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
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Product Folder Link(s): ADS8484