
AD7634
Data Sheet
Rev. B | Page 8 of 32
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
P
DBUF
P
DRE
F
RE
F
BUF
IN
TE
M
P
AV
D
IN
+
AG
ND
VEE
VC
C
IN
–
RE
F
G
N
D
RE
F
D6/
E
X
T
/I
NT
D7
/I
NV
S
Y
NC
D8/
INV
S
C
L
K
D
9/
RDC/
S
DI
N
OG
N
D
OV
D
DV
DD
DG
ND
D1
0/
S
D
O
U
T
D
11/
S
DCL
K
D
12
/SYN
C
D1
3/
RDE
RR
O
R
AGND
AVDD
MODE0
MODE1
D0/OB/2C
D1/A0
D3
D4/DIVSCLK[0]
D5/DIVSCLK[1]
IMPULSE
WARP
BIPOLAR
CNVST
PD
RESET
CS
RD
TEN
NOTES
1. FOR THE LEAD FRAME CHIP SCALE PACKAGE (LFCSP), THE EXPOSED PAD
SHOULD BE CONNECTED TO VEE. THIS CONNECTION IS NOT REQUIRED TO
MEET THE ELECTRICAL PERFORMANCES.
BUSY
D17/SCCS
D16/SCCLK
D15/SCIN
D14/HW/SW
48 47 46 45 44 43 42 41 40 39 38 37
35
34
33
30
31
32
36
29
28
27
25
26
2
3
4
7
6
5
1
8
9
10
12
11
13 14 15 16 17 18 19 20 21 22 23 24
PIN 1
AD7634
TOP VIEW
(Not to Scale)
D2/A1
06
406
-004
Figure 4. Pin Configuration
Table 6. Pin Function Descriptions
Pin No.
Mnemonic
Description
1, 42
AGND
P
Analog Power Ground Pins. Ground reference point for all analog I/O. All analog I/O should be refer-
enced to AGND and should be connected to the analog ground plane of the system. In addition, the
AGND, DGND, and OGND voltages should be at the same potential.
2, 44
AVDD
P
Analog Power Pins. Nominally 4.75 V to 5.25 V and decoupled with 10 μF and 100 nF capacitors.
3, 4
MODE[0:1]
DI
Data Input/Output Interface Mode Selection.
Interface Mode
MODE1
MODE0
Description
0
Low
18-bit interface
1
Low
High
16-bit interface
2
High
Low
8-bit (byte) interface
3
High
Serial interface
5
D0/OB/2C
In 18-bit parallel mode, this output is used as Bit 0 of the parallel port data output bus and the data
coding is straight binary. In all other modes, this pin allows the choice of straight binary or twos
complement.
When OB/2C = high, the digital output is straight binary
When OB/2C = low, the MSB is inverted resulting in a twos complement output from its internal shift
register.
6
WARP
Conversion Mode Selection. See the
Modes of Operation section for a more detailed description. Used
in conjunction with the IMPULSE input per the following:
Conversion Mode
WARP
IMPULSE
Normal
Low
Impulse
Low
High
Warp
High
Low
Normal
High
7
IMPULSE
Conversion Mode Selection. See the WARP pin description in this table. See the
Modes of Operationsection for a more detailed description.