AD7634 Analog Devices, AD7634 Datasheet - Page 11

• Manufacturer Part Number: AD7634
• Manufacturer: Analog Devices

Specifications of AD7634

• Resolution (bits): 18bit
• # Chan: 1
• Sample Rate: 670kSPS
• Interface: Byte,Par,Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni
• Ain Range: 10V p-p,20 V p-p,40 V p-p
• Adc Architecture: SAR
• Pkg Type: CSP,QFP

Pin No.
36
37
38
39
40
41
43
45
46
47
48
49
1
2
3
Table 7. Data Bus Interface Definition
MODE
0
1
1
2
2
2
2
3
AI = analog input; AI/O = bidirectional analog; AO = analog output; DI = digital input; DI/O = bidirectional digital; DO = digital output; P = power, NC = no internal
connection.
LFCSP_VQ package only.
In serial configuration mode (MODE[1:0] = 3, HW/ SW = low), this input is programmed with the serial configuration register and this pin is a don’t care. See the
MODE1
0
0
0
1
1
1
1
1
Mnemonic
BIPOLAR
REF
REFGND
IN−
VCC
VEE
IN+
TEMP
REFBUFIN
PDREF
PDBUF
EPAD
3
MODE0
0
1
1
0
0
0
0
1
section and the
Type
DI
AO/I
AI
AI
P
P
AI
AO
AI
DI
DI
NC
2
1
D0/OB/2C
R[0]
OB/2C
OB/2C
OB/2C
OB/2C
OB/2C
OB/2C
OB/2C
Description
Input Range Select. See description for Pin 30.
Reference Input/Output. When PDREF/PDBUF = low, the internal reference and buffer are enabled, produc-
ing 5 V on this pin. When PDREF/PDBUF = high, the internal reference and buffer are disabled, allowing
an externally supplied voltage reference up to AVDD volts. Decoupling with at least a 22 μF capacitor is
required with or without the internal reference and buffer. See the Voltage Reference Input/Output
section.
Reference Input Analog Ground. Connected to analog ground plane.
Analog Input. Referenced to IN+.
In the 0 V to 5 V input range, IN− is between 0 V and V
range, IN− is between 0 V and 2 V
In the ±5 V and ±10 V ranges, IN− is true bipolar up to ±2 V
and centered about 0 V.
In all ranges, IN− must be driven 180° out of phase with IN+.
High Voltage Positive Supply. Normally 7 V to 15 V.
High Voltage Negative Supply. Normally 0 V to −15 V (0 V in unipolar ranges).
Analog Input. Referenced to IN−.
In the 0 V to 5 V input range, IN+ is between 0 V and V
range, IN+ is between 0 V and 2 V
In the ±5 V and ±10 V ranges, IN+ is true bipolar up to ±2 V
and centered about 0 V.
In all ranges, IN+ must be driven 180° out of phase with IN−
Temperature Sensor Analog Output. When the internal reference is enabled (PDREF = PDBUF = low),
this pin outputs a voltage proportional to the temperature of the AD7634. See the Voltage Reference
Input/Output section.
Reference Buffer Input. When using an external reference with the internal reference buffer (PDBUF = low,
PDREF = high), applying 2.5 V on this pin produces 5 V on the REF pin. See the Voltage Reference
Input/Output section.
Internal Reference Power-Down Input.
When low, the internal reference is enabled.
When high, the internal reference is powered down, and an external reference must be used.
Internal Reference Buffer Power-Down Input.
When low, the buffer is enabled (must be low when using internal reference).
When high, the buffer is powered-down.
Exposed Pad. The exposed pad is not connected internally. It is recommended that the pad be
soldered to VEE.
D1/A0
R[1]
A0 = 0
A0 = 1
A0 = 0
A0 = 0
A0 = 1
A0 = 1
All High-Z
section.
D2/A1
R[2]
R[0]
A1 = 0
A1 = 1
R[2]
A1 = 0
A1 = 1
Rev. A | Page 11 of 32
R[3]
R[1]
D[3]
R[3]
REF
REF
All High-Z
All High-Z
All High-Z
All High-Z
V centered about V
V centered about V
D[4:9]
R[4:9]
R[4:9]
D[10:11]
R[10:11]
R[10:11]
R[10:11]
R[2:3]
R[0:1]
REF
REF
Serial interface
REF
REF
All zeros
V centered about V
V centered about V
All zeros
.
.
REF
REF
V (±5 V range) or ±4 V
V (±5 V range) or ±4 V
D[12:15]
R[12:15]
R[12:15]
R[12:15]
R[4:7]
All zeros
D[16:17]
R[16:17]
R[16:17]
R[16:17]
R[8:9]
R[0:1]
REF
REF
/2. In the 0 V to 10 V
/2. In the 0 V to 10 V
REF
REF
V (±10 V range)
V (±10 V range)
Description
18-bit parallel
16-bit high word
16-bit low word
8-bit high byte
8-bit midbyte
8-bit low byte
8-bit low byte
Serial interface
AD7634