AD7329 Analog Devices, AD7329 Datasheet - Page 9

• Manufacturer Part Number: AD7329
• Description: 1 MSPS , 8-Channel, Software Selectable True Bipolar Input, 12-Bit Plus Sign A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7329

• Resolution (bits): 13bit
• # Chan: 8
• Sample Rate: 1MSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni,SE-Uni
• Ain Range: Bip (Vref),Bip (Vref) x 2,Bip (Vref) x 4,Bip 10V,Bip 2.5V,Bip 5.0V,Uni (Vref),Uni 10V
• Adc Architecture: SAR
• Pkg Type: SOP

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 5. Pin Function Descriptions
Pin No.
24
22
1
2
21
3, 23
4
5
20
19
6
7
8
SCLK
DOUT
Mnemonic
CS
DIN
V
DGND
AGND
REF
V
V
V
ADC
MUX
DRIVE
CC
DD
SS
IN
IN
OUT
/REF
+
+
OUT
Descriptions
Serial Clock, Logic Input. A serial clock input provides the SCLK used for accessing the data from the AD7329.
This clock is also used as the clock source for the conversion process.
Serial Data Output. The conversion output data is supplied to this pin as a serial data stream. The bits are
clocked out on the falling edge of the SCLK input, and 16 SCLKs are required to access the data. The data
stream consists of three channel identification bits, the sign bit, and 12 bits of conversion data. The data is
provided MSB first (see the Serial Interface section).
Chip Select. Active low logic input. This input provides the dual function of initiating conversions on the
AD7329 and frames the serial data transfer.
Data In. Data to be written to the on-chip registers is provided on this input and is clocked into the register
on the falling edge of SCLK (see the Registers section).
Logic Power Supply Input. The voltage supplied at this pin determines at what voltage the interface operates.
This pin should be decoupled to DGND. The voltage at this pin can be different than that at V
not exceed V
Digital Ground. Ground reference point for all digital circuitry on the AD7329. The DGND and AGND voltages
should ideally be at the same potential and must not be more than 0.3 V apart, even on a transient basis.
Analog Ground. Ground reference point for all analog circuitry on the AD7329. All analog input signals and
any external reference signal should be referred to this AGND voltage. The AGND and DGND voltages should
ideally be at the same potential and must not be more than 0.3 V apart, even on a transient basis.
Reference Input/Reference Output. The on-chip reference is available on this pin for use external to the AD7329.
The nominal internal reference voltage is 2.5 V, which appears at the pin. A 680 nF capacitor should be placed
on the reference pin. Alternatively, the internal reference can be disabled and an external reference can be
applied to this input. On power-up, the external reference mode is the default condition (see the Reference
section).
Analog Supply Voltage, 2.7 V to 5.25 V. This is the supply voltage for the ADC core on the AD7329. This supply
should be decoupled to AGND.
Positive Power Supply Voltage. This is the positive supply voltage for the analog input section.
Negative Power Supply Voltage. This is the negative supply voltage for the analog input section.
Positive ADC Input. This pin allows access to the on-chip track-and-hold. The voltage applied to this pin is still
a high voltage signal (±10 V, ±5 V, ±2.5 V, or 0 V to +10 V).
Positive Multiplexer Output. The output of the multiplexer appears at this pin. The voltage at this pin is still a
high voltage signal equivalent to the voltage applied to the V
register or sequence register. If no external filtering or buffering is required, this pin should be tied to the
ADC
IN
+ pin.
CC
by more than 0.3 V.
REF
IN
MUX
/REF
ADC
DGND
AGND
Figure 3. TSSOP Pin Configuration
OUT
V
V
V
V
V
DIN
OUT
CS
IN
IN
IN
IN
IN
SS
+
+
0
1
4
5
12
10
11
1
2
3
4
5
6
7
8
9
Rev. A | Page 9 of 40
(Not to Scale)
AD7329
TOP VIEW
24
23
22
21
20
19
18
17
16
15
14
13
SCLK
DGND
DOUT
V
V
V
ADC
MUX
V
V
V
V
DRIVE
CC
DD
IN
IN
IN
IN
2
3
6
7
IN
OUT
–
–
IN
+ input channel, as selected in the control
CC
but should
AD7329