AD7329 Analog Devices, AD7329 Datasheet - Page 22

• 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

AD7329
Pseudo Differential Inputs
The AD7329 can have four pseudo differential pairs or seven
pseudo differential inputs referenced to a common V
The V
an amplitude within the selected range for that channel, as
programmed in the range register. A dc input is applied to the
V
the V
inputs separate the analog input signal ground from the ADC
ground, allowing cancellation of dc common-mode voltages.
Figure 42 shows the configuration of the AD7329 in pseudo
differential mode.
When a conversion takes place, the pseudo ground corresponds
to Code −4096 and the maximum amplitude corresponds to
Code +4095.
Figure 43 and Figure 44 show the typical voltage range on the
V
the pseudo differential mode.
For example, when the AD7329 is configured to operate in
pseudo differential mode and the ±5 V range is selected with
16.5 V V
pin can vary from −6.5 V to +6.5 V.
IN
IN
− pin. The voltage applied to this input provides an offset for
− pin for various analog input ranges when configured in
IN
IN
+ input from ground or pseudo ground. Pseudo differential
+ inputs are coupled to the signal source and must have
DD
, −16.5 V V
1
ADDITIONAL PINS OMITTED FOR CLARITY.
Figure 42. Pseudo Differential Inputs
V+
V–
SS
, and 5 V V
V
V
IN
IN
–
+
AD7329
CC
, the voltage on the V
V
V
DD
SS
1
V
5V
CC
IN
− pin.
IN
−
Rev. A | Page 22 of 40
–2
–4
–6
–8
–2
–4
–6
–8
8
6
4
2
0
4
2
0
Figure 43. Pseudo Differential Input Range with V
Figure 44. Pseudo Differential Input Range with V
V
V
V
V
CC
REF
CC
REF
= 5V
= 3V
RANGE
= 2.5V
RANGE
= 2.5V
±10V
±10V
±5V RANGE
±5V RANGE
±16.5V V
±16.5V V
RANGE
RANGE
±2.5V
±2.5V
DD
DD
0V TO +10V
0V TO +10V
/V
/V
RANGE
RANGE
SS
SS
RANGE
RANGE
±10V
±10V
±12V V
±12V V
±5V RANGE
±5V RANGE
DD
DD
/V
/V
SS
RANGE
SS
RANGE
±2.5V
±2.5V
0V TO +10V
0V TO +10V
RANGE
RANGE
CC
CC
= 5 V
= 3 V