Datasheet
AD7327
Rev. B | Page 20 of 36
±16.5V V
DD
/V
SS
±12V V
DD
/V
SS
5
–6
V
COM
RANGE (V)
4
3
2
1
0
–1
–2
–3
–4
–5
V
CC
=3V
V
REF
=3V
±2.5V
RANGE
±10V
RANGE
±5V RANGE
±2.5V
RANGE
±5V RANGE
±10V
RANGE
05401-045
Figure 35. Common-Mode Range for V
CC
= 3 V and REFIN/OUT = 3 V
±16.5V V
DD
/V
SS
±12V V
DD
/V
SS
V
COM
RANGE (V)
V
CC
=5V
V
REF
=3V
8
–4
6
4
2
0
–2
±2.5V
RANGE
±10V
RANGE
±5V RANGE
±2.5V
RANGE
±5V RANGE
±10V
RANGE
05401-046
Figure 36. Common-Mode Range for V
CC
= 5 V and REFIN/OUT = 3 V
6
–8
4
2
0
–2
–4
–6
±16.5V V
DD
/V
SS
±12V V
DD
/V
SS
V
COM
RANGE (V)
V
CC
=3V
V
REF
=2.5V
±2.5V
RANGE
±10V
RANGE
±5V RANGE
±2.5V
RANGE
±5V RANGE
±10V
RANGE
05401-047
Figure 37. Common-Mode Range for V
CC
= 3 V and REFIN/OUT = 2.5 V
8
–8
6
4
2
0
–2
–4
–6
±16.5V V
DD
/V
SS
±12V V
DD
/V
SS
V
COM
RANGE (V)
V
CC
=5V
V
REF
=2.5V
±2.5V
RANGE
±10V
RANGE
±5V RANGE
±2.5V
RANGE
±5V RANGE
±10V
RANGE
05401-048
Figure 38. Common-Mode Range for V
CC
= 5 V and REFIN/OUT = 2.5 V
Pseudo Differential Inputs
The AD7327 can have four pseudo differential pairs or seven
pseudo differential inputs referenced to a common V
IN
− pin.
The V
IN
+ inputs are coupled to the signal source and must have
an amplitude within the selected range for that channel as
programmed in the range registers. A dc input is applied to the
V
IN
− pin. e voltage applied to this input provides an oset for
the V
IN
+ input from ground or a pseudo ground. Pseudo
differential inputs separate the analog input signal ground from
the ADC ground, allowing cancellation of dc common mode
voltages.
When a conversion takes place, the pseudo ground corresponds
to Code −4096 and the maximum amplitude corresponds to
Code +4095.
AD7327
1
V
IN
+
V
+
V–
V
DD
V
SS
V
CC
5V
1
ADDITIONAL PINS OMITTED FOR CLARITY.
V
IN
–
05401-028
Figure 39. Pseudo Differential Inputs
Figure 40 and Figure 41 show the typical voltage range on the
V
IN
− pin for the different analog input ranges when configured
in the pseudo differential mode.
For example, when the AD7327 is configured to operate in
pseudo differential mode and the ±5 V range is selected, with
±16.5 V V
DD
/V
SS
supplies and 5 V V
CC
, the voltage on the V
IN
−
pin can vary from −6.5 V to +6.5 V.