tc7107a Microchip Technology Inc., tc7107a Datasheet - Page 14

• Manufacturer Part Number: tc7107a
• Description: 3-1/2 Digit Analog-to-digital Converters
• Manufacturer: Microchip Technology Inc.

TC7106/A/TC7107/A
In some applications, a scale factor other than unity
may exist between a transducer output voltage and the
required digital reading. Assume, for example, a pres-
sure transducer output is 400mV for 2000 lb/in
than dividing the input voltage by two, the reference
voltage should be set to 200mV. This permits the trans-
ducer input to be used directly.
The differential reference can also be used when a
digital zero reading is required when V
zero. This is common in temperature measuring instru-
mentation. A compensating offset voltage can be
applied between analog common and V
ducer output is connected between V
common.
The internal voltage reference potential available at
analog common will normally be used to supply the
converter’s reference. This potential is stable when-
ever the supply potential is greater than approximately
7V. In applications where an externally generated
reference voltage is desired, refer to Figure 7-1.
DS21455C-page 14
IN
IN
IN
is not equal to
+ and analog
-. The trans-
2
. Rather
FIGURE 7-1:
TC7106A
TC7107A
V+
(a)
V
V
REF
REF
+
-
V+
6.8V
Zener
External Reference
I
Z
© 2006 Microchip Technology Inc.
TC7106A
TC7107A
Common
V+
(b)
V
V
REF
REF
+
-
20kΩ
V+
1.2V
Ref
6.8kΩ