TC7107IPL Microchip Technology, TC7107IPL Datasheet - Page 20

• Manufacturer Part Number: TC7107IPL
• Description: IC ADC 3 1/2DGT LED DVR 40-DIP
• Manufacturer: Microchip Technology

Specifications of TC7107IPL

• Display Type: LED
• Configuration: 7 Segment
• Digits Or Characters: A/D 3.5 Digits
• Current - Supply: 800µA
• Voltage - Supply: 5V
• Operating Temperature: -25°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -

TC7106/A/TC7107/A
10.0
10.1
The TEST pin is connected to the internally generated
digital logic supply ground through a 500Ω resistor. The
TEST pin may be used as the negative supply for
external CMOS gate segment drivers. LCD display
annunciators for decimal points, low battery indication,
or function indication may be added without adding an
additional supply. No more than 1 mA should be
supplied by the TEST pin; its potential is approximately
5V below V+ (see
FIGURE 10-1:
Test as Logic Ground.
10.2
The true differential input and differential reference
make ratiometric reading possible. Typically in a
ratiometric operation, an unknown resistance is
measured, with respect to a known standard
resistance. No accurately defined reference voltage is
needed.
The unknown resistance is put in series with a known
standard and a current passed through the pair. The
voltage developed across the unknown is applied to the
DS21455D-page 20
TC7106A
TC7106A
TEST
V+
TYPICAL APPLICATIONS
Decimal Point and Annunciator
Drive
V+
Ratiometric Resistance
Measurements
TEST
BP
BP
21
37
Figure 10-1
Decimal
Select
Point
Decimal Point Drive Using
).
4030
4049
GND
GND
V+
V+
To LCD
Decimal
Point
To LCD
Backplane
To LCD
Decimal
Point
input and the voltage across the known resistor is
applied to the reference input. If the unknown equals
the standard, the display will read 1000.
The displayed reading can be determined from the
following expression:
EQUATION 10-1:
The display will over range for:
FIGURE 10-2:
Ratiometric Resistance Measurement.
FIGURE 10-3:
R
UNKNOWN
R
STANDARD
160 k
1N4148
Sensor
Displayed (Reading)
R
Ω
50 k
UNKNOWN
R
Ω
2
300 k
50 k
R
Ω
≥
Low Parts Count
1
Temperature Sensor.
Ω
V
Analog
Common
V
V
V
© 2008 Microchip Technology Inc.
2 x R
REF
IN
IN
REF
TC7106A
+
-
300k
=
+
-
STANDARD
---------------------------- -
R
R
V+
Ω
UNKNOWN
STANDARD
V
V
V
V
Common
V+
IN
IN
REF
REF
-
+
+
-
+
TC7106A
V
FS
×
= 2V
9V
1000
LCD Display
V-