TC7129CPL Microchip Technology, TC7129CPL Datasheet - Page 9

• Manufacturer Part Number: TC7129CPL
• Description: IC ADC 4 1/2DGT LCD DVR 40-DIP
• Manufacturer: Microchip Technology

Specifications of TC7129CPL

• Display Type: LCD
• Configuration: 7 Segment
• Digits Or Characters: A/D 4.5 Digits
• Current - Supply: 800µA
• Voltage - Supply: 6 V ~ 12 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 40-DIP (0.600", 15.24mm)
• Resolution (bits): 4.5bit
• Input Channel Type: Differential
• Data Interface: Parallel
• Supply Current: 800µA
• Digital Ic Case Style: DIP
• No. Of Pins: 40
• Operating Temperature Range: 0°C To +70°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: TC7129CPLR; TC7129CPLR

3.5
The reference potentiometer (R
adjustment for adjusting the reference voltage; any
value above 20 k
(R
150 A. The reference filter capacitor (C
RC filter with R
3.6
For added stability, an RC input noise filter is usually
included in the circuit. The input filter resistor value
should not exceed 100 k . A typical RC time constant
value is 16.7 msec to help reject line frequency noise.
The input filter capacitor should have low leakage for a
high-impedance input.
3.7
The typical circuit uses a 9V battery as a power source.
However, any value between 6V and 12V can be used.
For operation from batteries with voltages lower than
6V and for operation from power supplies, see
Section 4.2 “Powering the TC7129”.
4.0
4.1
The TC7129 is a direct pin-for-pin replacement part for
the ICL7129. Note, however, that the ICL7129 requires
a capacitor and resistor between pins 26 and 28 for
phase compensation. Since the TC7129 uses internal
phase compensation, these parts are not required and,
in fact, must be removed from the circuit for stable
operation.
4.2
While the most common power source for the TC7129
is a 9V battery, there are other possibilities. Some of
the more common ones are explained below.
4.2.1
Measurements are made with respect to power supply
ground. DGND (pin 36) is set internally to about 5V less
than V
input and must not be tied directly to power supply
ground. It can be used as a reference for external logic,
as explained in Section 4.3 “Connecting to External
Logic”, (see Figure 4-1).
© 2006 Microchip Technology Inc.
BIAS
) limits the current through D
+
(pin 24); it is not intended to be a power supply
Voltage Reference
(D
Input Filter (R
Battery
TYPICAL APPLICATIONS
Powering the TC7129
TC7129 as a Replacement Part
±5V Power Supply
REF
BIAS
, R
REF
to help eliminate noise.
is adequate. The bias resistor
, R
IF
BIAS
, C
IF
, C
)
REF
RF
REF
) provides an
)
RF
to less than
) forms an
Figure 4-1:
a ±5V Power Supply.
4.2.2
A battery with voltage between 3.8V and 6V can be
used to power the TC7129 when used with a voltage
doubler circuit, as shown in Figure 4-2. The voltage
doubler uses the TC7660 DC-to-DC voltage converter
and two external capacitors.
Figure 4-2:
a Low-Voltage Battery.
+
3.8V
to
6V
-5V
+5V
TC7660
0.1 µF
0.1 µF
0.1 µF
8
Low Voltage Battery Source
3
36
2
4
5
DGND
+
10 µF
+
36
TC7129
Powering the TC7129 From
10 µF
Powering the TC7129 From
COMMON
DGND
V–
V+
TC7129
REF LO
REF HI
24
23
COMMON
IN LO
IN HI
V–
V+
REF LO
REF HI
23
24
IN LO
IN HI
34
35
28
33
32
TC7129
34
35
28
33
32
DS21459D-page 9
V
IN
V
IN
+
–
+
–