TC7129CPL Microchip Technology, TC7129CPL Datasheet - Page 12

• 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

TC7126/A
6.5
C
equation:
EQUATION 6-2:
For a 48kHz clock (3 conversions per second),
R = 180kΩ.
Note that F
nal clock. The backplane drive signal is derived by
dividing F
To achieve maximum rejection of 60Hz noise pickup,
the signal integrate period should be a multiple of
60Hz. Oscillator frequencies of 24kHz, 12kHz, 80kHz,
60kHz, 40kHz, etc. should be selected. For 50Hz rejec-
tion,
66-2/3kHz, 50kHz, 40kHz, etc. would be suitable. Note
that 40kHz (2.5 readings per second) will reject both
50Hz and 60Hz.
6.6
A full scale reading (2000 counts) requires the input
signal be twice the reference voltage.
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 for 2000lb/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 where 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.
DS21458B-page 12
Required Full Scale Voltage*
OSC
Note:
oscillator
should be 50pF; R
Oscillator Components
Reference Voltage Selection
OSC
OSC
V
FS
20mV
by 800.
2V
= 2V
is 44 to generate the TC7126A's inter-
frequencies
REF
F
OSC
.
= 0.45
OSC
RC
of
is selected from the
2
20kHz,
is 400mV. Rather
IN
IN
100mV
IN
is not equal to
+ and analog
V
-. The trans-
1V
REF
100kHz,
7.0
(Pin Numbers Refer to the 40-Pin PDIP.)
7.1
The TC7126A is designed with true differential inputs
and accepts input signals within the input stage
Common mode voltage range (V
V+ – 1V to V- + 1V. Common mode voltages are
removed from the system when the TC7126A operates
from a battery or floating power source (isolated from
measured system), and V
common (V
In systems where Common mode voltages exist, the
TC7126A's 86 dB Common mode rejection ratio mini-
mizes error. Common mode voltages do, however,
affect the integrator output level. A worst case condition
exists if a large positive V
a full scale negative differential signal. The negative
signal drives the integrator output positive along with
V
grator output swing can be reduced below the recom-
mended 2V full scale swing. The integrator output
will swing within 0.3V of V+ or V- without increased
linearity error.
FIGURE 7-1:
CM
–
+
V
V
CM
IN
(see Figure 7-1). For such applications, the inte-
DEVICE PIN FUNCTIONAL
DESCRIPTION
Differential Signal Inputs
V
IN
COM
+
–
+ (Pin 31), V
Input
Buffer
) (see Figure 7-2).
Where:
VOLTAGE REDUCES
AVAILABLE INTEGRATOR
SWING (V
COMMON MODE
V
C
R
©
I
t
I
I
I
R
CM
2002 Microchip Technology Inc.
=
= Integration capacitor
= Integration resistor
= Integration time =
IN
I
IN
- is connected to analog
R I C I
exists in conjunction with
- (Pin 30)
t I
CM
COM
[
). Typical range is
V
–
+
CM
C
Integrator
≠ V
I
– V
IN
IN
4000
F
)
OSC
[
V
I