TC7107CPL Microchip Technology, TC7107CPL Datasheet - Page 14

• Manufacturer Part Number: TC7107CPL
• Description: IC ADC 3 1/2DGT LED DVR 40-DIP
• Manufacturer: Microchip Technology

Specifications of TC7107CPL

• Package / Case: 40-DIP (0.600", 15.24mm)
• Display Type: LED
• Configuration: 7 Segment
• Digits Or Characters: A/D 3.5 Digits
• Current - Supply: 800µA
• Voltage - Supply: 5V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Architecture: Dual Slope
• Input Type: Voltage
• Maximum Power Dissipation: 1230 mW
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 158-1129; 158-1129

TC7106/A/TC7107/A
7.0
7.1
The C
noise. A 0.47 µF capacitor is recommended for 200 mV
full scale applications where 1LSB is 100 µV. A
0.047 µF capacitor is adequate for 2.0V full scale
applications. A mylar type dielectric capacitor is
adequate.
7.2
The reference voltage used to ramp the integrator out-
put voltage back to zero during the reference integrate
cycle is stored on C
acceptable when V
large Common mode voltage exists (V
common) and the application requires 200 mV full
scale, increase C
held to less than 1/2 count. A mylar dielectric capacitor
is adequate.
7.3
C
output voltage swing without causing output saturation.
Due to the TC7106A/TC7107A superior temperature
coefficient specification, analog common will normally
supply the differential voltage reference. For this case,
a ±2V full scale integrator output swing is satisfactory.
For 3 readings/second (F
value is suggested. If a different oscillator frequency is
used, C
maintain the nominal ±2V integrator swing.
An exact expression for C
EQUATION 7-1:
C
rollover
recommended.
DS21455D-page 14
Where:
INT
INT
F
R
V
must have low dielectric absorption to minimize
OSC
V
should be selected to maximize the integrator
AZ
INT
INT
FS
INT
COMPONENT VALUE
SELECTION
Auto-Zero Capacitor (C
Reference Voltage Capacitor
(C
Integrating Capacitor (C
capacitor size has some influence on system
error.
must be changed in inverse proportion to
REF
=
=
=
=
C
INT
Clock Frequency at Pin 38
Full Scale Input Voltage
Integrating Resistor
Desired Full Scale Integrator Output
Swing
)
REF
=
A
IN
(
----------------------------------------------------- -
- is tied to analog common. If a
4000
to 1.0 µF. Rollover error will be
polypropylene
REF
INT
)
OSC
⎛
⎝
. A 0.1 µF capacitor is
------------ -
F
V
is:
OSC
INT
1
= 48 kHz), a 0.22 µF
⎞ V
⎠
⎛
⎝
-----------
R
INT
FS
AZ
REF
⎞
⎠
INT
capacitor
)
- – analog
)
is
7.4
The input buffer amplifier and integrator are designed
with class A output stages. The output stage idling
current is 100 µA. The integrator and buffer can supply
20 µA drive currents with negligible linearity errors.
R
region, but not so large that printed circuit board
leakage currents induce errors. For a 200 mV full scale,
R
TABLE 7-1:
7.5
R
selected using the equation:
EQUATION 7-2:
Note that F
TC7106A internal control clock. The backplane drive
signal is derived by dividing F
To achieve maximum rejection of 60 Hz noise pickup,
the signal integrate period should be a multiple of
60 Hz. Oscillator frequencies of 240 kHz, 120 kHz,
80 kHz, 60 kHz, 48 kHz, 40 kHz, etc. should be
selected. For 50 Hz rejection, oscillator frequencies of
200 kHz, 100 kHz, 66-2/3 kHz, 50 kHz, 40 kHz, etc.
would be suitable. Note that 40 kHz (2.5 readings/
second) will reject both 50 Hz and 60 Hz.
7.6
A full scale reading (2000 counts) requires the input
signal be twice the reference voltage.
Component
Where:
Required Full Scale Voltage*
INT
INT
OSC
Note:
* V
C
F
Value
R
C
is chosen to remain in the output stage linear drive
is 47 kΩ. 2.0V full scale requires 470 kΩ.
C
OSC
OSC
FS
INT
INT
(Pin 40 to Pin 39) should be 100 kΩ. C
AZ
Integrating Resistor (R
Oscillator Components
Reference Voltage Selection
= 2V
200.0 mV
F
=
=
OSC
2.000V
OSC
REF
48 kHz
100 pF
= 48 kHz (3 readings per sec).
is divided by four to generate the
COMPONENT VALUES AND
NOMINAL FULL SCALE
VOLTAGE
200.0 mV
Nominal Full Scale Voltage
0.47 µF
0.22 µF
F
47 kΩ
OSC
© 2008 Microchip Technology Inc.
=
0.45
--------- -
OSC
RC
by 800.
100.0 mV
INT
1.000V
0.047 µF
0.22 µF
2.000V
470 kΩ
V
)
REF
OSC
is