TC7107ACPL Microchip Technology, TC7107ACPL Datasheet - Page 13

• Manufacturer Part Number: TC7107ACPL
• Description: IC ADC 3 1/2DGT LED DVR 40-DIP
• Manufacturer: Microchip Technology

Specifications of TC7107ACPL

• 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
• Package / Case: 40-DIP (0.600", 15.24mm)
• Resolution (bits): 3.5bit
• Input Channel Type: Differential
• Data Interface: Parallel
• Supply Voltage Range - Analog: 5V
• Supply Current: 800µA
• Digital Ic Case Style: DIP
• No. Of Pins: 40
• 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: 158-1128; 158-1128; TC7107ACPLR; TC7107ACPLR

7.0
7.1
The C
noise. A 0.47µF capacitor is recommended for 200mV
full scale applications where 1LSB is 100µV. A 0.047µF
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
when V
mode voltage exists (V
application requires 200mV full scale, increase C
1.0µF. Rollover error will be held to less than 1/2 count.
A mylar dielectric capacitor is adequate.
7.3
C
put voltage swing without causing output saturation.
Due to the TC7106A/7107A superior temperature coef-
ficient specification, analog common will normally sup-
ply the differential voltage reference. For this case, a
±2V full scale integrator output swing is satisfactory.
For 3 readings/second (F
is suggested. If a different oscillator frequency is used,
C
the nominal ±2V integrator swing.
An exact expression for C
EQUATION 7-1:
C
rollover error. A polypropylene capacitor is recom-
mended.
©
Where:
INT
INT
INT
2002 Microchip Technology Inc.
F
V
R
V
should be selected to maximize the integrator out-
must be changed in inverse proportion to maintain
must have low dielectric absorption to minimize
OSC
AZ
FS
INT
INT
IN
COMPONENT VALUE
SELECTION
Auto-Zero Capacitor (C
Reference Voltage Capacitor
(C
Integrating Capacitor (C
capacitor size has some influence on system
- is tied to analog common. If a large Common
= Clock Frequency at Pin 38
= Full Scale Input Voltage
= Integrating Resistor
= Desired Full Scale Integrator Output Swing
C
REF
INT
)
=
(4000)
REF
. A 0.1µF capacitor is acceptable
REF
OSC


INT
- – analog common) and the
F
V
OSC
1
INT
= 48kHz), a 0.22µF value
is:




R
V
INT
FS
AZ


INT
)
)
REF
to
7.4
The input buffer amplifier and integrator are designed
with class A output stages. The output stage idling cur-
rent is 100µA. The integrator and buffer can supply
20µA drive currents with negligible linearity errors.
R
region, but not so large that printed circuit board leak-
age currents induce errors. For a 200mV full scale,
R
7.5
R
selected using the equation:
EQUATION 7-2:
For F
Note that F
TC7106A internal control 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 240kHz, 120kHz,
80kHz, 60kHz, 48kHz, 40kHz, etc. should be selected.
For 50Hz rejection, oscillator frequencies of 200kHz,
100kHz, 66-2/3kHz, 50kHz, 40kHz, etc. would be suit-
able. Note that 40kHz (2.5 readings/second) will reject
both 50Hz and 60Hz.
7.6
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 is 400mV for 2000 lb/in
Rather than dividing the input voltage by two, the refer-
ence voltage should be set to 200mV. This permits the
transducer input to be used directly.
Component
Required Full Scale Voltage*
* V
INT
INT
OSC
Note:
TC7106/A/TC7107/A
Value
is chosen to remain in the output stage linear drive
R
C
is 47kΩ. 2.0V full scale requires 470kΩ.
FS
C
OSC
INT
INT
(Pin 40 to Pin 39) should be 100kΩ. C
AZ
= 2V
Integrating Resistor (R
Oscillator Components
Reference Voltage Selection
of 48kHz, C
F
200.0mV
OSC
OSC
2.000V
REF.
= 48kHz (3 readings per sec).
is divided by four to generate the
200.0mV
Nominal Full Scale Voltage
F
0.47µF
0.22µF
OSC
47kΩ
OSC
is 100pF nominally.
=
0.45
RC
OSC
by 800.
DS21455B-page 13
INT
100.0mV
1.000V
0.047µF
V
2.000V
0.22µF
470kΩ
)
REF
OSC
is
2
.