TC7107ACLW713 Microchip Technology, TC7107ACLW713 Datasheet - Page 8
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TC7107ACLW713
Manufacturer Part Number
TC7107ACLW713
Description
IC ADC 3 1/2DGT LED DVR 44-PLCC
Manufacturer
Microchip Technology
Datasheet
1.TC7107CPL.pdf
(34 pages)
Specifications of TC7107ACLW713
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
Surface Mount
Package / Case
44-PLCC
Lead Free Status / RoHS Status
Request inventory verification / Request inventory verification
Interface
-
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
TC7107ACLW713
Manufacturer:
Microchip Technology
Quantity:
10 000
TC7106/A/TC7107/A
3.0
(All Pin designations refer to 40-Pin PDIP.)
3.1
The TC7106A and TC7107A are dual slope, integrating
Analog-to-Digital Converters. An understanding of the
dual slope conversion technique will aid in following the
detailed operation theory.
The conventional dual slope converter measurement
cycle has two distinct phases:
• Input Signal Integration
• Reference Voltage Integration (De-integration)
The input signal being converted is integrated for a
fixed time period (T
clock pulses. An opposite polarity constant reference
voltage is then integrated until the integrator output
voltage returns to zero. The reference integration time
is directly proportional to the input signal (T
Figure
FIGURE 3-1:
In a simple dual slope converter, a complete
conversion requires the integrator output to “ramp-up”
and “ramp-down.” A simple mathematical equation
relates the input signal, reference voltage and
integration time.
EQUATION 3-1:
DS21455D-page 8
Where:
T
T
V
SI
RI
R
Analog
Signal
Voltage
Input
3-1.
REF
Integrate
DETAILED DESCRIPTION
Dual Slope Conversion Principles
=
=
=
+/–
Signal
Fixed
Time
Reference voltage
Signal integration time (fixed)
Reference voltage integration time
(variable).
------- -
RC
Polarity Control
1
Variable
Reference
Integrate
Time
∫
DISPLAY
T
0
SI
SI
Switch
Driver
Integrator
). Time is measured by counting
V
–
+
Basic Dual Slope Converter.
IN
V
V
t ( )dt
C
IN
Phase
Control
IN
µ V
µ
1/2
REF
=
V
–
+
Comparator
REF
V
-------------- -
RC
Control
R
Logic
T
RI
Counter
RI
). See
For a constant V
EQUATION 3-2:
The dual slope converter accuracy is unrelated to the
integrating resistor and capacitor values as long as
they are stable during a measurement cycle. An
inherent benefit is noise immunity. Noise spikes are
integrated or averaged to zero during the integration
periods. Integrating ADCs are immune to the large
conversion
approximation converters in high noise environments.
Interfering signals with frequency components at
multiples of the averaging period will be attenuated.
Integrating ADCs commonly operate with the signal
integration period set to a multiple of the 50/60Hz
power line period (see
FIGURE 3-2:
Dual Slope Converter.
Where:
F
20
10
30
R
V
OSC
V
0
INT
INT
FS
0.1/T
=
=
=
=
C
INT
errors
Clock Frequency at Pin 38
Full Scale Input Voltage
Integrating Resistor
Desired Full Scale Integrator Output
Swing
IN
:
=
V
(
----------------------------------------------------- -
IN
4000
Normal Mode Rejection of
Input Frequency
Figure
= V
© 2008 Microchip Technology Inc.
that
)
R
⎛
⎝
1/T
------------ -
F
V
T = Measured Period
3-2).
T
T
OSC
1
INT
RI
SI
plague
⎞ V
⎠
⎛
⎝
-----------
R
INT
FS
⎞
⎠
successive
10/T