TC7116CPL Microchip Technology, TC7116CPL Datasheet - Page 14

IC ADC 3 1/2DGT LCD DVR 40-DIP

TC7116CPL

Manufacturer Part Number
TC7116CPL
Description
IC ADC 3 1/2DGT LCD DVR 40-DIP
Manufacturer
Microchip Technology
Datasheet

Specifications of TC7116CPL

Display Type
LCD
Configuration
7 Segment
Digits Or Characters
A/D 3.5 Digits
Current - Supply
800µA
Voltage - Supply
9V
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 - Analogue
9V
Supply Current
800µA
No. Of Pins
40
Operating Temperature Range
0°C To
Digital Ic Case Style
DIP
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Interface
-
Lead Free Status / RoHS Status
Lead free / RoHS Compliant, Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
TC7116CPL
Manufacturer:
WR
Quantity:
6 227
Part Number:
TC7116CPL
Manufacturer:
MICROCHIP/微芯
Quantity:
20 000
TC7116/A/TC7117/A
6.0
The TC7117/TC7117A sink the LED display current,
causing heat to build up in the IC package. If the inter-
nal voltage reference is used, the changing chip tem-
perature can cause the display to change reading. By
reducing the LED common anode voltage, the TC7117/
TC7117A package power dissipation is reduced.
Figure 6-1 is a curve tracer display showing the rela-
tionship between output current and output voltage for
typical TC7117CPL/TC7117ACPL devices. Since a
typical LED has 1.8V across it at 8mA and its common
anode is connected to +5V, the TC7117/TC7117A out-
put is at 3.2V (Point A, Figure 6-1). Maximum power
dissipation is 8.1mA x 3.2V x 24 segments = 622mW.
However, notice that once the TC7117/TC7117A’s out-
put voltage is above 2V, the LED current is essentially
constant as output voltage increases. Reducing the
output voltage by 0.7V (Point B Figure 6-1) results in
7.7mA of LED current, only a 5% reduction. Maximum
power dissipation is now only 7.7mA x 2.5V x 24 =
462mW, a reduction of 26%. An output voltage reduc-
tion of 1V (Point C) reduces LED current by 10%
(7.3mA), but power dissipation by 38% (7.3mA x 2.2V
x 24 = 385mW).
FIGURE 6-1:
vs. Output Voltage
DS21457C-page 14
TYPICAL APPLICATIONS
10.000
9.000
8.000
6.000
7.000
2.00
C
2.50
O ut put V o lt a ge ( V )
TC7117/TC7117A Output
B
3.00
A
3.50
4.00
Reduced power dissipation is very easy to obtain.
Figure 6-2 shows two ways: either a 5.1Ω, 1/4W resis-
tor, or a 1A diode placed in series with the display (but
not in series with the TC7117/TC7117A). The resistor
reduces the TC7117/TC7117A’s output voltage (when
all 24 segments are ON) to Point C of Figure 6-1. When
segments turn off, the output voltage will increase. The
diode, however, will result in a relatively steady output
voltage, around Point B.
In addition to limiting maximum power dissipation, the
resistor reduces change in power dissipation as the
display changes. The effect is caused by the fact that,
as fewer segments are ON, each ON output drops
more voltage and current. For the best-case of six
segments (a “111” display) to worst-case (a “1888”
display), the resistor circuit will change about 230mW,
while a circuit without the resistor will change about
470mW. Therefore, the resistor will reduce the effect of
display dissipation on reference voltage drift by about
50%.
The change in LED brightness caused by the resistor is
almost unnoticeable as more segments turn off. If
display brightness remaining steady is very important
to the designer, a diode may be used instead of the
resistor.
FIGURE 6-2:
Package Power Dissipation
TP5
40
100
1
1.5W, 1/4Ω
100
pF
1N4001
24kΩ
TP2
TP1
1kΩ
+5V
35
0.1
μF
1MΩ
TP3
TC7117A
Diode or Resistor Limits
TC7117
© 2006 Microchip Technology Inc.
+
10
Display
0.01
μF
In
30
0.47
47
μF
0.22
TP
4
μF
-5V
Display
150kΩ
20
21

Related parts for TC7116CPL