TC820 TelCom Semiconductor, TC820 Datasheet - Page 2

• Manufacturer Part Number: TC820
• Description: 3-3/4 DIGIT A/D CONVERTER WITH FREQUENCY COUNTER AND LOGIC PROBE
• Manufacturer: TelCom Semiconductor

TC820
GENERAL DESCRIPTION
bining an integrating analog-to-digital converter, frequency
counter, and logic level tester in a single package. The
TC820 supersedes the TC7106 in new designs by improv-
ing performance and reducing system cost. The TC820
adds features that are difficult, expensive, or impossible to
provide with older A/D converters (see the competitive
evaluation). The high level of integration permits TC820-
based instruments to deliver higher performance and more
features, while actually reducing parts count. Fabricated in
low-power CMOS, the TC820 directly drives a 3-3/4 digit
(3999 maximum) LCD.
provides 10 times greater resolution in the 200mV to 400mV
range than traditional 3-1/2 digit meters. An auto-zero cycle
guarantees a zero reading with a 0V input. CMOS process-
ing reduces analog input bias current to only 1pA. Rollover
error (the difference in readings for equal magnitude but
opposite polarity input signals) is less than 1 count. Differ-
ential reference inputs permit ratiometric measurements for
ohms or bridge transducer applications.
of an instrument well-suited to both analog and digital
troubleshooting: voltage, current, and resistance measure-
ments, plus precise frequency measurements to 4MHz
(higher frequencies can be measured with an external
prescaler), and a simple logic probe. The frequency counter
will automatically adjust its range to match the input fre-
quency, over a four-decade range.
based meter to function as a logic probe. When combined
with external level shifters, the TC820 will display logic levels
on the LCD and also turn on a piezoelectric buzzer when the
measured logic level is low.
reduce parts count. On-chip decimal point drivers are in-
cluded, as is a low battery detection annunciator. A piezo-
electric buzzer can be controlled with an external switch or
by the logic probe inputs. Two oscillator options are pro-
vided: A crystal can be used if high accuracy frequency
measurements are desired, or a simple RC option can be
used for low-end instruments.
3-150
The TC820 is a 3-3/4 digit measurement system com-
With a maximum range of 3999 counts, the TC820
The TC820's frequency counter option simplifies design
Two logic level measurement inputs permit a TC820-
Other TC820 features simplify instrument design and
the highest A/D or frequency reading. This feature is useful
in measuring motor starting current, maximum tempera-
ture, and similar applications.
No additional design effort is required to create instruments
with 3-3/4 digit resolution.
typical power of 10 mW. Packages include a 40-pin plastic
DIP, 44-pin plastic flat package, and 44-pin PLCC.
COMPETITIVE EVALUATION
Features Comparison
3-3/4 Digit Resolution
Auto-Ranging Frequency Counter
Logic Probe
Decimal Point Drive
Peak Reading Hold
(Frequency or Voltage)
Display Hold
Simple 10:1 Range Change
Buzzer Drive
Low Battery Detection
With Annunciator
Overrange Detection
With Annunciator
Low Drift Reference
Underrange/Overrange
Logic Output
Input Overload Display
LCD Annunciator Driver
LCD Drive Type
LCD Pin Connections
LCD Elements
A "peak reading hold" input allows the TC820 to retain
A family of instruments can be created with the TC820.
The TC820 operates from a single 9V battery, with
3-3/4 DIGIT A/D CONVERTER WITH
FREQUENCY AND LOGIC PROBE
TELCOM SEMICONDUCTOR, INC.
Triplexed
TC820
"OL"
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
15
36
Direct
7106
No
No
No
No
No
No
No
No
No
No
No
No
"1"
No
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