TC818A
Auto-Ranging Analog-to-Digital Converter
with 3-1/2 Digit Display
Features
General Description
• Auto-Ranging Analog-to-Digital Converter with
3-1/2 Digit Display
The TC818A is an integrating analog-to-digital con-
verter (ADC) with a 3-1/2 digit numeric LCD driver,
automatic ranging, and single 9V battery operation.
The numeric display provides 0.05% resolution and a
full set of annunciators that spell out the TC818A's
many operating modes.
• Annunciator Outputs Permit Customizing of LCD
• Auto-Range Operation for AC and DC Voltage
and Resistance Measurements
• Two User Selected AC/DC
• Current Ranges: 20mA and 200mA
• 22 Operating Ranges: 9 DC/AC Voltage
• 4 AC/DC Current
Automatic range selection is provided for both voltage
(DC and AC) and ohms (high and low power) measure-
ments. Expensive and bulky mechanical range
switches are not required. Five full scale ranges are
available, with automatic selection of external volt/ohm
attenuators over a 1 to 10,000 range. Two current
ranges, 20mA and 200mA, can be manually selected.
The auto-range feature can be bypassed, allowing
input attenuator selection through a single line input.
• 9 Resistance and Low Power Ohms
• Display Hold Function
• 3-1/2 Digit Resolution in Auto-Range
Mode: 1/2000
• Extended Resolution in Manual Range
Mode: 1/3000
During Manual mode operation, resolution is extended
to 3000 counts full scale. Extended resolution is also
available during 2000kΩ and 2000V full scale auto-
range operation. The extended range operation is indi-
cated by a flashing 1 MSD and by the fully extended bar
graph.
• Internal AC-to-DC Conversion Op Amp
• Triplex LCD Drive for Decimal Points, Digits,
• Bar Graphs, and Annunciators
• Continuity Detection and Piezoelectric
Transducer Driver
The TC818A includes an AC-to-DC converter for AC
voltage and current measurements. Only external
diodes/resistors/capacitors are required. Other fea-
tures include a Memory mode, low battery detection,
display HOLD input, and continuity buzzer driver.
• Low Drift Internal Reference: 75ppm/°C
• 9V Battery Operation: 10mW
• Low Battery Detection and LCD Annunciator
Device Selection Table
The 3-1/2 digit numeric display includes a full set of
annunciators. Decimal points are adjusted as auto-
matic or manual range changes occur, and Voltage,
Current, and Ohms Operating modes are displayed.
Additional annunciators are activated for manual, auto,
memory, HOLD, AC, low power ohms, and low battery
conditions.
Operating
Temperature Range
Part Number
Package
TC818ACBU 64-Pin PQFP
0°C to +70°C
The TC818A is available in a surface mounted 64-pin
flat package. Combining a numeric display driver, sin-
gle 9V battery operation, internal range switching, and
compact surface mounting, the TC818A is ideal for
advanced portable instruments.
2002 Microchip Technology Inc.
DS21475B-page 1