TC815 Datasheet, PDF (1/26 Pages) Microchip Technology – 3-1/2 Digit Auto-Ranging A/D Converter with Triplex LCD Drive and Display Hold Function

TC815
3-1/2 Digit Auto-Ranging A/D Converter with
Triplex LCD Drive and Display Hold Function
Features
• 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
- 9 Resistance and Low Power Ohms
• Display HOLD Function
• 3-1/2 Digit Resolution in Auto-Range Mode:
- 1/2000
• Extended Resolution in Manual Mode: 1/3000
• Memory Mode for Relative Measurements:
- ±5% F.S.
• Internal AC to DC Conversion Op Amp
• Triplex LCD Drive for Decimal Points, Digits
and Annunciators
• Continuity Detection and Piezoelectric
Transducer Driver
• Compact Surface Mounted 64-pin
Plastic Flat Package
• Low Drift Internal Reference: 75ppm/°C
• 9V Battery Operation: 10mW
• Low Battery Detection and LCD Annunciator
Device Selection Table
Part Number
TC815CBU
Package
64-Pin PQFP
Operating
Temperature Range
0°C to +70°C
General Description
The TC815 is a 3-1/2 digit integrating analog-to-digital
converter with triplex LCD display drive and automatic
ranging. A display hold function is on-chip. Input volt-
age/ohm attenuators ranging from 1 to 1/10,000 are
automatically selected. Five full scale ranges are pro-
vided. The CMOS TC815 contains all the logic and
analog switches needed to manufacture an auto-
ranging instrument for ohms and voltage measure-
ments. User selected 20mA and 200mA current ranges
are available. Full scale range and decimal point LCD
annunciators are automatically set in auto-range oper-
ation. Auto-range operation is available during ohms
(high and low power ohms) and voltage (AC and DC)
measurements, eliminating expensive range switches
in hand-held DMM designs. The auto-range feature
may be bypassed allowing decimal point selection and
input attenuator selection control through a single line
input. Expensive rotary switches are not required.
During Manual mode operation, resolution is extended
to 3000 counts full scale. The extended range opera-
tion is indicated by a flashing 1 MSD. The extended
resolution is also available during 200kΩ and 2000V
full scale auto-range operation.
The Memory mode subtracts a reading, up to ±5% of
full scale from subsequent measurements. Typical
applications involve probe resistance compensation for
resistance measurements, tolerance measurements,
and tare weight measurements.
The TC815 includes an AC to DC converter for
AC measurements. Only external diodes/resistors/
capacitors are required.
A complete LCD annunciator set describes the TC815
meter function and measurement range during ohms,
voltage and current operation. AC measurements are
indicated as well as auto-range operation. A low battery
detection circuit also sets the low battery display
annunciator. The triplex LCD display drive levels may
be set and temperature compensation applied via the
V_DISP pin. With HOLD low, the display is not updated.
A HOLD mode LCD annunciator is activated.
The “low ohms” measurement option allows in-circuit
resistance measurements by preventing semiconduc-
tor junctions from being forward biased.
© 2002 Microchip Technology Inc.
DS21474B-page 1