TC820CLW Microchip Technology, TC820CLW Datasheet - Page 16

• Manufacturer Part Number: TC820CLW
• Description: IC ADC 3 3/4DGT LGC PROBE 44PLCC
• Manufacturer: Microchip Technology

Specifications of TC820CLW

• Display Type: LCD
• Configuration: 7 Segment + 2 Annunciators
• Digits Or Characters: A/D 3.75 Digits
• Current - Supply: 1mA
• Voltage - Supply: 9V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -

TC820
4.2.1
EOC/HOLD is a dual purpose, bi-directional pin. As an
output, this pin goes low for 10 clock cycles at the end
of each conversion. This pulse latches the conversion
data into the display driver section of the TC820.
EOC/HOLD can be used to hold (or "FREEZE") the
display. Connecting this pin to V
update process. Conversions will continue, but the
display will not change. EOC/HOLD will hold the
display reading for either analog-to-digital, or frequency
measurements.
The input/output structure of the EOC/HOLD pin is
shown in
few microAmps, so EOC/HOLD can easily be over-
driven by an open collector logic gate, as well as a FET,
bipolar transistor, or mechanical switch. When used as
an output, EOC/HOLD will have a slow rise and fall
time due to the limited output current drive. A CMOS
Schmitt trigger buffer is recommended.
FIGURE 4-2:
DS21476C-page 16
EOC/HOLD
Figure
EOC/HOLD
4
4-2. The output drive current is only a
TC820
EOC/HOLD Pin.
≈ 500kΩ
DD
inhibits the display
EOC
Display
Update
4.2.2
The OR output will be high when the analog input
signal is greater than full scale (3999 counts). The UR
output will be high when the display reading is 380
counts or less.
The OR and UR outputs can be used to provide an
auto-ranging meter function. By logically ANDing these
outputs with the inverted EOC/HOLD output, a single
pulse will be generated each time an under ranged or
over ranged conversion occurs
FIGURE 4-3:
And Over Range Pulses.
4.2.3
The V
voltage. In the 40-pin package, V
internally to DGND, providing a typical LCD drive
voltage of 5V
separate V
variable or temperature compensated LCD drive volt-
age. See the applications information for suggested
circuits.
EOC/HOLD
DISP
OR
UR
OVER RANGE (OR),
UNDER RANGE (UR)
V
DISP
input sets the peak-to-peak LCD drive
DISP
P-P
. The 44-pin package includes a
input for applications requiring a
*74HC132
Generating Under Range
*
© 2007 Microchip Technology Inc.
(Figure
*
*
DISP
4-2).
is connected
TC820