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TC811
3-1/2 DIGIT A/D CONVERTER WITH HOLD AND DIFFERENTIAL
REFERENCE INPUTS
FEATURES
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Differential Reference Input
Display Hold Function
Fast Over-Range Recovery, Guaranteed Next
Reading Accuracy
Low Temperature Drift Internal
Reference ....................................... 35ppm/
°
C (Typ)
Guaranteed Zero Reading With Zero Input
Low Noise ..................................................... 15
µ
V
p-p
High Resolution (0.05%) and Wide Dynamic
Range (72 dB)
High Impedance Differential Input
Low Input Leakage Current ....................... 1pA Typ
10pA Max
Direct LCD Drive – No External Components
Precision Null Detection with True Polarity at Zero
Crystal Clock Oscillator
Available in DIP, Compact Flat Package or PLCC
Convenient 9V Battery Operation with
Low Power Dissipation (600
µ
A Typical, 1mW
Maximum)
2
3
4
Max V
REF
Tempco
TYPICAL APPLICATIONS
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Thermometry
Digital Meters
— Voltage/Current/Power
— pH Measurement
— Capacitance/Inductance
— Fluid Flow Rate/Viscosity
— Humidity
— Position
Panel Meters
LVDT Indicators
Portable Instrumentation
Digital Scales
Process Monitors
Gaussometers
Photometers
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ORDERING INFORMATION
Part No.
Package
Temp.
Range
FUNCTIONAL BLOCK DIAGRAM
TC811CKW 44-PQFP
0°C to +70°C 75 ppm/°C
TC811CPL 40-Pin Plastic DIP 0°C to +70°C 75 ppm/°C
TYPICAL SEGMENT OUTPUT
+
V
0.5mA
SEGMENT
OUTPUT
2mA
5
6
7
LCD DISPLAY
TC811CPL
INTERNAL DIGITAL GROUND
BACKPLANE
21
+
C REF
+
VREF
35
36
CREF
–
VREF
33
RINT
–
C REF V BUFF
34
28
V
+
38
CAZ
CINT
VINT
LCD SEGMENT DRIVERS
29
INTEGRATOR
27
TO
DIGITAL
SECTION
7 SEGMENT
DECODE
7 SEGMENT
DECODE
7 SEGMENT
DECODE
200
10
µA
31
INT
A/Z
32
ZI & A/Z
ZI &
A/Z
–
+
ZI
–
+
+
–
DATA LATCH
A/Z
COMPARATOR
THOUSANDS
HUNDREDS
TENS
UNITS
+
V IN
DE
(–)
DE
(+)
–
LOW
TEMPCO
VREF
ANALOG
COMMON
DE (+)
DE (–)
+
V+– 3.0V
TO SWITCH DRIVERS
FROM COMPARATOR OUTPUT
CLOCK
fOSC
≈70kΩ
4
CONTROL LOGIC
38
6.2V
V+
– 30
V IN
INT
AZ & DE (±)
26
–
INTERNAL DIGITAL GOUND
TEST
VTH
= 1V
1
500Ω
26
V–
V
40
OSC 1
39
22MΩ
OSC 2
HLDR
470k
V
+
10pF
kH
20pF
V
+
8
TC811-7 11/5/96
TELCOM SEMICONDUCTOR, INC.
3-137
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
