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Электронный компонент: TC820CKW

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3-149
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
GENERAL DESCRIPTION
The TC820 is a 3-3/4 digit, multi-measurement system
especially suited for use in portable instruments. It inte-
grates a dual slope A/D converter, auto-ranging frequency
counter and logic probe into a single 44-pin surface mount
or 40-pin through hole package. The TC820 operates from
a single 9V input voltage (battery) and features a built-in
battery low flag. Function and decimal point selection are
accomplished with simple logic inputs designed for direct
connection to an external microcontroller or rotary switch.
Ease of use, low power operation and high functional
integration make the TC820 desirable in a variety of analog
measurement applications.
3-3/4 DIGIT A/D CONVERTER WITH FREQUENCY
COUNTER AND LOGIC PROBE
FEATURES
s
Multiple Analog Measurement System
-- Digit A/D Converter
-- Frequency Counter
-- Logic Probe
s
Low Noise A/D Converter:
-- Differential Inputs, (1pA Bias Current)
-- On-Chip 50PPM/
C Voltage Reference
s
Frequency Counter:
-- 4Mhz Maximum Input Frequency
-- Auto-ranging Over Four Decade Range
s
Logic Probe:
-- Two LCD Annunciators
-- Buzzer Driver
s
3-3/4 Digit Display with Overrange Indicator
s
LCD Display Driver with Built-in Contrast Control
s
Data Hold Input for Comparison Measurements
s
Low Battery Detect with LCD Annunciator
s
Underrange and Overrange Outputs
s
On-Chip Buzzer Driver with Control Input
s
44-Pin Plastic Flat Pack or PLCC or 40-Pin Plastic
DIP Packages
PEAK HOLD
COMPARATOR
3-3/4 DIGIT
A/D CONVERTER
LOW
BATTERY
DETECT
DECIMAL
POINT
DRIVERS
BUZZER
DRIVER
FUNCTION
SELECT
LOGIC
PROBE
AUTORANGING
FREQUENCY
COUNTER
CLOCK
OSCILLATOR
TRIPLE LCD
DRIVERS
LOW DRIFT VOLTAGE
DIFFERENTIAL
REFERENCE
LOGIC HIGH
LOGIC LOW
OVERRANGE
PKHOLD
LOW BATT
ANNUNCIATOR DRIVE
DECIMAL
POINT
SELECT
BUZZER
CONTROL
FUNCTION
SELECT
DIGITAL GROUND
TO LCD
AND BUZZER
PEAK
HOLD
LOGIC
PROBE
INPUT
FREQUENCY
INPUT
FULL-SCALE
SELECT
UNDERRANGE
OVERRANGE
ANALOG GND
VOLTS
FREQUENCY
LOGIC
TRIPLEX LCD
9V
TC820
ANALOG
INPUT
+
EOC
FUNCTIONAL BLOCK DIAGRAM
ORDERING INFORMATION
Temperature
Part No.
Resolution
Package
Range
TC820CKW
3-3/4 Digits
44-Pin Plastic
0
C to +70
C
Quad Flat Package
TC820CLW
3-3/4 Digits
44-Pin Plastic
0
C to +70
C
Leadless Chip
Carrier
TC820CPL
3-3/4 Digits
40-Pin Plastic DIP
0
C to +70
C
TC820-10 10/17/96
TC820
3-150
TELCOM SEMICONDUCTOR, INC.
3-3/4 DIGIT A/D CONVERTER WITH
FREQUENCY AND LOGIC PROBE
TC820
A "peak reading hold" input allows the TC820 to retain
the highest A/D or frequency reading. This feature is useful
in measuring motor starting current, maximum tempera-
ture, and similar applications.
A family of instruments can be created with the TC820.
No additional design effort is required to create instruments
with 3-3/4 digit resolution.
The TC820 operates from a single 9V battery, with
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
TC820
7106
3-3/4 Digit Resolution
Yes
No
Auto-Ranging Frequency Counter
Yes
No
Logic Probe
Yes
No
Decimal Point Drive
Yes
No
Peak Reading Hold
Yes
No
(Frequency or Voltage)
Display Hold
Yes
No
Simple 10:1 Range Change
Yes
No
Buzzer Drive
Yes
No
Low Battery Detection
Yes
No
With Annunciator
Overrange Detection
Yes
No
With Annunciator
Low Drift Reference
Yes
No
Underrange/Overrange
Yes
No
Logic Output
Input Overload Display
"OL"
"1"
LCD Annunciator Driver
Yes
No
LCD Drive Type
Triplexed
Direct
LCD Pin Connections
15
24
LCD Elements
36
23
GENERAL DESCRIPTION
The TC820 is a 3-3/4 digit measurement system com-
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.
With a maximum range of 3999 counts, the TC820
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.
The TC820's frequency counter option simplifies design
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.
Two logic level measurement inputs permit a TC820-
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.
Other TC820 features simplify instrument design and
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.
3-151
TELCOM SEMICONDUCTOR, INC.
7
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ELECTRICAL CHARACTERISTICS:
V
S
= 9V, T
A
= 25
C, unless otherwise specified.
Symbol
Parameter
Test Conditions
Min
Typ
Max
Units
Zero Input Reading
V
IN
= 0V
000
000
+000
Digital
Full Scale = 400 mV
Reading
RE
Roll-Over Error
V
IN
=
390mV
1
0.2
+1
Counts
Full-Scale = 400mV
NL
Nonlinearity (Maximum
Full-Scale = 400mV
1
0.2
+1
Count
Deviation From Best
Straight Line Fit)
Ratiometric Reading
V
IN
= V
REF
, TC820
1999
1999/2000
2000
Digital
CMRR
Common-Mode Rejection
V
CM
=
1V, V
IN
= 0V
--
50
--
V/V
Ratio
Full-Scale = 400mV
(V
FS
= 200 mV)
VCMR
Common-Mode Voltage
Input High, Input Low
V
SS
+ 1.5
--
V
DD
1
V
Range
e
N
Noise (P-P Value Not
V
IN
= 0V
--
15
--
V
Exceeded 95% of Time)
Full-Scale = 400mV
I
IN
Input Leakage Current
V
IN
= 0V
T
A
= 25
C
--
1
10
pA
0
C
T
A
+70
C
--
20
--
40
C
T
A
+85
C
--
100
--
V
COM
Analog Common Voltage
25 k
Between Common and V
DD
(V
SS
V
COM
)
3.15
3.3
3.45
V
V
CTC
Common Voltage
25 k
Between Common and V
DD
Temperature Coefficient
0
C
T
A
+70
C
--
35
50
ppm/
C
40
C
T
A
+85
C
--
50
--
TC
ZS
Zero Reading Drift
V
IN
= 0V
0
C
T
A
+70
C
--
0.2
--
V/
C
40
C
T
A
+85
C
1
TC
FS
Scale Factor
V
IN
= 399mV
Temperature Coefficient
0
C
T
A
+70
C
--
1
5
ppm/
C
40
C
T
A
+85
C
--
5
--
Ext Ref = 0 ppm/
C
I
S
Supply Current
V
IN
= 0V
--
1
1.5
mA
Peak-to-Peak Backplane
V
S
= 9V
4.25
4.7
5.3
V
Drive Voltage
V
DISP
= DGND
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage (V
DD
to GND) ..................................... 15V
Analog Input Voltage (Either Input) (Note 1) .... V
DD
to V
SS
Reference Input Voltage (Either Input) ............. V
DD
to V
SS
Digital Inputs ............................................... V
DD
to DGND
V
DISP
............................................. V
DD
to (DGND 0.3V)
Package Power Dissipation (T
A
70
C) (Note 2)
40-Pin Plastic DIP ............................................. 1.23W
44-Pin PLCC ..................................................... 1.23W
44-Pin Plastic Flat Package .............................. 1.00W
Operating Temperature Range
"C" Devices ............................................ 0
C to +70
C
"E" Devices ....................................... 40
C to +85
C
Storage Temperature Range ................ 65
C to +150
C
Lead Temperature (Soldering, 10 sec) ................... 300
C
*Static-sensitive devices. Unused devices should be stored in conductive
material to protect against static discharge and static fields. Stresses above
those listed under Absolute Maximum Ratings may cause permanent
damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions above those
indicated in the operational sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
NOTES: 1. Input voltages may exceed the supply voltages provided that
input current is limited to
100
A. Current above this value
may result in invalid display readings but will not destroy the
device if limited to
1mA.
2. Dissipation ratings assume device is mounted with all leads
soldered to printed circuit board.
TC820
3-3/4 DIGIT A/D CONVERTER WITH
FREQUENCY AND LOGIC PROBE
3-152
TELCOM SEMICONDUCTOR, INC.
ELECTRICAL CHARACTERISTICS (Cont.)
Symbol
Parameter
Test Conditions
Min
Typ
Max
Units
Buzzer Frequency
f
OSC
= 40kHz
--
5
--
kHz
Counter Timebase Period
f
OSC
= 40kHz
--
1
--
Second
Low Battery Flag Voltage
V
DD
to V
SS
6.7
7
7.3
V
V
IL
Input Low Voltage
--
--
DGND + 1.5
V
V
IH
Input High Voltage
V
DD
1.5
--
--
V
V
OL
Output Low Voltage,
I
L
= 50
A
--
--
DGND + 0.4
V
UR, OR Outputs
V
OL
Output High Voltage,
I
L
= 50
A
V
DD
1.5
--
--
V
UR, OR Outputs
Control Pin
V
IN
= V
DD
--
5
--
A
Pull-Down Current
PIN DESCRIPTION
Pin No.
Pin No.
(40-Pin
(44-Pin Flat
Package)
Package)
Symbol
Description
1
40
L-E4
LCD segment driver for L ("logic LOW"), polarity, and "e" segment of most
significant digit (MSD).
2
41
AGD4
LCD segment drive for "a," "g," and "d" segments of MSD.
3
42
BC4P3
LCD segment drive for "b" and "c" segments of MSD and decimal point 3.
4
43
HFE3
LCD segment drive for H ("logic HIGH"), and "f" and "e" segments of third LSD.
5
44
AGD3
LCD segment drive for "a," "g," and "d" segments of third LSD.
6
1
BC3P2
LCD segment drive for "b" and "c" segments of third LSD and decimal point 2.
7
2
OFE2
LCD segment drive for "overrange," and "f" and "e" segments of second LSD.
8
3
AGD2
LCD segment drive for "a," "g," and "d" segments of second LSD.
9
4
BC2P1
LCD segment drive for "b " and "c" segments of second LSD and decimal point 1.
10
5
PKFE1
LCD segment drive for "hold peak reading," and "f" and "e" segments of LSD.
11
6
AGD1
LCD segment drive for "a," "g," and "d" segments of LSD.
12
7
BC1BT
LCD segment drive for "b" and "c" segments of LSD and "low battery."
13
8
BP3
LCD backplane #3.
14
9
BP2
LCD backplane #2.
15
10
BP1
LCD backplane #1.
--
11
V
DISP
Sets peak LCD drive signal: V
PEAK
= (V
DD
) V
DISP
. V
DISP
may also be used to
compensate for temperature variation of LCD crystal threshold voltage.
16
12
DGND
Internal logic digital ground, the logic "0" level. Nominally 4.7V below V
DD
.
17
13
ANNUNC
Square-wave output at the backplane frequency, synchronized to BP1. ANNUNC
can be used to control display annunciators. Connecting an LCD segment to
ANNUNC turns it on; connecting it to its backplane turns it off.
18
14
LOGIC
Logic mode control input. When connected to V
DD
, the converter is in logic mode.
The LCD displays "OL" and the decimal point inputs control the HIGH and LOW
annunciators. When the "low" annunciator is on, the buzzer will also be on. When
unconnected or connected to DGND, the TC820 is in the voltage/frequency
measurement mode. This pin has a 5
A internal pull-down to DGND.
19
15
RANGE/
Dual-purpose input. In range mode, when connected to V
DD
, the integration time
FREQ
will be 200 counts instead of 2000 counts and the LCD will display the analog input
divided by 10. (See text for limitation with TC820.) In frequency mode, this pin is the
frequency input. A digital signal applied to this pin will be measured with a 1-second
time base. There is an internal 5
A pull-down to DGND.
3-3/4 A/D CONVERTER WITH
FREQUENCY COUNTER
AND LOGIC PROBE
TC820
3-153
TELCOM SEMICONDUCTOR, INC.
7
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8
PIN DESCRIPTION
Pin No.
Pin No.
(40-Pin
(44-Pin Flat
Package)
Package)
Symbol
Description
20
16
DP0/LO
Dual-purpose input. Decimal point select input for voltage measurements. In logic
mode, connecting this pin to V
DD
will turn on the "low" LCD segment. There is an
internal 5
A pull-down to DGND in volts mode only. Decimal point logic:
DP1
DP0
Decimal Point Selected
0
0
None
0
1
DP1
1
0
DP2
1
1
DP3
21
17
DP1/HI
Dual-purpose input. Decimal point select input for voltage measurements. In logic
mode, connecting this pin to V
DD
will turn on the "high" LCD segment. There is an
internal 5
A pull-down to DGND in volts mode only.
22
18
BUZOUT
Buzzer output. Audio frequency, 5kHz, output which drives a piezoelectric buzzer.
23
19
BUZIN
Buzzer control input. Connecting BUZIN to V
DD
turns the buzzer on. BUZIN is
logically ORed (internally) with the "logic level low" input. There is an internal 5
A
pull-down to DGND.
24
20
FREQ/
Voltage or frequency measurement select input. When unconnected, or connected
VOLTS
to DGND, the A/D converter function is active. When connected to V
DD
, the
frequency counter function is active. This pin has an internal 5
A pull-down
to DGND.
25
21
PKHOLD
Peak hold input. When connected to V
DD
, the converter will only update the display
if a new conversion value is greater than the preceding value. Thus, the peak
reading will be stored and held indefinitely. When unconnected, or connected to
DGND, the converter will operate normally. This pin has an internal 5
A pull-down
to DGND.
22
UR
Underrange output. This output will be HIGH when the digital reading is 380 counts
or less.
23
OR
Overrange output. This output will be HIGH when the analog signal input is greater
than full scale. The LCD will display "OL" when the input is overranged.
26
24
V
SS
Negative supply connection. Connect to negative terminal of 9V battery.
27
25
COM
Analog circuit ground reference point. Nominally 3.3V below V
DD
.
28
26
C
+
REF
Positive connection for reference capacitor.
29
27
C
REF
Negative connection for reference capacitor.
30
28
V
+
REF
High differential reference input connection.
31
29
V
REF
Low differential reference input connection.
32
30
V
IN
Low analog input signal connection.
33
31
V
+
IN
High analog input signal connection.
34
32
V
BUFF
Buffer output. Connect to integration resistor.
35
33
C
AZ
Auto-zero capacitor connection.
36
34
V
INT
Integrator output. Connect to integration capacitor.
35
EOC/
Bidirectional pin. Pulses low (i.e., from V
DD
to DGND) at the end of each
HOLD
conversion. If connected to V
DD
, conversions will continue, but the display is not
updated.
37
36
OSC1
Crystal oscillator (input) connection.
38
37
OSC2
Crystal oscillator (output) connection.
39
38
OSC3
RC oscillator connection.
40
39
V
DD
Positive power supply connection, typically 9V.
TC820
3-3/4 A/D CONVERTER WITH
FREQUENCY COUNTER
AND LOGIC PROBE