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Электронный компонент: ICL8212MTY

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7-161
TM
Description
The Intersil ICL8211/8212 are micropower bipolar monolithic
integrated circuits intended primarily for precise voltage
detection and generation. These circuits consist of an
accurate voltage reference, a comparator and a pair of
output buffer/drivers.
Specifically, the ICL8211 provides a 7mA current limited out-
put sink when the voltage applied to the `THRESHOLD'
terminal is less than 1.15V (the internal reference). The
ICL8212 requires a voltage in excess of 1.15V to switch its
output on (no current limit). Both devices have a low current
output (HYSTERESIS) which is switched on for input
voltages in excess of 1.15V. The HYSTERESIS output may
be used to provide positive and noise free output switching
using a simple feedback network.
Ordering Information
PART NUMBER
TEMPERATURE
RANGE
PACKAGE
ICL8211CPA
0
o
C to +70
o
C
8 Lead Plastic DIP
ICL8211CBA
0
o
C to +70
o
C
8 Lead SOlC (N)
ICL8211CTY
0
o
C to +70
o
C
8 Pin Metal Can
ICL8211MTY
(Note 1)
-55
o
C to +125
o
C
8 Pin Metal Can
ICL8212CPA
0
o
C to +70
o
C
8 Lead Plastic DIP
ICL8212CBA
0
o
C to +70
o
C
8 Lead SOlC (N)
ICL8212CTY
0
o
C to +70
o
C
8 Pin Metal Can
ICL8212MTY
(Note 1)
-55
o
C to +125
o
C
8 Pin Metal Can
NOTE:
1. Add /883B to part number if 883B processing is required
Features
High Accuracy Voltage Sensing and Generation
Internal Reference 1.15V Typical
Low Sensitivity to Supply Voltage and Temperature
Variations
Wide Supply Voltage Range Typ. 1.8V to 30V
Essentially Constant Supply Current Over Full Supply
Voltage Range
Easy to Set Hysteresis Voltage Range
Defined Output Current Limit ICL8211
High Output Current Capability ICL8212
Applications
Low Voltage Sensor/Indicator
High Voltage Sensor/Indicator
Nonvolatile Out-of-Voltage Range Sensor/Indicator
Programmable Voltage Reference or Zener Diode
Series or Shunt Power Supply Regulator
Fixed Value Constant Current Source
FN3184.2
October 1999
Pinouts
ICL8211 (PDIP, SOIC)
TOP VIEW
ICL8211 (CAN)
TOP VIEW
NC
HYSTERESIS
THRESHOLD
OUTPUT
1
2
3
4
8
7
6
5
V+
NC
NC
GROUND
HYSTERESIS
NC
OUTPUT
GROUND
THRESHOLD
NC
V+
NC
2
4
6
1
3
7
5
8
ICL8211, ICL8212
Programmable Voltage Detectors
OBSO
LETE
PROD
UCT
NO RE
COMM
ENDE
D REP
LACE
MENT
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
|
Intersil (and design) is a trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2002. All Rights Reserved
7-162
ICL8211, ICL8212
Functional Diagram
X X X X
Q2
Q3
Q4
Q6
Q5
Q1
R1
20M
Q7
Q8
1.15V
V
REF
R3
360k
Q9
Q10
Q11
R2
30k
Q12
Q13
Q20
R6
100k
V+
HYST
THRESHOLD
OUTPUT
GROUND
8
2
3
4
5
Q21
Q14 Q15
R4
1M
R5
4.5k
Q17
Q18
Q16
Q19
X X X X X X
ICL8211 OPTION
ICL8212 OPTION
VOLTAGE REFERENCE
COMPARATOR
OUTPUT BUFFERS
Q23
7-163
Specifications ICL8211, ICL8212
Absolute Maximum Ratings
Thermal Information
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to +30V
Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to +30V
Hysteresis Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.5V to -10V
Threshold Input Voltage . . . . . . . . . . . . . +30V to -5V with respect to
GROUND and +0V to -30V with respect to V+
Current into Any Terminal
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30mA
Thermal Resistance
JA
JC
Plastic DIP Package . . . . . . . . . . . . . . . .
150
o
C/W
-
Plastic SOIC Package . . . . . . . . . . . . . . .
180
o
C/W
-
Metal Can . . . . . . . . . . . . . . . . . . . . . . . .
156
o
C/W
68
o
C/W
Lead Temperature (Soldering, 10s). . . . . . . . . . . . . . . . . . . . . 300
o
C
(SOIC - Lead Tips Only)
Current into Any Terminal
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30mA
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
Operating Conditions
Operating Temperature Range
ICL8211M/8212M . . . . . . . . . . . . . . . . . . . . . . . . -55
o
C to +125
o
C
ICL8211C/8212C . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
o
C to +70
o
C
Storage Temperature Range . . . . . . . . . . . . . . . . . . -65
o
C to +150
o
C
Electrical Specifications
V+ = 5V, T
A
= +25
o
C Unless Otherwise Specified
PARAMETER
SYMBOL
TEST CONDITIONS
ICL8211 ICL8212
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
Supply Current
I+
2.0 < V+ < 30
V
TH
= 1.3V
10
22
40
50
110
250
A
V
TH
= 0.9V
50
140
250
10
20
40
A
Threshold Trip Voltage
V
TH
I
OUT
= 4mA
V
OUT
= 2V
V+ = 5V
0.98
1.15
1.19
1.00
1.15
1.19
V
V+ = 2V
0.98
1.145
1.19
1.00
1.145
1.19
V
V+ = 30V
1.00
1.165
1.20
1.05
1.165
1.20
V
Threshold Voltage
Disparity Between
Output & Hysteresis
Output
V
THP
I
OUT
= 4mA
I
HYST
= 7mA
V
OUT
= 2V
V
HYST
= 3V
-
-0.8
-
-
-0.5
-
mV
Guaranteed Operating
Supply Voltage Range
V
SUPPLY
+25
o
C (Note 3)
2.0
-
30
2.0
-
30
V
0
o
C to +70
o
C (Note 3)
2.2
-
30
2.2
-
30
V
Minimum Operating
Supply Voltage Range
V
SUPPLY
+25
o
C
-
1.8
-
-
1.8
-
V
+125
o
C
-
1.4
-
-
1.4
-
V
-55
o
C
-
1.5
-
-
2.5
-
V
Threshold Voltage Tem-
perature Coefficient
V
TH
/
T
I
OUT
= 4mA, V
OUT
= 2V
-
200
-
-
200
-
ppm/
o
C
Variation of Threshold
Voltage with Supply
Voltage
V
TH
/
V+
V+ = 10% at V+ = 5V
-
1.0
-
-
1.0
-
mV
Threshold Input Current
I
TH
V
TH
= 1.15V
-
100
250
-
100
250
nA
V
TH
= 1.00V
-
5
-
-
5
-
nA
Output Leakage Current
I
OLK
V
OUT
= 30V
V
TH
= 0.9V
-
-
-
-
-
10
A
V
TH
= 1.3V
-
-
10
-
-
-
A
V
OUT
= 5V
V
TH
= 0.9V
-
-
-
-
-
1
A
V
TH
= 1.3V
-
-
1
-
-
-
A
Output Saturation
Voltage
V
SAT
I
OUT
= 4mA
V
TH
= 0.9V
-
0.17
0.4
-
-
-
V
V
TH
= 1.3V
-
-
-
-
0.17
0.4
V
Max Available Output
Current
I
OH
(Notes 3 & 4)
V
OUT
= 5V
V
TH
= 0.9V
4
7.0
12
-
-
-
mA
V
TH
= 1.3V
-
-
-
15
35
-
mA
Hysteresis Leakage
Current
I
LHYS
V+ = 10V,
V
HYST
= GND
V
TH
= 1.0V
-
-
0.1
-
-
0.1
A
7-164
ICL8211, ICL8212
Hysteresis Sat Voltage
V
HYS(MAX)
I
HYST
= -7
A,
measured with
respect to V+
V
TH
= 1.3V
-
-0.1
-0.2
-
-0.1
-0.2
V
Max Available
Hysteresis Current
I
HYS (MAX)
V
TH
= 1.3V
-15
-21
-
-15
-21
-
A
Electrical Specifications
ICL8211MTY/8212MTY
V+ = 5V, T
A
= -55
o
C to +125
o
C
PARAMETER
SYMBOL
TEST CONDITIONS
ICL8211
ICL8212
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
Supply Current
I+
2.8 < V+ < 30
-
-
-
-
-
-
-
V
T
= 1.3V
-
-
100
-
350
350
A
V
T
= 0.8V
-
-
350
-
100
100
A
Threshold Trip Voltage
V
TH
I
OUT
= 2mA
V
OUT
= 2V
V+ = 2.8V
0.80
-
1.30
0.80
-
1.30
V
V+ = 30V
0.80
-
1.30
0.80
-
1.30
V
Guaranteed Operating
Supply Voltage Range
V
SUPPLY
(Note 5)
2.8
-
30
2.8
-
30
V
Threshold Input Current
I
TH
V
TH
= 1.15V
-
-
400
-
-
400
nA
Output Leakage Current
I
OLK
V
OUT
= 30V
V
TH
= 0.8V
-
-
-
-
-
20
A
V
TH
= 1.3V
-
-
20
-
-
-
A
Output Saturation
Voltage
V
SAT
I
OUT
= 3mA
V
TH
= 0.8V
-
-
0.5
-
-
-
V
V
TH
= 1.3V
-
-
-
-
-
0.5
V
Max Available Output
Current
I
OH
(Notes 3 & 4)
V
OUT
= 5V
V
TH
= 0.8
3
-
15
-
-
-
mA
V
TH
= 1.3V
-
-
-
9
-
-
mA
Hysteresis Leakage
Current
I
LHYS
V+ = 10V
V
HYST
= GND
V
TH
= 0.8V
-
-
0.2
-
-
0.2
A
Hysteresis Saturation
Voltage
V
HYS(MAX)
I
HYST
= -7
A
measured with
respect to V+
V
TH
= 1.3V
-
-
0.3
-
-
0.3
V
Max Available
Hysteresis Current
I
HYS (MAX)
V
TH
= 1.3V
10
-
-
10
-
-
A
NOTES:
1. The maximum output current of the ICL8211 is limited by design to 15mA under any operating conditions. The output voltage may be
sustained at any voltage up to +30V as long as the maximum power dissipation of the device is not exceeded.
2. The maximum output current of the ICL8212 is not defined. And systems using the ICL8212 must therefore ensure that the output current
does not exceed 30mA and that the maximum power dissipation of the device is not exceeded.
3. Threshold Trip Voltage is 0.80V(min) to 1.30V(mas). At I
OUT
= 3mA.
Electrical Specifications
V+ = 5V, T
A
= +25
o
C Unless Otherwise Specified
(Continued)
PARAMETER
SYMBOL
TEST CONDITIONS
ICL8211 ICL8212
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
7-165
ICL8211, ICL8212
Typical Performance Curves
(ICL8211 and ICL8212)
FIGURE 1. THRESHOLD INPUT CURRENT AS A FUNCTION OF
THRESHOLD VOLTAGE
FIGURE 2. HYSTERESIS OUTPUT SATURATION CURRENT AS
A FUNCTION OF TEMPERATURE
Typical Performance Curves
(ICL8211 ONLY)
FIGURE 3. SUPPLY CURRENT AS A FUNCTION OF SUPPLY
VOLTAGE
FIGURE 4. SUPPLY CURRENT AS A FUNCTION OF THRESH-
OLD VOLTAGE
10,000
1,000
100
10
0.0
1.1
1.15 1.2
2.0
3.0
6.0
8.0
10.0
THRESHOLD VOLTAGE (V
TH
)
(IRREGULAR SCALE)
T
HRE
S
H
O
L
D INP
U
T
CURRE
NT
(
n
A)
T
A
= +25
o
C
V+ = +10V
ICL8211 OR ICL8212
0
-5
-10
-20
-25
-30
-40
-20
0
+20
+40
+60
+80
TEMPERATURE (
o
C)
HY
S
T
E
R
E
S
IS
O
U
T
P
UT
CURRE
NT
(
A)
ICL8211 OR ICL8212
(OR -0.5V WITH RESPECT
TO V+ SUPPLY)
V+ = +5V
V
TH
= 1.2V
V
HYS
= 4.5V
150
125
100
75
50
25
0
10
20
30
SUPPLY VOLTAGE
S
U
P
P
L
Y
CURRE
NT

(
A)
V
TH
= 0.9V
V
TH
= 1.3V
T
A
= +25
o
C
OUTPUTS OPEN CIRCUIT
150
125
100
75
50
25
0.0
1.0
1.1
1.15
1.2
2.0
4.0
THRESHOLD VOLTAGE (V
TH
)
(IRREGULAR SCALE)
T
A
= +25
o
C
V+ = +5V
OUTPUTS OPEN
S
U
P
P
L
Y
CURRE
NT
(
A)
0
CIRCUIT
7-166
ICL8211, ICL8212
FIGURE 5. SUPPLY CURRENT AS A FUNCTION OF TEMPERA-
TURE
FIGURE 6. OUTPUT SATURATION CURRENTS AS A FUNC-
TION OF THRESHOLD VOLTAGE
FIGURE 7. THRESHOLD VOLTAGE TO TURN OUTPUTS "JUST
ON" AS A FUNCTION OF TEMPERATURE
FIGURE 8. THRESHOLD VOLTAGE TO TURN OUTPUTS "JUST
ON" AS A FUNCTION OF SUPPLY VOLTAGE
FIGURE 9. OUTPUT SATURATION CURRENT AS A FUNCTION
OF TEMPERATURE
FIGURE 10. OUTPUT CURRENT AS A FUNCTION OF OUTPUT
VOLTAGE
Typical Performance Curves
(ICL8211 ONLY)
(Continued)
S
U
P
P
L
Y
CURRE
NT
(
A)
150
125
100
75
50
25
-55
-25
+5
+35
+65
+95
+125
TEMPERATURE
o
C
V
TH
= 0.9V
V
TH
= 1.3V
0
12
8
6
4
2
0
10
1.12
1.13
1.14
1.15
1.16
1.17
1.18
THRESHOLD VOLTAGE
O
U
T
P
UT
CURRE
NT

(
m
A)
HYSTERESIS
OUTPUT
T
A
= +25
o
C
V+ = +5V
V
O
= 0.5V
V
HYS
= V+ - 0.25V
0
-5
-10
-15
-20
-25
-30
HY
S
T
E
R
E
S
IS
O
U
T
P
UT
CURRE
NT
(
A)
8mV
OUTPUT
1.15
1.14
1.13
-55
-25
+5
+35
+65
+95
+125
TEMPERATURE (
o
C)
T
HRE
S
H
O
L
D V
O
L
T
AG
E
OUTPUT
HYSTERESIS OUTPUT
V+ = +5V
I
O
= 1mA, V
OUT
= +5V
I
HYS
= -7
A, V
HST
= 0V
1.18
1.17
1.16
1.15
1.14
1.13
1
2
3 4 5
10
20 30 4050
100
SUPPLY VOLTAGE
T
HRE
S
H
O
L
D V
O
L
T
AG
E
HYSTERESIS OUTPUT
OUTPUT
I
O
= 4mA, V
O
= 1V
I
HYS
= -7
A, V
HYS
= (V+ -2) V
8
7
6
5
O
U
T
P
UT
CURRE
NT
(
m
A)
-55
-25
+5
+35
+65
+95
+125
V+ = +5V
V
TH
= 1.1V
V
O
= 1.0V
TEMPERATURE (
o
C)
12
9
6
3
0
O
U
T
P
UT
CURRE
NT

(
m
A)
0.1
1.0
10.0
100.0
OUTPUT VOLTAGE
V
TH
= 1.0V
V
TH
= 1.152V
V
TH
= 1.147V
T
A
= +25
o
C
V+ = +5V
(
A)
0
-5
V = 1.143V
7-167
ICL8211, ICL8212
Typical Performance Curves
(ICL8212 ONLY)
FIGURE 12. SUPPLY CURRENT AS A FUNCTION OF SUPPLY
VOLTAGE
FIGURE 13. SUPPLY CURRENT AS A FUNCTION OF THRESH-
OLD VOLTAGE
FIGURE 14. SUPPLY CURRENT AS A FUNCTION OF TEMPER-
ATURE
FIGURE 15. OUTPUT SATURATION CURRENTS AS A FUNC-
TION OF THRESHOLD VOLTAGE
FIGURE 16. THRESHOLD VOLTAGE TO TURN OUTPUTS "JUST
ON" AS A FUNCTION OF TEMPERATURE
FIGURE 17. THRESHOLD VOLTAGE TO TURN OUTPUTS "JUST
ON" AS A FUNCTION OF SUPPLY VOLTAGE
150
125
100
75
50
25
0
0
10
20
30
SUPPLY VOLTAGE
S
U
P
P
L
Y
CURRE
NT
(
A)
V
TH
= 0.9V
V
TH
= 1.3V
T
A
= +25
o
C
OUTPUTS OPEN CIRCUIT
150
125
100
75
50
25
0
0.0
1.0
1.1
1.15
1.2
2.0
4.0
THRESHOLD VOLTAGE (V
TH
)
(IRREGULAR SCALE)
S
U
P
P
L
Y
CURRE
NT
-
I+ (
A)
T
A
= +25
o
C
V+ = +5V
OUTPUTS OPEN CIRCUIT
150
125
100
75
50
25
-55
-25
+5
+35
+65
+95
+125
S
U
P
P
L
Y
CURRE
NT
-
I
+
(
A)
TEMPERATURE (
o
C)
0
V
TH
= 1.3V
V
TH
= 0.9V
V+ = 5V
OUTPUTS
OPEN
CIRCUIT
30
25
20
15
10
5
0
O
U
T
P
UT
CURRE
NT

(
m
A)
1.14
1.15
1.16
1.17
1.18
1.19
1.20
THRESHOLD VOLTAGE
0
-5
-10
-15
-20
-25
-30
HY
S
T
E
R
E
S
I
S
O
U
T
P
UT
CURRE
NT
(
A)
T
A
= +25
o
C
V+ = 5V
V
OUT
= 4V
V
HYS
= V+ -0.25V
HYSTERESIS OUTPUT
OUTPUT
1.17
1.16
1.15
1.14
-55
-25
+5
+35
+65
+95
+125
TEMPERATURE (
o
C)
BOTH OUTPUT AND
HYSTERESIS OUTPUT
I
O
= 1mA, V
OUT
= 5V
I
HYS
= -7
A, V
HYS
= 0V
T
HRE
S
H
O
L
D V
O
L
T
AG
E
1.18
1.17
1.16
1.15
1.14
1.13
1
2
3
4 5
10
20 30 4050
100
SUPPLY VOLTAGE
T
HRE
S
H
O
L
D V
O
L
T
A
G
E
BOTH OUTPUT AND
HYSTERESIS OUTPUT
T
A
= +25
o
C
I
OUT
= 4mA, V
OUT
= 1V
I
HYS
= -7
A, V
HYS
= (V+ -2) V
7-168
ICL8211, ICL8212
Typical Performance Curves
(ICL8212 ONLY)
(Continued)
FIGURE 18. OUTPUT SATURATION VOLTAGE AND CURRENT
AS A FUNCTION OF TEMPERATURE
FIGURE 19. OUTPUT CURRENT AS A FUNCTION OF OUTPUT
VOLTAGE
FIGURE 20. HYSTERESIS OUTPUT CURRENT AS A FUNCTION
OF HYSTERESIS OUTPUT VOLTAGE
-55
-25
+5
+35
+65
+95
+125
TEMPERATURE (
o
C)
0.6
0.5
0.4
0.3
0.2
0.1
0
O
U
T
P
UT
S
A
T
URA
T
I
O
N

V
O
L
T
AG
E
OUTPUT SAT.
CURRENT
VOLTAGE SAT.
CURRENT
V+ = +5V
V
TH
= 1.2V
(V
O
= 4.0V)
(I
O
= 10mA)
40
30
20
10
0
0.1
1.0
10.0
30.0 100.0
OUTPUT VOLTAGE
O
U
T
P
UT
CURRE
NT
(
m
A)
V
TH
= 1.153V
V
TH
=1.25V
V
TH
= 1.158V
T
A
= +25
o
C
V+ = +5V
0
-5
-10
-15
-20
-25
-30
-35
-40
-10.00
-1.00
-0.10
-0.01
HYSTERESIS OUTPUT VOLTAGE
HY
S
T
E
R
E
S
I
S
O
U
T
P
UT
CURRE
NT
(
A)
V
T
= 1.18V
V
T
= 1.153V
V
T
= 1.152V
T
A
= +25
o
C
V+ = +10V
Detailed Description
The ICL8211 and ICL8212 use standard linear bipolar
integrated circuit technology with high value thin film
resistors which define extremely low value currents.
Components Q
1
through Q
10
and R
1
, R
2
and R
3
set up an
accurate voltage reference of 1.15V. This reference voltage
is close to the value of the bandgap voltage for silicon and is
highly stable with respect to both temperature and supply
voltage. The deviation from the bandgap voltage is
necessary due to the negative temperature coefficient of the
thin film resistors (-5000 ppm per
o
C).
Components Q
2
through Q
9
and R
2
make up a constant
current source; Q
2
and Q
3
are identical and form a current
mirror. Q
8
has 7 times the emitter area of Q
9
, and due to the
current mirror, the collector currents of Q
8
and Q
9
are forced
to be equal and it can be shown that the collector current in
Q
8
and Q
9
is
or approximately 1
A at +25
o
C
Transistors Q
5
, Q
6
, and Q
7
assure that the V
CE
of Q
3
, Q
4
,
and Q
9
remain constant with supply voltage variations. This
ensures a constant current supply free from variations.
The base current of Q
1
provides sufficient start up current for
the constant source; there being two stable states for this
type of circuit - either ON as defined above, or OFF if no start
up current is provided. Leakage current in the transistors is
not sufficient in itself to guarantee reliable startup.
Q
4
is matched to Q
3
and Q
2
; Q
10
is matched to Q
9
. Thus the
IC and V
BE
of Q
10
are identical to that of Q
9
or Q
8
. To
generate the bandgap voltage, it is necessary to sum a
voltage equal to the base emitter voltage of Q
9
to a voltage
proportional to the difference of the base emitter voltages of
two transistors Q
8
and Q
9
operating at two current densities.
The total supply current consumed by the voltage reference
section is approximately 6
A at room temperature. A voltage
at the THRESHOLD input is compared to the reference 1.15V
by the comparator consisting of transistors Q
11
through Q
17
.
The outputs from the comparator are limited to two diode
drops less than V+ or approximately 1.1V. Thus the base cur-
rent into the hysteresis output transistor is limited to about
500nA and the collector current of Q
19
to 100
A.
In the case of the ICL8211, Q
21
is proportioned to have 70
times the emitter area of Q
20
thereby limiting the output
current to approximately 7mA, whereas for the ICL8212
IC (Q
8
or Q
9
) =
1
x
kT
In7
R2
q
Where k = Boltzman's Constant
q = Charge on an Electron
and T = Absolute Temperature in
o
K
Thus 1.5 = V
BE
(Q
9
or Q
10
) +
R
3
x
kT
R
2
q
which provides:
R
3
= 12 (approximately.)
R
2
7-169
ICL8211, ICL8212
almost all the collector current of Q
19
is available for base
drive to Q
21
, resulting in a maximum available collector
current of the order of 30mA. It is advisable to externally limit
this current to 25mA or less.
Applications
The ICL8211 and ICL8212 are similar in many respects, espe-
cially with regard to the setup of the input trip conditions and
hysteresis circuitry. The following discussion describes both
devices, and where differences occur they are clearly noted.
General Information
Threshold Input Considerations
Although any voltage between -5V and V+ may be applied to
the THRESHOLD terminal, it is recommended that the
THRESHOLD voltage does not exceed about +6V since
above that voltage the threshold input current increases
sharply. Also, prolonged operation above this voltage will
lead to degradation of device characteristics.
The outputs change states with an input THRESHOLD
voltage of approximately 1.15V. Input and output waveforms
are shown in Figure 21 for a simple 1.15V level detector.
FIGURE 21. VOLTAGE LEVEL DETECTION
The HYSTERESIS output is a low current output and is
intended primarily for input threshold voltage hysteresis
applications. If this output is used for other applications it is
suggested that output currents be limited to 10
A or less.
The regular OUTPUT's from either the ICL8211 or ICL8212
may be used to drive most of the common logic families
such as TTL or CMOS using a single pullup resistor. There is
a guaranteed TTL fanout of 2 for the ICL8211 and 4 for the
ICL8212.
A principal application of the ICL8211 is voltage level
detection, and for that reason the OUTPUT current has been
limited to typically 7mA to permit direct drive of an LED
connected to the positive supply without a series current
limiting resistor.
On the other hand the ICL8212 is intended for applications
such as programmable zener references, and voltage
regulators where output currents well in excess of 7mA are
desirable. Therefore, the output of the ICL8212 is not current
limited, and if the output is used to drive an LED, a series
current limiting resistor must be used.
In most applications an input resistor divider network may be
used to generate the 1.15V required for V
TH
. For high accu-
racy, currents as large as 50
A may be used, however for
those applications where current limiting may be desirable,
(such as when operating from a battery) currents as low as
6mA may be considered without a great loss of accuracy.
6mA represents a practical minimum, since it is about this
level where the device's own input current becomes a signif-
icant percentage of that flowing in the divider network.
FIGURE 22. OUTPUT LOGIC INTERFACE
FIGURE 23. INPUT RESISTOR NETWORK CONSIDERATIONS
Case 1. High accuracy required, current in resistor network
unimportant Set I = 50
A for V
TH
= 1.15V
R
1
20k
Case 2. Good accuracy required, current in resistor network
important Set I = 7.5
A for V
TH
= 1.15V
R
1
150k
1
2
3
4
8
7
6
5
INPUT VOLTAGE
(RECOMMENDED
RANGE -5 TO +5V)
V
TH
V+
(V+ MUST BE
EQUAL OR
EXCEED 1.8V)
R
L1
V
O
V
HYST
V
O2
V
O1
R
L2
0
V+
1.15V
0V
V+
0V
ICL8211 OUTPUT
ICL8212 OUTPUT
1
2
3
4
8
7
6
5
V
TH
V+
PULLUP RESISTOR
CMOS OR
TTL GATES
1
2
3
4
8
7
6
5
V
TH
V+
INPUT
V-
R
1
R
2
7-170
ICL8211, ICL8212
FIGURE 24. RANGE OF INPUT VOLTAGE GREATER THAN
+1.15 VOLTS
Setup Procedures For Voltage Level Detection
Case 1. Simple voltage detection no hysteresis
Unless an input voltage of approximately 1.15V is to be
detected, resistor networks will be used to divide or multiply
the unknown voltage to be sensed. Figure 25 shows
procedures on how to set up resistor networks to detect
INPUT VOLTAGES of any magnitude and polarity.
FIGURE 25. INPUT RESISTOR NETWORK SETUP
PROCEDURES
For supply voltage level detection applications the input
resistor network is connected across the supply terminals as
shown in Figure 26.
FIGURE 26. COMBINED INPUT AND SUPPLY VOLTAGES
Case 2. Use of the HYSTERESIS function
The disadvantage of the simple detection circuits is that
there is a small but finite input range where the outputs are
neither totally `ON' nor totally `OFF'. The principle behind
hysteresis is to provide positive feedback to the input trip
point such that there is a voltage difference between the
input voltage necessary to turn the outputs ON and OFF.
The advantage of hysteresis is especially apparent in
electrically noisy environments where simple but positive
voltage detection is required. Hysteresis circuitry, however,
is not limited to applications requiring better noise perfor-
mance but may be expanded into highly complex systems
with multiple voltage level detection and memory applica-
tions-refer to specific applications section.
There are two simple methods to apply hysteresis to a circuit
for use in supply voltage level detection. These are shown in
Figure 27.
The circuit of Figure 27A requires that the full current flowing
in the resistor network be sourced by the HYSTERESIS out-
put, whereas for circuit Figure 27B the current to be sourced
by the HYSTERESIS output will be a function of the ratio of
the two trip points and their values. For low values of hyster-
esis, circuit Figure 27B is to be preferred due to the offset
voltage of the hysteresis output transistor.
A third way to obtain hysteresis (ICL8211 only) is to connect
a resistor between the OUTPUT and the THRESHOLD
terminals thereby reducing the total external resistance
between the THRESHOLD and GROUND when the
OUTPUT is switched on.
Practical Applications
Low Voltage Battery Indicator (Figure 28)
This application is particularly suitable for portable or remote
operated equipment which requires an indication of a depleted
or discharged battery. The quiescent current taken by the sys-
tem will be typically 35
A which will increase to 7mA when the
lamp is turned on. R
3
will provide hysteresis if required.
Nonvolatile Low Voltage Detector (Figure 29)
In this application the high trip voltage V
TR2
is set to be
above the normal supply voltage range. On power up the
initial condition is A. On momentarily closing switch S
1
the
operating point changes to B and will remain at B until the
supply voltage drops below VTR1, at which time the output
will revert to condition A. Note that state A is always retained
if the supply voltage is reduced below V
TR1
(even to zero
volts) and then raised back to V
NOM
.
Nonvolatile Power Supply Malfunction Recorde
(Figure 30 and Figure 31)
In many systems a transient or an extended abnormal (or
absence of a) supply voltage will cause a system failure.
This failure may take the form of information lost in a volatile
semiconductor memory stack, a loss of time in a timer or
even possible irreversible damage to components if a supply
voltage exceeds a certain value.
It is, therefore, necessary to be able to detect and store the
fact that an out-of-operating range supply voltage condition
1
2
3
4
8
7
6
5
V+
INPUT
V-
R
1
R
2
INPUT
VOLTAGE
Input voltage to change to output states
=
(R
1
+ R
2
)
R
1
x 1.15V
1
2
3
4
8
7
6
5
V+
R
1
R
2
V
REF (+VE)
MAY BE ANY STABLE VOLTAGE
VOLTAGE REFERENCE
GREATER THAN 1.15V
Range of input voltage less than +1.15V
Input voltage to change the output states
=
(R
1
+ R
2
) x 1.15
R
1
R
2
V
REF
R
1
-
1
2
3
4
8
7
6
5
V+
INPUT VOLTAGE
R
1
R
2
OR
SUPPLY VOLTAGE
V
O
7-171
ICL8211, ICL8212
FIGURE 27. TWO ATERNATIVE VOLTAGE DETECTION
CIRCUITS EMPLOYING HYSTERESIS TO
PROVIDE PAIRS OF WELL DEFINED TRIP
VOLTAGES
1
2
3
4
8
7
6
5
V+
R
1
R
2
FIG 7
V
O
R
3
Low trip voltage
V
TR1
=
(R
1
+ R
2
) x 1.15 + 0.1V
R
1
volts
High trip voltage
V
TR2
=
(R
1
+ R
2
+ R
3
)
R
1
x 1.15V
1
2
3
4
8
7
6
5
V+
R
P
R
S
V
O
R
Q
Low trip voltage
V
TR1
=
R
Q
R
S
(R
Q
+ R
S
)
+ R
P
x
R
P
x 1.15V
1
High trip voltage
V
TR2
=
(R
P
+ R
Q
)
R
P
x 1.15V
V
TR1
V
TR2
OFF
ON
I
C
L8
2
1
1
O
U
TP
U
T
S
T
A
T
E
SUPPLY VOLTAGE
ON
OFF
IC
L
8
2
12 O
U
T
P
U
T
S
T
A
T
E
FIGURE 27A.
FIGURE 27B.
FIGURE 27C.
FIGURE 28. LOW VOLTAGE BATTERY INDICATOR
FIGURE 29. NON-VOLATILE LOW VOLTAGE INDICATOR
1
2
3
4
8
7
6
5
R
3
R
2
LED
LAMP
ICL8211
150k
NOTE 1. R
3
OPTIONAL
(NOTE 1)
1
2
3
4
8
7
6
5
V+
R
1
R
2
OUTPUT
R
3
S
1
R
L
FIGURE 29A.
V
TR1
V
TR2
OFF
ON
IC
L
821
1 O
U
T
P
U
T
S
T
A
T
E
ON
OFF
IC
L
821
2 O
U
T
P
U
T
S
T
A
T
E
V
NOM
A
B
SUPPLY VOLTAGE
FIGURE 29B.
7-172
ICL8211, ICL8212
has occurred, even in the case where a supply voltage may
have dropped to zero. Upon power up to the normal
operating voltage this record must have been retained and
easily interrogated. This could be important in the case of a
transient power failure due to a faulty component or
intermittent power supply, open circuit, etc., where direct
observation of the failure is difficult.
A simple circuit to record an out of range voltage excursion
may be constructed using an ICL8211, an ICL8212 plus a
few resistors. This circuit will operate to 30V without exceed-
ing the maximum ratings of the ICs. The two voltage limits
defining the in range supply voltage may be set to any value
between 2.0V and 30V.
The ICL8212 is used to detect a voltage, V
2
, which is the
upper voltage limit to the operating voltage range. The
ICL8211 detects the lower voltage limit of the operating
voltage range, V
1
. Hysteresis is used with the ICL8211 so
that the output can be stable in either state over the
operating voltage range V
1
to V
2
by making V
3
- the upper
trip point of the ICL8211 much higher in voltage than V
2
.
The output of the ICL8212 is used to force the output of the
ICL8211 into the ON state above V
2
. Thus there is no value
of the supply voltage that will result in the output of the
ICL8211 changing from the ON state to the OFF state. This
may be achieved only by shorting out R3 for values of supply
voltage between V
1
and V
2
.
Constant Current Sources (Figure 32)
The ICL8212 may be used as a constant current source of
value of approximately 25
A by connecting the THRESH-
OLD terminal to GROUND. Similarly the ICL8211 will pro-
vide a 130
A constant current source. The equivalent
parallel resistance is in the tens of megohms over the supply
voltage range of 2V to 30V. These constant current sources
may be used to provide basing for various circuitry including
differential amplifiers and comparators. See Typical Operat-
ing Characteristics for complete information.
Programmable Zener Voltage Reference (Figure 33)
The ICL8212 may be used to simulate a zener diode by
connecting the OUTPUT terminal to the V
Z
output and using
a resistor network connected to the THRESHOLD terminal
FIGURE 30. NON-VOLATILE POWER SUPPLY MALFUNCTION RECORDER
OUTPUT ICL8211
ICL8212 DISCONNECTED
OUTPUT ICL8212
OUTPUT ICL8211
AS PER FIGURE 7
FIGURE 31. OUTPUT STATES OF THE ICL8211 AND ICL8212 AS A FUNCTION OF THE SUPPLY VOLTAGE
1
2
3
4
8
7
6
5
R
5
R
4
ICL8212
1
2
3
4
8
7
6
5
ICL8211
OUTPUT
RESET
S
1
R
1
R
2
R
6
V+
R
3
V
1
V
3
OFF
ON
SUPPLY VOLTAGE
V
2
V
NOM
OFF
ON
V
2
V
NOM
SUPPLY VOLTAGE
OFF
ON
SUPPLY VOLTAGE
V
2
V
1
7-173
ICL8211, ICL8212
to program the zener voltage
Since there is no internal compensation in the ICL8212 it is
necessary to use a large capacitor across the output to
prevent oscillation.
Zener voltages from 2V to 30V may be programmed and typ-
ical impedance values between 300
A and 25
A will range
from 4
to 7
. The knee is sharper and occurs at a signifi-
cantly lower current than other similar devices available.
FIGURE 32. CONSTANT CURRENT SOURCE APPLICATIONS
FIGURE 33. PROGRAMMABLE ZENER VOLTAGE REFERENCE
Precision Voltage Regulator (Figure 34)
The ICL8212 may be used as the controller for a highly sta-
ble series voltage regulator. The output voltage is simply pro-
grammed, using a resistor divider network R
1
and R
2
. Two
capacitors C
1
and C
2
are required to ensure stability since
the ICL8212 is uncompensated internally.
FIGURE 34. PRECISION VOLTAGE REGULATOR
This regulator may be used with lower input voltages than
most other commercially available regulators and also con-
sumes less power for a given output control current than any
commercial regulator. Applications would therefore include
battery operated equipment especially those operating at
low voltages.
High Supply Voltage Dump Circuit (Figure 35)
In many circuit applications it is desirable to remove the
power supply in the case of high voltage overload. For
circuits consuming less than 5mA this may be achieved
using an ICL8211 driving the load directly. For higher load
currents it is necessary to use an external pnp transistor or
darlington pair driven by the output of the ICL8211. Resistors
R
1
and R
2
set up the disconnect voltage and R
3
provides
optional voltage hysteresis if so desired.
FIGURE 35. HIGH VOLTAGE DUMP CIRCUITS
Frequency Limit Detector (Figure 36)
Simple frequency limit detectors providing a GO/NO-GO out-
put for use with varying amplitude input signals may be con-
veniently implemented with the ICL8211/8212. In the
V
ZENER
=
(R
1
+ R
2
)
x 1.l5V.
R
1
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
I
=
OR
V+
I
I = 25
A (ICL8212)
I = 130
A (ICL8211)
ICL
8212
V
TH
OUT
V+
I
S
V+
500K
150K
R
2
R
1
+
V
ZE
N
E
R
5
F
6
5
4
3
2
1
0
0.01
0.1
1.0
10
100
SUPPLY CURRENT (mA)
Z
E
NE
R V
O
L
T
AG
E
1
2
3
4
8
7
6
5
V+
R
3
V+
R
1
R
2
C
2
UNREG-
ULATED
DC SUPPLY
ICL8212
Q
1
C
1
V
OUT
=
R
2
+ R
1
R
1
x 1.15V
1
2
3
4
8
7
6
5
R
1
R
2
R
3
ICL8211
V-
V+
(a)
1
2
3
4
8
7
6
5
R
1
R
2
R
3
ICL8211
V-
V+
CIRCUIT
BEING
PROTECTED
V-
V+
(b)
R
4
CIRCUIT
BEING
PROTECTED
V-
V+
7-174
ICL8211, ICL8212
application shown, the first ICL8212 is used as a zero cross-
ing detector. The output circuit consisting of R
3
, R
4
and C
2
results in a slow output positive ramp. The negative range is
much faster than the positive range. R
5
and R
6
provide hys-
teresis so that under all circumstances the second ICL8212
is turned on for sufficient time to discharge C
3
. The time con-
stant of R
7
C
3
Is much greater than R
4
C
2
. Depending upon
the desired output polarities for low and high input frequen-
cies, either an ICL8211 or an ICL8212 may be used as the
output driver.
This circuit is sensitive to supply voltage variations and
should be used with a stabilized power supply. At very low
frequencies the output will switch at the input frequency.
Switch Bounce Filter (Figure 37)
Single pole single throw (SPST) switches are less costly and
more available than single pole double throw (SPDT) switches.
SPST switches range from push button and slide types to cal-
culator keyboards. A major problem with the use of switches is
the mechanical bounce of the electrical contacts on closure.
Contact bounce times can range from a fraction of a millisecond
to several tens of milliseconds depending upon the switch type.
During this contact bounce time the switch may make and
break contact several times. The circuit shown in Figure 37 pro-
vides a rapid charge up of C
1
to close to the positive supply
FIGURE 36. FREQUENCY LIMIT DETECTOR
FIGURE 37. SWITCH BOUNCE FILTER
FIGURE 38. LOW VOLTAGE POWER SUPPLY DISCONNECT
1
2
3
4
8
7
6
5
R
1
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
OUTPUT
R
6
ICL8211
OR
ICL8212
#3
B
R
7
R
5
A
R
2
R
3
C
2
C
3
C
1
INPUT
R
6
V+
R
4
ON TIME #2
INPUT
1.15V
A
1.15V
B
INDETERMINATE
BELOW F
O
OFF
ON
FREQUENCY
F
O
ON
OFF
OU
T
P
U
T
S
T
A
T
E
IC
L
8212
OU
T
P
U
T
S
T
A
T
E
IC
L
821
1
TIME CONSTANT R
3
C
2
< R
4
C
2
R
7
C
3
VARY R
1
FOR OPTION ZERO CROSSING DETECTION
VARY R
4
TO SET DETECTION FREQUENCY
ICL8212
ICL8212
1
2
3
4
8
7
6
5
V+
R
3
R
2
V
O
R
1
C
1
R
4
100
R
L
ICL8211
OR
ICL8212
1
2
3
4
8
7
6
5
V-
500k
56k
OUTPUT
REFERENCE
LM199
4.7k
3.9k
ICL8212