Datasheet ICL8211CTY Datasheet (Intersil Corporation)

October 1999

TM

ICL8211, ICL8212

T

C

U

D

O

O

C

E

R

O

N

M

M

N

E

R

D

E

D

E

L

O

S

B

C

A

L

P

E

O

R

P

E

T

T

N

E

M

E

Prog rammable Voltage Detect ors

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 Volt age Range

• Defined Output Current Limit ICL8211

• High Output Current Capability ICL8212

Applications

• Low Voltage Sensor/Indicator

• Hi g h Volta ge Sens or/Indi c ator

• Nonvolatile Out-of-Voltage Range Sensor/Indicator

• Programmable Voltage Reference or Zener Diode

• Series or Shunt Power Supply Regulator

• Fixed Value Constant Current Source

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 buff er/drivers.

Specifically, the ICL8211 provides a 7mA current limited out­put 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

ICL8211CPA 0
ICL8211CBA 0
ICL8211CTY 0
ICL8211MTY

(Note 1)
ICL8212CPA 0
ICL8212CBA 0
ICL8212CTY 0
ICL8212MTY

(Note 1)

NOTE:

1. Add /883B to part number if 883B processing is required

TEMPERATURE

RANGE PACKAGE

o

C to +70oC 8 Lead Plastic DIP

o

C to +70oC 8 Lead SOlC (N)

o

C to +70oC 8 Pin Metal Can

o

C to +125oC 8 Pin Metal Can

-55

o

C to +70oC 8 Lead Plastic DIP

o

C to +70oC 8 Lead SOlC (N)

o

C to +70oC 8 Pin Metal Can

o

C to +125oC 8 Pin Metal Can

-55

Pinouts

ICL8 211 (PDIP, SOIC)

TOP VIEW

NC

1

HYSTERESIS

THRESHOLD

OUTPUT

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
Copyright © Intersil Americas Inc. 2002. All Rights Reserved

2
3
4

| Intersil (and design) is a trademark of Intersil Americas Inc.

8

V+

7

NC

6

NC

5

GROUND

7-161

THRESHOLD

OUTPUT

NC

ICL8211 (CAN)

TO P VIEW

HYSTERESIS

8

1

2

3

4

GROUND

7

V+

6

NC

5

NC

FN3184.2

Functional Diagram

VOLTAGE REFERENCE COMPARATOR OUTPUT BUFFERS

ICL8211, ICL8212

8

V+

R1

20MΩ

Q1

Q7

Q2

Q3

Q5

1.15V

Q23

Q4

Q6

V

REF

R3
360kΩ

Q16

Q12

Q14 Q15

Q17 Q18

R4
1MΩ

Q13

X X X X

Q19

R5

4.5kΩ

2

HYST

3

THRESHOLD

Q8

R2

30kΩ

X X X X X X

Q9

ICL8211 OPTION
ICL8212 OPTION

Q10

Q11

Q20

R6
100kΩ

Q21

4

5

OUTPUT

GROUND

7-162

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

CAUTION: Stresses above those listed i n “Abso lute Ma ximum Rati ngs ” may cause pe rmanent dam age to the dev ice. T his is a str ess 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 C o ndi t io ns

Operating Temperature Range

ICL8211M/8212M . . . . . . . . . . . . . . . . . . . . . . . . -55

ICL8211C/8212C . . . . . . . . . . . . . . . . . . . . . . . . . . .0

o

C to +125oC

o

C to +70oC

Thermal Resistance θ

Plastic DIP Package . . . . . . . . . . . . . . . . 150oC/W -

Plastic SOIC Package . . . . . . . . . . . . . . . 180

Metal Can . . . . . . . . . . . . . . . . . . . . . . . . 156

JA

o

C/W -

o

C/W 68oC/W

Lead Temperature (Soldering, 10s). . . . . . . . . . . . . . . . . . . . . 300

θ

JC

o

(SOIC - Lead Tips Only)

Current into Any Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 30mA

o

Storage Temperature Range . . . . . . . . . . . . . . . . . . -65

C to +150oC

C

Electrical Specifications V+ = 5V, T

= +25oC Unless Otherwise Specified

A

PARAMETER SYMBOL TEST CONDITIONS

Supply Current I+ 2.0 < V+ < 30 V

Threshold Trip Vo ltage V

Threshold Voltage
Dispari ty Between
Outp ut & Hy s tere s is
Output

Guara n tee d O pe r ati ng

V

Supply Voltage Range

Minimum Operating

V

Supply Voltage Range

V

THP

SUPPLY

SUPPLY

I

TH

OUT

V

OUT

I

OUT

I

HYST

V

OUT

V

HYST

= 4mA

= 2V

= 4mA

= 7mA
= 2V

= 3V
+25oC (Note 3) 2.0 - 30 2.0 - 30 V
0oC to +70oC (Note 3) 2.2 - 30 2.2 - 30 V
+25oC-1.8--1.8-V

o

+125

C-1.4--1.4-V

-55oC-1.5--2.5-V

Threshold Voltage Tem-

∆V

TH

/∆TI

OUT

= 4mA, V

= 2V - ± 20 0 - - ± 200 - ppm/oC

OUT

perature C oeffi ci en t
Variation of Threshold

Voltag e w ith Su pp ly

∆V

/∆V+ ∆V+ = 10% at V+ = 5V - 1.0 - - 1.0 - mV

TH

Voltage
Threshold Input Current I

Outp ut Le ak ag e Current I

Output Satura ti on
Voltage

Max Available Output
Current

Hystere sis Leakage
Current

TH

OLK

V

SAT

I

OH

I

LHYS

VTH = 1.15V - 100 250 - 100 250 nA
V

= 1.00V - 5 - - 5 - nA

TH

V

= 30V VTH = 0.9V-----10µA

OUT

V

= 5V VTH = 0.9V-----1µA

OUT

I

= 4mA VTH = 0.9V - 0.17 0.4 - - - V

OUT

(Notes 3 & 4)
V

= 5V

OUT

V+ = 10V,
V

= GND

HYST

ICL8211 ICL8212

UNITSMIN TYP MAX MIN TYP MAX

= 1.3V 10 22 40 50 110 250 µA

TH

VTH = 0.9V 50 140 250 10 20 40 µA
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

--0.8- --0.5- mV

VTH = 1.3V--10---µA

V

= 1.3V--1---µA

TH

V

= 1.3V----0.170.4V

TH

= 0.9V 4 7.0 12 - - - mA

V

TH

VTH = 1.3V - - - 15 35 - mA

= 1.0V - - 0.1 - - 0.1 µA

V

TH

7-163

ICL8211, ICL8212

Electrical Specifications V+ = 5V, T

= +25oC Unless Otherwise Specified (Continued)

A

ICL8211 ICL8212

PARAMETER SYMBOL TEST CONDITIONS

Hysteresis Sat Voltage V

HYS(MAX)IHYST

= -7µA,

measured with

V

= 1.3V - -0.1 -0.2 - -0.1 -0.2 V

TH

UNITSMIN TYP MAX MIN TYP MAX

respect to V+

Max Available
Hysteresis Curre nt

I

HYS (M A X)

Electrical Specifications ICL8211MTY/8212MTY V+ = 5V, T

VTH = 1.3V -15 -21 - -15 -21 - µA

= -55oC to +125oC

A

ICL8211 ICL8212

PARAMETER SYMBOL TEST CONDITIONS

UNITSMIN TYP MAX MIN TYP MAX

Supply Current I+2.8 < V+ < 30 ------ -

V

= 1.3V - - 100 - 350 350 µA

T

VT = 0.8V - - 350 - 100 100 µA

Threshold Trip Vo ltage V

Guara n tee d O pe r ati ng

V

Supply Voltage Range
Threshold Input Current I
Outp ut Le ak ag e Current I

Output Satura ti on
Voltage

Max Available Output
Current

Hystere sis Leakage
Current

Hysteresis Saturation
Voltage

V

HYS(MAX)IHYST

SUPPLY

TH

OLK

V

SAT

I

OH

I

LHYS

I

TH

OUT

V

OUT

= 2mA

= 2V

V+ = 2.8V 0.80 - 1.30 0.80 - 1.30 V
V+ = 30V 0.80 - 1.30 0.80 - 1.30 V

(Note 5) 2.8 - 30 2.8 - 30 V

VTH = 1.15V - - 400 - - 400 nA
V

= 30V VTH = 0.8V-----20µA

OUT

V

= 1.3V--20---µA

TH

I

= 3mA VTH = 0.8V--0.5---V

OUT

VTH = 1.3V-----0.5V

(Notes 3 & 4)
V

= 5V

OUT

V+ = 10V
V

= GND

HYST

= -7µA

= 0.8 3 - 15 - - - mA

V

TH

V

= 1.3V---9--mA

TH

= 0.8V - - 0.2 - - 0.2 µA

V

TH

VTH = 1.3V - - 0.3 - - 0.3 V
measured with
respect to V+

Max Available
Hysteresis Curre nt

I

HYS (M A X)

VTH = 1.3V 10 - - 10 - - µA

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 ma ximum outp ut curre nt of the ICL 8212 is not de fined. And sy stems usi ng th e ICL8 212 mu st ther efor e ensure that th e out put 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.

7-164

ICL8211, ICL8212

Typical Performance Curves (ICL8211 and ICL8212)

10,000

THRESHOLD INPUT CURRENT (nA)

TA = +25oC
V+ = +10V

1,000

ICL8211 OR ICL8212

100

10

0.0 1.1 1.15 1.2 2.0 3.0 6.0 8.0 10.0
THRESHOLD VOLTAGE (V

(IRREGULAR SCALE)

)

TH

FIGURE 1. THRESHOLD INPUT CURRENT AS A FUNCTION OF

THRESHOLD VOLTAGE

Typical Performance Curves

150

125

100

75

TA = +25oC
OUTPUTS OPEN CIRCUIT

(ICL8211 ONLY)

VTH = 0.9V

0

V+ = +5V

= 1.2V

V

TH

V

-5

= 4.5V

HYS

(OR -0.5V WITH RESPECT

TO V+ SUPPLY)

-10

-20

-25
ICL8211 OR ICL8212

-30

HYSTERESIS OUTPUT CURRENT (µA)

-40 -20 0 +20 +40 +60 +80
TEMPERATURE (

o

C)

FIGURE 2. HYSTERESIS OUTPUT SATURATION CURRENT AS

A FUNCTION OF TEMPERATURE

150

125

100

75

TA = +25oC
V+ = +5V
OUTPUTS OPEN
CIRCUIT

50

SUPPLY CURRENT (µA)

25

VTH = 1.3V

0102030

SUPPLY VOLTAGE

FIGURE 3. SUPPLY CURRENT AS A FUNCTION OF SUPPLY

VOLTAGE

50

SUPPLY CURRENT (µA)

25

0

0.0 1.0 1.1 1.15 1.2 2.0 4.0
THRESHOLD VOLTAGE (V

(IRREGULAR SCALE)

)

TH

FIGURE 4. SUPPLY CURRENT AS A FUNCTION OF THRESH-

OLD VOLTAGE

7-165

ICL8211, ICL8212

Typical Performance Curves (ICL8211 ONLY) (Continued)

150

125

100

75

50

SUPPLY CURRENT (µA)

25

0

-55 -25 +5 +35 +65 +95 +125

VTH = 0.9V

VTH = 1.3V

TEMPERATURE

o

C

FIGURE 5. SUPPLY CURRENT AS A FUNCTION OF TEMPERA-

TURE

OUTPUT

1.15

1.14
HYSTERESIS OUTPUT

12

10

8

6

OUTPUT

4

OUTPUT CURRENT (mA)

2

0

1.12 1.13 1.14 1.15 1.16 1.17 1.18
THRESHOLD VOLTAGE

TA = +25oC
V+ = +5V
V

= 0.5V

O

V

= V+ - 0.25V

HYS

HYSTERESIS
OUTPUT

8mV

0

-5

-10

-15

-20

-25

-30

HYSTERESIS OUTPUT CURRENT (µA)

FIGURE 6. OUTPUT SATURATION CURRENTS AS A FUNC-

TION OF THRESHOLD VOLTAGE

1.18
IO = 4mA, VO = 1V

I

1.17

1.16

1.15

= -7µA, V

HYS

HYS

OUTPUT

= (V+ -2) V

THRESHOLD VOLTAGE

1.13

-55 -25 +5 +35 +65 +95 +125

V+ = +5V

= 1mA, V

I

O

= -7µA, V

I

HYS

TEMPERATURE (

= +5V

OUT

= 0V

HST

o

C)

FIGURE 7. THRESHOLD VOLTAGE TO TURN OUTPUTS “JUST

ON” AS A FUNCTION OF TEMPERATURE

8

7

6

OUTPUT CURRENT (mA)

5

-55 -25 +5 +35 +65 +95 +125
TEMPERATURE (

V+ = +5V
V

= 1.1V

TH

= 1.0V

V

O

o

C)

THRESHOLD VOLTAGE

1.14

1.13
1 2 3 4 5 10 20 304050 100

HYSTERESIS OUTPUT

SUPPLY VOLTAGE

FIGURE 8. THRESHOLD VOLTAGE TO TURN OUTPUTS “JUST

ON” AS A FUNCTION OF SUPPLY VOLTAGE

12

TA = +25oC
V+ = +5V

9

VTH = 1.0V

6

3

OUTPUT CURRENT (mA)

0

0.1 1.0 10.0 100.0

VTH = 1.147V

VTH = 1.152V

OUTPUT VOLTAGE

FIGURE 9. OUTPUT SATURATION CURRENT AS A FUNCTION

OF TEMPERATURE

0

µA)

FIGURE 10. OUTPUT CURRENT AS A FUNCTION OF OUTPUT

VOLTAGE

7-166

ICL8211, ICL8212

Typical Performance Curves (ICL8212 ON LY)

150

TA = +25oC
OUTPUTS OPEN CIRCUIT

125

100

75

50

SUPPLY CURRENT (µA)

25

0

0102030

VTH = 1.3V

VTH = 0.9V

SUPPLY VOLTA G E

FIGURE 12. SUPPLY CURRENT AS A FUNCTION OF SUPPLY

VOLTAGE

150

V+ = 5V
OUTPUTS

125

OPEN
CIRCUIT

100

75

50

SUPPLY CURRENT - I+ (µA)

25

0

-55 -25 +5 +35 +65
TEMPERATURE (oC)

VTH = 1.3V

VTH = 0.9V

+95

+125

150

TA = +25oC
V+ = +5V

125

OUTPUTS OPEN CIRCUIT

100

75

50

SUPPLY CURRENT - I+ (µA)

25

0

0.0 1.0 1.1 1.15 1.2 2.0 4.0
THRESHOLD VOLTAGE (V

(IRREGULAR SCALE)

)

TH

FIGURE 13. SUPPLY CURRENT AS A FUNCTION OF THRESH-

OLD VOLTAGE

30

25

TA = +25oC

20

15

10

OUTPUT CURRENT (mA)

5

0

1.14 1.15 1.16 1.17 1.18 1.19 1.20

OUTPUT

THRESHOLD VOLTAGE

V+ = 5V

= 4V

V

OUT

= V+ -0.25V

V

HYS

HYSTERESIS OUTPUT

0

-5

-10

-15

-20

-25

HYSTERESIS OUTPUT CURRENT (µA)

-30

FIGURE 14. SUPPLY CURRENT AS A FUNCTION OF TEMPER-

ATURE

1.17
IO = 1mA, V

I

= -7µA, V

HYS

1.16

1.15

THRESHOLD VOLTAGE

1.14

-55 -25 +5 +35 +65 +95 +125

= 5V

OUT

= 0V

HYS

BOTH OUTPUT AND
HYSTERESIS OUTPUT

TEMPERATURE (

o

C)

FIGURE 16. THRESHOLD VOLTAGE TO TURN OUTPUTS “JUST

ON” AS A FUNCTION OF TEMPERATURE

FIGURE 15. OUTPUT SATURATION CURRENTS AS A FUNC-

TION OF THRESHOLD VOLTAGE

1.18

1.17

1.16

BOTH OUTPUT AND

1.15

THRESHOLD VOLTAGE

1.14

1.13
123451020304050100

HYSTERESIS OUTPUT

TA = +25oC

= 4mA, V

I

OUT

I

= -7µA, V

HYS

SUPPLY VOLTAGE

OUT
HYS

= 1V

= (V+ -2) V

FIGURE 17. THRESHOLD VOLTAGE TO TURN OUTPUTS “JUST

ON” AS A FUNCTION OF SUPPLY VOLTAGE

7-167

ICL8211, ICL8212

Typical Performance Curves

(ICL8212 ONLY) (Continued)

0.6

0.5

0.4

0.3

0.2

0.1

OUTPUT SATURATION VOLTAGE

0

-55 - 25 +5 +35 +65 +95 +1 25

FIGURE 18. OUTPUT SATURATION VOLTAGE AND CURRENT

AS A FUNCTION OF TEMPERATURE

40

TA = +25oC
V+ = +5V

30

OUTPUT SAT.
CURRENT

(VO = 4.0V)

VOLTAGE SAT.
CURRENT
(I

TEMPERATURE (

VTH =1.25V

= 10mA)

O

V+ = +5V
V

TH

o

C)

= 1.2V

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
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 resis tors (-5000 ppm per

Components Q
current source; Q
mirror. Q

8

current mirror, the collector currents of Q
to be equal and it can be shown that the collector current in
Q

and Q9 is

8

or approximately 1µA at +25

Where k = Boltzman’s Constant

q = Charge on an Electron

and T = Absolute Temperature in

through Q10 and R1, R2 and R3 set up an

1

o

C).

through Q9 and R2 make up a constant

2

and Q3 are identical and form a current

2

has 7 times the emitter area of Q9, and due to the

and Q9 are forced

8

IC (Q8 or Q9) =

1

R2 q

o

C

kT

x

o

K

In7

20

VTH = 1.158V

10

OUTPUT CURRENT (mA)

VTH = 1.153V

0

0.1 1.0 10.0 30.0 100.0
OUTPUT VOLTAGE

FIGURE 19. OUTPUT CURRENT AS A FUNCTION OF OUTPUT

VOLTAGE

0

-5

-10

-15

-20

-25

-30

-35

HYSTERESIS OUTPUT CURRENT (µA)

-40

-10.00 -1.00 -0.10 -0.01

VT = 1.152V

VT = 1.153V

VT = 1.18V

TA = +25oC
V+ = +10V

HYSTERESIS OUTPUT VOLTAGE

FIGURE 20. HYSTERESIS OUTPUT CURRENT AS A FUNCTION

OF HYSTERESIS OUTPUT VOLTAGE

Transistors Q
and Q

9

, Q6, and Q7 assure that the VCE of Q3, Q4,

5

remain constant with supply voltage variations. This

ensures a constant current supply free from variations.
The base current of Q

provides sufficient start up current for

1

the constant source; there being two stable states for this
type of circuit - either ON as defin ed above, or OFF if no star t
up current is provided. Leakage current in the transistors is
not suffi cient in itself to guarantee reliable startup.

Q

is matched to Q3 and Q2; Q10 is matche d to Q9. Thus the

4

IC and V

of Q10 are identical to that of Q9 or Q8. To

BE

generate the bandgap voltage, it is necessary to sum a
voltage equal to the base emitter voltage of Q

to a voltage

9

proportional to the difference of the base emitter voltages of
two transistors Q

Thus 1. 5 = V

which provides :

and Q9 operating at two current densities.

8

BE (Q9

or Q10) +

R

3

= 12 (approximately.)

R

2

R

3

R

2

kT

x

q

The total su pply current consu med by the voltage re ference
section is approximately 6µA at room temperature. A voltage
at the THRESHOLD input is compared to the reference 1.15V
by the compa rator consisti ng of transisto rs Q

through Q17.

11

The outputs from the comparator are limited to two diode
drops less t ha n V + or approxim a t ely 1 . 1V. Thus the base cur­rent into the hysteresis output transistor is limited to about
500nA and the collector current of Q

In the case of the ICL8211, Q
times the emitter area of Q

20

to 100µA.

19

is proportioned to have 70

21

thereby limiting the output

current to approximately 7mA, whereas for the ICL8212

7-168

ICL8211, ICL8212

I
(
R

)

S

almost all the collector current of Q19 is available for base
drive to Q

, resulting in a maximum available collector

21

current of the order of 30mA. I t i s advisable to ext ernally limit
this current to 25mA or l ess.

Applications

The ICL8211 and ICL8212 are similar in many respects, espe­cially 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 not ed.

General Inf orma t ion

Threshold Input Considerations

Although any voltage betwee n -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 degradat ion 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 si mp le 1. 15V level detector.

R

L1

V+

(V+ MUST BE
EQUAL OR
EXCEED 1.8V

V

HYST

V

O

NPUT VOLTAGE
RECOMMENDED

ANGE -5 TO +5V)

V

TH

1
2
3
4

8
7
6
5

such as TTL or CMOS using a single pullup resist or. 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 re ason the OUTPUT curre nt has been
limited to typically 7mA to permit direct drive of an LED
connected to the positive supply without a series current
limiting re s is to r.

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

. For high accu-

TH

racy, currents as large as 50µA 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 signif­icant percent age of that flowing in the divider network.

V+

1
2

V

TH

3
4

8
7
6
5

PULLUP RESISTOR

CMOS OR
TTL GATE

R

L2

V

O2

1.15V
0

V+
0V

V+
0V

ICL8211 OUTPUT

ICL8212 OUTPUT

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 10µA or less.

The regular OUTPUT’s from either the ICL8211 or ICL8212
may be used to drive most of the common logic families

V

O1

FIGURE 22. OUTPUT LOGIC INTERFACE

INPUT

R

2

V

R

1

V-

1
2

TH

3
4

V+

8
7
6
5

FIGURE 23. INPUT RESISTOR NETWORK CONSIDERATIONS

Case 1. High accu racy required, current in resistor n etwork

unimportant Set I = 5 0µA for V

= 1.15V ∴ R1 →

TH

20kΩ

Case 2. Good accuracy required, current in resistor network

important Set I = 7.5µA for V

= 1.15V ∴ R1 →

TH

150kΩ

7-169

ICL8211, ICL8212

V+

INPUT

INPUT

VOLT AGE

V-

R

2

R

1

1
2
3
4

8
7
6
5

Input voltage to change to output states

(R

+ R2)

1

=

x 1.15V

R

1

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 VOL TAGES of any magnitude and polarity.

MAY BE ANY STABLE VOLTAGE
VOLTAGE REFERENCE
GREATER THAN 1.15V

1
2
3
4

8
7
6
5

V+

R

V

2

REF (+VE)

R

1

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 perfor­mance but may be expanded into highly complex systems
with multiple voltage level detection and memory applica­tions-refer to specific applications section.

There are two simple methods to apply hysteres is to a circuit
for use in supply voltage level detecti o n. These are shown in
Figure 27.

The circuit of Fi gure 27A requires that the full current flowing
in the resistor network be sourced by the HYSTERESIS out­put, 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 val ues. For low values of hyster­esis, circuit Figure 27B is to be preferred due to the offset
voltage of t he 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)

Range of input v oltage less than +1.15V
Input voltag e to change the output states

(R

=

+ R2) x 1.15

1

R

1

R2V

REF

­R

1

FIGURE 25. INPUT RESISTOR NETWORK SETUP

PROCEDURES

For supply voltage level detection applications the input
resistor network is connected across the sup ply terminals as
shown in Figure 26.

V+

R

2

R

1

1
2
3
4

FIGURE 26. COMBINED INPUT AND SUPPLY VOLTAGES

8
7
6
5

INPUT VOLTAGE

SUPPLY VOLTAGE

OR

V

O

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 sys­tem will be typically 35µA which will increase to 7mA when t he
lamp is turned on. R

will provide hysteresis if required.

3

Nonvolatile Low Volt age Detector (Figure 29)

In this application the high trip voltage V

is set to be

TR2

above the normal supply voltage range. On power up the
initial c ondition is A. O n momentari ly closing swit ch 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
volts) and t hen rai sed back to V

NOM

.

(even to zero

TR1

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 failu re m a y tak e th e fo rm o f in fo r m a tion lo s t in a vo la ti le
semiconductor memory stack, a loss of time in a timer or
even possible irreversible da ma ge 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 ran ge supply vol t age condi tion

7-170

ICL8211, ICL8212

V+

R

3

1

R

2

R

1

2
3
4

8
7
6
5

V

O

R

150kΩ

2

R

3

(NOTE 1)

1

ICL8211

2
3
4

8

LED

7

LAMP

6
5

Low trip vol tag e

V

High trip voltage
V

R

Q

R

S

R

P

Low trip voltage

V

TR1

High trip volt age
V

TR2

TR1

TR2

=

=

1
2
3
4

=

=

FIG 7

(R

(R

+ R2) x 1.15 + 0.1V

1

(R

+ R2 + R3)

1

R

1

FIGURE 27A.

RQR

S

(RQ + RS)

+ RQ)

P

R

P

+ R

x 1.15V

FIGURE 27B.

R

8
7
6
5

1

P

x 1.15V

1

x

R

x 1.15V

P

volts

NOTE 1. R

OPTIONAL

3

FIGURE 28. LOW VOLTAGE BATTERY INDICATOR

V+

S

R

R

V

O

R

1

3

2

1

1
2
3
4

8
7

R

L

6
5

V+

OUTPUT

FIGURE 29A.

OFF

ON

ICL821 1 OUTPUT STATE

V

TR1

SUPPLY VOLTA G E

V

TR2

FIGURE 27C.

FIGURE 27. TWO ATERNATIVE VOLTAGE DETECTION

CIRCUITS EMPLOYING HYSTERESIS TO
PROVIDE PAIRS OF WELL DEFINED TRIP
VOLTAGES

ON

OFF

ICL8212 OUTPUT STATE

OFF

ON

ICL8211 OUTPUT STA TE

V

TR1

SUPPLY VOLTA G E

B

A

V

NOM

FIGURE 29B.

FIGURE 29. NON-VOLATILE LOW VOLTAGE INDICATOR

7-171

ON

OFF

ICL8212 OUTPUT STATE

V

TR2

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 exceed­ing 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

, which is the

2

upper voltage limit to the operating voltage range. The
ICL8211 detects the lower voltage limit of the operating
voltage range, V

. Hysteresis is used with the ICL8211 so

1

that the output can be stable in either state over the
operating voltage range V
trip point of the ICL8211 much higher in voltage than V

to V2 by making V3 - the upper

1

.

2

The output of the ICL8212 is used to force the output of the

ICL8211 into the ON state above V

. Thus there is no value

2

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 achi eved only by shorting out R3 for values of supply
voltage between V

and V2.

1

Constant Current Sources (Figure 32)

The ICL8212 may be used as a constant current source of
value of approximately 25µA by connecting the THRESH­OLD terminal to GROUND. Similarly the ICL8211 will pro­vide a 130µA 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 Operat­ing Characteristics for complet e inf ormation.

Programmable Zener Voltage Reference (Figure 33)

The ICL8212 may be used to simulate a zener diode by
connecting the OUTPUT terminal to the V

output and using

Z

a resistor network connected to the THRESHOLD terminal

V+

R

R

4

R

5

1

ICL8212

2
3
4

8
7
6
5

3

FIGURE 30. NON-VOLATILE POWER SUPPLY MALFUNCTION RECORDER

OUTPUT ICL8211

ICL8212 DISCONNECTED OUTPUT ICL8212

V

NOM

OFF

OFF

RESET

R

2

V

S

R

NOM

1

1

1

ICL8211

2
3
4

8
7
6
5

R

6

OUTPUT

OUTPUT ICL8211

AS PER FIGURE 7

OFF

ON

V

1

SUPPLY VOLTAGE

ON

V

V

3

2

SUPPLY VOLTAGE

V

2

ON

V

1

SUPPLY VOLTAGE

FIGURE 31. OUTPUT STATES OF THE ICL8211 AND ICL8212 AS A FUNCTION OF THE SUPPLY VOLTAGE

7-172

V

2

ICL8211, ICL8212

to program the zener volt age

(R

+ R2)

V

ZENER

=

1

R

x 1.l5V.

1

Since there is no internal compensation in the ICL8212 it is
necessary to use a large capacitor across the output to
prevent oscil lation.

Zener voltag es from 2V to 30V may be programmed and typ ­ical impedance values between 300µA and 25µA will range
from 4 Ω to 7 Ω. The knee is sharper and occurs at a signifi­cantly lower current than other similar devices available.

V+

1

=

1
2
3
4

I

8
7
6
5

I = 25µA (ICL8212)
I = 130µA (ICL8211)

OR

2
3
4

8
7
6
5

I

FIGURE 32. CONSTANT CURRENT SOURCE APPLICATIONS

6

5

V+

ICL

V

OUT

V+

TH

I

S

500K

150K

R

2

+

R

5µF

–

1

ZENER

V

4

3

8212

2

ZENER VOLTAGE

1

0

0.01 0.1 1.0 10 100
SUPPLY CURRENT (mA)

FIGURE 33. PROGRAMMABLE ZENER VOLTAGE REFERENCE

Precision Voltage Regulator (Figure 34)

The ICL8212 may be used as the controller for a highly sta­ble series volt age regul ator. The output voltage is simply pro­grammed, using a resistor divider network R
capacitors C

and C2 are required to ensure stability since

1

and R2. Two

1

the ICL8212 is uncompensated internally.

Q

V+

UNREG­ULATED
DC SUPPLY

1
2
3
4

ICL8212

V

OUT

R

8
7
6
5

R

+ R

2

=

1

x 1.15V

R

1

1

3

R

2

R

1

C

1

V+

C

2

FIGURE 34. PRECISION VOLTAGE REGULATOR

This regulator may be used with lower input voltages than
most other commercially available regulators and also con­sumes less po we r 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 (F igure 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

and R2 set up the disconnect voltage and R3 provides

1

optional voltage hysteresis if so desired.

V+

R

V+

2

R

3

R

1

V-

R

2

R

3

R

1

V-

1
2
3
4

1
2
3
4

ICL8211

ICL8211

(a)

(b)

8
7
6
5

R

8
7
6
5

4

V+

CIRCUIT

BEING

PROTECTED

V-

V+

CIRCUIT

BEING

PROTECTED

V-

FIGURE 35. HIGH VOLTAGE DUMP CIRCUITS

Frequency Limit Detector (Figure 36)

Simple freq uency limit detectors providing a GO/NO-GO out­put for use with varying amplitude input signals may be con­veniently implemented with the ICL8211/8212. In the

7-173

ICL8211, ICL8212

E

application shown, the first ICL8212 is used as a zero cross­ing detector. The output circuit consisting of R

, R4 and C

3

results in a slow output positive ramp. The negative range is
much faster than the positive range. R

and R6 provide hys-

5

teresis so that under all circumstances the second ICL8212
is turned on for sufficient time to discharge C
stant of R

Is much greater than R4 C2. Depending upon

7 C3

. The time con-

3

the desired output polarities for low and high input frequen­cies, 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

V+

INPUT

1
2

C

1

R

2

R

1

ICL8212 ICL8212

3
4

R

8

R

4

7

A

6
5

3

C

TIME CONSTANT R3C2 < R4C2 ≤ R7C
VARY R1 FOR OPTION ZERO CROSSING DETECTION
VARY R

R

6

R

5

2

TO SET DETECTION FREQUENCY

4

frequencies the output will switch at the input frequency.

2

Switch Bounce Filter (Figure 37)

Single pole single throw (SPST) swi tches are less costly and
more available than single pole double throw (SPDT) switches.
SPST switches range from push button and slide types to cal­culator 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 pro­vides a rapid charge up of C

1
2
3
4

8

R

7

7

B

6
5

3

to close to the positive supply

1

1

ICL8211

OR

2

ICL8212

#3

3
4

C

3

8
7
6
5

R

6

OUTPUT

INPUT

R

2

R

3

1.15V
A

1.15V
B

INDETERMINATE

ON TIME #2

BELOW F

OFF

ICL8211

OUTPUT STATE

ON

O

O

ON

ICL8212

OUTPUT STATE

OFF

FREQUENCYF

FIGURE 36. FREQUENCY LIMIT DETECTOR

V+

R

100Ω

4

R

C

1

1

1

ICL8211

2

OR

3

ICL8212

4

8
7

R

6
5

L

500k

56k

V

O

1
2

ICL8212

3
4

4.7k

8
7
6

3.9k

5

V-

OUTPUT

REFERENC

LM199

FIGURE 37. SWITCH BOUNCE FILTER FIGURE 38. LOW VOLTAGE POWER SUPPLY DISCONNECT

7-174