Datasheet HCPL-3760, HCPL-3700 Datasheet (HP)

1-348

H

AC/DC to Logic Interface
Optocouplers

Technical Data

HCPL-3700
HCPL-3760

Description

The HCPL-3700 and HCPL-3760
are voltage/current threshold
detection optocouplers. The
HCPL-3760 is a low-current
version of the HCPL-3700. To
obtain lower current operation,
the HCPL-3760 uses a high­efficiency AlGaAs LED which
provides higher light output at
lower drive currents. Both
devices utilize threshold sensing
input buffer ICs which permit
control of threshold levels over a
wide range of input voltages with
a single external resistor.

Features

• Standard (HCPL-3700) and
Low Input Current
(HCPL-3760) Versions

• AC or DC Input

• Programmable Sense Voltage

• Hysteresis

• Logic Compatible Output

• Thresholds Guaranteed over
Temperature

• Thresholds Independent of
LED Optical Parameters

• Recognized under UL 1577
and CSA Approved for
Dielectric Withstand Proof
Test Voltage of 2500 Vac, 1
Minute

Applications

• Limit Switch Sensing

• Low Voltage Detector

• 5 V-240 V AC/DC Voltage
Sensing

• Relay Contact Monitor

• Relay Coil Voltage Monitor

• Current Sensing

• Microprocessor Interfacing

CAUTION: It is advised that normal static precautions be taken in handling and assembly of this component to
prevent damage and/or degradation which may be induced by ESD.

The input buffer incorporates
several features: hysteresis for
extra noise immunity and
switching immunity, a diode
bridge for easy use with ac input
signals, and internal clamping

Functional Diagram

1

2

3

4

8

7

6

5

AC

DC+

DC-

AC

V

CC

V

O

GND

TRUTH TABLE

(POSITIVE LOGIC)

INPUT

H
L

OUTPUT

L
H

NC

5965-3582E

1-349

diodes to protect the buffer and
LED from a wide range of over­voltage and over-current
transients. Because threshold
sensing is done prior to driving
the LED, variations in optical
coupling from the LED to the
detector will have no effect on the
threshold levels.

The HCPL-3700's input buffer IC
has a nominal turn on threshold
of 2.5 mA (ITH +) and 3.7 volts
(VTH +).

The buffer IC for the HCPL-3760
was redesigned to permit a lower
input current. The nominal turn
on threshold for the HCPL-3760
is 1.2 mA (ITH +) and 3.7 volts
(VTH +).

The high gain output stage
features an open collector output
providing both TTL compatible

saturation voltages and CMOS
compatible breakdown voltages.

By combining several unique
functions in a single package, the
user is provided with an ideal
component for industrial control
computer input boards and other
applications where a predeter­mined input threshold level is
desirable.

Ordering Information

Specify Part Number followed by Option Number (if desired)

Example

HCPL-3700#XXX

300 = Gull Wing Surface Mount Option
500 = Tape/Reel Package Option (1 K min.)

Option data sheets available. Contact your Hewlett-Packard sales representative or authorized distributor for
information.

Schematic

1-350

Package Outline Drawings

Standard DIP Package

Gull Wing Surface Mount Option 300

9.40 (0.370)

9.90 (0.390)

1.78 (0.070) MAX.

1.19 (0.047) MAX.

HP XXXX



YYWW

DATE CODE

0.76 (0.030)

1.40 (0.056)

2.28 (0.090)

2.80 (0.110)

0.51 (0.020) MIN.

0.65 (0.025) MAX.

4.70 (0.185) MAX.

2.92 (0.115) MIN.

DIMENSIONS IN MILLIMETERS AND (INCHES).

5678

4321

0.20 (0.008)

0.33 (0.013)

6.10 (0.240)

6.60 (0.260)
5° TYP.

7.36 (0.290)

7.88 (0.310)

1

2

3

4

8

7

6

5

AC

AC

DC+

DC-

GND

V

CC

NC

V

O

PIN ONE

TYPE NUMBER

UL
RECOGNITION

UR

0.635 ± 0.25

(0.025 ± 0.010)

12° NOM.

0.20 (0.008)

0.33 (0.013)

9.65 ± 0.25

(0.380 ± 0.010)

0.635 ± 0.130

(0.025 ± 0.005)

7.62 ± 0.25

(0.300 ± 0.010)

5

6

7

8

4

3

2

1

9.65 ± 0.25

(0.380 ± 0.010)

6.350 ± 0.25

(0.250 ± 0.010)

1.016 (0.040)

1.194 (0.047)

1.194 (0.047)

1.778 (0.070)

9.398 (0.370)

9.906 (0.390)

4.826

(0.190)



TYP.

0.381 (0.015)

0.635 (0.025)

PAD LOCATION (FOR REFERENCE ONLY)

1.080 ± 0.320

(0.043 ± 0.013)

4.19

(0.165)

MAX.

1.780

(0.070)

MAX.

1.19

(0.047)

MAX.

2.540

(0.100)

BSC

DIMENSIONS IN MILLIMETERS (INCHES).
TOLERANCES (UNLESS OTHERWISE SPECIFIED):

LEAD COPLANARITY 
MAXIMUM: 0.102 (0.004)

xx.xx = 0.01
xx.xxx = 0.005

HP XXXX



YYWW

DATE CODE

TYPE NUMBER

UL
RECOGNITION

UR

MOLDED

1-351

Maximum Solder Reflow Thermal Profile

240

∆T = 115°C, 0.3°C/SEC

0

∆T = 100°C, 1.5°C/SEC

∆T = 145°C, 1°C/SEC

TIME – MINUTES

TEMPERATURE – °C

220

200
180
160
140
120
100

80
60
40
20

0

260

123456789101112

(NOTE: USE OF NON-CHLORINE ACTIVATED FLUXES IS RECOMMENDED.)

Regulatory Information

The HCPL-3700/60 has been
approved by the following
organizations:

UL

Recognized under UL 1577,
component recognition program,
File E55361.

CSA

Approved under CSA Component
Acceptance Notice #5, File CA

88324.

1-352

Insulation and Safety Related Specifications

Parameter Symbol Value Units Conditions

Min. External Air Gap L(IO1) 7.1 mm Measured from input terminals to output terminals,
(External Clearance) shortest distance through air

Min. External Tracking L(IO2) 7.4 mm Measured from input terminals to output terminals,
Path (External Creepage) shortest distance path along body

Min. Internal Plastic 0.08 mm Through insulation distance, conductor to conductor,
Gap (Internal Clearance) usually the direct distance between the photoemitter

and photodetector inside the optocoupler cavity

Tracking Resistance CTI 200 V DIN IEC 112/VDE 0303 PART 1
(Comparative
Tracking Index)

Isolation Group IIIa Material Group (DIN VDE 0110, 1/89, Table 1)

Option 300 – surface mount classification is Class A in accordance with CECC 00802.

Absolute Maximum Ratings (No derating required up to 70°C)

Parameter Symbol Min. Max. Units Note

Storage Temperature T

S

-55 125 °C

Operating Temperature T

A

-40 85 °C

Lead Soldering Cycle Temperature 260 °C1

Time 10 s

Input Current Average 50 2

Surge I

IN

140 mA 2, 3

Transient 500

Input Voltage (Pins 2-3) V

IN

-0.5 V

Input Power Dissipation P

IN

230 mW 4

Total Package Power Dissipation P

T

305 mW 5

Output Power Dissipation P

O

210 mW 6

Output Current Average I

O

30 mA 7

Supply Voltage (Pins 8-5) V

CC

-0.5 20 V

Output Voltage (Pins 6-5) V

O

-0.5 20 V

Solder Reflow Temperature Profile See Package Outline Drawings section

Recommended Operating Conditions

Parameter Symbol Min. Max. Units Note

Supply Voltage V

CC

218 V

Operating Temperature T

A

070°C

Operating Frequency f 0 4 kHz 8

1-353

Parameter Sym. Device Min. Typ.

[9]

Max. Units Conditions Fig. Note

Input Threshold I

TH+

HCPL-3700 1.96 2.5 3.11 mA VIN = V

TH+

; VCC = 4.5 V; 2, 3 14

HCPL-3760 0.87 1.2 1.56

I

TH-

HCPL-3700 1.00 1.3 1.62 VIN = V

TH-

; VCC = 4.5 V;

HCPL-3760 0.43 0.6 0.80

Input DC V

TH+

3.35 3.7 4.05 V VIN = V2 - V3; Pins 1 & 4 Open

Threshold (Pins 2, 3) V

CC

= 4.5 V; VO = 0.4 V;

Voltage I

O

≥ 4.2 mA

V

TH-

2.01 2.6 2.86 V VIN = V2 - V3; Pins 1 & 4 Open
V

CC

= 4.5 V; VO = 2.4 V;

I

O

≤ 100 µA

AC V

TH+

4.23 4.9 5.50 V VIN = |V1 - V4|; 14, 15

(Pins 1, 4) Pins 2 & 3 Open

V

CC

= 4.5 V; VO = 0.4 V;

I

O

≥ 4.2 mA

V

TH-

2.87 3.7 4.20 V VIN = |V1 - V4|;
Pins 2 & 3 Open
V

CC

= 4.5 V; VO = 2.4 V;

I

O

≤ 100 µA

Hysteresis I

HYS

HCPL-3700 1.2 mA I

HYS

= I

TH+

– I

TH-

2

HCPL-3760 0.6

V

HYS

1.2 V V

HYS

= V

TH+

– V

TH-

Input Clamp Voltage V

IHC1

5.4 6.0 6.6 V V

IHC1

= V2 - V3; V3 = GND; 1

I

IN

= 10 mA; Pins 1 & 4

Connected to Pin 3

V

IHC2

6.1 6.7 7.3 V V

IHC2

= |V1 - V4|;

|I

IN

| = 10 mA;

Pins 2 & 3 Open

V

IHC3

12.0 13.4 V V

IHC3

= V2 - V3; V3 = GND;

I

IN

= 15 mA; Pins 1 & 4 Open

V

ILC

-0.76 V V

ILC

= V2 - V3; V3 = GND;

I

IN

= -10 mA

Input Current IINHCPL-3700 3.0 3.7 4.4 mA VIN = V2 – V3 = 5.0 V 5

HCPL-3760 1.5 1.8 2.2

Bridge Diode V

D1,2

HCPL-3700 0.59 V IIN = 3 mA
HCPL-3760 0.51 IIN = 1.5 mA

V

D3,4

HCPL-3700 0.74 IIN = 3 mA
HCPL-3760 0.71 IIN = 1.5 mA

Logic Low Output V

OL

0.1 0.4 V VCC = 4.5 V; IOL = 4.2 mA 5 14

Voltage
Logic High I

OH

100 µAVOH = VCC = 18 V 14

Output Current
Logic Low Supply I

CCL

HCPL-3700 1.2 4 mA V2 – V3 = 5.0 V; VO = Open; 6
HCPL-3760 0.7 3 VCC = 5.0 V

Logic High Supply I

CCH

0.002 4 µAVCC = 18 V; VO = Open 4 14

Current
Input Capacitance C

IN

50 pF f = 1 MHz; VIN = 0 V,

Pins 2 & 3, Pins 1 & 4 Open

VO = 0.4 V; IO ≥ 4.2 mA

V

O

= 2.4 V; IOH ≤ 100 µA

Forward Voltage

Electrical Specifications

Over Recommended Temperature TA = 0°C to 70°C, Unless Otherwise Specified.

Current

Current

Pins 1 & 4 Open

1-354

Parameter Sym. Device Min. Typ. Max. Units Test Conditions Fig. Note

Propagation Delay HCPL-3700 4.0
Time to Logic Low t

PHL

15.0 µsRL = 4.7 kΩ, CL = 30 pF 10

at Output HCPL-3760 4.5

7, 10

Propagation Delay HCPL-3700 10.0
Time to Logic High t

PLH

40.0 µsRL = 4.7 kΩ, CL = 30 pF 11

at Output HCPL-3760 8.0

HCPL-3700 20

Output Rise Time t

r

µsRL = 4.7 kΩ, CL = 30 pF

(10-90%) HCPL-3760 14

8

HCPL-3700 0.3

Output Fall Time t

f

µsRL = 4.7 kΩ, CL = 30 pF

(90-10%) HCPL-3760 0.4

Common Mode IIN = 0 mA, RL = 4.7 kΩ,
Transient Immunity |CMH| 4000 V/µsV

O min

= 2.0 V, VCM = 1400 V

at Logic High Output

9, 11 12, 13

Common Mode HCPL-3700 IIN = 3.11 mA RL = 4.7 kΩ,
Transient Immunity |CML| 600 V/µsV

O max

= 0.8 V,

at Logic Low Output HCPL-3760 IIN = 1.56 mA VCM = 140 V

Switching Specifications

TA = 25°C, VCC = 5.0 V, Unless Otherwise Specified.

Package Characteristics

Over Recommended Temperature TA = 0°C to 70°C, Unless Otherwise Specified.

Parameter Sym. Min. Typ.

[9]

Max. Units Conditions Fig. Note

Input-Output Momentary V

ISO

2500 V rms RH ≤ 50%, t = 1 min; 16,

Withstand Voltage* TA = 25°C17
Input-Output Resistance R

I-O

10

12

Ω V

I-O

= 500 Vdc 16

Input-Output Capacitance C

I-O

0.6 pF f = 1 MHz; V

I-O

= 0 Vdc

*The Input-Output Momentary Withstand Voltage is a dielectric voltage rating that should not be interpreted as an input-output
continuous voltage rating. For the continuous voltage rating refer to the VDE 0884 Insulation Characteristics Table (if applicable), your
equipment level safety specification, or HP Application Note 1074, “Optocoupler Input-Output Endurance Voltage.”

1-355

Notes:

1. Measured at a point 1.6 mm below seating plane.

2. Current into/out of any single lead.

3. Surge input current duration is 3 ms at 120 Hz pulse repetition rate. Transient input current duration is 10 µs at 120 Hz pulse

repetition rate. Note that maximum input power, PIN, must be observed.

4. Derate linearly above 70°C free-air temperature at a rate of 4.1 mW/°C. Maximum input power dissipation of 230 mW allows an input
IC junction temperature of 125°C at an ambient temperature of TA = 70°C with a typical thermal resistance from junction to ambient
of θ

JA1

= 240°C/W. Excessive PIN and TJ may result in IC chip degradation.

5. Derate linearly above 70°C free-air temperature at a rate of 5.4 mW/°C.

6. Derate linearly above 70°C free-air temperature at a rate of 3.9 mW/°C. Maximum output power dissipation of 210 mW allows an
output IC junction temperature of 125°C at an ambient temperature of TA = 70°C with a typical thermal resistance from junction to
ambient of θ

JA0

= 265°C/W.

7. Derate linearly above 70°C free-air temperature at a rate of 0.6 mA/°C.

8. Maximum operating frequency is defined when output waveform Pin 6 obtains only 90% of VCC with RL = 4.7 kΩ, CL = 30 pF using
a 5 V square wave input signal.

9. All typical values are at TA = 25°C, VCC = 5.0 V unless otherwise stated.

10. The t

PHL

propagation delay is measured from the 2.5 V level of the leading edge of a 5.0 V input pulse (1 µs rise time) to the 1.5 V

level on the leading edge of the output pulse (see Figure 10).

11. The t

PLH

propagation delay is measured from the 2.5 V level of the trailing edge of a 5.0 V input pulse (1 µs fall time) to the 1.5 V

level on the trailing edge of the output pulse (see Figure 10).

12. Common mode transient immunity in Logic High level is the maximum tolerable (positive) dVCM/dt on the leading edge of the
common mode pulse, VCM, to insure that the output will remain in a Logic High state (i.e., VO > 2.0 V). Common mode transient
immunity in Logic Low level is the maximum tolerable (negative) dVCM/dt on the trailing edge of the common mode pulse signal,
VCM, to insure that the output will remain in a Logic Low state (i.e., VO < 0.8 V). See Figure 11.

13. In applications where dVCM/dt may exceed 50,000 V/µs (such as static discharge), a series resistor, RCC, should be included to
protect the detector IC from destructively high surge currents. The recommended value for RCC is 240 Ω per volt of allowable drop
in VCC (between Pin 8 and VCC) with a minimum value of 240 Ω.

14. Logic low output level at Pin 6 occurs under the conditions of VIN ≥ V

TH+

as well as the range of VIN > V

TH–

once VIN has exceeded

V

TH+

. Logic high output level at Pin 6 occurs under the conditions of VIN ≤ V

TH-

as well as the range of VIN < V

TH+

once VIN has

decreased below V

TH-

.

15. AC voltage is instantaneous voltage.

16. Device considered a two terminal device: Pins 1, 2, 3, 4 connected together, and Pins 5, 6, 7, 8 connected together.

17. In accordance with UL 1577, each optocoupler is proof tested by applying an insulation test voltage ≥ 3000 V rms for 1 second
(leakage detection current limit, I

i-o

≤ 5 µA).

Figure 1. Typical Input Characteristics, IIN vs. VIN (AC Voltage is Instantaneous Value).

1-356

INPUT

DEVICE TH+TH–CONNNECTION

ITHHCPL-3700 2.5 mA 1.3 mA PINS 2, 3

HCPL-3760 1.2 mA 0.6 mA OR 1, 4

V

TH(dc)

BOTH 3.7 V 2.6 V PINS 2, 3

V

TH(ac)

BOTH 4.9 V 3.7 V PINS 1, 4

Figure 3. Typical DC Threshold Levels vs. Temperature.

Figure 2. Typical Transfer Characteristics.

V

TH

– VOLTAGE THRESHOLD – V

TA – TEMPERATURE – °C

2.4

-20

4.2

04060

1.8

3.4

3.8

-40 80

2.2

2.0

20

HCPL-3700

2.6

2.8

3.0

3.2

3.6

4.0

1.4

3.2

0.8

2.4

2.8

1.2

1.0

1.6

1.8

2.0

2.2

2.6

3.0

I

TH

– CURRENT THRESHOLD – mA

I

TH+

V

TH-

I

TH-

V

TH+

V

TH

– VOLTAGE THRESHOLD – V

TA – TEMPERATURE – °C

2.4

-25

4.2

05075

1.8

3.4

3.8

-40 85

2.2

2.0

25

HCPL-3760

2.6

2.8

3.0

3.2

3.6

4.0

0.7

1.6

0.4

1.2

1.4

0.6

0.5

0.8

0.9

1.0

1.1

1.3

1.5

I

TH

– CURRENT THRESHOLD – mA

V

TH+

I

TH+

V

TH-

I

TH-

1-357

Figure 5. Typical Input Current, IIN, and Low Level Output Voltage, VOL, vs. Temperature.

Figure 6. Typical Logic Low Supply Current vs. Supply Voltage.

I

IN

– INPUT CURRENT – mA

TA – TEMPERATURE – °C

2.4

-20

4.2

04060

1.8

3.4

3.8

-40 80

2.2

2.0

20

HCPL-3700

2.6

2.8

3.0

3.2

3.6

4.0

60

240

0

160

200

40
20

80

100

120

140

180

220

V

OL

– LOW LEVEL OUTPUT VOLTAGE – mV

V

IN

= 5.0 V
(PINS 2, 3)
V

CC

= 5.0 V

I

IN

V

CC

= 5.0 V

I

OL

= 4.2 mA

V

OL

Figure 4. Typical High Level Supply Current, I

CCH

vs.

Temperature.

I

IN

– INPUT CURRENT – mA

TA – TEMPERATURE – °C

1.2

-25

2.1

05075

0.9

1.7

1.9

-40 85

1.1

1.0

25

HCPL-3760

1.3

1.4

1.5

1.6

1.8

2.0

60

240

0

160

200

40
20

80

100

120

140

180

220

V

OL

– LOW LEVEL OUTPUT VOLTAGE – mV

V

IN

= 5.0 V
(PINS 2, 3)
V

CC

= 5.0 V

I

IN

V

CC

= 5.0 V

I

OL

= 4.2 mA

V

OL

I

CCL

– LOGIC LOW SUPPLY CURRENT – mA

VCC – SUPPLY VOLTAGE – V

2.50

2.00

6.0

4.00

8.0 12.0 14.0

0

3.00

3.50

4.0 20.018.0

1.50

1.00

0.50

10.0 16.0

HCPL-3700

I

CCL

– LOGIC LOW SUPPLY CURRENT – mA

V

CC

– SUPPLY VOLTAGE – V

1.50

6.0

3.00

8.0 12.0 14.0

0

2.00

2.50

4.0 20.018.0

1.00

0.50

10.0 16.0

HCPL-3760

I

CCH

– HIGH LEVEL SUPPLY CURRENT – µA

TA – TEMPERATURE – °C

-25

10

0

05075

10

-5

10

-1

-40 85

10

-4

25

10

-3

10

-2

V

CC

= 18 V

V

O

= OPEN

I

IN

= 0 mA

I

CCH

I

CCH

1-358

t

p

– PROPAGATION DELAY – µs

TA – TEMPERATURE – °C

6

-202404060

0

16

20

-40 80

4
2

20

HCPL-3700

8

10

12

14

18

22

R

L

= 4.7 kΩ

C

L

= 30 pF

V

CC

= 5.0 V

V

IN

=

t

PLH

5.0 V
1 ms PULSE WIDTH
f = 100 Hz
t

r

, tf = 1 µs (10-90%)

t

PHL

Figure 7. Typical Propagation Delay vs. Temperature.

t

r

– RISE TIME – µs

TA – TEMPERATURE – °C

-206004060

0

40

50

-40 80

10

20

HCPL-3700

20

30

R

L

= 4.7 kΩ

C

L

= 30 pF

V

CC

= 5.0 V

V

IN

=

t

r

5.0 V
1 ms PULSE WIDTH
f = 100 Hz
t

r

, tf = 1 µs (10-90%)

600

0

400

500

100

200

300

t

f

– FALL TIME – ns

t

f

t

p

– PROPAGATION DELAY – µs

TA – TEMPERATURE – °C

6

-252405075

0

16

20

-40 85

4
2

25

HCPL-3760

8

10

12

14

18

22

R

L

= 4.7 kΩ

C

L

= 30 pF

V

CC

= 5.0 V

V

IN

=

t

PLH

5.0 V
1 ms PULSE WIDTH
f = 100 Hz
t

r

, tf = 1 µs (10-90%)

t

PHL

t

r

– RISE TIME – µs

TA – TEMPERATURE – °C

-253005075

0

20

25

-40 85

5

25

HCPL-3760

10

15

R

L

= 4.7 kΩ

C

L

= 30 pF

V

CC

= 5.0 V

V

IN

=

t

f

5.0 V
1 ms PULSE WIDTH
f = 100 Hz
tr, tf = 1 µs (10-90%)

t

r

t

f

– FALL TIME – ns

700

100

500

600

200

300

400

Figure 8. Typical Rise, Fall Times vs. Temperature.

Figure 9. Common Mode Transient Immunity
vs. Common Mode Transient Amplitude.

CM – COMMON MODE TRANSIENT IMMUNITY – V/ µs

VCM – COMMON MODE TRANSIENT AMPLITUDE – V

400

5000

800 1600

0

3000

4000

0 2000

500

1200

1000

2000

V

CC

= 5.0 V

I

IN

= 3.11 mA (3700)

I

IN

= 1.53 mA (3760)

V

OL

= 0.8 V

R

L

= 4.7 kΩ

T

A

= 25 °C

V

CC

= 5.0 V

I

IN

= 0 mA

V

OH

= 2.0 V

R

L

= 4.7 kΩ

T

A

= 25 °C

CM

L

CM

H

1-359

Figure 12. Typical External Threshold Characteristics, V ± vs. R

X

.

Figure 10. Switching Test Circuit.

Figure 11. Test Circuit for Common Mode Transient Immunity and Typical Waveforms.

V

TH+

= 3.7 V

V

TH–

= 2.6 V

V

TH+

= 4.9 V

V

TH–

= 3.7 V

I

TH+

= 2.5 mA

I

TH–

= 1.3 mA

T

A

= 25 °C

1-360

Electrical Considerations

The HCPL-3700/3760 optocoup­lers have internal temperature
compensated, predictable voltage
and current threshold points
which allow selection of an
external resistor, RX, to determine
larger external threshold voltage
levels. For a desired external
threshold voltage, V±, a corre­sponding typical value of RX can
be obtained from Figure 12.
Specific calculation of RX can be
obtained from Equation (1).
Specification of both V+ and V

-

voltage threshold levels simul­taneously can be obtained by the
use of RX and RP as shown in
Figure 13 and determined by
Equations (2) and (3).

RX can provide over-current
transient protection by limiting
input current during a transient
condition. For monitoring con­tacts of a relay or switch, the
HCPL-3700/3760 in combination
with RX and RP can be used to
allow a specific current to be
conducted through the contacts
for cleaning purposes (wetting
current).

The choice of which input voltage
clamp level to choose depends
upon the application of this
device (see Figure 1). It is recom­mended that the low clamp
condition be used when possible.

The low clamp condition in
conjunction with the low input
current feature will ensure
extremely low input power
dissipation.

In applications where dVCM/dt
may be extremely large (such as
static discharge), a series resistor,
RCC, should be connected in
series with VCC and Pin 8 to pro­tect the detector IC from destruc­tively high surge currents. See
Note 13 for determination of RCC.
In addition, it is recommended
that a ceramic disc bypass
capacitor of 0.01 µF be placed
between Pins 8 and 5 to reduce
the effect of power supply noise.

For interfacing ac signals to TTL
systems, output low pass filtering
can be performed with a pullup
resistor of 1.5 kΩ and 20 µF
capacitor. This application
requires a Schmitt trigger gate to
avoid slow rise time chatter
problems. For ac input applica­tions, a filter capacitor can be
placed across the dc input
terminals for either signal or
transient filtering.

Either ac (Pins 1, 4) or dc
(Pins 2, 3) input can be used to
determine external threshold
levels.

V+ - V

TH+

(-) (-)

RX = (1)

I

TH+

(-)

For two specifically selected
external threshold voltage levels,
V+ and V-, the use of RX and R

P

will permit this selection via
equations (2), (3) provided the
following conditions are met. If
the denominator of equation (2)
is positive, then

V

+

V

TH+

V+ - V

TH+ITH+

≥ and <

V

-

V

TH-

V- - V

TH-

I

TH-

Conversely, if the denominator of
equation (2) is negative, then

V

+

V

TH+

V+ - V

TH+ITH+

≤ and >

V

-

V

TH-

V- - V

TH-

I

TH-

V

TH-

(V+) - V

TH+

(V-)

RX = (2)

I

TH+

(V

TH-

) - I

TH-

(V

TH+

)

V

TH-

(V+) - V

TH+

(V-)

RP = (3)

I

TH+(V--VTH-

)+I

TH-(VTH+-V+

)

Figure 13. External Threshold Voltage Level Selection.

For one specifically selected
external threshold voltage level
V+ or V-, RX can be determined
without use of RP via