ACPL-K370, ACPL-K376
Isolated Voltage/Current Detector
Data Sheet
Description
The ACPL-K370 and ACPL-K376 are voltage/current
threshold detection optocouplers. The ACPL-K376 is a low-
current version of the ACPL-K370. To obtain lower current
operation, the ACPL-K376 uses a high-eciency AlGaAs
LED which has higher light output at lower drive currents.
Both devices have a threshold sensing input buer IC
that allows threshold levels to be set by a single external
resistor over a wide range of input voltages.
The input buer has several performance enhancing
features: hysteresis for extra noise immunity and
switching immunity, a diode bridge for easy use with AC
input signals, and internal clamping diodes to protect the
buer and LED from over-voltage and over-current tran-
sients. Because threshold sensing is done prior to driving
the LED, variations in optical coupling from the LED to the
detector will not eect the threshold levels.
The ACPL-K370 input buer IC has a nominal turn-on
threshold of 3.8 V(VTH+) and 2.77 mA (ITH+). The buer
IC for the ACPL-K376 is designed for lower input current.
The nominal turn-on threshold for the ACPL-K376 is 3.8 V
(VTH+) and 1.32 mA (ITH+), which reduces power dissipa-
tion by 52%.
The high-gain output stage features an open-collector
output for both TTL compatible saturation voltages and
CMOS compatible breakdown voltages.
By combining many unique functions in a single package, the
ACPL-K370 and ACPL-K376 are ideal components for indus-
trial control computer input boards and other applications
where a predetermined input threshold level is needed.
Functional Diagram
Features
x ± 5% voltage detection accuracy
x Wide AC or DC detection range: up to 1140 Vpeak
x User congurable single/dual detection levels
x Built-in hysteresis improves noise immunity
x Very low threshold current: 1.32 mA (ACPL-K376)
x Logic compatible output
x Wide output supply voltage: 2 V to 18 V
x –40°C to +105°C operating temperature range
x SSO-8 package with 8 mm creepage and clearance
x Safety and regulatory approval:
– IEC/EN/DIN EN 60747-5-5: 1140 Vpeak working
insulation voltage
– UL 1577: 5000 Vrms/1minute double protection
rating
– CSA: Component Acceptance Notice #5
Applications
x Limit switch sensing
x Low voltage detector
x AC mains and DC-link voltage detection
x Relay contact monitor
x Relay coil voltage monitor
x Current sensing
x Microprocessor interfacing
x Telephone ring detection
Connection Diagram
1
2
3
4
8
7
6
5
AC1
DC+
DC
AC2
VCC
VO
GND
TRUTH TABLE
(POSITIVE LOGIC)
INPUT
H
L
OUTPUT
L
H
NC
ICC
IO
D1 D2
D3 D4
Figure 1. Functional Diagram
AC/DC
POWER CONTROLLER
ISOLATION BARRIER
ACPL-K370
ACPL-K376
GND1 GND2
RX
Figure 2. Connection Diagram
2
Table 1. Ordering Information
The ACPL-K370 and ACPL-K376 are UL recognized with 5000 Vrms for 1 minute per UL1577.
Part number
Option
Package Surface Mount
Tape
& Reel
IEC/EN/
DIN EN
60747-5-2 Quantity
RoHS
Compliant
ACPL-K370
ACPL-K376
-000E
Stretched
SO-8
X80 per tube
-060E XX
80 per tube
-500E XX 1000 per reel
-560E XXX
1000 per reel
To form a complete ordering part number, choose a part number from the part number column and combine it with the
desired option from the option column.
Example 1:
ACPL-K370-560E orders an RoHS compliant part with an IEC/EN/DIN EN 60747-5-5 certication and Tape & Reel
packaging.
Package Outline Drawings
Stretched SO-8 Package (SSO-8)
5.850 ± 0.50
(0.230 ± 0.010)
5
678
4321
Dimensions in millimeters and (inches).
Lead coplanarity = 0.1 mm (0.004 inches).
6.807 ± 0.127
(0.268 ± 0.005)
RECOMMENDED LAND PATTERN
12.650 (0.5)
1.905 (0.1)
3.180 ± 0.127
(0.125 ± 0.005)
0.381 ± 0.130
(0.015 ± 0.005)
1.270
(0.050) BSG
7°
(0.453 ± 0.010)
(0.008 ± 0.004)
(0.0295 ± 0.010) 0.200 ± 0.100
0.750 ± 0.250
11.50 ± 0.250
(0.063 ± 0.005)
1.590 ± 0.127
(0.018)
0.450
45°
Z = OPTION CODE[1]
RoHS-COMPLIANCE
INDICATOR
PART NUMBER
DATE CODE
K370
Z
YYWW
Note 1. “V” = Options comprise 060; other options are not marked.
Figure 3.
3
Recommended Lead-Free IR Soldering Prole
The recommended reow soldering prole is per JEDEC Standard J-STD-020 (latest revision). Non-halide ux should be
used.
Table 2. Insulation Related Specications
Parameter Symbol Value Units Conditions
Minimum External Air Gap
(Clearance)
L(IO1) 8 mm L(IO1)
Minimum External Tracking Path
(Creepage)
L(IO2) 8 mm Measured from input terminals to output terminals
Minimum Internal Plastic Gap
(Clearance)
0.08 mm Through insulation distance conductor to conductor
Tracking Resistance CTI 175 V DIN IEC 112/VDE 0303 Part 1
Isolation Group
(per DIN VDE 0109)
IIIa Material Group DIN VDE 0109
Regulatory Information
The ACPL-K370/K376 is approved by the following organizations:
IEC/EN/DIN EN 60747-5-5 (with option 060)
Approved with a maximum working insulation voltage of
VIORM = 1140 Vpeak, and with a highest allowable over-
voltage of VIOTM = 8000 Vpeak.
UL
Approval under the UL 1577 component recognition
program up to VISO = 5000 VRMS / 1 minute. File E55361.
CSA
Approval under CSA Component Acceptance Notice #5,
File CA 88324.
4
Table 3. IEC/EN/DIN EN 60747-5-5 Insulation Related Characteristics [1] (with option 060)
Description Symbol Characteristic Units
Installation Classication per DIN VDE 0110/1.89, Table 1:
for rated mains voltage ≤ 300 Vrms
for rated mains voltage ≤ 450 Vrms
for rated mains voltage ≤ 600 Vrms
for rated mains voltage ≤ 1000 Vrms
I-IV
I-III
I-III
I-II
Climatic Classication 55/105/21
Pollution Degree (DIN VDE 0110/1.89) 2
Maximum Working Insulation Voltage VIORM 1140 Vpeak
Input to Output Test Voltage, Method b
VIORM x 1.875 = VPR, 100% Production Test with tm = 1 second,
Partial Discharge < 5 pC
VPR 2137 Vpeak
Input to Output Test Voltage, Method a
VIORM x 1.6 = VPR, Type and sample test, tm = 10 seconds,
Partial Discharge < 5 pC
VPR 1824 Vpeak
Highest Allowable Overvoltage (Transient overvoltage, tini = 60 seconds) VIOTM 8000 Vpeak
Safety Limiting Values (Maximum values allowed in the event of a failure)
Case Temperature
Input Current [2]
Output Power [2]
TS
IS,INPUT
PS,OUTPUT
175
230
600
°C
mA
mW
Insulation Resistance at TS, VIO = 500 V RS109:
Notes:
1. Insulation characteristics are guaranteed only within the safety maximum ratings, which must be ensured by protective circuits within the
application.
2. Safety-limiting parameters are dependent on case temperature. The input current, IS,INPUT, should be derated linearly above 25°C free-air case
temperature at a rate of 1.53 mA / °C; the Output Power, PS,OUTPUT, should be derated linearly above 25°C free-air case temperature at a rate of
4 mW / °C.
5
Table 4. Absolute Maximum Ratings
Parameter Symbol Min Max Units Note
Storage Temperature TS–55 125 °C
Operating Temperature TA–40 105 °C
Input Current, Average IIN 50 mA 1
Input Current, Surge IIN 140 mA 1, 2
Input Current, Transient IIN 500 mA 1, 2
Input Voltage (Pins 2-3) VIN –0.5 V
Input Power Dissipation PIN 200 mW 3
Total Package Power Dissipation PT269 mW 4
Output Power Dissipation PO163 mW 5
Output Current, Average IO30 mA 6
Supply Voltage (Pins 8-5) VCC –0.5 20 V
Output Voltage (Pins 6-5) VO–0.5 20 V
Lead Solder Temperature 260°C for 10 seconds, measured at 1.6 mm below seating plane.
Notes:
1. Current into or out of any single lead.
2. Surge input current duration is 3 ms at a 120 Hz pulse repetition rate. Transient input current duration is 10 μs at a 120 Hz pulse repetition rate. Note
that the maximum input power, PIN, must be observed.
3. Derate linearly above 105°C free-air temperature at a rate of 10 mW / °C. The maximum input power dissipation of 200 mW allows an input IC
junction temperature of 125°C at an ambient temperature of TA = 105°C. Excessive PIN and TJ may result in IC chip degradation.
4. Derate linearly above 105°C free-air temperature at a rate of 13.5 mW / °C.
5. Derate linearly above 105°C free-air temperature at a rate of 8.2 mW / °C. A maximum output power dissipation of 163 mW allows an output IC
junction temperature of 125°C at an ambient temperature of TA = 105°C.
6. Derate linearly above 105°C free-air temperature at a rate of 1.5 mA / °C.
Table 5. Recommended Operating Conditions
Parameter Symbol Min Max Units Note
Supply Voltage VCC 218V
Operating Temperature TA–40 105 °C
Operating Frequency, VCC = 5 V f 0 9 kHz 1
Operating Frequency, VCC = 3.3 V f 0 5 kHz 1
Notes:
1. Maximum operating frequency is dened when the output waveform at pin 6 obtains only 90% of VCC with RL = 4.7 k:, CL = 30 pF using a 5 V
square wave input signal.
6
Table 6. Electrical Specications
Unless otherwise noted, TA = –40°C to +105°C and VCC = 3 V to 5.5 V.
Parameter Sym. Device Min Typ[1] Max Units Test Conditions/Notes Fig.
Upper Threshold
Voltage, DC Input
(Pins 2, 3)
VTH+ 3.6
(–5%) 3.8 4
(+5%) VT
A = 25°C, VIN = VDC+ – VDC–;
AC1 and AC2 open 5, 6
3.35 4.05 V VIN = VDC+ – VDC–; AC1 and AC2 open 5, 6
Lower Threshold
Voltage, DC Input
(Pins 2, 3)
VTH– 2.45
(–5%) 2.59 2.72
(+5%) VT
A = 25°C, VIN = VDC+ – VDC–;
AC1 and AC2 open 5, 6
2.01 2.96 V VIN = VDC+ – VDC–; AC1 and AC2 open 5, 6
Upper Threshold
Voltage, AC Input
(Pins 1, 4)
VTH+ 4.7
(–6%) 5 5.3
(+6%) VT
A = 25°C, VIN = VAC1 – VAC2,
DC+ and DC– open; Note 2 5, 6
4.23 5.5 V VIN = VAC1 – VAC2, DC+ and DC– open 5, 6
Lower Threshold
Voltage, AC Input
(Pins 1, 4)
VTH– 3.57
(–6%) 3.8 4.03
(+6%) VT
A = 25°C, VIN = VAC1 – VAC2,
DC+ and DC– open 5, 6
2.87 4.42 V VIN = VAC1 – VAC2, DC+ and DC– open 5, 6
Upper Threshold
Current ITH+ ACPL-K370 2.26 2.77 2.99 mA TA = 25°C 5, 6
1.96 3.11 mA 5, 6
Upper Threshold
Current ITH+ ACPL-K376 1.03 1.32 1.46 mA TA = 25°C 5, 6
0.87 1.56 mA 5, 6
Lower Threshold
Current ITH– ACPL-K370 1.09 1.44 1.59 mA TA = 25°C 5, 6
1 1.62 mA 5, 6
Lower Threshold
Current ITH– ACPL-K376 0.48 0.68 0.77 mA TA = 25°C 5, 6
0.43 0.8 mA 5, 6
Current Hysteresis IHYS ACPL-K370 1.2 mA IHYS = ITH+ – ITH– 5
ACPL-K376 0.6 mA
Voltage Hysteresis VHYS 1.2 V VHYS = VTH+ – VTH– 5
Input Clamp Voltage VIHC1 5.4 6.1 6.8 V VIHC1 = VDC+ – VDC–, IIN = 10 mA,
AC1 & AC2 connected to DC– 4
VIHC2 6.1 6.8 7.4 V VIHC2 = |VAC1 – VAC2|, |IIN| = 10 mA,
DC+ and DC– open 4
VIHC3 12.5 13.4 V VIHC3 = VDC+ – VDC–, IIN = 15 mA,
AC1 & AC2 open 4
VILC –0.76 V VILC = VDC+ – VDC–, IIN = –10 mA
Input Current IIN ACPL-K370 3.2 3.9 4.4 mA VDC+ – VDC– = 5 V, AC1 and AC2 open 8
Input Current IIN ACPL-K376 1.5 1.9 2.2 mA VDC+ – VDC– = 5 V, AC1 and AC2 open 8
Bridge Diode
Forward Voltage VD1,2 ACPL-K370 0.59 V IIN = 3 mA
ACPL-K376 0.47 V IIN = 1.5 mA
VD3,4 ACPL-K370 0.78 V IIN = 3 mA
ACPL-K376 0.73 V IIN = 1.5 mA
Logic Low Output
Voltage VOL 0.05 0.4 V VCC = 4.5 V, IOL = 4.2 mA; Note 3 8
Logic High Output
Current IOH 100 PAVOH = VCC = 18 V; Note 4
Logic Low Supply
Current ICCL ACPL-K370 0.9 4 mA VDC+ – VDC– = 5 V, VO open 9
ACPL-K376 0.5 3 mA
Logic High Supply
Current ICCH 0.002 4 PAVCC = 18 V, VO open 7
Input Capacitance CIN 50 pF f = 1 MHz, VIN = 0 V
Notes:
1. All typical values are at TA = 25°C unless otherwise stated.
2. AC voltage is instantaneous voltage.
3. A logic “Low” output level at pin 6 occurs under the conditions of VIN ≥ VTH+ as well as the range of VIN > VTH– once VIN has exceeded VTH+.
4. A logic “High” output level at pin 6 occurs under the conditions of VIN ≤ VTH– as well as the range of VIN < VTH+ once VIN has decreased below VTH–.
7
Table 7. Switching Specications
Unless otherwise noted, TA = –40°C to +105°C.
Parameter Sym Device Min Typ[1] Max Units Test Conditions/Notes Fig.
VCC = 4.5 V
Propagation Delay
Time to Logic Low
at Output
tPHL ACPL-K370 3.7 7.5 PsR
L = 4.7 k:, CL = 30 pF; Note 2 10
ACPL-K376 6.2 12.5 Ps
ACPL-K370 3.7 7.5 PsR
L = 1.8 k:, CL = 15 pF; Note 2
ACPL-K376 6.3 12.5 Ps
Propagation Delay
Time to Logic High
at Output
tPLH ACPL-K370 13.8 70 PsR
L = 4.7 k:, CL = 30 pF; Note 3 10
ACPL-K376 13.3 70 Ps
ACPL-K370 8.5 45 PsR
L = 1.8 k:, CL = 15 pF; Note 3
ACPL-K376 6.4 45 Ps
Output Rise Time
(10-90%) tRACPL-K370 25 PsR
L = 4.7 k:, CL = 30 pF 11
ACPL-K376 24 Ps
Output Fall Time
(90-10%) tFACPL-K370 0.3 PsR
L = 4.7 k:, CL = 30 pF 11
ACPL-K376 0.4 Ps
VCC = 3.3 V
Propagation Delay
Time to Logic Low
at Output
tPHL ACPL-K370 4 7.5 PsR
L = 4.7 k:, CL = 30 pF; Note 2
ACPL-K376 6.8 12.5 Ps
ACPL-K370 4 7.5 PsR
L = 1.8 k:, CL = 15 pF; Note 2
ACPL-K376 6.9 12.5 Ps
Propagation Delay
Time to Logic High
at Output
tPLH ACPL-K370 19 90 PsR
L = 4.7 k:, CL = 30 pF; Note 3
ACPL-K376 18.5 90 Ps
ACPL-K370 12.8 70 PsR
L = 1.8 k:, CL = 15 pF; Note 3
ACPL-K376 12.5 70 Ps
Output Rise Time
(10-90%) tRACPL-K370 27 PsR
L = 4.7 k:, CL = 30 pF
ACPL-K376 26 Ps
Output Fall Time
(90-10%) tFACPL-K370 0.3 PsR
L = 4.7 k:, CL= 30 pF
ACPL-K376 0.5 Ps
VCC = 3 V to 5.5 V
Common Mode
Transient Immunity
at Logic High Output
|CMH|10
kV/PsI
IN = 0 mA, RL = 4.7 k:, VO,MIN = 2 V,
VCM = 1500 V; Notes 4, 5
Common Mode
Transient Immunity
at Logic Low Output
|CML| ACPL-K370 1 kV/PsI
IN = 3.11 mA, RL = 4.7 k:, VO,MAX =
0.8 V, VCM = 500 V; Notes 4, 5
ACPL-K376 1 kV/PsI
IN = 1.56 mA, RL = 4.7 k:, VO,MAX =
0.8 V, VCM = 500 V; Notes 4, 5
Notes:
1. All typical values are at TA = 25°C unless otherwise stated.
2. The tPHL propagation delay is measured from the 2.5 V level of the leading edge of a 5.0 V input pulse (1 Ps rise time) to the 1.5 V level on the leading
edge of the output pulse. CL includes probe and stray wiring capacitance.
3. The tPLH propagation delay is measured from the 2.5 V level of the trailing edge of a 5.0 V input pulse (1 Ps fall time) to the 1.5 V level on the trailing
edge of the output pulse. CL includes probe and stray wiring capacitance.
4. Common mode transient immunity with a 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).
5. In applications where dVCM/dt may exceed 50 kV / μs (such as when a static discharge occurs), a series resistor, RCC, should be included to protect
the detector IC from destructive high surge currents. The recommended value for RCC is 240 : per volt of allowable drop in VCC (between pin 8 and
VCC) with a minimum value of 240 :.
8
Table 8. Package Characteristics
Over recommended temperature range of TA = –40°C to 105°C unless otherwise specied.
Parameter Symbol Min Typ Max Units Test Conditions
Input-Output Momentary
Withstand Voltage
VISO 5000 Vrms RH ≤ 50%, t = 1 min; TA = 25°C;
Notes 1 to 3
Input-Output Resistance RI-O 1012 :VI-O = 500 Vdc; Note 2
Input-Output Capacitance CI-O 0.6 pF f = 1 MHz, VI-O = 0 Vdc; Note 2
Notes:
1. 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 IEC/EN/DIN EN 60747-5-5 Insulation Characteristics Table (if applicable), your equipment level
safety specication, or Avago Application Note 1074, Optocoupler Input-Output Endurance Voltage.
2. Device considered a two terminal device: pins 1, 2, 3, 4 connected together, and pins 5, 6, 7, 8 connected together.
3. In accordance with UL 1577, each optocoupler is proof tested by applying an insulation test voltage ≥ 6000 Vrms for 1 second (leakage detection
current limit, II-O ≤ 5 PA).
9
Figure 4. Typical input characteristics IIN vs. VIN
(AC voltage is an instantaneous value).
Figure 5. (a) Typical transfer characteristics, and (b) Input threshold levels.
Figure 6. Typical DC threshold levels vs. temperature for (a) ACPL-K370, and (b) ACPL-K376.
Typical Performance Plots
Unless otherwise noted, TA = 25°C.
0
5
10
15
20
25
30
35
40
45
50
01234567891011 121314
VIN - INPUT VOLTAGE - V
IIN - INPUT CURRENT - mA
AC INPUT, PINS
2, 3 OPEN
DC INPUT, SHORT
PINS 1 & 2, SHORT
PINS 3 & 4.
DC INPUT, PINS
1, 4 OPEN
0
1
2
3
4
5
6
INPUT SIGNAL
(a)
VO - OUTPUT VOLTAGE - V
VCC = 5 V
RL = 4.7 kΩ
ITH ACPL-K3702.77mA1.44mA
ACPL-K376 1.32mA0.68mA
VTH(AC)ALL 5V 3.8V PINS 1, 4
Input
Signal
PINS 2, 3
OR 1, 4
Device TH+ TH–
Input
Connection
(b)
VTH(DC)ALL 3.8V 2.59V PINS 2, 3
TH- TH+
ACPL-K370
1.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
3.8
4
4.2
-60 -40 -20 0 20406080100 120
TA - TEMPERATURE - °C
V
TH
- THRESHOLD VOLTAGE - V
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
3.1
3.3
I
TH
- THRESHOLD CURRENT -mA
VTH+
ITH–
ITH+
VTH–
ACPL-K376
1.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
3.8
4
4.2
-60 -40 -20 0 20406080100 120
TA - TEMPERATURE - °C
VTH - THRESHOLD VOLTAGE - V
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
ITH - THRESHOLD CURRENT -mA
VTH+
ITH–
ITH+
VTH–
10
Figure 7. Typical high level supply current, ICCH vs. temperature.
Figure 8. Typical input current, IIN, and low level output voltage, VOL vs. temperature for (a) ACPL-K370 and (b) ACPL-K376.
Figure 9. Typical logic low supply current vs. supply voltage for (a) ACPL-K370 and (b) ACPL-K376.
1E-5
1E-4
1E-3
1E-2
1E-1
1E+0
-60 -40 -20 0 20 40 60 80 100 120
TA - TEMPERATURE - °C
ICCH - HIGH LEVEL SUPPLY CURRENT - PA
ACPL-K370
2.4
2.6
2.8
3
3.2
3.4
3.6
3.8
4
4.2
4.4
-60 -40 -20 0 20 40 60 80 100 120
TA - TEMPERATURE - °C
IIN - INPUT CURRENT - mA
10
20
30
40
50
60
70
80
90
100
110
VOL - LOW OUTPUT VOLTAGE - mV
(a)
ACPL-K376
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
-60 -40 -20 0 20 40 60 80 100 120
TA - TEMPERATURE - °C
IIN - INPUT CURRENT - mA
10
20
30
40
50
60
70
80
90
100
110
VOL - LOW OUTPUT VOLTAGE - mV
(b)
ACPL-K370
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
024681012141618
VCC - SUPPLY VOLTAGE - V
ICCL - LOGIC LOW SUPPLY CURRENT - mA
(a)
ACPL-K376
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
024681012141618
VCC - SUPPLY VOLTAGE - V
ICCL - LOGIC LOW SUPPLY CURRENT - mA
(b)
IIN
VDC+ – VDC– = 5V,
AC1 AND AC2 OPEN
VOL
VCC = 4.5V,
IOL = 4.2mA
VOL
VCC = 4.5V,
IOL = 4.2mA
11
Figure 10. Typical propagation delay vs. temperature for (a) ACPL-K370 and (b) ACPL-K376.
Figure 11. Typical rise, fall times vs. temperature for (a) ACPL-K370,and (b) ACPL-K376.
Figure 12. Typical external threshold characteristics, V± vs. RX for (a) ACPL-K370 and (b) ACPL-K376.
ACPL-K370
0
5
10
15
20
25
30
35
40
-60 -40 -20 0 20 40 60 80 100 120
TA - TEMPERATURE - °C
tP - PROPAGATION DELAY - Ps
tPLH
tPHL
(a)
ACPL-K376
0
5
10
15
20
25
30
35
40
-60 -40 -20 0 20 40 60 80 100 120
TA - TEMPERATURE - °C
tP - PROPAGATION DELAY - Ps
RL = 4.7k:,
CL = 30pF,
VCC = 4.5V
RL = 4.7k:,
CL = 30pF,
VCC = 4.5V tPLH
tPHL
(b)
TA - TEMPERATURE - °C
(a)
TA - TEMPERATURE - °C
(b)
ACPL-K376
0
50
100
150
200
250
300
0 100 200 300 400 500
RX - EXTERNAL SERIES RESISTOR - k:
V± - EXTERNAL THRESHOLD VOLTAGE - V
DC: VTH+ = 3.8V, VTH– = 2.59V;
AC: VTH+ = 5V, VTH– = 3.8V;
ITH+ = 1.32mA, ITH– = 0.68mA
(AC VOLTAGE IS
INSTANTANEOUS VALUE)
(b)
ACPL-K370
0
50
100
150
200
250
300
0 40 80 120 160 200 240
RX - EXTERNAL SERIES RESISTOR - k:
V± - EXTERNAL THRESHOLD VOLTAGE - V
(a)
DC: VTH+ = 3.8V, VTH– = 2.59V;
AC: VTH+ = 5V, VTH– = 3.8V;
ITH+ = 2.77mA, ITH– = 1.44mA
(AC VOLTAGE IS
INSTANTANEOUS VALUE)
V+(AC)
V+(DC)
V–(AC)
V–(DC)
V+(AC)
V+(DC)
V–(AC)
V–(DC)
ACPL-K370
0
10
20
30
40
50
60
70
80
-60 -40 -20 0 20 40 60 80 100 120
tR - RISE TIME - Ps
100
200
300
400
500
600
700
800
900
tF - Fall Time - ns
tR
tF
ACPL-K376
0
10
20
30
40
50
60
70
80
-60 -40 -20 0 20 40 60 80 100 120
tR - RISE TIME - Ps
200
300
400
500
600
700
800
900
1000
tF - Fall Time - ns
tR
tF
RL = 4.7k:,
CL = 30pF,
VCC = 4.5V
RL = 4.7k:,
CL = 30pF,
VCC = 4.5V
12
Electrical Considerations
The ACPL-K370/K376 optocouplers have internally tem-
perature compensated, predictable voltage and current
threshold points. This allows a single external resistor, RX,
to determine larger external threshold voltage levels. For
a desired external threshold voltage, V±, the approximate
Rx value is shown in Figure 12. Equation 1 can be used to
calculate Rx.
V+ and V– voltage threshold levels can be simultaneously
set with two resistors, RX and RP, as shown in Figure 13 and
determined by Equations 4 and 5.
RX can provide over-current transient protection by
limiting input current during a transient condition. For
monitoring contacts of a relay or switch, the ACPL-K370/
K376 in combination with RX and RP can be used to allow a
specic 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 4).
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 with a static discharge), a series resistor, RCC,
should be connected in series with VCC and pin 8 to protect
the detector IC from destructive high surge currents. The
recommended value for RCC is 240 : per volt of allowable
drop in VCC (between Pin 8 and VCC) with a minimum value
of 240 :. In addition, it is recommended that a ceramic
disc bypass capacitor of 0.01 PF be placed between pins 5
and 8 to reduce the eect of power supply noise.
For interfacing ac signals to TTL systems, output low pass
ltering can be performed with a pull-up resistor of 1.5 k:
and 20 PF capacitor. This application requires a Schmitt
trigger gate to avoid slow rise time chatter problems.
For AC input applications, a lter capacitor can be placed
across the DC input terminals for either signal or transient
ltering.
Figure 13. External threshold voltage level selection.
Either AC (pins 1 and 4) or DC (pins 2 and 3) input can be
used to determine external threshold levels. For single
specically selected external threshold voltage level V+ or
V–, RX can be determined without use of RP via:
V+(–) – VTH+(–)
RX = Equation 1
ITH+(–)
For dual specically selected external threshold voltage
levels, V+ and V–, the use of RX and RP will permit this
selection. Two equations can be written:
VTH+
V+ = Rx ( ITH+ + ) + VTH+ Equation 2
RP
VTH–
V– = Rx ( ITH– + ) + VTH– Equation 3
RP
Solving these equations for RX and RP yields the following
two expressions:
VTH– (V+) – VTH+ (V–)
RX = Equation 4
I
TH+ (VTH–) – ITH– (VTH+)
VTH– (V+) – VTH+ (V–)
RP = Equation 5
I
TH+ (V– – VTH–) + ITH– (VTH+ – V+)
where
V+ and V– are the desired external voltage threshold
levels, and values for VTH± and ITH± are found from the
data sheet.
Equations 4 and 5 are valid only if the conditions of
Equations 6 or 7 are met. With the VTH± and ITH± values,
the denominator of Equation 4 is checked to see if it is
positive or negative. If it is positive, then the following
ratios must be met:
V+ VTH+ V+ – VTH+ ITH+
≥ and < Equation 6
V– VTH– V
– – VTH– I
TH–
Conversely, if the denominator of Equation 4 is negative,
then the following ratios must hold:
V+ VTH+ V+ – VTH+ ITH+
≤ and > Equation 7
V– VTH– V
– – VTH– I
TH–
Refer to Application Note 1004 for more application infor-
mation and worked out examples.
ISOLATION
BARRIER
CL
GND
RX
1
2
3
4
8
7
6
5
AC1
DC+
DC–
AC2
VCC
NC
VO
GND
ITH±
VTH±
V±RL
VO
VCC
RP
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Data subject to change. Copyright © 2005-2011 Avago Technologies. All rights reserved.
AV02-2153EN - January 19, 2011