Voltage/Current Detector. ACPL-K370 Datasheet
Isolated Voltage/Current Detector
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-efficiency AlGaAs
LED which has higher light output at lower drive currents.
Both devices have a threshold sensing input buffer IC
that allows threshold levels to be set by a single external
resistor over a wide range of input voltages.
The input buffer 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
buffer 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 effect the threshold levels.
The ACPL-K370 input buffer IC has a nominal turn-on
threshold of 3.8 V(VTH+) and 2.77 mA (ITH+). The buffer
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.
x ± 5% voltage detection accuracy
x Wide AC or DC detection range: up to 1140 Vpeak
x User configurable 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
– UL 1577: 5000 Vrms/1minute double protection
– CSA: Component Acceptance Notice #5
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
Figure 1. Functional Diagram
IO 6 VO
Figure 2. Connection Diagram
Table 1. Ordering Information
The ACPL-K370 and ACPL-K376 are UL recognized with 5000 Vrms for 1 minute per UL1577.
80 per tube
80 per tube
1000 per reel
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.
ACPL-K370-560E orders an RoHS compliant part with an IEC/EN/DIN EN 60747-5-5 certification and Tape & Reel
Package Outline Drawings
Stretched SO-8 Package (SSO-8)
RECOMMENDED LAND PATTERN
Z = OPTION CODE 
5.850 ± 0.50
(0.230 ± 0.010)
6.807 ± 0.127
(0.268 ± 0.005)
3.180 ± 0.127
(0.125 ± 0.005)
1.590 ± 0.127
(0.063 ± 0.005)
0.381 ± 0.130
(0.015 ± 0.005)
Note 1. “V” = Options comprise 060; other options are not marked.
0.750 ± 0.250
(0.0295 ± 0.010)
11.50 ± 0.250
(0.453 ± 0.010)
0.200 ± 0.100
(0.008 ± 0.004)
Dimensions in millimeters and (inches).
Lead coplanarity = 0.1 mm (0.004 inches).
Recommended Lead-Free IR Soldering Profile
The recommended reflow soldering profile is per JEDEC Standard J-STD-020 (latest revision). Non-halide flux should be
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.
Approval under the UL 1577 component recognition
program up to VISO = 5000 VRMS / 1 minute. File E55361.
Approval under CSA Component Acceptance Notice #5,
File CA 88324.
Table 2. Insulation Related Specifications
Minimum External Air Gap
Minimum External Tracking Path
Minimum Internal Plastic Gap
Measured from input terminals to output terminals
Through insulation distance conductor to conductor
DIN IEC 112/VDE 0303 Part 1
(per DIN VDE 0109)
IIIa Material Group DIN VDE 0109