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-eciency AlGaAs
LED which has higher light output at lower drive currents.
Both devices have a threshold sensing input buer IC
that allows threshold levels to be set by a single external
resistor over a wide range of input voltages.
The input buer 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
buer 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 eect the threshold levels.
The ACPL-K370 input buer IC has a nominal turn-on
threshold of 3.8 V(V
TH+
) and 2.77 mA (I
TH+
). The buer
IC for the ACPL-K376 is designed for lower input current.
The nominal turn-on threshold for the ACPL-K376 is 3.8 V
(V
TH+
) and 1.32 mA (I
TH+
), 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 congurable 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
V
CC
V
O
GND
TRUTH TABLE
(POSITIVE LOGIC)
INPUT
H
L
OUTPUT
L
H
NC
I
CC
I
O
D1
D2
D3
D4
Figure 1. Functional Diagram
AC/DC
POWER
CONTROLLER
ISOLATION BARRIER
ACPL-K370
ACPL-K376
GND1 GND2
R
X
Figure 2. Connection Diagram
