9
Applications
The HCPL-2300/HCPL-0300
optocoupler has the unique
combination of low 0.5 mA LED
operating drive current at a
5 MBd speed performance. Low
power supply current
requirement of 10 mA maximum
at 5.25 V and the ability to
provide isolation between logic
systems fulfills numerous
applications ranging from logic
level translations, line receiver
and party line receiver
applications, microprocessor I/O
port isolation, etc. The open col-
lector output allows for wired-OR
arrangement. Specific interface
circuits are illustrated in Figures
12-16, and 18 with correspond-
ing component values, perform-
ance data and recommended
layout in Figures 17 and 19.
For -40°C to 85°C operating
temperature range, a mid-range
LED forward current (IF) of
0.625 mA is recommended in
order to prevent overdriving the
integrated circuit detector due to
increased LED efficiency at
temperatures between 0°C and
-40°C. For narrower temperature
range of 0°C to 85°C, a suggested
operating LED current of
0.75 mA is recommended for the
mid-range operating point and for
minimal propagation delay skew.
A peaking capacitance of 20 pF
in parallel with the current
limiting resistor for the LED
shortens tPHL by approximately
33% and tPLH by 13%. Maintain-
ing LED forward voltage (VF)
below 0.8 V will guarantee that
the HCPL-2300/HCPL-0300
output is off.
The recommended shunt drive
technique for TTL/LSTTL/CMOS
of Figure 12 provides for optimal
speed performance, no leakage
current path through the LED,
and reduced common mode
influences associated with series
switching of a “floating” LED.
Alternate series drive techniques
with either an active CMOS
inverter or an open collector TTL/
LSTTL inverter are illustrated in
Figures 13 and 14 respectively.
Open collector leakage current of
250 µA has been compensated by
the 3.16 KΩ resistor (Figure 14)
at the expense of twice the
operating forward current.
An application of the HCPL-2300/
HCPL-0300 as an unbalanced line
receiver for use in long line
twisted wire pair communication
links is shown in Figure 15. Low
LED IF and VF allow longer line
length, higher speed and multiple
stations on the line in comparison
to higher IF, VF optocouplers.
Greater speed performance along
with nearly infinite common
mode immunity are achieved via
the balanced split phase circuit
of Figure 16. Basic balanced
differential line receiver can
be accomplished with one
HCPL-2300/HCPL-0300 in
Figure 16, but with a typical
400 V/µs common mode
immunity. Data rate versus
distance for both the above
unbalanced and balanced line
receiver applications are com-
pared in Figure 17. The RS-232-C
interface circuit of Figure 18
Figure 10. Test Circuit for Common Mode Transient Immunity and Typical Waveforms.
Figure 11. Thermal Derating Curve,
Dependence of Safety Limiting Value
with Case Temperature per IEC/EN/
DIN EN 60747-5-2.
OUTPUT POWER – PS, INPUT CURRENT – IS
0
0
TS – CASE TEMPERATURE – °C
20050
400
12525 75 100 150
600
800
200
100
300
500
700
PS (mW)
IS (mA)
175
HCPL-0300/
HCPL-2300