1-296

Applications

The HCPL-2300 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

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

below 0.8 V will guarantee that

the HCPL-2300 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 K

Ω resistor (Figure 14)

at the expense of twice the

operating forward current.

An application of the HCPL-2300

as an unbalanced line receiver for

use in long line twisted wire pair

communication links is shown in

allow longer line length, higher

speed and multiple stations on

the line in comparison to higher

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 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

VDE 0884.

0

0

TS – CASE TEMPERATURE – °C

200

50

400

125

25

75 100

150

600

800

200

100

300

500

700

PS (mW)

IS (mA)

175