Fig. 1

H11L1, 6N137A, FED8183, TLP2662 Digital Output Optocouplers

by Lewis Loflin

Here we explore digital output optocouplers. They all consists of a LED emitter but the output circuit often consists of a photodiode detector, an op-amp Schmitt trigger, comparator, or amplifier, and an open collector out transistor.

Besides voltage and noise isolation these are designed for high speed switching such as a engine controller in one's automobile or high speed controls for production machinery.

Applications include:

Microprocessor system interface
PLC, ATE input/output isolation
Computer peripheral interface
Digital fieldbus isolation: CC-link, DeviceNet, profibus, SDS
High speed A/D and D/A conversion
AC plasma display panel level shifting
Multiplexed data transmission
Digital control power supply
Ground loop elimination

An excellent example is the FOD8193 with an open collector output. This is a surface mount device.

6N137 optocoupler internal diagram and pin out.

Fig. 2

The 6N137A is single channel 10 MBd optocouplers utilizing a high efficient input LED coupled to a very high speed integrated photo-detector logic gate with a strobable output. This detector features an open collector.

The internal shield provides a guaranteed common mode transient immunity of 1 kV/us. The use of a 0.1 uF bypass capacitor connected between pin 5 and 8 is recommended.

Fig. 3

The TLP2662/TLP2662F consists of high-intensity infrared light-emitting diodes (LEDs) optically coupled to a high-gain, high-speed photoreceptor chip. The TLP2662/TLP2662F guarantees operation at up to 125 degrees C and on supplies from 2.7 V to 5.5 V.

It is offered in the DIP8 package. With two LED-photoreceptor pairs, the TLP2662/TLP2662F helps save board space. An internal noise shield provides superior common-mode rejection for improved noise immunity.

Fig. 4

Internal diagram of the TLP2662.

H11L1 pin connections and electrical connections.

Fig. 5

The H11L1 and H11L2 have a gallium arsenide infra-red LED optically coupled to a high-speed integrated detector with Schmitt trigger output. Designed for applications requiring electrical isolation, fast response time, noise immunity and digital logic compatibility.

Fig. 6

Uses for the H11L1:

Interfacing Computer Terminals to Peripheral Equipment
Digital Control of Power Supplies
Line Receiver - Eliminates Noise
Digital Control of Motors and Other Servo Machine Applications
Logic to Logic Isolator
Logic Level Shifter - Couples TTL to CMOS