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HCPL4503 High Speed Optocoupler

The HCPL4503 is a Dual channel high-speed Optocoupler with Transistor output. HCPL4503 consists of an AIGaAS LED optically coupled to a high-speed photodetector transistor.  It can switch at a speed of 1 Mbit/s with Bandwidth 2MHz.


Pin Description 0f HCPL4503M:

Pin Number

Pin Name




Anode pin of the IR LED. Connected to logic input of channel 1



Cathode pin of the IR LED. Connected to logic input channel 1



Anode pin of the IR LED. Connected to logic input of channel 2



Cathode pin of the IR LED. Connected to logic input channel 2



Ground pin of the IC


Output (V01)

Isolated Output pin of channel 1


Output (V02)

Isolated Output pin of channel 2



Powers the IC


Features and Specifications HCPL4503M

  • High-Speed Optocoupler (1Mbit/s)         
  • Isolation Voltage: 5000 Vrms
  • Vf - Forward Voltage: 1.45 V
  • If - Forward Current: 16 mA
  • Vr - Reverse Voltage:5 V
  • Power Dissipation: 100 mW
  • Available as 8-pin DIP and SMD Packages.

Note: More details can be found at the HCPL4503M datasheet which is available for download at the end of this page.


Equivalent for HCPL4503:  6N133


Alternatives Optocouplers: MOC3021 (Zero-crossing), MCT2E (non-Zero transistor), MOC3041 (Non-Zero Cross TRIAC), FOD3180 (High-Speed MOSFET), PC817, 4N25, 6N137


Where to use HCPL4503 Optocoupler:

The HCPL4503 is a High-Speed Optocoupler. As we know the term Optocoupler/optoisolator means we use light to indirectly couple (isolate) two sets of circuits. The specialty of HCPL4503 is that it has a high speed LED and hence can switch at 1Mbit/sec the output of the coupler is a TTL logic transistor making it easy to interface with other circuits.

The maximum operating voltage of HCPL4503 is 15V and the transistor has an output current of 8mA making it suitable to drive medium level loads. So if you are looking for dual-channel high-speed Optocoupler then this IC could be the right choice for you.


How to use HCPL4503:

Even though HCPL4503M is capable of working with both AC and DC it is commonly used with Digital circuits and works with 5V as supply voltage. The application circuit for HCPL4503M is shown below. 

HCPL4503 Circuit Diagram

The Capacitor 0.1uF is a bypass capacitor across the supply rail. The input signal should have an impedance of a minimum of 50 ohms with the rise time of 5nS of greater for the IC to respond. As told earlier the output is an open-drain transistor and hence it can either sink current or remain floating. So to avoid floating we should use a pull-up resistor RL, the value of RL can be in between 330 ohms to 4K depending upon the load connected.


Applications of HCPL4503

  • Camera Strode lights
  • High-speed ADC and DAC
  • Fiber/optic communication
  • Noise isolation circuits
  • Input / Output isolation circuits


2-D Model of HCPL4503

Dimensions for HCPL4503M IC is given below. These dimensions are for the DIP package. If you are using different package IC please refer to the HCPL4503M datasheet.

 HCPL4503 Dimensions

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