4N35 Optocoupler IC: Datasheet, Pinout, Circuit Diagram & Uses

As we delve into the intricate realm of electronic components, one crucial player takes center stage – the Optocoupler IC. In the ever-evolving landscape of technology, understanding the fundamental aspects of Optocoupler ICs becomes imperative. These electronic devices, characterized by their ingenious design, serve a pivotal role in ensuring the seamless functioning of electronic circuits. In this exploration, we embark on a journey to unravel the definition and purpose of Optocoupler ICs, shedding light on their significance within the intricate tapestry of electronic circuits. In this article, we'll delve into the 4N35 Optocoupler IC, including its circuit diagram, pinout, datasheet, uses and more details, uncover the crucial role this component plays, not only in connecting different parts of a circuit but also in maintaining the integrity and reliability of electronic systems.

What is IC 4N35?

The IC 4N35 serves as a versatile optocoupler with applications across various fields. It comprises a light-emitting diode optically linked to a phototransistor. Its composition includes a gallium arsenide infrared LED and a silicon NPN phototransistor. Upon applying the input signal to the LED at the input terminal, the LED illuminates. Subsequently, the light receiver converts the received light signal into an electrical signal, which is then output directly or after amplification to a standard digital level. This completes the transition and transmission of electricity-light-electricity. Since light serves as the transmission medium, the input and output terminals are electrically isolated, a process known as electrical isolation. Encased in a 6-pin DIP package, it offers wide lead spacing options and lead bending SMD options. Typically, it boasts a response time of 3 µs, and the minimum Current Transfer Ratio (CTR) at an input current of 10 mA is 100%.

4N35 Pinout

The IC 4N35 is presented in a dual inline package with a total of 6 pins. Refer to the table below for a comprehensive understanding of the pin configuration:

IC 4N35 Pin Configuration

Pin Number	Pin Type	Pin Description
1	A	Anode
2	C	Cathode
3	NC	Not Connected
4	E	Emitter
5	C	Collector
6	B	Base

Features of 4N35

• Isolation test voltage of 5000 VRMS

• Compatible with general logic series

• Input-output coupling capacitance less than 0.5 pF

• Dual in-line 6-pin package following industry standards

• Conforms to RoHS Directive 2002/95/EC and complies with WEEE 2002/96/EC

4N35 Specifications

Parameter	Value	Unit	Notes
Number of Channels	1	-	-
Isolation Voltage	3550 Vrms	1 minute	UL1577 standard
Collector-Emitter Voltage (Vce)	30	V	-
Emitter-Collector Breakdown Voltage (Bveco)	60	V	-
Collector Current (Ic)	50	mA	DC
Forward Current (If)	100	mA	-
Forward Voltage (Vf)	1.5	V	-
Peak Forward Current Surge (Ifsm)	1.5	A	10μs pulse
Collector Dark Current (Icbo)	100	nA	Vce = 20V
Collector-Emitter Leakage Current (Ice)	10	μA	Vce = 20V, If = 0mA
Current Transfer Ratio (CTR)	50% min	-	If = 10mA
Rise Time (tr)	10	μs	-
Fall Time (tf)	15	μs	-
Operating Temperature Range (TA)	-40 to +100	°C	-
Storage Temperature Range (TSTG)	-55 to +125	°C	-
Package	6-pin DIP	-	-

4N35 Schematic

4N35 Functional Diagram

How Does the Optocoupler IC Work?

The optocoupler IC comprises a gallium arsenide infrared LED and a silicon NPN phototransistor, making it user-friendly. The base pin (pin 6) is not required to use the IC as a phototransistor. The suggested circuit below guides the design of your circuit using the optocoupler IC.

Connect the anode (pin 1) and cathode (pin 2) pins of the infrared LEDs to the logic input and ground, respectively. Pull up the collector pin (pin 5) using a resistor and connect the output device to the other end. In this case, an output probe is connected to monitor the output. Ground the emitter pin (pin 4).

Note: Ensure that the emitter and the cathode pin are not connected to the same ground, as they are meant to be isolated.

Working: When a logic 0 input is applied to the IR LED, the LED remains OFF, not triggering the transistor, and the output received is HIGH across the collector-emitter terminal. Conversely, when the LED receives a logic 1, it turns on, triggering the transistor and shorting the collector-emitter junction, resulting in a 0 at the output.

Note: The Collector-emitter voltage can be set up to a maximum of 30V.

How to Use 4N35?

Step 1: Components

• Arduino Uno board * 1

• USB Cable * 1

• 4N35 * 1

• Resistor (220Ω) * 1

• Resistor (1kΩ) * 1

• Breadboard * 1

• Jumper Wires

Step 2: Principle:

The 4N35 is an optocoupler designed for general applications. It comprises a gallium arsenide infrared LED and a silicon NPN phototransistor.

The purpose of an optocoupler is to break the connection between the signal source and the signal receiver, preventing electrical interference. In other words, it is used to shield against interference from external electrical signals. The 4N35 can be employed in AV conversion audio circuits and finds widespread use in electrical isolation for general optocouplers.

Refer to the internal structure of the 4N35 above. Pins 1 and 2 are connected to the infrared LED. When the LED is powered, it emits infrared light. To prevent LED burnout, a resistor (approximately 1K) is typically connected to pin 1. Then, when the phototransistor receives the radiation, it opens the circuit. This can be used to control the load connected to the phototransistor. Even in the case of a load short circuit, it won't affect the control board, ensuring effective electrical isolation.

Step 3: Schematic:

Step 4: Procedure:

In this experiment, the LED is used as a load connected to the NPN phototransistor. Connect pin 2 of the 4N35 to pin 7 of the control board and connect pin 1 to a 1K current-limiting resistor, then to 5V. Connect pin 4 to Uno's GND, and pin 5 to the cathode of the LED. Then, use a 220-ohm resistor to connect the anode of the LED to 5V. During programming, when pin 7 is at a low level, the infrared LED emits infrared light. The phototransistor then receives the infrared light and becomes energized, making the LED cathode low, thereby turning on the LED. Similarly, you can control the LED by grounding pin 2, making it light up.

• Step 1:

Build the circuit.

• Step 2:

Download Arduino.

• Step 3:

Upload the code to the Arduino Uno board.

Click the "Upload" icon to upload the code to the control board.

If "Done uploading" appears at the bottom of the window, the sketch has been successfully uploaded.

• Step 4: Code:

// Turn on a led by

4n35

// turn on the LED

for half a second, then off for half a second, repeatedly

// info@primerobotics.in

// www.primerobotics.in

int OptoPin = 7;

// attach the input of the 4n35 to pin 7

void setup() {

pinMode(OptoPin, OUTPUT); // set it as OUTPUT

}

void loop() {

digitalWrite(OptoPin, LOW); // set the OptoPin as LOW level, then the led

connected on the output of 4n35 will be light

delay(500);

// delay 500ms

digitalWrite(OptoPin, HIGH); // turn off the led

delay(500);

// delay 500ms

}

4N35 Alternatives/Equivalents

MCT2E, PC817, and 6N137 can be equivalent to 4N35.

4N35 Application

• Detection of AC power

• Driving reed relays

• Feedback in switch mode power supplies

• Detection of phone ring signals

• Isolation of logic ground

• Coupling logic with a function to suppress high-frequency noise

Conclusion

The 4N35 Optocoupler has modern electronics. Its ability to facilitate electrical isolation, protect sensitive components, and enhance the overall reliability of electronic systems is unparalleled. In an era where electronic devices are omnipresent, the 4N35 stands as a silent sentinel, ensuring the smooth and secure transmission of signals.

Read More

• PC817 IC Optocoupler Pinout, Circuit, Datasheet, and Uses

• 7408 Integrated Circuit: Pin Diagram, Datasheet and Truth Table

• Understandings LM350: A Comprehensive Guide to Adjustable Voltage Regulators

• What is a 10k Resistor? 10k Ohm Resistor Color Code

Vorherige: CD4017BE CMOS Counter: Circuit, Pinout and Datasheet

Nächste: The Ultimate Guide to IR2104 Half Bridge MOSFET Driver