An opto-isolator is an electronic component that transfers electrical signals between two isolated circuits with light. It is also known by different names like; photocoupler, optical isolator, or optocoupler. Generally, an Opto-isolator prevents higher voltages from influencing the system obtaining the signal. An optocoupler integrated circuit combines optical elements that perform as a simple switch. These are very simple to use in different electronic circuits for isolation between circuit blocks that run at different voltages. They are also perfect to utilize within feedback loops in between various circuit blocks, particularly wherever isolation is necessary. There are different optocoupler ICs are available that can be imported quickly into your electrical (or) electro-optical system like; ACS71020, MID400, UC1903, etc.
What is a MID400 Optocoupler?
The MID400 is an 8-pin-based optocoupler IC that is available in DIP & SMD Packages. This IC is used to identify the AC line voltage by connecting LEDs in series with an external resistor. Once this optocoupler device recognizes the AC voltage, the output pin of this IC will go low & whenever there is no AC voltage identified then it will stay high. This optocoupler has high voltage isolation between input & output. It is also obtainable with an externally changeable AC voltage sensing level.
The MID400 is an AC line to logic power line monitor optocoupler which means the output of this IC goes low once it detects an AC voltage. When there is no AC voltage then the output of this IC goes high. So this feature helps monitor the AC line and is helpful in AC to DC control applications (or) Relay/solenoid latching-based applications wherever excellent optical isolation and remarkable solid-state reliability are required. This IC can also used with low-frequency operations wherever small size, TTL compatibility, and low power are necessary.
MID400 Optocoupler Pin Configuration:
The pin configuration of the MID400 Optocoupler is shown below. This IC includes 8 pins which are discussed below.
MID400 Optocoupler Circuit
- Pin-1 (AC Live): Alternating Current (AC) Live wire is connected simply to Pin1
- Pins -2 & 4 (No Connection): These are NC pins that are not used.
- Pin-3 (AC Neutral): AC Neutral wire is connected to this Pin3
- Pin-5 (GND): It is the Ground pin of the optocoupler IC
- Pin-6 (V o/p): It is an open collector o/p pin.
- Pin-7 (Auxiliary): This pin is used for adjusting AC voltage sensing & time delay by simply including a capacitor.
- Pin8 (Vcc): It is an operating voltage pin.
Features & Specifications:
The features and specifications of the MID400 Optocoupler include the following.
- It is a power line monitor IC.
- This IC is available in 8-pin SMD & DIP packages.
- Its maximum working insulation voltage is 630Vpeak.
- The input current of LED on-state is ±30mA.
- Its low-range output current is 20mA.
- Its low-range output voltage is 0.18V.
- The forward voltage drop of LED is 1.5V.
- Its voltage supply or Vcc is 7V.
- Turn-on & Turn-off Time is 1ms each.
- It can be operated from any line voltage using an external resistor.
- Time delay and AC voltage sensing level are adjusted externally.
- It is compatible with the logic level.
- Its max working insulation voltage is 630Vpeak.
- The input current of LED on-state is ±30mA.
- The mount type is Through Hole.
- The packaging type is Tube.
- It includes 8-pins
- Its operating temperature ranges from -40°C to 85°C.
- Moisture Sensitivity Level or MSL is 1 (Unlimited).
- The terminal finish is Tin (Sn).
- Height x Width x Length is 3.94mm x 6.86mm x 9.91mm.
- Its rise time and fall time is 1μs.and 1 ms.
- Its propagation delay max is 1 ms.
Equivalent and Alternatives
The equivalent MID400 optocouplers are; ACS71020 & UC1903. Alternative MID400 optocouplers are; PC817, LCR-0202, 6N137, 4N35 IC, EL817 SMD-4.
MID400 Optocoupler Circuit
The MID400 optocoupler circuit is shown below. The optocoupler used in this circuit is MID400 IC which is an AC Line Monitor IC, both the phase and neutral wires are connected directly to pins 1 and 3 of the IC using a RIN resistor. Once the AC voltage is noticed, pin 6 like the output pin will go low or else this pin will go too high. Here both the AC Line & the output voltage are isolated completely with the Optocoupling property.
MID400 Optocoupler Circuit
The Resistor ‘Rin’ within the circuit is used to restrict the flow of current from the AC line. Here the resistor value can be calculated with the following formula.
RIN = Vin-VfIin
Where the ‘Vin’ is the i/p RMS voltage of the AC line.
‘Vs’ is the forward voltage drop of the inside LED.
‘Iin’ is the required input current to turn on the LED.
The pin-6 is an output pin and is also an open collector pin that needs a 300-ohm pull-up resistor connected to the VCC pin. The capacitor which is connected to pin-7 is used for adjusting the sensing range & output’s time delay.
Advantages and Disadvantages
The advantages of the MID400 optocoupler include the following.
- MID400 optocoupler provides solid state reliability, excellent optical isolation, TTL compatibility, low power, small size, low-frequency operations, etc.
- It can be directly operated from any line voltage using an external resistor.
- The time delay can be adjusted externally.
- It is compatible with the logic level.
- High voltage isolation is possible in between input & output.
- It is available with an externally adaptable AC voltage sensing level.
- It offers a variable time delay to change the external level.
- It is available with external variable AC volts detecting.
The disadvantages of the MID400 optocoupler include the following.
- Optocouplers are not capable of handling high currents.
- They need outside biasing voltage mainly for their operation.
- It has a poor higher frequency response.
Applications
The applications of the MID400 optocoupler include the following.
- The MID400 optocoupler is designed exclusively for use as an AC line monitor.
- It is also suggested to use in any AC to DC control application wherever solid-state reliability, outstanding optical isolation, small size, TTL compatibility, low-frequency & low power operations are necessary.
- It can be used as a closed−loop interface between different electromechanical elements like; relay contacts, solenoids, microprocessors, and small motors.
- This optocoupler is used for time delay isolation switches, AC-to-DC optical isolation circuits, AC-to-DC converters, latching circuits, and AC sensing applications.
- The MID400 optocoupler IC is used for monitoring the ON/OFF condition of an AC power line.
Please refer to this link to learn more about the MID400 Optocoupler Datasheet.
Thus, this is an overview of the MID400 Optocoupler, pin configuration, features, specifications, circuit, working, and applications. MID400 optocoupler IC is an optically isolated-based AC line−to−logic interface device. This IC is packaged within an 8-lead plastic-based DIP. The AC line voltage in this IC is monitored using two GaAs LEDs which are connected in series back−to−back with an external resistor. The MID400 IC has been designed only for use as an AC line monitor. It is recommended to utilize in any AC to DC control application wherever small size, excellent optical isolation, solid-state reliability, and operations are necessary. Here is a question for you, what is the function of an optocoupler?