The LM-series ICs were the first analog integrated circuits produced commercially since late 1965. The LM series was invented with integrated circuits launched by National Semiconductor. In LM series ICs, the prefix LM is linear monolithic which means the analog components incorporated onto a single silicon chip. Different types of LM series voltage regulators are available like; LM105, LM309, LM317, LM120, LM123, LM325, LM350, and many more. This article discusses an overview of the LM350 voltage regulator IC, working, and its applications.
What is the LM350 Voltage Regulator?
The LM350 is a 3-terminal adjustable positive voltage regulator that supplies above 3.0 Amps over a 1.2 V – 33 V output voltage range. This IC is an adaptable, easy-to-utilize voltage regulator that only needs two external resistors to set the output voltage. In advance, this type of LM series voltage regulator uses internal current limiting, thermal shutdown, compensation of secure area, etc. Different applications utilize this voltage regulator such as local & on-card regulation. It can also be used to design an adjustable switching regulator, programmable output regulator, or precision current regulator by placing a fixed resistor between the two adjustment and output pins.
Pin Configuration:
The pin configuration of the LM350 voltage regulator is shown below. This IC includes three pins Vin, Vout & Adj which are discussed below.
LM350 Voltage Regulator PinOut
- Pin-1 (Adjust): This Adj pin is used to adjust the o/p voltage
- Pin-2 (Vout): It is an output voltage pin. The adjust pin can set the regulated o/p voltage.
- Pin-3(Vin): It is an input voltage pin. The i/p voltage that must be changed can be given to this pin.
Features & Specifications:
The features and specifications of the LM350 voltage regulator include the following.
- It is a 3-terminal adjustable positive voltage regulator.
- This regulator is available in SOT223, To-220 and TO263 Packages.
- Its output voltage can be set from 1.25V to 33V range.
- Its output current maximum is 3Amps.
- Max i/p to o/p voltage variation is 35V, suggested 15V.
- Its operating junction temperature is 125°Cemtigrade.
- It guaranteed a 3A output current.
- Typical load regulation is 0.1%.
- Typical line regulation is 0.005%/Volts.
- It has thermal overload protection internally.
- It removes stocking various fixed voltages.
- Pb-free packages are available.
- Floating operation mainly for high voltage-based applications.
- Internal short circuit current limiting constant through temperature.
- Output transistor secure area compensation.
Equivalent & Alternative Voltage Regulators
Equivalent LM350 voltage regulators are; LT1086, LM317, LM1117 (SMD), LM337, PB137, , etc. So, alternative LM350 voltage regulators are; LM7805, LM7809, LM7806, LM7812, LM7912, LM7905, XC6206P332MR, LM117V33, etc.
LM350 Adjustable Voltage Regulator Circuit
LM350 voltage regulator circuit is shown below which is similar to a variable DC power supply. The required components to make this circuit mainly include like; AC220V/AC110V supply, LM350 IC, S1 switch, 0.5A fuse, BD1 bridge diode, C1-4700uF, C2-0.1uF, C3-47uF, C4 -100uF and C5-0.1uF, Resistors R1 & R2 – 120 ohms, VR1 variable resistor and IN4007 D1,D2 & D3 diodes. So, connect the circuit as per the circuit shown below.
LM350 Adjustable Voltage Regulator Circuit
Working
The working of this adjustable voltage regulator circuit follows as; whenever we provide AC220V/AC110V supply by simply pressing the ‘S1’ switch to switch on this power supply. The AC voltage will supply throughout the F1 fuse for protection in case of too much input voltage or overload. After that, the AC voltage will flow into a transformer that can change an AC voltage from higher to lower ranges of AC 18V.
This voltage is given to the BD1 bridge diode which converts AC to DC. After that, this converted voltage is provided to a C1-4700uF capacitor to filter the pulsating voltage into a steady DC from a transformer. At this point, we have voltage from 22V to 25V. Next, the current supplies throughout the input pin of the LM350 IC. We know that it is a 3Amps adjustable voltage regulator IC, so the regulated output voltage can be controlled from 1.2V to 22V by turning variable resistor VR1.
Advantages & Disadvantages
The advantages of the LM350 voltage regulator include the following.
- The LM350 is an adaptable and positive voltage regulator.
- Its output is adjustable from 1.2 V to 33 V.
- Its load regulation typically is 0.1%.
- The typical line regulation of this regulator is 0.005%/V.
- It has internal thermal overload protection.
- Removes stocking various fixed voltages.
- Floating operation is possible for high-voltage applications.
- It has internal short-circuit protection
- This regulator’s regulated output does not change significantly through a change in input voltage (or) output load.
- This positive voltage regulator is a user-friendly yet very efficient option.
- It is versatile, so it functions as either a precision current regulator or a programmable voltage output regulator based on the specific requirements of your circuit.
- This voltage regulator includes internal features like; safe area compensation, current limiting, & thermal shutdown.
The disadvantages of the LM350 voltage regulator include the following.
- It has a huge loss.
- Its efficiency is poor whenever there is a huge variation in the I/O voltage.
- When the variation between input & output voltage is large then a huge amount of heat can be produced
- It decreases its highest output current whenever it has >10V from its i/p to its o/p.
Applications
The applications of the LM350 voltage regulator include the following.
- The LM350 series voltage regulator is used in various applications such as local and on-card regulation.
- This regulator also helps to create a particularly simple adjustable switching regulator and a programmable output regulator.
- You can utilize this voltage regulator as a precision current regulator by connecting a fixed resistor between the adjustment and output pins.
- Users apply this regulator for positive voltage regulations, as well as in variable power supply, reverse polarity circuits, and motor control.
Please refer to this link for the LM350 adjustable voltage regulator Datasheet.
Thus, this is an overview of the LM350 adjustable voltage regulator, pinout, specifications, working, and its applications. This is an adjustable and three-terminal-based positive voltage regulator that can supply more than 3.0 Amps above 1.2 V to 33 V output voltage range. This is very easy to use & needs two external resistors only to set the o/p voltage. Therefore, if you are seeking a variable voltage regulator IC to set voltage between 1.25V to 33V & to deliver a current supply up to 3Amps then this voltage regulator IC might be the correct choice for your application. Here is a question for you, what is LM317 IC?