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A Comprehensive Introduction to LM2940

Author: Mia Date: 16 Apr 2021  515

lm2940 pinout

The LM2940 is a common low-dropout (LDO) linear regulator. 

 

This is a comprehensive introduction to LM2940 voltage regulator, from its pinout, feature, parameter to its application, its difference between LM7805 and more.


Catalog

LM2940 Description

LM2940 Pinout

LM2940 Features

LM2940 Parameters

LM2940 Equivalent

LM2940 VS LM7805

LM2940 Typical Application

LM2940 Package

LM2940 Application

Component Datasheet


LM2940 Description

The LM2940 is a common low-dropout (LDO) linear regulator.

 

The dropout voltage of a regulator is the voltage required between the input and the regulated output voltage. The regulator wastes this voltage (multiplied by current), so the lower the dropout on a linear regulator, the more efficient it is.

 

This means that the LM2940, with a 5V dropout at 1 amp, can be used with a 6 volt wall wart to provide a regulated 5V output. This also means that the regulator will operate at a much lower temperature than a standard 7805, which would require a much higher input voltage (around 7.5 volts) for a regulated 5V output.


LM2940 Pinout

LM2940 voltage regulator LM2940 Pinout
LM2940 voltage regulator LM2940 Pinout

 

Pin No. Pin Name Description
1 Vin A (+ve) voltage is given as input to this pin.
2 GND Common to both Input and Output.
3 Vout Output regulated 12V is taken at this pin of the IC.

LM2940 Features

  • Input Voltage Range = 6 V to 26 V

  • Dropout Voltage Typically 0.5 V at IOUT = 1 A

  • Output Current in Excess of 1 A

  • Output Voltage Trimmed Before Assembly

  • Reverse Battery Protection

  • Internal Short Circuit Current Limit

  • Mirror Image Insertion Protection

  • P+ Product Enhancement Tested


LM2940 Parameters

Output options Fixed Output
Iout (Max) (A) 1
Vin (Max) (V) 26
Vin (Min) (V) 6
Vout (Max) (V) 15
Vout (Min) (V) 5
Fixed output options (V) 5, 8, 9, 10, 12, 15
Noise (uVrms) 150
Iq (Typ) (mA) 10
Thermal resistance θJA (°C/W) 23
Load capacitance (Min) (µF) 22
Rating Catalog
Regulated outputs (#) 1
Features -
Accuracy (%) 2
PSRR @ 100 KHz (dB) 48
Dropout voltage (Vdo) (Typ) (mV) 500
Operating temperature range (C) -40 to 125, -40 to 85

LM2940 Equivalent

 

The equivalent for LM2940 is LM7805.


LM2940 VS LM7805

LM7805 voltage regulator

 

The LM7805 is a popular linear voltage regulator because it requires no additional components to operate. It is a very low-cost component.

 

Because of its characteristics, it reduces the output voltage at the expense of heat dissipation, making it inefficient.

 

The LM7805 requires a minimum input voltage of 7.3V to function properly. It can handle a maximum current of 1A. Some models can handle up to 1.5A.

 

It is recommended, and in some cases required, to use capacitors to reduce or eliminate the effects of the frequencies introduced by the other elements of the circuit. They also help to reduce the impact of peak consumption.

 

While the LM2940 is from a different generation, but its pin is still compatible with the LM7805.

 

It is a Low-dropout (LDO) Linear Regulator that is more efficient than the LM7805, but it will require capacitors.

 

The main difference between LM2940 and LM7805 is that the maximum output current of LM2940 is 1A. The maximum output current of LM7805 is 1.5A. Others are very close, so if the circuit only requires 1A or below, LM2940 can be used instead of LM7805.

 

What's more, the 7805 is expending the excess power as heat. Which is very lossy especialy if your project uses batteries. The other chip is a buck converter is so it approaches 90% efficiency by switching so there is no waste heat, thats why even though LM7805 is cheaper and easier to use but there's still a lot of people would go for LM2940.

 

LM2940 & LM7805 Schematic Comparison

lm2940 schematic lm7805 schematic
LM2940 Schematic LM7805 Schematic

LM2940 Typical Application

The LM2940 is a common low-dropout (LDO) linear regulator.      This is a comprehensive introduction to LM2940 voltage regulator, from its pinout, feature, parameter to its application, its difference between LM7805 and more.  Catalog  LM2940 Description     LM2940 Pinout     LM2940 Features     LM2940 Parameters     LM2940 Equivalent     LM2940 VS LM7805     LM2940 Package     LM2940 Application     Component Datasheet  LM2940 Description  The LM2940 is a common low-dropout (LDO) linear regulator.     The dropout voltage of a regulator is the voltage required between the input and the regulated output voltage. The regulator wastes this voltage (multiplied by current), so the lower the dropout on a linear regulator, the more efficient it is.     This means that the LM2940, with a 5V dropout at 1 amp, can be used with a 6 volt wall wart to provide a regulated 5V output. This also means that the regulator will operate at a much lower temperature than a standard 7805, which would require a much higher input voltage (around 7.5 volts) for a regulated 5V output.  LM2940 Pinout  	  LM2940 voltage regulator	LM2940 Pinout     Pin No.	Pin Name	Description 1	Vin	A (+ve) voltage is given as input to this pin. 2	GND	Common to both Input and Output. 3	Vout	Output regulated 12V is taken at this pin of the IC. LM2940 Features  Input Voltage Range = 6 V to 26 V  Dropout Voltage Typically 0.5 V at IOUT = 1 A  Output Current in Excess of 1 A  Output Voltage Trimmed Before Assembly  Reverse Battery Protection  Internal Short Circuit Current Limit  Mirror Image Insertion Protection  P+ Product Enhancement Tested  LM2940 Parameters Output options	Fixed Output Iout (Max) (A)	1 Vin (Max) (V)	26 Vin (Min) (V)	6 Vout (Max) (V)	15 Vout (Min) (V)	5 Fixed output options (V)	5, 8, 9, 10, 12, 15 Noise (uVrms)	150 Iq (Typ) (mA)	10 Thermal resistance θJA (°C/W)	23 Load capacitance (Min) (µF)	22 Rating	Catalog Regulated outputs (#)	1 Features	- Accuracy (%)	2 PSRR @ 100 KHz (dB)	48 Dropout voltage (Vdo) (Typ) (mV)	500 Operating temperature range (C)	-40 to 125, -40 to 85 LM2940 Equivalent  The equivalent for LM2940 is LM7805.  LM2940 VS LM7805     The LM7805 is a popular linear voltage regulator because it requires no additional components to operate. It is a very low-cost component.     Because of its characteristics, it reduces the output voltage at the expense of heat dissipation, making it inefficient.     The LM7805 requires a minimum input voltage of 7.3V to function properly. It can handle a maximum current of 1A. Some models can handle up to 1.5A.     It is recommended, and in some cases required, to use capacitors to reduce or eliminate the effects of the frequencies introduced by the other elements of the circuit. They also help to reduce the impact of peak consumption.     While the LM2940 is from a different generation, but its pin is still compatible with the LM7805.     It is a Low-dropout (LDO) Linear Regulator that is more efficient than the LM7805, but it will require capacitors.     The main difference between LM2940 and LM7805 is that the maximum output current of LM2940 is 1A. The maximum output current of LM7805 is 1.5A. Others are very close, so if the circuit only requires 1A or below, LM2940 can be used instead of LM7805.     What's more, the 7805 is expending the excess power as heat. Which is very lossy especialy if your project uses batteries. The other chip is a buck converter is so it approaches 90% efficiency by switching so there is no waste heat, thats why even though LM7805 is cheaper and easier to use but there's still a lot of people would go for LM2940.     LM2940 & LM7805 Schematic Comparison   	  LM2940 Schematic	LM7805 Schematic LM2940 Package     LM2940 Application  Post regulator for switching supplies  Logic power Supplies  Industrial Instrumentation  Component Datasheet  LM2940 Datasheet


LM2940 Package

LM2940 Package


LM2940 Application

  • Post regulator for switching supplies

  • Logic power Supplies

  • Industrial Instrumentation


Component Datasheet 

LM2940 Datasheet

 

Ordering & Quality

Photo Mfr. Part # Company Description Package PDF Qty Pricing
(USD)
LM2940CS-12 LM2940CS-12 Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.90000
10+: $2.61000
25+: $2.46200
100+: $2.09750
250+: $1.96948
500+: $1.72330
1000+: $1.42787
2500+: $1.39350
Inquiry
LM2940CS-12-NOPB LM2940CS-12-NOPB Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.26000
10+: $2.02800
25+: $1.91320
100+: $1.63010
250+: $1.53064
500+: $1.33932
1000+: $1.10971
2500+: $1.08300
Inquiry
LM2940CS-15 LM2940CS-15 Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.90000
10+: $2.61000
25+: $2.46200
100+: $2.09750
250+: $1.96948
500+: $1.72330
1000+: $1.42787
2500+: $1.39350
Inquiry
LM2940CS-15-NOPB LM2940CS-15-NOPB Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.26000
10+: $2.02800
25+: $1.91320
100+: $1.63010
250+: $1.53064
500+: $1.33932
1000+: $1.10971
2500+: $1.08300
Inquiry
LM2940CS-5-0 LM2940CS-5-0 Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.90000
10+: $2.61000
25+: $2.46200
100+: $2.09750
250+: $1.96948
500+: $1.72330
1000+: $1.42787
2500+: $1.39350
Inquiry
LM2940CS-5-0-NOPB LM2940CS-5-0-NOPB Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.26000
10+: $2.02800
25+: $1.91320
100+: $1.63010
250+: $1.53064
500+: $1.33932
1000+: $1.10971
2500+: $1.08300
Inquiry
LM2940CS-9-0 LM2940CS-9-0 Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
LM2940CS-9-0-NOPB LM2940CS-9-0-NOPB Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.26000
10+: $2.02800
25+: $1.91320
100+: $1.63010
250+: $1.53064
500+: $1.33932
1000+: $1.10971
2500+: $1.08300
Inquiry
LM2940CSX-12-NOPB LM2940CSX-12-NOPB Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
1+: $1.93000
10+: $1.73600
25+: $1.63760
100+: $1.39530
250+: $1.31016
500+: $1.14640
1000+: $0.94987
2000+: $0.92700
Inquiry
LM2940CSX-15 LM2940CSX-15 Company:Texas Instruments Remark:Linear Voltage Regulator IC Output 1A DDPAK/TO-263-3 Package:TO-263-4, D²Pak (3 Leads + Tab), TO-263AA
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry

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