LM2940S-5.0 Voltage Regulator: Basics, Pin Configuration & Features | Heisener Electronics
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LM2940S-5.0 Voltage Regulator: Basics, Pin Configuration & Features

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投稿日: 2024-10-30

LM2940S-5.0 Basics

The LM2940S-5.0 is a positive voltage regulator capable of delivering up to 1 A of output current, with a typical dropout voltage of 0.5 V and a maximum of 1 V across the entire temperature range. It features a quiescent current reduction circuit that minimizes ground current when the voltage difference between the input and output exceeds about 3 V. As a result, with 1 A of output current and a 5 V differential, the quiescent current is only 30 mA. Higher quiescent currents occur only when the regulator is in dropout mode, where the input-output voltage difference is less than or equal to 3 V.

LM2940S-5.0 Pin Configuration

IN: Input voltage pin. Connect this to the input voltage source (greater than 5V).

GND: Ground pin. This should be connected to the system ground.

OUT: Output voltage pin. This provides the regulated output of 5.0V.

GND: Another ground pin. Often there are multiple ground pins to facilitate easier connections.

N/C (No Connect): This pin is not connected and can be left unconnected.

LM2940S-5.0 Symbol

LM2940S-5.0 Footprint

LM2940S-5.0 3D Model

LM2940S-5.0 Functional Block Diagram

LM2940S-5.0 Specification

Specification Value
Output Voltage (Max) 26 V
Output Voltage (Min) 5V
Output Current 1 A
Voltage Dropout (Max) 1V @ 1A
Quiescent Current 10 mA
Supply Current (Max) 15 mA
Temperature Range -40°C ~ 125°C
Package Type TO-263-4, D2PAK (3 Leads + Tab), TO-263AA
Input Voltage Range Up to 26 V
PSRR 64dB (120Hz)

LM2940S-5.0 Typical Application Circuit

The LM2940S voltage regulators feature the ability to source 1 A of output current with adropout voltage of typically 0.5 V and a maximum of 1 V over the entire temperature range. The output capacitor, COUT, must have a capacitance value of at least 22 µF with an ESR of at least 100 mΩ, but no more than 1 Ω.

The minimum capacitance value and the ESR requirements apply across the entire expected operating ambient temperature range.


LM2940S-5.0 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 

LM2940S-5.0 Applications

Post Regulator for Switching Supplies

Logic Power Supplies

Industrial Instrumentation 

How to Use LM2940S-5.0?

First, gather the LM2940S-5.0 chip, the required power supply, output capacitor, input capacitor, and necessary connecting wires.

Next, connect the positive terminal of the power supply to the input pin (IN) of the LM2940S-5.0, and the negative terminal to pin (GND). Connect a 0.1μF capacitor between the input pin and ground. Then, connect the output pin (OUT) of the LM2940S-5.0 to the load you need to power, while also connecting a 22μF capacitor between the output pin and ground to ensure stable output. Note: The GND pin must be connected to the circuit's common ground.

Once everything is connected, power the circuit and use a multimeter to measure the output voltage, ensuring it is stable at 5V.

FAQs

What is the LM2940S-5.0 used for?

The LM2940S-5.0 is a positive voltage regulator designed to provide a stable output voltage of 5V. It is commonly used in power supply circuits for various electronic devices.

How do I connect the LM2940S-5.0 in a circuit?

To connect the LM2940S-5.0, connect the input pin (IN) to the power supply's positive terminal, the ground pin (GND) to the circuit ground, and the output pin (OUT) to the load. 

What capacitors should I use with the LM2940S-5.0?

It is recommended to use a 0.1μF capacitor at the input and a 22μF capacitor at the output to ensure stable operation.

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