LM2940T-5 Reference Tables, Pins & Specifications

Pin reference

Signal names, electrical functions and connection guidance

TO-220

Physical pin numbers3 pins

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LM2940T-5 pin functions and connections
Signal	Type	Function & connection
INPUT	Supply input	Feeds the series pass stage. Connection guidance Apply +7.5 V and fit 0.47 µF local input bypass.
GND	Reference, return and tab	Metal tab is electrically GND. Connection guidance Join supply return, load and capacitor returns.
OUTPUT	Regulated output	Supplies nominal +5 V within regulation and thermal limits. Connection guidance Connect the load and 22 µF to ground. Output capacitance and ESR are required for stability.

Front view, marking toward you

Manufacturer-referenced values3 parameters

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Parameter	Value	Conditions / notes
1 · INPUT	Feeds the series pass stage.	Apply +7.5 V and fit 0.47 µF local input bypass.
2 · GND	Metal tab is electrically GND.	Join supply return, load and capacitor returns.
3 · OUTPUT	Supplies nominal +5 V within regulation and thermal limits.	Connect the load and 22 µF to ground.

The exposed tab duplicates pin 2. Verify polarity before applying power.

LM2940CT-5.0/NOPB / LM2940CS-5.0/NOPB

Manufacturer-referenced values7 parameters

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Parameter	Value	Conditions / notes
Output at 25°C	4.85–5.15 V	5 mA–1 A; specified input range
Output across stated range	4.75–5.25 V	5 mA–1 A; selected C grade
Input for 5 V regulation specification	6.25–26 V	More specific than family headline
Load regulation	35 mV typical; 50 mV max	50 mA–1 A; LM2940C
Ground current at 1 A	30 mA typical; 45 mA max at 25°C	VIN = VOUT + 5 V; 60 mA max over temperature
Output noise	150 µV RMS typical	10 Hz–100 kHz; 5 mA
Ripple rejection	72 dB typical; 60 dB min	120 Hz; 100 mA; LM2940C

Read the exact test conditions. Typical values are not guaranteed limits.

Local components near the regulator

Manufacturer-referenced values5 parameters

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Parameter	Value	Conditions / notes
Input bypass	0.47 µF	IN 1 to GND 2
Output capacitor	22 µF	OUT 3 to GND 2
Capacitor selection	At least 22 µF, ESR 0.1–1 Ω	Maintain effective capacitance and ESR across temperature
Tab / thermal pad	GND	Electrically connected to pin 2
Dropout	0.5 V typical; 0.8 V max at 1 A, 25°C; 1 V max over temperature	Not an unconditional fixed input margin

Short return paths and correct capacitor characteristics matter.

100 mA nominal DC load

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
Input / output	+7.5 V / +5 V	DC source with sufficient headroom
Load	50 Ω	Dissipation 0.50 W; choose adequate derating
Current	5 V / 50 Ω = 0.10 A	Nominal calculation
Pass loss	0.25 W	(7.5 − 5) V × 0.10 A
Total regulator loss	Pass loss + \|VIN\| × IGND	Ground current also produces heat
Cooling	TJ ≈ TA + PD × θJA	Use thermal resistance for actual mounting

Respect resistor rating, input ripple and regulator dissipation.

LM2940CT-5.0/NOPB · TO-220

Manufacturer-referenced values5 parameters

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Parameter	Value	Conditions / notes
Lead pitch	2.54 mm	Through-hole
Selected temperature grade	0–125°C	LM2940C; other LM2940-N grades differ
Input stress limit	26 V operating maximum; see transient limits	Do not use stress limits as a normal design target
Storage	−65 to +150°C	Unpowered
Package mapping	1 INPUT; 2 GND; 3 OUTPUT	Thermal pad duplicates pin 2

Verify the manufacturer package drawing and footprint before PCB manufacture.