LM340T-12 NOPB Texas Instruments Integrated Circuit (Transistor Outline, Vertical) In Stock
Texas Instruments LM340T-12 NOPB is a fixed +12 V, 1 A positive linear voltage regulator in a 3-pin TO-220 through-hole package with internal thermal and overcurrent protection. It provides a stable 12 V output from supplies up to 35 V with worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- Transistor Outline, Vertical
- Pin Count
- 3
- Lifecycle
- ACTIVE
- Datasheet
- LM340T-12 NOPB Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of LM340T-12 NOPB?
- Fixed +12 V output at up to 1 A continuous current with internal current limiting eliminates external protection components
- Internal thermal shutdown circuit prevents damage at junction temperatures above 150°C, improving robustness in high-ambient environments
- 3-pin TO-220 package with tab allows direct heatsink attachment, enabling 1 A operation at ambient temperatures up to 70°C without derating
What is LM340T-12 NOPB used for?
The LM340T-12 NOPB is widely used to generate a stable 12 V rail for op-amp bias supplies, relay coil drivers, small DC motor supplies, and analog reference circuits in industrial and consumer equipment. Its fixed 12 V output and simple 3-pin topology make it a drop-in solution for benchtop power supplies, audio amplifier bias networks, and legacy industrial control boards that require a regulated 12 V from a 15 V or 18 V AC adapter. The TO-220 package with an exposed metal tab also suits applications where a chassis-mount heatsink provides passive thermal management without a fan.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Where can I find the LM340T-12 NOPB datasheet?
LM340T-12 NOPB Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for LM340T-12 NOPB?
Compatible alternatives and drop-in replacements for LM340T-12 NOPB:
Frequently Asked Questions
What is the output voltage and maximum continuous load current of LM340T-12 NOPB?
The LM340T-12 NOPB is factory-trimmed to a fixed +12 V output and can supply up to 1 A continuous load current with a dropout voltage of approximately 2 V, requiring an input supply of at least 14.5 V to maintain regulation. At 1 A load with a 15 V input, the device dissipates 3 W and requires a heatsink to remain within its 150°C maximum junction temperature rating.
How does the internal thermal shutdown in LM340T-12 NOPB protect the system during overload conditions?
When junction temperature exceeds approximately 150°C due to excessive current draw or inadequate heatsinking, the internal thermal shutdown circuit reduces output current automatically, preventing permanent damage to the regulator. Once the die cools below the thermal threshold, the device resumes normal regulation, making it self-recovering and tolerant of short-duration overloads common in relay activation or capacitive load inrush events.
What minimum input voltage does LM340T-12 NOPB require to maintain a regulated 12 V output?
With a typical dropout voltage of 2 V at 1 A load, the LM340T-12 NOPB requires a minimum input of approximately 14 V to 14.5 V to maintain a regulated 12 V output. For unregulated AC adapter supplies that can sag under load, choosing an adapter rated at 15 V or higher with adequate current capacity ensures the input stays above the dropout threshold across the full load range.
When does a designer choose LM340T-12 NOPB over a 12 V switching regulator for low-noise analog supply applications?
Linear regulators like LM340T-12 NOPB produce no switching-frequency ripple or EMI, making them the preferred choice for powering op-amp circuits, audio preamplifiers, and precision ADC reference supplies where even 50 mV of high-frequency noise degrades signal-to-noise ratio. A switching regulator operating at 300 kHz to 2 MHz introduces ripple that requires multi-stage LC filtering to suppress below 1 mV, whereas LM340T-12 NOPB achieves output noise below 100 µV RMS with only a single 0.1 µF output bypass capacitor.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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