LM137K STMicroelectronics Integrated Circuit (Other) In Stock
The LM137K is a high-current adjustable negative linear voltage regulator capable of supplying up to 1.5A with an output adjustable from -1.2V to -37V. It offers 0.02%/V line regulation and 0.5% load regulation in a rugged TO-3 metal power package.
- Manufacturer
- STMicroelectronics
- Package
- Other
- Pin Count
- 2
- Lifecycle
- OBSOLETE
- Datasheet
- LM137K Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -55.0°C to 150.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of LM137K?
- Adjustable output from -1.2V to -37V using two external resistors for flexible negative-rail design
- Up to 1.5A output current with only 3V to 40V input-to-output differential headroom required
- Excellent 0.02%/V line regulation and 0.5% load regulation for precision analog supply rails
- Rugged TO-3 metal case (O-MBFM-P2) provides low thermal resistance for high-power applications
- Internal short-circuit and thermal overload protection for robust operation without external protection circuits
What is LM137K used for?
The LM137K is used in dual-supply linear power supplies for op-amp circuits, audio amplifiers, and precision analog instrumentation where a regulated negative rail from -5V to -15V is required alongside a positive rail. Its high 1.5A current capacity and low dropout make it suitable for bench-top power supply modules, servo amplifier bias supplies, and RF power amplifier drain supplies operating from high-voltage secondary windings. The metal TO-3 package bolts directly to a chassis heatsink, enabling sustained high-current operation in industrial and laboratory power conditioning equipment.
What are the specifications of LM137K?
| Pbfree Code | Yes |
| YTEOL | 0 |
| Adjustability | ADJUSTABLE |
| Input-Output Voltage Differential-Max | 40V |
| Input-Output Voltage Differential-Min | 3V |
| JESD-30 Code | O-MBFM-P2 |
| JESD-609 Code | e3 |
| Line Regulation-Max (%/V) | 0.02 |
| Load Regulation-Max(%) | 0.5% |
| Number of Functions | 1 |
| Number of Outputs | 1 |
| Operating Temperature TJ-Max | 150°C |
| Operating Temperature TJ-Min | -55 °C |
| Output Current1-Max | 1.5A |
| Output Voltage1-Max | 37V |
| Output Voltage1-Min | 1.2V |
| Package Body Material | METAL |
| Package Equivalence Code | TO-204/-3 |
| Package Shape | ROUND |
| Package Style | FLANGE MOUNT |
| Qualification Status | Not Qualified |
| Regulator Type | ADJUSTABLE NEGATIVE SINGLE OUTPUT STANDARD REGULATOR |
| Surface Mount | NO |
| Technology | BIPOLAR |
| Terminal Finish | MATTE TIN |
| Terminal Form | PIN/PEG |
| Terminal Position | BOTTOM |
| Package | Other |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.60 |
Where can I find the LM137K datasheet?
LM137K Datasheet DownloadOfficial datasheet from STMicroelectronics
What are equivalent replacements for LM137K?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How is the output voltage of the LM137K set, and what component values produce a -15V regulated output?
The LM137K output voltage is set by a resistor divider between the output, adjust, and ground pins; a typical -15V design uses a 120-ohm resistor from output to adjust and a 1.3 kohm resistor from adjust to ground. The reference voltage between output and adjust pins is -1.25V, so the formula V_out = -1.25 x (1 + R2/R1) gives -15V with those values.
What is the maximum input-to-output differential the LM137K can handle, and why does that matter for transformer selection?
The LM137K tolerates up to 40V input-to-output differential and requires at least 3V of headroom to maintain regulation. A -15V output therefore requires the rectified input to stay between -18V (minimum) and -55V (maximum), guiding the transformer secondary voltage and filter capacitor sizing in an unregulated supply.
How does the TO-3 metal package of the LM137K affect thermal management in a 1.5A linear supply?
The TO-3 metal case (JESD-30 O-MBFM-P2) has a junction-to-case thermal resistance of approximately 5°C/W; at 1.5A with a 10V dropout the dissipation is 15W, requiring a heatsink with under 4°C/W resistance to keep junction temperature below 125°C at 25°C ambient. Mounting the TO-3 directly to an aluminum chassis with thermal compound is a common approach.
For a dual-supply op-amp circuit requiring both +15V and -15V rails at 500 mA, is the LM137K an appropriate choice for the negative rail?
Yes, the LM137K easily handles 500 mA at -15V, operating well within its 1.5A rated output current. Paired with an LM117K on the positive rail and a center-tapped transformer secondary, both regulators provide matched ±15V supplies with 0.5% load regulation suitable for precision audio and instrumentation op-amp circuits.
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About STMicroelectronics
STMicroelectronics is a global semiconductor leader serving customers across the spectrum of electronics applications. ST's products are found in a wide range of applications including automotive, industrial, personal electronics, and communications.
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