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
Key Features
- 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
Applications
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.
Specifications
| 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 |
Alternate & Equivalent Parts
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.
Related Guides
How to Choose a Digital Potentiometer: AD5204, AD5206, and AD8403 Selection Guide
Compare the AD5204, AD5206, and AD8403 multi-channel SPI digipots by channel count, resistance value, and package to choose the right Analog Devices digital potentiometer for your design.
Jun 21, 2026
AD7745 / AD7746 / AD7747 Capacitance-to-Digital Converter Design Guide
Complete application note for the AD774x CDC family: circuit design, shielding, conversion rate selection, and sourcing guidance for the AD7745, AD7746, and AD7747.
Jun 21, 2026
ECMF02-4CMX8 Common-Mode Filter with ESD Protection: Selection Guide
Compare ECMF02-4CMX8 vs ECMF02-2AMX6, ECMF04-4HSM10, and other ST ECMF filters. Choose the right 4-channel common-mode filter with ESD protection for USB 2.0.
Jun 20, 2026
AD5204 Quad Digital Potentiometer Selection Guide (2026)
How to choose the right AD5204 quad digital potentiometer: compare 10kΩ vs 100kΩ variants, TSSOP vs SOIC packages, and SPI interface options for your design.
Jun 20, 2026
Why Buy from FindMyChip
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.
In Stock · 24h Response · Worldwide Shipping
Response within 24 hours · Worldwide shipping
“The anti-counterfeit verification gave us confidence we'd never had with other China suppliers.”