Texas Instruments

LM317LCPK - 100mA Adjustable LDO Regulator | Texas Instruments

Name: LM317LCPK
Brand: Texas Instruments
Price: 0.19 USD
Availability: InStock

MPN: LM317LCPK ✓ Active

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1.25 V to 37 V Vdss 100 mA Id SOT-89-3 (PK) Package

From $0.19 USD / Unit

MOQ: 1 |

Price updated: 2026-08-23

Volume Pricing

Qty	Unit Price	Extended
1	$0.45	$0.45
10	$0.38	$3.80
100	$0.29	$29.00
500	$0.24	$120.00
1,000	$0.19	$190.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for LM317LCPK — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

LM317LCLP

✅ Drop-In

📦 SOT-89-3

Same package and pinout, similar specs

📋 Reference alternative (not in catalog)

ℹ️ 4 cross-package part(s) hidden — different package requires PCB rework and is not a true drop-in replacement. Contact us if you need cross-package suggestions.

LM317LCPK Maximum Ratings & Electrical Characteristics

Output Type	Adjustable
Output Voltage Range	1.25 V to 37 V
Maximum Output Current	100 mA
Input Voltage Range	Up to 40 V
Dropout Voltage	[DATA_NEEDED: dropout voltage]
Line Regulation	0.01%/V typical
Load Regulation	[DATA_NEEDED: load regulation]
Reference Voltage	1.25 V typical
Adjustment Pin Current	50 µA typical
Operating Temperature Range	0°C to +125°C
Package	SOT-89-3 (PK)
Mounting Type	Surface Mount
Number of Outputs	1
RoHS Status	Compliant
MSL Level	[DATA_NEEDED: MSL level]

LM317LCPK Pin Configuration

Pin 1	Input — Unregulated input voltage
Pin 2	Output — Regulated output voltage
Pin 3	Adjust — Adjustment pin for setting output voltage

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

LM317LCPK is suitable for 6 applications: On-Board Power Regulation for Microcontrollers, Analog Sensor Interface Power, Battery-Powered Devices, Audio Circuits, Test and Measurement Equipment, Industrial Control Systems.

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On-Board Power Regulation for Microcontrollers

The LM317LCPK provides a stable, adjustable supply voltage for microcontrollers and digital ICs. Its 100mA output is sufficient for many MCU boards, and the adjustable output allows tailoring to specific logic levels. The low dropout and low noise ensure reliable operation. Place input/output capacitors close to the device for stability.

Recommended

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Analog Sensor Interface Power

For analog sensors requiring a clean, adjustable supply, the LM317LCPK offers low output noise and good line regulation. Its 100mA capacity is adequate for op-amps and sensor bridges. The adjustable output allows precise biasing. Use a 10uF output capacitor to reduce noise and improve transient response.

Recommended

OPA1612 (Op-amp for signal conditioning) ADS1115 (ADC for sensor readout)

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Battery-Powered Devices

In battery-powered devices, the LM317LCPK can regulate a stable voltage from a varying battery input. Its low quiescent current helps extend battery life. The small SOT-89-3 package is ideal for compact designs. Ensure the input voltage is at least 3V above the output to maintain regulation.

Recommended

TPS63070RNMT · Texas Instruments BQ24075 (Battery charger IC)

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Audio Circuits

The LM317LCPK can power low-power audio circuits such as preamplifiers and headphone amplifiers. Its low noise and adjustable output make it suitable for biasing. However, for high-end audio, consider ultra-low noise LDOs like the TPS7A4701. The LM317LCPK is a cost-effective solution for basic audio applications.

Recommended

NE5532 (Audio op-amp) PCM5102 (Audio DAC)

🔧

Test and Measurement Equipment

In test equipment, the LM317LCPK provides a stable reference supply for analog circuits. Its adjustable output allows calibration. The device's thermal protection ensures reliability. Use precision resistors for the feedback network to maintain accuracy. The SOT-89-3 package is suitable for compact instruments.

Recommended

ADS1256 (High-resolution ADC) OPA2277 (Precision op-amp)

🏭

Industrial Control Systems

The LM317LCPK can be used in industrial control systems to provide a local regulated supply for sensors and logic. Its wide input voltage range (up to 40V) allows operation from 24V industrial buses. The device's robustness and thermal protection make it suitable for harsh environments. Add input protection diodes for transient immunity.

Recommended

TPS26600RHFR · Texas Instruments ISO7741 (Digital isolator for industrial interfaces)

Recommended Products Summary

LM317DCYR Texas Instruments Used in: On-Board Power Regulation for Microcontrollers TPS73501DRBR Texas Instruments Used in: On-Board Power Regulation for Microcontrollers OPA1612 Op-amp for signal conditioning Used in: Analog Sensor Interface Power ADS1115 ADC for sensor readout Used in: Analog Sensor Interface Power TPS63070RNMT Texas Instruments Used in: Battery-Powered Devices BQ24075 Battery charger IC Used in: Battery-Powered Devices NE5532 Audio op-amp Used in: Audio Circuits PCM5102 Audio DAC Used in: Audio Circuits ADS1256 High-resolution ADC Used in: Test and Measurement Equipment OPA2277 Precision op-amp Used in: Test and Measurement Equipment TPS26600RHFR Texas Instruments Used in: Industrial Control Systems ISO7741 Digital isolator for industrial interfaces Used in: Industrial Control Systems

What is the output voltage range of LM317LCPK?

The LM317LCPK has an adjustable output voltage range of 1.25V to 37V. According to the Texas Instruments datasheet, the output is set by two external resistors using the formula VOUT = 1.25V * (1 + R2/R1) + IADJ * R2. This wide range makes it versatile for various applications.

What is the maximum output current of LM317LCPK?

The LM317LCPK can supply up to 100 mA of output current. This is lower than the standard LM317 (1.5A) but sufficient for low-power applications such as biasing circuits, reference supplies, and small sensor modules. For higher current, consider the LM317T or LM317MDT.

Where can I buy LM317LCPK online?

LM317LCPK is available from major distributors such as DigiKey, Mouser, and Octopart. As of 2026-08-23, DigiKey lists it as 'ships today' with pricing starting at $0.45 for single units. You can also check TI.com for direct purchasing options and lead times.

What is the price of LM317LCPK?

As of 2026-08-23, the price of LM317LCPK is approximately $0.45 for 1 unit, $0.38 for 10 units, $0.29 for 100 units, $0.24 for 500 units, and $0.19 for 1000 units. Prices may vary by distributor and quantity, so check current quotes on DigiKey or Mouser.

What is the lead time for LM317LCPK?

The lead time for LM317LCPK is typically 1-2 weeks from major distributors like DigiKey and Mouser, as it is an active product. For bulk orders, lead time may extend to 4-6 weeks depending on stock levels. Check the distributor's website for real-time availability.

Is LM317LCPK in stock?

As of 2026-08-23, LM317LCPK is in stock at DigiKey and Mouser, with immediate shipping available. Octopart shows availability from 4 distributors. For the most current stock status, visit the product page on your preferred distributor's website.

LM317LCPK vs LM317DCYR - which is better for low-power applications?

For low-power applications, LM317LCPK is often preferred due to its smaller SOT-89-3 package and lower quiescent current. The LM317DCYR is also a 100mA adjustable regulator but in a SOT-223 package, which is larger. Both have similar electrical specs, but the LCPK saves PCB space. Choose based on your footprint requirements.

What is the difference between LM317LCPK and LM317T?

The LM317LCPK is a surface-mount SOT-89-3 package rated for 100 mA, while the LM317T is a through-hole TO-220 package rated for 1.5A. The LM317T can handle higher power dissipation and is suitable for higher current loads. The LCPK is for low-power, space-constrained designs.

When should I choose LM317LCPK over LM317DCYR?

Choose LM317LCPK when you need a smaller footprint (SOT-89-3 vs SOT-223) and are comfortable with the same 100mA current rating. The LCPK is ideal for compact PCBs where space is critical. If you need better thermal performance or a larger pad for heat dissipation, the DCYR might be preferable.

What is the best drop-in replacement for LM317LCPK?

The best drop-in replacement for LM317LCPK is the LM317DCYR from Texas Instruments, which is also a 100mA adjustable regulator but in a SOT-223 package. For a pin-compatible SOT-89-3 option, consider the LM317LCLP or LM317LZ from other manufacturers, but verify pinout and specs. Always check the datasheet for compatibility.

Can LM317DCYR replace LM317LCPK?

Yes, LM317DCYR can replace LM317LCPK functionally, as both are 100mA adjustable regulators with similar output voltage ranges. However, the package differs: LM317DCYR is SOT-223, while LM317LCPK is SOT-89-3. This means the PCB footprint is different, so it is not a drop-in replacement without layout changes.

Where can I download the LM317LCPK datasheet PDF?

You can download the LM317LCPK datasheet PDF from Texas Instruments' official website at https://www.ti.com/lit/ds/symlink/lm317l.pdf. It is also available on third-party sites like alldatasheet.com and datasheets.com. The datasheet contains full specifications, pinout, and application circuits.

Where can I find the LM317LCPK pinout?

The LM317LCPK pinout is available in the official datasheet from Texas Instruments. The SOT-89-3 package has three pins: Input (pin 1), Output (pin 2), and Adjust (pin 3). The thermal pad is connected to the output. Refer to the datasheet for exact pin assignments and recommended PCB layout.

What are the key specifications of LM317LCPK that engineers should know?

Engineers should know that the LM317LCPK is a 100mA adjustable linear regulator with an output range of 1.25V to 37V. It has a typical line regulation of 0.01%/V and operates over 0°C to +125°C. The device requires only two external resistors to set the output voltage, making it simple to use. It includes internal current limiting and thermal overload protection.

What is the best STMicroelectronics equivalent for LM317LCPK?

The best STMicroelectronics equivalent for LM317LCPK is the LM317LZ, which is a 100mA adjustable regulator in a TO-92 package. However, the package is different (TO-92 vs SOT-89-3), so it is not a drop-in replacement. For a surface-mount option, consider the LD1117 series, but verify pin compatibility and specs.

Engineering reference data for LM317LCPK — comparison, design guidance, and compliance information.

Selection Guide

Choose the LM317LCPK when you need a compact, adjustable linear regulator for low-power applications (up to 100mA) and space is limited. It is ideal for on-board regulation in MCU boards, sensor interfaces, and battery-powered devices. If you require a higher output current (up to 1.5A), consider the LM317T or LM317MDT. For a drop-in replacement with the same package, the LM317LCLP is a direct alternative. If you prefer a larger package with better thermal performance, the LM317DCYR (SOT-223) is a functional alternative but requires a different footprint. For ultra-low noise applications, consider the TPS7A4701 or TPS73501. Always verify pin compatibility and thermal requirements for your specific design.

Comparison with Alternatives

Parameter	This Product	LM317DCYR	LM317LCLP	LM317LZ
Package	SOT-89-3	SOT-223	SOT-89-3	TO-92
Brand	Texas Instruments	Texas Instruments	Texas Instruments	STMicroelectronics
Output Current	100 mA	100 mA	100 mA	100 mA
Output Voltage Range	1.25V to 37V	1.25V to 37V	1.25V to 37V	1.25V to 37V
Operating Temperature	0°C to +125°C	0°C to +125°C	0°C to +125°C	0°C to +125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Through Hole
Dropout Voltage	[DATA_NEEDED]	[DATA_NEEDED]	[DATA_NEEDED]	[DATA_NEEDED]
Line Regulation	0.01%/V	0.01%/V	0.01%/V	0.01%/V

Key Differentiators

Compact SOT-89-3 package (vs LM317DCYR)
Wide output voltage range (vs AMS1117-ADJ)
Low quiescent current (vs LM317MDT)

Design Notes

Place input and output capacitors (typically 0.1uF and 1uF) as close to the LM317LCPK pins as possible to ensure stability. The SOT-89-3 package has a thermal pad that should be soldered to a copper area for heat dissipation. Use a ground plane to minimize noise.

The LM317LCPK dissipates power as heat, calculated as (VIN - VOUT) * IOUT. For example, at VIN=12V, VOUT=5V, and 100mA, dissipation is 0.7W. The SOT-89-3 package has limited thermal capability; ensure adequate copper area or derate the output current at high input voltages.

Do not exceed the maximum input voltage of 40V. The output voltage is set by external resistors; use 1% tolerance resistors for accuracy. The adjustment pin current (50uA) can cause errors if resistor values are too high. Also, ensure the minimum load current (typically 3.5mA) is maintained for proper regulation.