LM317LCPK - 100mA Adjustable Positive Regulator | Texas Instruments
MPN: LM317LCPK β Active| 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 |
Drop-in alternatives for LM317LCPK β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
LM317LIPK
β Drop-Inπ Reference alternative (not in catalog)
LM317KC
β Drop-Inπ Reference alternative (not in catalog)
LM317MT
β Drop-Inπ Reference alternative (not in catalog)
TL783
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
L200
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
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 | 3.75 V to 35 V |
| Output Noise | 30 uVrms |
| Line Regulation | 0.01%/V (typical) |
| Quiescent Current | 1.5 mA (typical) |
| Adjustment Pin Current | 50 uA (typical) |
| Thermal Resistance | 52 C/W (theta_JA) |
| Operating Temperature | 0C to +125C |
| Package | SOT-89-3 (PK) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
LM317LCPK Pin Configuration
| Pin 1 | ADJ β Adjustment pin for setting output voltage |
| Pin 2 | OUT β Regulated output voltage |
| Pin 3 | IN β Input supply 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: Microcontroller Power Supply, Analog Sensor Interface, Low-Power Audio Circuits, Battery-Powered Devices, Industrial Control Systems, Test and Measurement Equipment.
Microcontroller Power Supply
The LM317LCPK provides a stable adjustable voltage rail for microcontrollers, with 100mA output sufficient for most MCU boards. Its low noise (30 uVrms) ensures reliable operation of analog peripherals. The SOT-89-3 package is compact for space-constrained designs. Place input/output capacitors close to the device to maintain stability.
Recommended
Analog Sensor Interface
The LM317LCPK is ideal for powering analog sensors that require a clean, adjustable supply. Its 30 uVrms noise and 0.01%/V line regulation minimize supply-induced errors in sensor readings. The adjustable output allows precise calibration of sensor bias voltages. Use a 10uF output capacitor to improve transient response.
Recommended
Low-Power Audio Circuits
The LM317LCPK provides a low-noise supply for audio preamplifiers and headphone amplifiers. Its 30 uVrms noise is well below audible levels, and the adjustable output allows optimization of the operating point. The linear regulation avoids switching noise, preserving audio fidelity. Ensure adequate heat dissipation for higher input-output differentials.
Recommended
Battery-Powered Devices
The LM317LCPK is suitable for battery-powered devices where a stable voltage is needed despite battery voltage variation. Its low quiescent current (1.5 mA) extends battery life, and the adjustable output allows matching the supply to the load requirements. For maximum efficiency, consider a switching regulator if the input-output differential is large.
Recommended
Industrial Control Systems
The LM317LCPK provides a reliable adjustable supply for industrial control circuits, such as PLC I/O modules and sensor transmitters. Its wide input range (up to 35V) accommodates 24V industrial buses, and the thermal overload protection ensures safe operation. The SOT-89-3 package is robust for harsh environments.
Recommended
Test and Measurement Equipment
The LM317LCPK is used in test equipment to provide a stable, adjustable reference voltage for calibration and measurement circuits. Its low noise and excellent line regulation ensure accurate readings. The adjustable output allows fine-tuning of reference levels. Use precision resistors for the adjustment network to maintain accuracy.
Recommended
Recommended Products Summary
Engineering reference data for LM317LCPK β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM317LIPK | LM317KC | LM317MT |
|---|---|---|---|---|
| Package | SOT-89-3 (PK) | SOT-89-3 (PK) - same | SOT-89-3 - same | SOT-89-3 - same |
| Brand | Texas Instruments | Texas Instruments | International Rectifier | Texas Instruments |
| 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 |
| Input Voltage Range | 3.75V to 35V | 3.75V to 35V | 3.75V to 35V | 3.75V to 35V |
| Output Noise | 30 uVrms | 30 uVrms | 30 uVrms | 30 uVrms |
| Operating Temperature | 0C to +125C | -40C to +125C | 0C to +125C | 0C to +125C |
| Quiescent Current | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA |
Key Differentiators
- Wide temperature range option (vs LM317LIPK)
- Low output noise (vs LM317KC)
- Compact SOT-89-3 package (vs LM317T)
Design Notes
The SOT-89-3 package has a thermal resistance of 52 C/W. At VIN=12V, VOUT=5V, and 100mA load, power dissipation is 0.7W, resulting in a 36.4C temperature rise. For higher dissipation, solder the tab to a larger copper pour or use a heatsink. Ensure the junction temperature stays within 0C to +125C.
Place input and output capacitors (typically 0.1uF and 1uF) as close to the device pins as possible. The adjustment pin should have a bypass capacitor (10uF) to improve ripple rejection. Use a ground plane to minimize noise and ensure stable operation.
Do not exceed the maximum input voltage of 35V. Maintain at least 3V input-to-output headroom for proper regulation. Use 1% or better resistors for the adjustment network to maintain output voltage accuracy. Avoid long traces to the adjustment pin to prevent noise pickup.
Compliance Information
RoHS compliant per TI product page. Not AEC-Q100 qualified.
