LM317L Adjustable Voltage Regulator SOP-8

LM317L Adjustable Voltage Regulator SOP-8 is a highly versatile three-terminal positive voltage regulator capable of supplying in excess of 100 mA over an output voltage range of 1.2 V to 37 V. This precision integrated circuit provides exceptional ease of use, as it requires only two external resistors to set the output voltage. Furthermore, the SOP-8 surface-mount package allows for significant space savings in compact electronic designs without compromising on thermal performance. Because the device features internal current limiting, thermal shutdown, and safe area compensation, it remains virtually blowout-proof under standard operating conditions. Consequently, engineers frequently select the LM317L for local on-card regulation, eliminating the distribution problems associated with single-point regulation in complex systems. Therefore, you can rely on this regulator to deliver stable, adjustable power for sensitive analog and digital circuitry.

Key Features:

• Adjustable Output Range: The device provides a wide output voltage range from 1.25 V to 37 V, offering maximum flexibility for diverse project requirements.
• Output Current Capability: It reliably delivers output current in excess of 100 mA, which is ideal for low-power applications and sensor nodes.
• Comprehensive Internal Protection: Features such as thermal overload protection and short-circuit current limiting ensure the longevity of both the regulator and the connected load.
• Excellent Regulation: The IC boasts high line and load regulation performance, typically maintaining 0.01% and 0.1% respectively for superior stability.
• Surface Mount Design: The SOP-8 package footprint facilitates automated assembly and fits perfectly into modern, high-density printed circuit boards.

Technical Specifications:

• Output Voltage Range: 1.2 V to 37 V
• Input-Output Voltage Differential: 40 V maximum
• Output Current: 100 mA (minimum) to 200 mA (typical peak)
• Reference Voltage (V_ref): 1.20 V to 1.30 V (Typically 1.25 V)
• Line Regulation: 0.01% / V (Typical)
• Load Regulation: 0.1% (Typical)
• Operating Junction Temperature: 0°C to +125°C

Mechanical Specifications:

• Package Type: SOP-8 (Small Outline Package)
• Number of Pins: 8
• Encapsulation: Plastic Molding Compound (UL 94V-0 Rated)
• Mounting Type: Surface Mount Technology (SMT)

Dimensions:

• Body Length: ≈ 4.90 mm
• Body Width: ≈ 3.90 mm
• Overall Width (including pins): ≈ 6.00 mm
• Height: ≈ 1.50 mm
• Pin Pitch: 1.27 mm

Pinout and Wiring:

• Pin 1 (Vout): This is the regulated output pin connected to the load.
• Pin 2, 3, 6, 7 (Vout): In many SOP-8 configurations, multiple pins connect to the output for better thermal dissipation.
• Pin 4 (Adjustment): Connect this pin to a resistor divider network to set the specific output voltage.
• Pin 5 (Vin): The unregulated input voltage pin; however, ensure it remains at least 3 V higher than the desired output.
• Pin 8 (Vin): Often serves as a second input connection to support higher current flow and heat management.

Datasheet Reference:

• Download Texas Instruments LM317L Datasheet

Commonly Used in:

• Precision Power Supplies: Creating variable bench-top power sources for low-current testing.
• Battery Chargers: Configuring constant current or constant voltage charging circuits for small lithium or NiMH cells.
• Local Card Regulators: Providing clean power to specific analog sections of a larger PCB to minimize crosstalk.

Applications:

• Adjustable Voltage Sources: Serving as the primary regulator for DIY electronics and prototyping modules.
• Current Limiting: Acting as a constant current regulator for LED string drivers.
• Post-Regulation: Cleaning up the output of switching power supplies for noise-sensitive audio equipment.

Equivalent Models:

• LM317LZ: The through-hole (TO-92) version of the same regulator sharing identical electrical specs.
• KA317L: The Fairchild/onsemi equivalent offering the same adjustable functionality in small packages.
• NTE1900: A broad-market replacement part often used for repair and maintenance of legacy equipment.

Package Includes:

• 1 x LM317L Adjustable Voltage Regulator SOP-8