LM317M

LM317M is an adjustable positive linear regulator (3-terminal) with a fixed 1.25 V reference between the output and adjust pins. It can regulate to about 1.25–37 V and source up to roughly 1.5 A (with proper heat sinking); input voltage up to about 40 V; dropout around 2 V at full load; it includes current limiting and thermal shutdown.
Key circuit ideas:
- Typical Vout = 1.25 × (1 + R2/R1) + Iadj × R2 (Iadj ≈ 50 µA).
- Use R1 ≈ 240 Ω; R2 sets the output.
- Capacitors: input 0.1 µF close to Vin; output 1–100 µF for stability; optional adjust-pin capacitor (≈10 µF) to improve ripple rejection.
- Pinout (TO-220/front view): left = ADJ, middle = OUT, right = IN.
Protection and notes:
- Protect against reverse currents if large output capacitors exist.
- Thermal and short-circuit protection operate automatically; line/load regulation improves with proper heatsinking.
Typical uses: lab power supplies, post-regulation stages, battery chargers, adjustable bench regulators. Always verify the exact package pinout from the datasheet you’re using.

Key features of LM317M:
- 3-terminal adjustable positive voltage regulator
- 1.25 V reference; output adjustable from ~1.25 V up to Vin−1.5 V (max ≈ 37–40 V input)
- Output current up to about 1.5 A
- Dropout voltage ≈ 2 V at higher currents
- Input voltage up to 40 V
- Built-in protections: current limit, thermal shutdown, safe-area protection
- Good line and load regulation
- Requires external resistor network to set Vout (typical R1 ≈ 240 Ω; R2 to set voltage)
- Stability enhanced with recommended input/output capacitors
- Package: TO-220 (LM317M) and other options
Note: Always follow datasheet recommendations for capacitors and layout to ensure stable operation.

TO-3 metal-can package (through-hole, three-lead regulator).

- Pin count: 3 pins (TO-220 package).
- Pinout (front view): Pin 1 = Adj, Pin 2 = Output, Pin 3 = Input. The tab is connected to Output.
- Function: Adjustable positive linear voltage regulator with a 1.25 V reference; output voltage set by external resistors (Vout ≈ Vref(1+R2/R1) + Iadj·R2).

Manufacturer: Texas Instruments (TI). TI is a multinational semiconductor company that designs and manufactures analog and mixed-signal ICs, power management, sensors, microcontrollers, and related products. (LM317 originated with National Semiconductor, which TI acquired in 2011.)

LM317M is an adjustable positive linear regulator. Common applications:
- Adjustable DC power supplies (bench PS, regulator modules) set Vout with a resistor divider
- Constant-current sources for LED driving and charging circuits
- Simple battery chargers (CC/CV with external resistors)
- Pre-regulator or post-regulator stages in power supplies to improve ripple and regulation
- General-purpose stable rails for analog/microcontroller circuits, op-amps, sensors

LM317M is the same adjustable regulator in the LM317 family. Equivalents/cross‑references include:
- LM317 (standard version from other manufacturers)
- LM317T / LM317K (TO‑220 variants)
- LM317L (lower-current version)
- LM117 (older pin‑compatible version)
- KA317 (cross‑ref from other vendors)
- LM350 (3 A version for higher current)