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Texas Instruments LM317MKTPR
- Part No.:
- LM317MKTPR
- Manufacturer:
- Texas Instruments
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
LM317MKTPR.pdf
- Description:
- IC REG LIN POS ADJ 500MA TO252-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,976
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Product details
Overview
LM317MKTPR from Texas Instruments is a 3-terminal adjustable positive linear voltage regulator delivering ≥500 mA output current, with output voltage adjustable from 1.25 V to 37 V and input-to-output differential up to 40 V. It features internal short-circuit current limiting, thermal-overload protection, and safe-area compensation, and is widely used in point-of-sale terminals, medical instrumentation, and appliance power supplies.
For engineers reviewing the LM317MKTPR datasheet, LM317MKTPR pinout, LM317MKTPR application, or LM317MKTPR equivalent, key selection considerations include its PFM (KTP) package thermal performance, ADJUST terminal current (50–100 µA), line regulation (0.02–0.07 %/V), load regulation (0.3–1.5 %VO), and minimum load current requirement (3.5–10 mA) to maintain regulation.
Technical Context
The LM317MKTPR operates as a floating regulator-no ground terminal exists, and quiescent current flows to the load rather than ground. Its feedback architecture references the ADJUST terminal to OUTPUT, enabling high-precision voltage or current regulation using only two external resistors.
It employs an NPN Darlington pass element with built-in overload protection scaling across voltage, thermal shutdown at 150 °C junction temperature, and safe-area compensation ensuring stable operation under varying VI–VO and IO conditions. The device requires ≥2.5 V headroom for regulation and supports ripple rejection up to 80 dB with 10 µF ADJUST capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | ≥500 mA max; sufficient for mid-power analog rails and embedded system supplies |
| Output voltage range | 1.25 V to 37 V; set via R1/R2 divider without needing ground-referenced components |
| Input-output differential | 2.5 V min / 40 V max; defines usable input headroom and maximum dropout-safe operating window |
| Reference voltage | 1.25 V (typ), ±0.05 V tolerance; sets baseline for precision output programming |
| Line regulation | 0.02–0.07 %/V; low sensitivity to input supply variation improves stability in unregulated DC inputs |
| Load regulation | 0.3–1.5 %VO; maintains tight output accuracy across 10 mA–500 mA load range |
| ADJUST current | 50–100 µA; must be sourced by feedback network to ensure regulation integrity |
Pinout & Package
LM317MKTPR uses the KTP (PFM) 3-pin surface-mount package (6.04 mm × 6.15 mm), featuring an exposed thermal pad for enhanced heat dissipation. The package is RoHS-compliant, moisture-sensitive level 3 (260 °C, 168 hr), and designed for reflow soldering with thermal pad grounding recommended.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| INPUT | Unregulated input supply connection | Accepts 2.5–40 V above OUTPUT; must sustain power dissipation (VI–VO) × IO |
| OUTPUT | Regulated output voltage node | Delivers stable voltage; carries both load current and ADJUST bias current (50–100 µA) |
| ADJUST | Feedback reference input | Sets output via resistor divider; voltage at this pin is held at 1.25 V relative to OUTPUT |
Key Features
| Feature | Design Value |
|---|---|
| Floating regulator architecture | Enables high-voltage outputs (e.g., >100 V) when referenced to floating loads-no ground terminal required |
| Internal safe-area compensation | Prevents thermal runaway during high VI–VO and high IO conditions by dynamically limiting power dissipation |
| Thermal-overload protection | Shuts down output above 150 °C virtual junction temperature and auto-recovers when cooled |
| Adjustable ripple rejection | Up to 80 dB achievable with 10 µF capacitor on ADJUST pin-critical for low-noise analog supplies |
| No mandatory output capacitor | Stable without output capacitance; optional ceramic/tantalum caps improve transient response but may cause ringing |
Applications
| Medical Instrumentation Power | Point-of-Sale Terminal Supply |
|---|---|
Use Scenario: Providing stable, low-noise ±5 V and +12 V rails for ECG front-end amplifiers and microcontroller subsystems in portable diagnostic devices. IC Role / Device Role / Timing Role: Adjustable linear regulator supplying isolated analog and digital domains with minimal PSRR degradation. Use Value: 1.25 V reference tolerance and <0.07 %/V line regulation ensure consistent ADC reference stability despite battery voltage sag. |
Use Scenario: Generating clean 5 V for thermal printer logic and 12 V for stepper motor drivers in compact retail kiosks. IC Role / Device Role / Timing Role: Primary DC-DC post-regulator converting unregulated 15 V DC bus to precise, ripple-free outputs. Use Value: 500 mA output capability and 80 dB ripple rejection (with CADJ) eliminate need for additional LDO stages before sensitive peripherals. |
| White Goods Control Board | Set-Top Box AV Power |
Use Scenario: Delivering 3.3 V and 5 V to MCU, display driver, and sensor interface circuits in washing machine main control boards. IC Role / Device Role / Timing Role: Cost-optimized, thermally robust voltage regulator handling wide ambient temperature swings (−40 °C to +125 °C). Use Value: Integrated thermal shutdown and −40 °C to +125 °C operating range ensure reliability in enclosed, high-temperature cabinet environments. |
Use Scenario: Regulating 12 V rail for HDMI PHY, audio DAC, and tuner modules in consumer STB designs where EMI compliance is critical. IC Role / Device Role / Timing Role: Low-EMI linear regulator replacing switching alternatives near RF-sensitive signal paths. Use Value: No switching noise generation and <0.3 %VO load regulation prevent video/audio artifacts caused by supply modulation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM317MDCYR | SOT-223-4 package (DCY); higher RθJA (60.2 °C/W) vs. KTP's lower thermal resistance; 4-pin layout includes tab-as-ground | Better suited for low-power, space-constrained PCBs where thermal pad routing is impractical | Select LM317MDCYR if board layout lacks thermal vias or requires standard SOT-223 footprint compatibility |
| LM317MKVURG3 | TO-252-3 (KVU) package; larger exposed pad, lower RθJCbot; rated for same 500 mA but with superior thermal performance at high VI–VO | Preferred for industrial applications requiring continuous 500 mA at >30 V differential or >85 °C ambient | Choose LM317MKVURG3 when sustained power dissipation exceeds 2.5 W and heatsinking is limited |
Compared with LM317MDCYR and LM317MKVURG3, the LM317MKTPR offers balanced thermal performance in a compact PFM outline-ideal for mid-power designs needing better heat spreading than SOT-223 but less board area than TO-252.
Availability
LM317MKTPR is available at Aetrix Electronics and suitable for medical instrumentation, point-of-sale systems, and white goods control boards requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM317MKTPR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with decades of leadership in power management ICs and precision analog design.
The LM317M family-including LM317MKTPR-is engineered for cost-sensitive, high-reliability linear regulation in industrial, medical, and consumer applications where simplicity, robustness, and wide output adjustability are essential.
FAQ
What is the maximum input-to-output voltage differential for LM317MKTPR?
The absolute maximum input-to-output differential voltage for LM317MKTPR is 40 V, as specified in the Absolute Maximum Ratings table. Operation beyond this limit risks permanent damage. For reliable continuous operation, TI recommends staying within 37 V differential under recommended conditions, with derating applied at elevated temperatures.
Does LM317MKTPR require an output capacitor to remain stable?
No, LM317MKTPR does not require an output capacitor for stability-its internal compensation ensures unconditional stability without it. However, adding a 1–10 µF tantalum or electrolytic capacitor improves transient response. Ceramic capacitors may be used but can cause output ringing due to zero-phase-margin interaction with the regulator's output impedance profile.
How is output voltage calculated for LM317MKTPR?
LM317MKTPR output voltage is calculated as VO = 1.25 V × (1 + R2/R1) + IADJ × R2, where R1 connects OUTPUT to ADJUST, R2 connects ADJUST to ground, and IADJ is the ADJUST terminal current (50–100 µA). Since IADJ is small, it is often omitted in initial design, yielding VO ≈ 1.25 V × (1 + R2/R1).
What thermal considerations apply to LM317MKTPR in the KTP package?
The LM317MKTPR in KTP (PFM) package relies on its exposed thermal pad for heat transfer. TI recommends soldering the pad to a large copper area with ≥4 thermal vias to an internal ground plane. Junction-to-board thermal resistance (RθJB) is not published for KTP, but its footprint and pad size align with TO-252-level thermal performance-enabling ~2.5 W dissipation with proper PCB layout.
Can LM317MKTPR be used as a constant-current source?
Yes, LM317MKTPR can function as a precision constant-current source by connecting a single resistor R between OUTPUT and ADJUST, with the load between OUTPUT and input supply. Current is set as IOUT ≈ 1.25 V / R. This exploits the fixed 1.25 V reference between OUTPUT and ADJUST, and is validated in TI's application notes for LED drivers and battery chargers.
LM317MKTPR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 37V
- Voltage Dropout (Max):
- -
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- -
- PSRR:
- 80dB ~ 65dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-252-3
LM317MKTPR FAQ
1.How can I place an order for LM317MKTPR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM317MKTPR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM317MKTPR reliable?
The price and inventory of LM317MKTPR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM317MKTPR is usually 5 days.
3.What payment methods are accepted for LM317MKTPR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM317MKTPR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM317MKTPR?
LM317MKTPR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM317MKTPR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM317MKTPR?
For technical support, including LM317MKTPR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM317MKTPR requirements.
6.How does Aetrix verify that LM317MKTPR is sourced from the original manufacturer or authorized distributors?
All LM317MKTPR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM317MKTPR meets industry standards.
7.What is the process for return or replacement of LM317MKTPR?
All LM317MKTPR units undergo pre-shipment inspection (PSI). If there is an issue with LM317MKTPR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM317MKTPR part is unused and in its original packaging.
Return procedure for LM317MKTPR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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