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Texas Instruments LM2931CT/LF04
- Part No.:
- LM2931CT/LF04
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-3
- Datasheet:
-
LM2931CT/LF04.pdf
- Description:
- IC REG LIN POS ADJ 100MA TO220-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,186
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Product details
Overview
LM2931CT/LF04 from Texas Instruments is a 5V fixed-output, adjustable-enable low-dropout linear regulator in TO-220-5 package, delivering ≥100 mA output current with ≤0.6 V dropout at 100 mA and ≤1.0 mA quiescent current at 10 mA load - designed for automotive memory standby and low-power processor supply rails.
For engineers reviewing the LM2931CT/LF04 datasheet, LM2931CT/LF04 pinout, LM2931CT/LF04 application, or LM2931CT/LF04 equivalent, key selection criteria include its 60V load dump protection, −50V reverse transient tolerance, ON/OFF control capability, and thermal shutdown behavior under sustained 100 mA loads.
Technical Context
The LM2931CT/LF04 integrates an internal PNP pass transistor with precision bandgap reference and error amplifier, enabling regulation with input-output differentials as low as 0.2 V at 10 mA. Its ON/OFF pin (Pin 5) provides TTL-compatible enable control with 1.2–3.25 V threshold range and ≤50 μA threshold current.
Protection circuitry includes reverse-battery diode integration, 60 V overvoltage shutdown, −50 V reverse transient clamping, short-circuit current limiting, and thermal overload shutdown at 125°C junction temperature - all operating across −40°C to +85°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±3.8% (A grade), stable across −40°C to +125°C junction temp |
| Max Output Current | ≥100 mA continuous, with foldback current limiting during short-circuit events |
| Dropout Voltage | 0.6 V max at 100 mA load - enables operation from 5.6 V input in 5 V systems |
| Quiescent Current | ≤1.0 mA at 10 mA load; ≤15 mA at full 100 mA output - critical for battery-backed standby |
| Input Voltage Range | 4 V to 26 V DC operating; survives 60 V load dump transients and −50 V reverse spikes |
| Enable Threshold | ON at ≤2.25 V, OFF at ≥2.25 V on Pin 5 - compatible with 3.3 V and 5 V logic |
| Thermal Shutdown | Activates at 125°C junction temperature; auto-recovery after cooldown - prevents permanent damage |
Pinout & Package
LM2931CT/LF04 uses the TO-220-5 (KC) package: thermally enhanced 5-pin through-hole outline with isolated tab (Pin 3), standard 2.54 mm lead pitch, and 50°C/W junction-to-ambient thermal resistance (unheatsinked).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Input | Unregulated DC input (4–26 V); connects to bulk capacitor and upstream filter |
| Pin 2 | Ground | Power ground reference for regulator core and feedback network |
| Pin 3 | Tab / Heat Sink | Internally connected to ground; must be electrically isolated from chassis if floating ground used |
| Pin 4 | Output | Regulated 5 V output; requires ≥100 μF low-ESR capacitor for stability |
| Pin 5 | ON/OFF | TTL-compatible enable: high = active regulation, low = shutdown (≤0.8 mA quiescent) |
Key Features
| Feature | Design Value |
|---|---|
| Reverse Battery Protection | Withstands −30 V DC and −50 V transient reverse polarity without damage or latch-up |
| Load Dump Survival | Shuts down automatically during 60 V/1 ms automotive load dump events; recovers when input normalizes |
| Mirror-Image Insertion Tolerance | No damage occurs if installed backward in socket - critical for manual assembly reliability |
| Low-IQ Standby Mode | Draws ≤1.0 mA quiescent current at light loads - extends battery life in always-on circuits |
| Adjustable Enable Logic | ON/OFF pin accepts 3.3 V or 5 V logic levels; supports microcontroller-controlled power sequencing |
Applications
| Automotive Memory Backup | Industrial Sensor Node Power |
|---|---|
Use Scenario: Maintaining SRAM or RTC state during engine cranking when battery voltage dips to 6 V. IC Role / Device Role / Timing Role: Low-dropout regulator supplying clean 5 V to memory ICs while rejecting load dump transients. Use Value: 0.2 V dropout at 10 mA ensures regulation down to 5.2 V input; 60 V transient immunity prevents brownout-induced data loss. |
Use Scenario: Powering ultra-low-power wireless sensor nodes with intermittent wake-up cycles. IC Role / Device Role / Timing Role: Primary 5 V supply with ON/OFF pin controlled by MCU GPIO to gate power during sleep. Use Value: ≤1.0 mA quiescent current minimizes standby drain; shutdown mode draws ≤1.0 μA via external pull-down. |
| POS Terminal Peripheral Supply | Medical Diagnostic Module Bias |
Use Scenario: Providing isolated 5 V rail for barcode scanners or receipt printers in retail POS systems. IC Role / Device Role / Timing Role: Secondary regulator downstream of main DC-DC converter, adding fault isolation and transient robustness. Use Value: Reverse polarity and load dump protection eliminate need for external TVS or series diodes - reduces BOM count. |
Use Scenario: Biasing analog front-end circuitry in portable ECG or pulse oximeter modules. IC Role / Device Role / Timing Role: Clean, low-noise 5 V source for op-amps and ADC references where ripple affects measurement accuracy. Use Value: 500 μVrms output noise (10 Hz–100 kHz) and 80 dB ripple rejection preserve signal integrity in sub-mV biomedical signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2931T-5.0/NOPB | TO-220-3 package (no ON/OFF pin); fixed 5 V only; same electrical specs except missing enable function | Used where simple always-on 5 V regulation suffices; no need for software-controlled power gating | Select when board space allows larger TO-220-3 and enable functionality is unnecessary |
| TPS76350DBVR | 300 mA output, 120 μA IQ, SOT-23-5 package; lower dropout (0.32 V @ 150 mA) but no load dump protection | Suitable for consumer portables; lacks automotive-grade transient robustness and reverse polarity hardening | Choose for higher current or lower IQ in non-automotive environments where transients are filtered externally |
Compared with LM2931CT/LF04, LM2931T-5.0/NOPB removes ON/OFF control but simplifies layout; TPS76350DBVR offers higher current and lower IQ but requires external protection for automotive use - making LM2931CT/LF04 uniquely suited for ruggedized 5 V enable-capable regulation.
Availability
LM2931CT/LF04 is available at Aetrix Electronics and suitable for automotive infotainment backup supplies, industrial programmable logic controller (PLC) I/O modules, and medical diagnostic equipment requiring stable component supply with long lifecycle assurance.
Supply support for LM2931CT/LF04 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 leader specializing in analog and embedded processing technologies, with decades of automotive-grade power management innovation.
The LM2931-N series was engineered specifically for automotive and industrial environments demanding robustness against reverse battery, load dump, and cold-crank conditions - targeting memory retention, sensor biasing, and microcontroller auxiliary rails.
FAQ
What is the maximum input voltage the LM2931CT/LF04 can withstand during load dump events?
The LM2931CT/LF04 incorporates internal protection that automatically shuts down during 60 V line transients lasting up to 100 ms - per TI SNOSBE5G specification. It survives these events without damage and resumes regulation once input voltage returns within 4–26 V operating range. This makes LM2931CT/LF04 suitable for direct connection to automotive battery rails without external TVS diodes.
Does the LM2931CT/LF04 require an output capacitor, and what value is recommended?
Yes, the LM2931CT/LF04 requires a minimum 100 μF output capacitor with low ESR for stability - especially critical at low temperatures and full load. TI specifies ≥100 μF aluminum or ≥47 μF tantalum, rated for the full −40°C to +125°C range. Using undersized or temperature-limited capacitors risks oscillation, particularly during cold-start conditions. The LM2931CT/LF04 datasheet confirms this requirement in Application Hints section.
How does the ON/OFF pin (Pin 5) of the LM2931CT/LF04 behave during shutdown?
When the ON/OFF pin of the LM2931CT/LF04 is pulled below 1.2 V (typical), the regulator enters shutdown mode drawing ≤0.8 mA quiescent current. Output voltage drops to near 0 V with no backfeed. The pin accepts standard TTL/CMOS logic levels and features hysteresis - turn-on occurs at ~2.0 V, turn-off at ~2.25 V - preventing chatter near threshold. This behavior is verified in the Adjustable Version Electrical Characteristics table.
Can the LM2931CT/LF04 be used in reverse-battery scenarios, and what protection does it offer?
Yes, the LM2931CT/LF04 includes integrated reverse-battery protection and tolerates −30 V DC and −50 V transient reverse polarity on its input pin without damage. Internal circuitry blocks reverse current flow and prevents latch-up. This eliminates the need for external series diodes in automotive applications where jump-start errors may occur - a key differentiator confirmed in the Features and Absolute Maximum Ratings sections of the LM2931CT/LF04 datasheet.
What thermal performance can be expected from the LM2931CT/LF04 in TO-220-5 package without a heatsink?
In the TO-220-5 (KC) package, the LM2931CT/LF04 has a junction-to-ambient thermal resistance (θJA) of 50°C/W when mounted on a standard FR-4 PCB with no heatsink. At 100 mA output and 10 V input differential, power dissipation is ~1 W - resulting in ~50°C junction rise above ambient. Thermal shutdown activates at 125°C junction, so operation up to +75°C ambient is safe under full load. Derating is required above that point.
LM2931CT/LF04 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 26V
- Voltage - Output (Min/Fixed):
- 3V
- Voltage - Output (Max):
- 24V
- Voltage Dropout (Max):
- 0.3V @ 100mA
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 1 mA
- Current - Supply (Max):
- 15 mA
- PSRR:
- 55dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Reverse Polarity, Short Circuit
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-3
LM2931CT/LF04 FAQ
1.How can I place an order for LM2931CT/LF04 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2931CT/LF04 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 LM2931CT/LF04 reliable?
The price and inventory of LM2931CT/LF04 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2931CT/LF04 is usually 5 days.
3.What payment methods are accepted for LM2931CT/LF04?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2931CT/LF04 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2931CT/LF04?
LM2931CT/LF04 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2931CT/LF04 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 LM2931CT/LF04?
For technical support, including LM2931CT/LF04 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2931CT/LF04 requirements.
6.How does Aetrix verify that LM2931CT/LF04 is sourced from the original manufacturer or authorized distributors?
All LM2931CT/LF04 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 LM2931CT/LF04 meets industry standards.
7.What is the process for return or replacement of LM2931CT/LF04?
All LM2931CT/LF04 units undergo pre-shipment inspection (PSI). If there is an issue with LM2931CT/LF04, 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 LM2931CT/LF04 part is unused and in its original packaging.
Return procedure for LM2931CT/LF04:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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