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Texas Instruments LM3671MF-1.25
- Part No.:
- LM3671MF-1.25
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MF-1.25.pdf
- Description:
- IC REG BUCK 1.25V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,678
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Product details
Overview
LM3671MF-1.25 from Texas Instruments is a fixed-output 1.25 V, 600 mA synchronous step-down DC-DC converter optimized for single Li-Ion battery (2.7–5.5 V input) power delivery in portable electronics. It integrates PFET/NFET switches, operates at 2 MHz (typ.), delivers 16 µA quiescent current in PFM mode, and requires only three external components: one inductor and two ceramic capacitors. It powers core logic rails in mobile phones and digital still cameras.
For engineers reviewing the LM3671MF-1.25 datasheet, LM3671MF-1.25 pinout, LM3671MF-1.25 application, or LM3671MF-1.25 equivalent, this page provides verified technical context, package-specific pin functions, real-world efficiency behavior across load and temperature, validated alternatives for voltage-matched buck conversion, and supply-chain support for high-reliability portable designs.
Technical Context
The LM3671MF-1.25 uses voltage-mode PWM control with input-voltage feed-forward to maintain stable regulation across 2.7–5.5 V input. Its internal 0.5 V reference feeds a precision error amplifier that drives a ramp-based PWM comparator, enabling tight line/load regulation (0.031 %/V and 0.0013 %/mA).
It automatically transitions between fixed-frequency 2 MHz PWM mode (>80 mA load), hysteretic PFM mode (16 µA IQ, ~0.6–1.7% output overvoltage headroom), and 0.01 µA shutdown-controlled solely by EN pin logic levels (<0.4 V = off, >1.0 V = on). Internal thermal shutdown (150°C trip) and cycle-by-cycle current limiting (1020 mA typ.) ensure robust operation under fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.25 V ±4% (guaranteed across −40°C to +125°C junction temp) |
| Max Output Current | 600 mA continuous (maintains regulation across full input range 2.7–5.5 V) |
| Switching Frequency | 2 MHz typical (enables use of 2.2 µH inductor and small 10 µF ceramic output cap) |
| Quiescent Current | 16 µA typical in PFM mode (extends battery life during standby in portable devices) |
| Shutdown Current | 0.01 µA typical (minimizes leakage during system sleep or power-off states) |
| Input Voltage Range | 2.7 V to 5.5 V (optimized for single-cell Li-Ion; supports full discharge down to 2.7 V) |
| Feedback Reference | 0.5 V internal bandgap (sets output via internal resistor divider; no external resistors needed) |
Pinout & Package
SOT-23-5 package (DBV, 2.92 mm × 2.84 mm × 1.2 mm); lead-free (NOPB) variant confirmed for LM3671MF-1.25/NOPB.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Connects to input filter capacitor; accepts 2.7–5.5 V; must be ≥2.7 V before enabling |
| GND | Power ground | Primary return path for PFET/NFET switching currents; requires low-inductance PCB connection |
| EN | Enable control | Logic input: <0.4 V = shutdown (0.01 µA IQ), >1.0 V = active; must not float |
| FB | Feedback node | Internally connected to 1.25 V output divider; connect directly to output capacitor for regulation |
| SW | Switching node | Drives external inductor; carries high di/dt PWM current; requires tight layout and ground plane |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Integrated NFET replaces Schottky diode, reducing conduction loss and improving efficiency at 1.25 V output |
| Automatic PFM/PWM mode switching | Seamless transition at ~50–100 mA (VIN = 3.6 V), optimizing IQ vs. ripple trade-off without external control |
| Soft-start circuit | Staged current limit (70 → 140 → 280 → 1020 mA) prevents inrush into 10 µF output caps; startup time ~275–400 µs |
| Thermal & overload protection | Auto-recovering thermal shutdown (150°C trip) and cycle-by-cycle current limit (1020 mA typ.) protect IC and board |
| Minimal external components | Only 2.2 µH inductor + 4.7 µF input + 10 µF output ceramic caps required-no compensation network needed |
Applications
| Mobile Phone Core Logic | Digital Still Camera Sensor Rail |
|---|---|
Use Scenario: Powering ARM Cortex-A series application processor I/O and memory interface rails in slim smartphone designs. IC Role / Device Role / Timing Role: Primary 1.25 V buck regulator delivering up to 600 mA with <1% load regulation and 2 MHz switching to minimize EMI near RF sections. Use Value: Enables compact layout using 2.2 µH inductor and 10 µF X5R output cap; PFM mode extends standby battery life by reducing IQ to 16 µA. |
Use Scenario: Supplying image sensor analog front-end (AFE) and ADC reference voltage domain in 12 MP+ camera modules. IC Role / Device Role / Timing Role: Low-noise, tightly regulated 1.25 V source with <0.0013 %/mA load regulation to prevent sensor gain drift during exposure bursts. Use Value: Internal 0.5 V reference and precision feedback divider ensure ±4% output accuracy over −40°C to +85°C ambient, critical for consistent color fidelity. |
| Portable Hard Disk Drive Controller | W-LAN Baseband Processor |
Use Scenario: Generating 1.25 V core voltage for 2.5-inch HDD controller ASIC during spin-up and sustained read/write operations. IC Role / Device Role / Timing Role: High-current (600 mA) buck converter with thermal shutdown (150°C) and current limiting (1020 mA) to survive transient overloads during motor acceleration. Use Value: Synchronous rectification maintains >90% efficiency at 500 mA, reducing thermal stress on small PCB areas adjacent to drive electronics. |
Use Scenario: Powering IEEE 802.11n baseband SoC in handheld hotspot devices operating from single-cell Li-Ion. IC Role / Device Role / Timing Role: Fast-transient 2 MHz buck regulator supporting dynamic DVFS; transitions from PFM to PWM in <10 µs when packet burst demand spikes. Use Value: Load transient response (Fig. 25–26) holds 1.25 V within ±30 mV during 10–100 mA steps, preventing MAC layer timing errors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 1.25 V fixed output, 600 mA, 3 MHz switching, 17 µA IQ, SOT-23-5 package | Higher frequency enables smaller inductor (1 µH), but lower thermal margin (θJA = 220°C/W vs. LM3671's 130°C/W) | Prefer TPS62231DRYR for space-constrained layouts where 3 MHz EMI filtering is manageable; LM3671MF-1.25 better for thermally dense boards. |
| AP3012KTR-G1 | 1.25 V fixed output, 500 mA, 1.5 MHz, 25 µA IQ, SOT-23-5 package | Lower max current and higher IQ reduce suitability for sustained 600 mA loads or ultra-low-power standby | Choose AP3012KTR-G1 only if peak load ≤500 mA and cost sensitivity outweighs 16 µA IQ advantage of LM3671MF-1.25. |
Compared with TPS62231DRYR and AP3012KTR-G1, the LM3671MF-1.25 offers superior thermal performance (130°C/W θJA) and lowest quiescent current (16 µA) in its class-making it optimal for thermally constrained, battery-sensitive portable applications requiring full 600 mA capability at 1.25 V.
Availability
LM3671MF-1.25 is available at Aetrix Electronics and suitable for mobile phone core logic, digital still camera sensor rails, portable hard disk drive controllers, and W-LAN baseband processors requiring stable component supply across production lifecycles.
Supply support for LM3671MF-1.25 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, embedded processing, and power management technologies, with decades of expertise in high-efficiency DC-DC conversion for portable systems.
The LM3671 product line delivers compact, low-IQ buck converters for Li-Ion-powered consumer electronics-designed specifically to replace linear regulators in space- and battery-life-critical applications like smartphones and cameras.
FAQ
What is the guaranteed output voltage tolerance for LM3671MF-1.25 across temperature?
The LM3671MF-1.25 guarantees ±4% output voltage tolerance over the full junction temperature range of −40°C to +125°C, as specified in the Electrical Characteristics table for the MF (SOT-23) package. This is achieved via a precision 0.5 V internal reference and matched on-die feedback resistors calibrated during production test.
Does LM3671MF-1.25 require external compensation components?
No, the LM3671MF-1.25 does not require external compensation components. Its voltage-mode control architecture with integrated ramp generator and feed-forward is factory-compensated for stability with standard 2.2 µH inductors and 10 µF ceramic output capacitors, eliminating the need for external RC networks or type-II/III compensators.
What is the minimum input voltage required before enabling LM3671MF-1.25?
The LM3671MF-1.25 must not be enabled until VIN reaches at least 2.7 V. The datasheet explicitly recommends holding EN low until input voltage exceeds this threshold to prevent improper start-up or regulation failure. Enabling below 2.7 V may result in unregulated output or excessive dropout.
How does LM3671MF-1.25 handle short-circuit conditions on its output?
Under output short-circuit, the LM3671MF-1.25 activates cycle-by-cycle current limiting (1020 mA typical) and enters timed current limit mode: the NFET remains on longer to allow inductor current decay, preventing thermal runaway. If junction temperature exceeds 150°C, thermal shutdown engages and auto-recovers once cooled below 130°C.
Can LM3671MF-1.25 operate with a 1 µH inductor instead of the recommended 2.2 µH?
No-using a 1 µH inductor with LM3671MF-1.25 violates the design intent and may cause instability or excessive ripple. The 2.2 µH value is optimized for 2 MHz operation, peak current limits, and EMI performance. Lower inductance increases peak switch current beyond safe limits and degrades PFM/PWM transition behavior per datasheet Figures 31–34.
LM3671MF-1.25 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- -
- Current - Output:
- 600mA
- Frequency - Switching:
- 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM3671MF-1.25 FAQ
1.How can I place an order for LM3671MF-1.25 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MF-1.25 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 LM3671MF-1.25 reliable?
The price and inventory of LM3671MF-1.25 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3671MF-1.25 is usually 5 days.
3.What payment methods are accepted for LM3671MF-1.25?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MF-1.25 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MF-1.25?
LM3671MF-1.25 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MF-1.25 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 LM3671MF-1.25?
For technical support, including LM3671MF-1.25 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MF-1.25 requirements.
6.How does Aetrix verify that LM3671MF-1.25 is sourced from the original manufacturer or authorized distributors?
All LM3671MF-1.25 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 LM3671MF-1.25 meets industry standards.
7.What is the process for return or replacement of LM3671MF-1.25?
All LM3671MF-1.25 units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MF-1.25, 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 LM3671MF-1.25 part is unused and in its original packaging.
Return procedure for LM3671MF-1.25:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3671MF-1.25 Tags
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