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Texas Instruments LM3671MF-1.8
- Part No.:
- LM3671MF-1.8
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MF-1.8.pdf
- Description:
- IC REG BUCK 1.8V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,358
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Product details
Overview
LM3671MF-1.8 from Texas Instruments is a fixed-output 1.8 V, 600 mA synchronous step-down DC-DC converter optimized for single Li-Ion battery (2.7–5.5 V input) power management in portable electronics. It delivers up to 600 mA load current with 2 MHz fixed-frequency PWM operation, automatic PFM/PWM mode switching, and internal synchronous rectification for high efficiency in compact designs.
For engineers reviewing the LM3671MF-1.8 datasheet, LM3671MF-1.8 pinout, LM3671MF-1.8 application, or LM3671MF-1.8 equivalent, this page provides verified technical context, package-specific pin definitions, real-world application mappings, and validated alternative options for low-voltage portable power supply design.
Technical Context
The LM3671MF-1.8 uses voltage-mode control with input voltage feed-forward to maintain stable regulation across 2.7–5.5 V input. Its internal 0.5 V reference enables precise 1.8 V output via integrated feedback divider, eliminating external resistors.
It implements three operational modes: 2 MHz PWM for medium-to-heavy loads (≥80 mA), hysteretic PFM for light-load efficiency (16 µA quiescent current), and shutdown (0.01 µA). Internal PFET/NFET synchronous rectification reduces conduction loss, while soft-start limits inrush current during enable transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% over −40°C to +125°C junction temperature |
| Max Output Current | 600 mA continuous at VIN ≥ 3.6 V; derated per thermal resistance (θJA = 130°C/W for SOT-23) |
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-Ion and regulated 3.3 V/5 V rails |
| Switching Frequency | 2 MHz typical - enables use of small 2.2 µH inductors and 4.7 µF/10 µF ceramic capacitors |
| Quiescent Current | 16 µA typical in PFM mode - extends battery life in standby and light-load states |
| Shutdown Current | 0.01 µA typical - minimizes battery drain when disabled via EN pin |
| Feedback Reference | 0.5 V internal bandgap - sets output via internal resistor divider; no external FB network required |
Pinout & Package
SOT-23-5 package (DBV, 2.92 mm × 2.84 mm × 1.2 mm) with exposed pad for thermal performance. Pinout matches standard LM3671MF series and is not shared with DSBGA or USON variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Connects to input filter capacitor; accepts 2.7–5.5 V; must be ≥2.7 V before enabling |
| GND (Pin 2) | Power ground | Main return path for input, output, and switch currents; tie directly to PCB ground plane |
| EN (Pin 3) | Enable control | Active-high logic: <0.4 V = shutdown, >1.0 V = enabled; must not float |
| FB (Pin 4) | Feedback node | Internally connected to output divider; fixed 1.8 V version requires direct connection to VOUT |
| SW (Pin 5) | Switching node | Drives external inductor; connects to source of internal PFET and drain of NFET synchronous rectifier |
Key Features
| Feature | Design Value |
|---|---|
| Automatic PFM/PWM mode switching | Transitions at ~50 mA (VIN = 3.6 V) to optimize efficiency across 0–600 mA load range |
| Internal synchronous rectification | PFET/NFET pair replaces external Schottky diode - eliminates 0.3–0.5 V forward drop, improving light-load efficiency |
| Integrated soft-start | Staged current limit ramp (70 → 140 → 280 → 1020 mA) prevents output overshoot and inrush stress on 10 µF COUT |
| Thermal & overload protection | Thermal shutdown engages at TJ ≈ 150°C; cycle-by-cycle current limit trips at 1020 mA typical |
| Minimal external components | Only one 2.2 µH inductor and two ceramic caps (4.7 µF CIN, 10 µF COUT) required for full operation |
Applications
| Mobile Phone Core Logic | MP3 Player Audio Codec |
|---|---|
Use Scenario: Powering ARM Cortex-A/M core voltage rail in dual-mode GSM/UMTS handsets with Li-Ion battery input. IC Role / Device Role / Timing Role: Primary buck regulator delivering stable 1.8 V to processor I/O and memory interface circuits. Use Value: 2 MHz switching avoids AM radio band interference; PFM mode extends talk time by reducing IQ to 16 µA during idle screen states. |
Use Scenario: Supplying clean 1.8 V bias to stereo DAC/ADC and headphone amplifier in flash-based audio players. IC Role / Device Role / Timing Role: Low-noise, high-PSRR DC-DC source replacing LDO to improve battery runtime without compromising analog signal integrity. Use Value: Synchronous rectification achieves >90% efficiency at 100 mA, doubling playback time versus linear regulator under same load. |
| Digital Still Camera Image Sensor | Portable Hard Disk Drive Interface |
Use Scenario: Generating 1.8 V for CMOS image sensor digital backend and column ADC in compact point-and-shoot cameras. IC Role / Device Role / Timing Role: Fast-transient buck converter supporting burst capture mode with rapid load steps from 1 mA (standby) to 400 mA (exposure). Use Value: Load transient response settles within 20 µs; PFM→PWM transition at ~100 mA ensures stable VDD during frame readout. |
Use Scenario: Powering 1.8 V SATA PHY and controller logic in 2.5″ portable HDD enclosures powered by USB or battery. IC Role / Device Role / Timing Role: High-current, thermally robust DC-DC stage handling intermittent 500 mA spin-up surges and sustained 200 mA active reads. Use Value: 600 mA capability with thermal shutdown (TJ = 150°C) prevents lockup during extended data transfers; SOT-23 footprint fits tight board space. |
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 | 1.8 V fixed, 600 mA, 3–6 MHz adjustable frequency, 17 µA IQ, 0.01 µA shutdown | Higher switching frequency allows smaller inductors; lacks PFM mode - uses forced PWM only | Prefer for noise-sensitive RF sections where fixed-frequency EMI is easier to filter |
| AP3012KTR-G1 | 1.8 V fixed, 500 mA, 1.5 MHz, 25 µA IQ, no PFM mode, no internal sync rectifier | Requires external Schottky diode; lower max current and higher quiescent current reduce battery life in portable use | Consider only if cost sensitivity outweighs efficiency and size requirements |
Compared with LM3671MF-1.8, TPS62231DRYR offers tighter EMI control via programmable frequency but sacrifices light-load efficiency due to absence of PFM. AP3012KTR-G1 trades integration and efficiency for lower BOM cost, requiring external diode and delivering 100 mA less current.
Availability
LM3671MF-1.8 is available at Aetrix Electronics and suitable for mobile phone power management, portable audio systems, and digital imaging modules requiring stable component supply with consistent lead times and full traceability.
Supply support for LM3671MF-1.8 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 ICs, with decades of expertise in high-efficiency DC-DC conversion for battery-powered systems.
The LM3671 product line targets ultra-compact, high-efficiency power delivery in space-constrained portable devices - designed specifically for Li-Ion input and sub-2 V logic rails in consumer handhelds.
FAQ
What is the recommended input capacitor for LM3671MF-1.8?
The LM3671MF-1.8 datasheet specifies a 4.7 µF X5R/X7R ceramic capacitor at the VIN pin, placed as close as possible to Pins 1 (VIN) and 2 (GND). This value ensures stable operation across 2.7–5.5 V input and suppresses high-frequency switching noise generated at the SW node. Larger values do not improve performance and may affect startup behavior.
Does LM3671MF-1.8 require an external feedback resistor network?
No. The LM3671MF-1.8 is a fixed-output variant with internal feedback divider calibrated for 1.8 V. Pin 4 (FB) must be connected directly to the output capacitor (VOUT); adding external resistors will disrupt regulation and cause incorrect output voltage. Only adjustable versions (e.g., LM3671MF-ADJ) require external dividers.
Can LM3671MF-1.8 operate from a 2.5 V input?
No. The absolute minimum input voltage for LM3671MF-1.8 is 2.7 V per the Operating Ratings table. At 2.5 V, the device enters undervoltage lockout and will not regulate. For 2.5 V input compatibility, consider the LM3671MF-1.2 or LM3671MF-1.375 variants, which support lower dropout conditions.
What thermal derating applies to LM3671MF-1.8 in SOT-23 package?
In the SOT-23-5 (DBV) package, LM3671MF-1.8 has θJA = 130°C/W on a 4-layer JEDEC board. At 85°C ambient, maximum continuous power dissipation drops to 310 mW - limiting practical 1.8 V output current to ~350 mA with adequate copper pour. Thermal shutdown activates at TJ ≈ 150°C to prevent damage.
How does the EN pin behave during system power-up?
The EN pin of LM3671MF-1.8 must be held low (<0.4 V) until VIN reaches ≥2.7 V, then driven high (>1.0 V) to initiate soft-start. If EN rises before VIN stabilizes, the device may fail to start or exhibit output overshoot. TI recommends using a simple RC delay or dedicated supervisor IC to coordinate EN activation with input rail readiness.
LM3671MF-1.8 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):
- 1.8V
- 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-1.8 FAQ
1.How can I place an order for LM3671MF-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MF-1.8 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-1.8 reliable?
The price and inventory of LM3671MF-1.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3671MF-1.8 is usually 5 days.
3.What payment methods are accepted for LM3671MF-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MF-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MF-1.8?
LM3671MF-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MF-1.8 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-1.8?
For technical support, including LM3671MF-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MF-1.8 requirements.
6.How does Aetrix verify that LM3671MF-1.8 is sourced from the original manufacturer or authorized distributors?
All LM3671MF-1.8 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-1.8 meets industry standards.
7.What is the process for return or replacement of LM3671MF-1.8?
All LM3671MF-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MF-1.8, 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-1.8 part is unused and in its original packaging.
Return procedure for LM3671MF-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3671MF-1.8 Tags
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