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Texas Instruments LM3671MF-2.8
- Part No.:
- LM3671MF-2.8
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MF-2.8.pdf
- Description:
- IC REG BUCK 2.8V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,287
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Product details
Overview
LM3671MF-2.8 from Texas Instruments is a fixed-output 2.8 V, 2-MHz synchronous step-down DC-DC converter optimized for single Li-Ion battery-powered portable electronics. It delivers up to 600 mA load current with 16 µA typical quiescent current, internal soft start, and automatic PFM-PWM mode switching - enabling efficient power delivery in mobile phones and digital still cameras.
For engineers reviewing the LM3671MF-2.8 datasheet, LM3671MF-2.8 pinout, LM3671MF-2.8 application, or LM3671MF-2.8 equivalent, key selection considerations include its 2.7–5.5 V input range, 2.8 V fixed output, 6-pin USON (2.0 mm × 2.0 mm) package, thermal shutdown protection, and compatibility with only three external components: one 2.2 µH inductor and two ceramic capacitors.
Technical Context
The LM3671MF-2.8 employs voltage-mode control with input-voltage feed-forward to maintain stable regulation across line and load variations. Its integrated PFET/NFET synchronous rectifier enables high efficiency at low output voltages, while the 2-MHz fixed-frequency PWM operation minimizes external component size.
Light-load operation triggers automatic transition to hysteretic PFM mode, reducing quiescent current to 16 µA and extending battery life. Shutdown mode draws just 0.01 µA, and internal soft-start limits inrush current by stepping switch current limit through 70 mA → 140 mA → 280 mA → 1020 mA during startup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8 V ±4% - eliminates need for external feedback resistors and simplifies layout. |
| Input Voltage Range | 2.7 V to 5.5 V - supports full discharge curve of single Li-Ion cell (3.0–4.2 V nominal). |
| Max Output Current | 600 mA - sufficient for core logic rails in smartphones and portable imaging systems. |
| Switching Frequency | 2 MHz (typical) - enables use of tiny 2.2 µH inductors and 4.7 µF/10 µF ceramic capacitors. |
| Quiescent Current | 16 µA (typical, PFM mode) - extends standby battery life in always-on sensor or communication subsystems. |
| Shutdown Current | 0.01 µA (typical) - critical for ultra-low-power wake-on-event architectures. |
| Internal Reference | 0.5 V - used with internal resistor divider to set 2.8 V output; improves accuracy vs. external references. |
Pinout & Package
LM3671MF-2.8 is housed in a 6-pin USON (NKH) package measuring 2.00 mm × 2.00 mm (nominal), with wettable flanks for automated optical inspection. Thermal resistance RθJA is 174.7°C/W on a 4-layer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Accepts 2.7–5.5 V supply; must be decoupled with 4.7 µF ceramic capacitor close to pin. |
| GND | Power ground | Primary return path for input and output currents; connects to system ground plane. |
| EN | Digital enable | Active-high logic input; device enabled when >1 V, shutdown when <0.4 V; must not float. |
| FB | Feedback input | Internally connected to fixed 2.8 V divider; tied directly to VOUT for regulation - no external resistors required. |
| SW | Switching node | Drives external 2.2 µH inductor; carries high di/dt square wave - requires tight loop layout with ground pour. |
| SGND | Signal ground | Separate analog ground for FB reference; should be connected to GND at single point near IC. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated PFET/NFET reduces conduction loss vs. diode-based buck, improving efficiency by ~8–12% at 3.3 V input / 2.8 V output. |
| Automatic PFM-PWM mode switching | Seamlessly transitions at ~80 mA load threshold - maintains >85% efficiency from 1 mA to 600 mA without manual control. |
| Internal soft start | Staged current-limit ramp prevents input rail collapse during power-up; typical 275–400 µs start time with 10 µF COUT. |
| Thermal & overload protection | Thermal shutdown engages at ~150°C junction temperature; cycle-by-cycle current limit trips at 1020 mA peak SW current. |
| Minimal BOM requirement | Only three external passive components needed: 2.2 µH shielded inductor + 4.7 µF input + 10 µF output ceramic caps - reduces PCB area and cost. |
Applications
| Mobile Phone Power Rail | Digital Still Camera Core Supply |
|---|---|
Use Scenario: Powers baseband processor I/O or camera interface logic in compact smartphone designs where space and battery life are constrained. IC Role / Device Role / Timing Role: Primary 2.8 V buck regulator delivering regulated power from shared Li-Ion battery rail. Use Value: 2-MHz switching allows ultra-compact 2.0 mm × 2.0 mm footprint and eliminates need for bulky tantalum capacitors. | Use Scenario: Supplies image signal processor (ISP) core voltage in DSLR or mirrorless camera bodies requiring stable low-noise 2.8 V under burst capture loads. IC Role / Device Role / Timing Role: Fixed-output DC-DC converter providing ripple-free 2.8 V with fast transient response to handle sensor readout current spikes. Use Value: Automatic PFM-PWM mode ensures >90% efficiency at idle (1 mA) and >88% at full 600 mA load - extending per-charge shot count. |
| Portable Medical Sensor Node | Wireless Home-Automation Hub |
Use Scenario: Powers Bluetooth LE transceiver and analog front-end in wearable ECG or SpO₂ monitors operating from coin-cell or small Li-Poly battery. IC Role / Device Role / Timing Role: Efficient step-down regulator maintaining 2.8 V for RF and ADC circuitry during intermittent wireless transmission bursts. Use Value: 0.01 µA shutdown current enables multi-month shelf life; 16 µA PFM quiescent current supports >1-year runtime on 120 mAh battery. | Use Scenario: Supplies 2.8 V to Zigbee or Matter-compliant SoC in battery-operated smart switches or sensors deployed in hard-to-reach locations. IC Role / Device Role / Timing Role: Primary power management IC converting 3.6 V Li-SOCl₂ or 4.2 V Li-Ion to stable 2.8 V for low-power microcontroller and radio subsystem. Use Value: Internal soft start prevents brownout during cold-start; thermal shutdown protects against enclosure overheating in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | Fixed 2.8 V output, 3-MHz switching, 400-mA max load, 5-pin WSON package (1.5 mm × 1.5 mm) | Lower max current and smaller package - suitable for space-constrained sub-100 mA rails like display bias or sensor interfaces | Select when board area is critical and load ≤400 mA; verify thermal performance with reduced copper area. |
| AP63202WU-7 | Adjustable 0.6–5.5 V output, 2-MHz, 2-A max, 8-pin WLCSP - requires external feedback resistors | Higher current capability and flexibility - appropriate for future-proofing or multi-rail designs needing 2.8 V + other voltages | Choose when scalability beyond 600 mA or programmability is required; adds two resistors and layout complexity. |
Compared with TPS62231DRYR, LM3671MF-2.8 offers 50% higher current capacity and proven PFM-PWM seamless transition; versus AP63202WU-7, it provides simpler fixed-voltage implementation with lower BOM count and smaller footprint for dedicated 2.8 V rails.
Availability
LM3671MF-2.8 is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable medical equipment requiring stable component supply with long-term manufacturability and automotive-grade reliability options (LM3671-Q1 variant).
Supply support for LM3671MF-2.8 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 technologies, with decades of expertise in high-efficiency DC-DC conversion for portable and automotive markets.
The LM3671 product line was designed specifically for space- and battery-constrained portable electronics, delivering high integration, minimal external components, and intelligent power-saving modes to extend runtime without sacrificing performance.
FAQ
What is the recommended input capacitor for LM3671MF-2.8?
The LM3671MF-2.8 datasheet specifies a 4.7 µF X5R/X7R ceramic capacitor placed as close as possible to the VIN and GND pins. This value ensures stable operation across the 2.7–5.5 V input range and suppresses high-frequency switching noise. Using a lower capacitance may cause input rail droop during heavy load transients, while larger values provide no measurable benefit and increase cost and board area. The LM3671MF-2.8 itself does not require bulk electrolytic input capacitance due to its high 2-MHz switching frequency.
Does LM3671MF-2.8 require an external feedback resistor network?
No, LM3671MF-2.8 does not require external feedback resistors. It is a fixed-output variant with an internal resistor divider configured for 2.8 V, referenced to the 0.5 V internal bandgap. The FB pin is internally connected and must be tied directly to the output capacitor's VOUT node for regulation. Adding external resistors would disrupt the factory-trimmed feedback ratio and cause output voltage inaccuracy or instability. This fixed architecture simplifies design and improves production yield compared to adjustable versions like LM3671-ADJ.
What is the thermal shutdown behavior of LM3671MF-2.8?
The LM3671MF-2.8 incorporates internal thermal shutdown that activates at approximately 150°C junction temperature and releases at ~130°C. During shutdown, the device halts switching, disables both PFET and NFET, and draws only 0.01 µA from VIN. Recovery is automatic once junction temperature falls below the hysteresis threshold. This protection is independent of load current and ambient conditions, safeguarding the IC and surrounding components during sustained overload, poor PCB thermal design, or high ambient temperatures. The USON package's RθJA of 174.7°C/W assumes a standard 4-layer board - derating is required for 2-layer layouts.
Can LM3671MF-2.8 operate from a 2.5 V input source?
No, LM3671MF-2.8 cannot reliably operate from a 2.5 V input. Its absolute minimum input voltage is 2.7 V per the Recommended Operating Conditions table, and undervoltage lockout (UVLO) disables operation below this threshold to prevent erratic regulation or excessive dropout. At 2.7 V input and 2.8 V output, the device operates near dropout - efficiency drops significantly, and maximum load current is reduced. For applications requiring operation down to 2.5 V, consider the LM3671-ADJ with external resistor divider or alternative regulators such as TPS6274x series optimized for ultra-low input voltages. The LM3671MF-2.8 is intended for Li-Ion (2.7–4.2 V usable range) or 3.3 V rail inputs.
How does the soft-start function work in LM3671MF-2.8?
The LM3671MF-2.8 implements hardware-based soft-start by progressively increasing the internal switch current limit during startup: from 70 mA → 140 mA → 280 mA → 1020 mA (typical final limit). This staged ramp prevents large inrush currents into the output capacitor, avoiding input rail collapse and minimizing stress on the input source and external components. Soft-start activates only when EN transitions high *after* VIN reaches ≥2.7 V. Typical startup time is 275 µs with 1 mA load and 400 µs with 300 mA load into a 10 µF output capacitor. No external components are needed - the timing is fully internal and unadjustable.
LM3671MF-2.8 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):
- 2.8V
- 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-2.8 FAQ
1.How can I place an order for LM3671MF-2.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MF-2.8 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-2.8 reliable?
The price and inventory of LM3671MF-2.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3671MF-2.8 is usually 5 days.
3.What payment methods are accepted for LM3671MF-2.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MF-2.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MF-2.8?
LM3671MF-2.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MF-2.8 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-2.8?
For technical support, including LM3671MF-2.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MF-2.8 requirements.
6.How does Aetrix verify that LM3671MF-2.8 is sourced from the original manufacturer or authorized distributors?
All LM3671MF-2.8 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-2.8 meets industry standards.
7.What is the process for return or replacement of LM3671MF-2.8?
All LM3671MF-2.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MF-2.8, 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-2.8 part is unused and in its original packaging.
Return procedure for LM3671MF-2.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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