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Texas Instruments LM3671MF-3.3/NOPB
- Part No.:
- LM3671MF-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MF-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,178
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Product details
Overview
LM3671MF-3.3/NOPB from Texas Instruments is a fixed-output 3.3 V, 600-mA synchronous step-down DC-DC converter optimized for single Li-Ion battery input (2.7 V to 5.5 V). It operates at 2 MHz fixed-frequency PWM mode with automatic PFM transition under light load, delivers 16 µA typical quiescent current, and requires only three external components: one 2.2 µH inductor and two ceramic capacitors. It powers core logic rails in mobile phones and portable instrumentation.
For engineers reviewing the LM3671MF-3.3/NOPB datasheet, LM3671MF-3.3/NOPB pinout, LM3671MF-3.3/NOPB application, or LM3671MF-3.3/NOPB equivalent, key selection criteria include output voltage accuracy (±4% over −40°C to +125°C), thermal shutdown behavior (150°C trip), internal synchronous rectification, soft-start timing (275–400 µs), and USON-6 package compatibility with space-constrained PCB layouts.
Technical Context
The LM3671MF-3.3/NOPB implements 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 feeds a precision error amplifier that compares FB voltage against this threshold to adjust PFET on-time.
It integrates dual power switches - a 380 mΩ PFET high-side switch and a 250 mΩ NFET synchronous rectifier - enabling >90% efficiency at 300 mA with 3.6 V input. Automatic mode switching between PWM (≥80 mA) and PFM (<80 mA) ensures low-noise operation during active use and ultra-low IQ (16 µA) during standby.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over −40°C to +125°C; eliminates external resistor divider and simplifies layout. |
| Max Output Current | 600 mA continuous; supports microcontroller cores, RF transceivers, and sensor interfaces without external boost. |
| Switching Frequency | 2 MHz typical (1.6–2.6 MHz over temp); enables use of 2.2 µH inductors and compact 10 µF ceramic output capacitors. |
| Quiescent Current | 16 µA typical in PFM mode; extends battery runtime in always-on sensor or BLE beacon applications. |
| Shutdown Current | 0.01 µA typical; reduces system leakage when host MCU disables EN pin. |
| Input Voltage Range | 2.7 V to 5.5 V; compatible with single-cell Li-ion (3.0–4.2 V), LiFePO₄ (2.8–3.6 V), and USB-powered systems. |
| Thermal Shutdown | 150°C typical trip temperature; protects IC and PCB during sustained overload or poor airflow conditions. |
Pinout & Package
LM3671MF-3.3/NOPB uses the USON-6 (NKH) package: 2.00 mm × 2.00 mm, 0.5 mm pitch, bottom-exposed thermal pad. Pin 1 is marked by dot; pin order follows standard top-view numbering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power Input | Accepts 2.7–5.5 V; must be decoupled with ≥4.7 µF ceramic capacitor close to pin to suppress switching noise. |
| GND (Pin 2) | Power Ground | Primary return path for input and output currents; connects to thermal pad for enhanced heat dissipation. |
| EN (Pin 3) | Digital Enable | Active-high logic input; device enables when >1 V, shuts down when <0.4 V; must not float-tie to VIN or MCU GPIO. |
| FB (Pin 4) | Feedback Input | Internally connected to 3.3 V divider; no external resistors needed-direct connection to VOUT required for regulation. |
| SW (Pin 5) | Switch Node | Drives external 2.2 µH inductor; high dv/dt node requiring tight loop area and ground shielding to minimize EMI. |
| SGND (Pin 6) | Signal Ground | Separate analog ground for FB reference; must connect to main GND at single point near IC to avoid noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Eliminates external Schottky diode; reduces conduction loss and improves full-load efficiency by up to 8% vs asynchronous designs. |
| Automatic PFM-PWM Transition | Seamlessly shifts modes at ~80 mA load; maintains >85% efficiency from 1 mA to 600 mA without manual control or external circuitry. |
| Integrated Soft Start | Ramps output voltage over ~275–400 µs (load-dependent); prevents inrush current into downstream LDOs or large capacitive loads. |
| Overcurrent & Thermal Protection | Current limit trips at 1020 mA (open-loop), thermal shutdown activates at 150°C; both features are self-resetting after fault removal. |
| Ultra-Small BOM | Only three passive components required: 2.2 µH shielded inductor, 4.7 µF input cap, 10 µF output cap-all 0603 or smaller footprints. |
Applications
| Mobile Phone Baseband Power | Portable Medical Sensor Hub |
|---|---|
Use Scenario: Powers ARM Cortex-M4 MCU, display driver, and touch controller from single Li-ion cell in slim smartphone form factor. IC Role / Device Role / Timing Role: Primary 3.3 V buck regulator delivering regulated rail with fast transient response to burst-mode CPU activity. Use Value: 2 MHz switching avoids AM radio band interference; 16 µA PFM IQ extends standby time beyond 7 days on 1000 mAh battery. | Use Scenario: Supplies 3.3 V to ECG front-end ADC, Bluetooth LE radio, and flash memory in handheld patient monitor. IC Role / Device Role / Timing Role: Main system power converter enabling low-noise analog acquisition while maintaining wireless connectivity. Use Value: Internal synchronous rectification achieves >92% efficiency at 200 mA, reducing thermal rise in sealed plastic enclosure. |
| Digital Still Camera Image Processor | Wireless Home-Automation Gateway |
Use Scenario: Powers image signal processor (ISP) and CMOS sensor interface in compact digital camera with auto-focus motor. IC Role / Device Role / Timing Role: High-current 3.3 V source supporting short-duration peak loads (>400 mA) during image capture and write-to-SD. Use Value: 600 mA capability and 2.2 µH inductor allow sub-1 mm height design; thermal shutdown prevents damage during lens motor stall events. | Use Scenario: Provides stable 3.3 V rail to Zigbee/Thread SoC, Wi-Fi coexistence module, and environmental sensors in wall-mounted smart hub. IC Role / Device Role / Timing Role: Primary DC-DC stage converting USB 5 V or coin-cell backup to clean 3.3 V system supply. Use Value: 0.01 µA shutdown current enables >1-year battery life in backup mode; USON-6 footprint fits narrow PCB edge zones. |
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 |
|---|---|---|---|
| TPS62231DRVR | 3.3 V fixed, 600 mA, 3 MHz switching, 17 µA IQ, WSON-6 (2.0 × 2.0 mm) | Higher frequency allows smaller inductor (1 µH); slightly higher IQ in PFM mode | Preferred where board space permits tighter LC filter roll-off or faster transient response is critical. |
| AP3418W6-7 | 3.3 V fixed, 600 mA, 1.5 MHz switching, 25 µA IQ, SOT-23-5 (2.9 × 1.6 mm) | Larger SOT-23 package; lower switching frequency increases inductor size; higher quiescent current | Suitable when USON-6 assembly capability is unavailable and thermal performance requirements are less stringent. |
Compared with LM3671MF-3.3/NOPB, TPS62231DRVR offers faster regulation but demands tighter layout control for EMI, while AP3418W6-7 trades compactness and efficiency for broader assembly compatibility and relaxed thermal design margins.
Availability
LM3671MF-3.3/NOPB is available at Aetrix Electronics and suitable for mobile phones, portable medical equipment, and wireless home-automation gateways requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for LM3671MF-3.3/NOPB 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 headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and power management solutions for industrial, automotive, and consumer markets.
The LM3671 product line targets ultra-compact, battery-powered portable electronics requiring high-efficiency, low-noise, and minimal external component count in sub-2 mm² footprints.
FAQ
What is the recommended input capacitor for LM3671MF-3.3/NOPB?
The LM3671MF-3.3/NOPB datasheet specifies a minimum 4.7 µF X5R/X7R ceramic capacitor placed within 2 mm of the VIN and GND pins. TI recommends using a 4.7–10 µF, 6.3 V rated capacitor with low ESR (<10 mΩ) to suppress high-frequency switching noise and ensure stable operation across temperature and load.
Does LM3671MF-3.3/NOPB require an external feedback resistor network?
No. The LM3671MF-3.3/NOPB is a fixed-output variant with internal resistor divider set to 3.3 V. The FB pin connects directly to the output capacitor; no external resistors are needed or permitted. Using external resistors would disrupt regulation and void specified output accuracy.
Can LM3671MF-3.3/NOPB operate from a 2.5 V input?
No. The absolute minimum input voltage for LM3671MF-3.3/NOPB is 2.7 V per the Recommended Operating Conditions table. At 2.5 V, the device will not start or may drop out of regulation due to insufficient headroom across the internal PFET and inductor DCR.
What is the thermal pad connection requirement for LM3671MF-3.3/NOPB in USON-6 package?
The exposed thermal pad on the LM3671MF-3.3/NOPB USON-6 package must be soldered to a dedicated PCB copper pour tied to GND. TI specifies ≥4 thermal vias (0.3 mm diameter) connecting the pad to inner-layer ground planes to achieve RθJA = 174.7°C/W and prevent junction temperature exceedance at full load.
How does LM3671MF-3.3/NOPB handle short-circuit conditions?
Under output short-circuit, LM3671MF-3.3/NOPB enters timed current-limit mode: the NFET remains on longer to allow inductor current decay, preventing thermal runaway. Peak switch current is limited to 1020 mA (typical), and thermal shutdown engages if junction temperature reaches 150°C. Both protections are fully self-recovering once fault is removed.
LM3671MF-3.3/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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):
- 3.3V
- 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-3.3/NOPB FAQ
1.How can I place an order for LM3671MF-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MF-3.3/NOPB 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-3.3/NOPB reliable?
The price and inventory of LM3671MF-3.3/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3671MF-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM3671MF-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MF-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MF-3.3/NOPB?
LM3671MF-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MF-3.3/NOPB 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-3.3/NOPB?
For technical support, including LM3671MF-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MF-3.3/NOPB requirements.
6.How does Aetrix verify that LM3671MF-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3671MF-3.3/NOPB 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-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM3671MF-3.3/NOPB?
All LM3671MF-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MF-3.3/NOPB, 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-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM3671MF-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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