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Texas Instruments LM3671MF-3.3
- Part No.:
- LM3671MF-3.3
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MF-3.3.pdf
- Description:
- IC REG BUCK 3.3V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,582
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Product details
Overview
LM3671MF-3.3 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 delivers high efficiency via internal PFET/NFET synchronous rectification, operates at 2 MHz fixed PWM frequency (typ.), switches automatically between PWM and PFM modes, and requires only three external components: one inductor and two ceramic capacitors. It powers core logic rails in mobile phones and portable instruments.
For engineers reviewing the LM3671MF-3.3 datasheet, LM3671MF-3.3 pinout, LM3671MF-3.3 application, or LM3671MF-3.3 equivalent, key selection criteria include its 3.3 V fixed output, 16 µA quiescent current in PFM mode, 0.01 µA shutdown current, SOT-23-5 package compatibility, and support for light-load efficiency optimization in battery-powered systems.
Technical Context
The LM3671MF-3.3 uses voltage-mode control with input voltage feed-forward to maintain stable regulation across 2.7 V–5.5 V input. Its internal 0.5 V reference and fixed 3.3 V output are achieved via factory-trimmed feedback divider - no external resistors required. The device integrates soft-start, thermal shutdown, and cycle-by-cycle current limiting (1020 mA typ.) for robust operation.
It implements intelligent mode switching: PWM mode dominates above ~100 mA load (2 MHz fixed frequency), while PFM mode engages below that threshold to reduce quiescent current to 16 µA (typ.) and extend battery life. Shutdown is activated by pulling EN < 0.4 V, reducing supply current to 0.01 µA (typ.).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% - eliminates need for external feedback resistors and simplifies layout. |
| Max Output Current | 600 mA - supports power-hungry digital cores and interface ICs in compact portable designs. |
| Input Voltage Range | 2.7 V to 5.5 V - compatible with single-cell Li-Ion (fully charged to 4.2 V) and regulated 3.3 V/5 V rails. |
| Quiescent Current | 16 µA (typ.) in PFM mode - enables >100-hour standby in always-on sensor nodes or low-power MCU applications. |
| Switching Frequency | 2 MHz (typ.) in PWM mode - allows use of small 2.2 µH inductors and 10 µF ceramic output capacitors. |
| Shutdown Current | 0.01 µA (typ.) - minimizes battery drain during system sleep or power-off states. |
| Internal FET RDS(ON) | PFET: 380 mΩ, NFET: 250 mΩ (at VIN = 3.6 V) - enables >90% peak efficiency at mid-load without external MOSFETs. |
Pinout & Package
SOT-23-5 package (DBV, 2.92 mm × 2.84 mm × 1.2 mm) with exposed pad for thermal performance. Pinout matches industry-standard buck converter layout for easy PCB reuse.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 VIN | Power input | Connects directly to input filter capacitor; accepts 2.7–5.5 V; must be decoupled within 2 mm for stability. |
| 2 GND | Power ground | Primary return path for input/output currents; ties to thermal pad for heat dissipation (θJA = 130°C/W). |
| 3 EN | Enable control | Logic-level input: <0.4 V = shutdown, >1.0 V = active; must not float; supports system-level power sequencing. |
| 4 FB | Feedback node | Internally connected to 3.3 V divider; connect directly to output capacitor for regulation - no external resistors needed. |
| 5 SW | Switching node | Drives external inductor; carries high di/dt; requires tight loop area with GND and VIN to minimize EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic PFM/PWM mode switching | Enables seamless transition between high-efficiency light-load operation (16 µA IQ) and low-noise full-load regulation (2 MHz PWM). |
| Internal synchronous rectification | Eliminates external Schottky diode, reduces conduction loss, and improves efficiency by 8–12% vs. asynchronous buck at 3.3 V output. |
| Integrated soft-start | Staged current limit ramp (70 → 140 → 280 → 1020 mA) prevents inrush into large output caps - startup time ~400 µs @ 300 mA load. |
| Thermal & overload protection | Auto-recovery thermal shutdown triggers at 150°C (typ.); cycle-by-cycle current limit protects against short-circuit and overcurrent faults. |
| Minimal BOM requirement | Only three external passive components required: 2.2 µH inductor, 4.7 µF input ceramic cap, 10 µF output ceramic cap - accelerates design-in. |
Applications
| Mobile Phone Core Power | Portable Instrument MCU Rail |
|---|---|
Use Scenario: Powers ARM Cortex-M4 microcontroller and associated peripherals in slim smartphone mainboard. IC Role / Device Role / Timing Role: Primary 3.3 V buck regulator supplying digital core logic, ADC reference, and I²C/SPI interface blocks. Use Value: Delivers stable 3.3 V at up to 600 mA with <±4% tolerance across temperature and line variations, enabling reliable firmware execution and sensor data acquisition. |
Use Scenario: Supplies 3.3 V rail to 32-bit MCU and analog front-end in handheld multimeter or environmental sensor node. IC Role / Device Role / Timing Role: Main system regulator converting single Li-Ion cell to clean 3.3 V for mixed-signal processing and display driver. Use Value: Achieves >92% efficiency at 100 mA load and drops to 16 µA quiescent current in standby - extends battery life to >12 months on 2×AA cells. |
| W-LAN Baseband Power | Digital Still Camera Image Processor |
Use Scenario: Provides regulated 3.3 V to Wi-Fi baseband IC during burst transmit/receive cycles in portable hotspot devices. IC Role / Device Role / Timing Role: High-transient-response buck converter supporting rapid load steps (0.5 mA ↔ 400 mA) without output droop. Use Value: Maintains <±30 mV output deviation during 100 ns load transients due to fast PFM→PWM mode transition (<5 µs), ensuring RF signal integrity. |
Use Scenario: Powers image signal processor (ISP) and CMOS sensor interface in compact digital camera module. IC Role / Device Role / Timing Role: Dedicated 3.3 V supply for ISP core and memory interface, synchronized with shutter timing signals. Use Value: Enables silent, ripple-free operation via 2 MHz switching - avoids beat frequencies with image sensor clocks and prevents visible banding in captured video. |
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 package (2 mm × 2 mm) | Higher switching frequency enables smaller inductors; lacks integrated soft-start ramp control | Preferred when board space is constrained and higher-frequency EMI filtering is acceptable. |
| AP3418KTR-G1 | 3.3 V fixed, 600 mA, 1.5 MHz switching, 25 µA IQ, SOT-23-5 package | Lower frequency increases inductor size; higher quiescent current reduces ultra-low-power runtime | Considered where cost sensitivity outweighs efficiency and transient response requirements. |
Compared with TPS62231DRVR and AP3418KTR-G1, the LM3671MF-3.3 offers superior light-load efficiency (16 µA IQ), proven PFM/PWM transition behavior in portable audio/video loads, and identical SOT-23-5 footprint - enabling drop-in replacement in existing layouts without rework.
Availability
LM3671MF-3.3 is available at Aetrix Electronics and suitable for mobile phone power management, portable instrument MCU rails, and W-LAN baseband applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance.
Supply support for LM3671MF-3.3 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 experience in high-efficiency DC-DC conversion for portable electronics.
The LM3671 product line delivers compact, low-quiescent-current buck converters for battery-powered devices - designed specifically to replace linear regulators in space-constrained, energy-sensitive applications like smartphones and wearables.
FAQ
What is the output voltage tolerance of the LM3671MF-3.3 under full operating conditions?
The LM3671MF-3.3 provides a fixed 3.3 V output with ±4% tolerance over the full junction temperature range (−40°C to +125°C) and input voltage range (2.7 V to 5.5 V), as specified in the Electrical Characteristics table. This tolerance includes line, load, and temperature effects - no external trimming is required, and the internal feedback divider is factory-calibrated.
Does the LM3671MF-3.3 require external feedback resistors to set the output voltage?
No. The LM3671MF-3.3 is a fixed-output variant with an internally trimmed feedback network configured for 3.3 V. The FB pin connects directly to the output capacitor - no external resistors are needed. This simplifies layout, reduces BOM count, and ensures consistent regulation without resistor tolerance drift.
How does the LM3671MF-3.3 handle load transients between 1 mA and 400 mA?
The LM3671MF-3.3 transitions automatically from PFM to PWM mode within microseconds when load jumps above ~100 mA (at VIN = 3.6 V), minimizing output droop. Typical load transient response shows <±30 mV deviation with 100 ns recovery - enabled by fast comparator response and internal compensation optimized for ceramic output capacitors.
What package type is used for the LM3671MF-3.3/NOPB ordering option?
The LM3671MF-3.3/NOPB is supplied in the SOT-23-5 package (TI package code DBV), measuring 2.92 mm × 2.84 mm × 1.2 mm with a standard lead-free finish. This package is pin-compatible with other LM3671 fixed-output variants and supports reflow soldering per JEDEC J-STD-020.
Can the LM3671MF-3.3 operate from a 2.5 V input source?
No. The absolute minimum input voltage for functional operation is 2.7 V, as defined in the Operating Ratings. At 2.5 V, the device may fail to start or regulate correctly due to undervoltage lockout activation. For sub-2.7 V inputs, consider the LM3671MF-1.8 or other lower-VOUT variants with appropriate dropout margin.
LM3671MF-3.3 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):
- 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 FAQ
1.How can I place an order for LM3671MF-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MF-3.3 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 reliable?
The price and inventory of LM3671MF-3.3 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 is usually 5 days.
3.What payment methods are accepted for LM3671MF-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MF-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MF-3.3?
LM3671MF-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MF-3.3 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?
For technical support, including LM3671MF-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MF-3.3 requirements.
6.How does Aetrix verify that LM3671MF-3.3 is sourced from the original manufacturer or authorized distributors?
All LM3671MF-3.3 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 meets industry standards.
7.What is the process for return or replacement of LM3671MF-3.3?
All LM3671MF-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MF-3.3, 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 part is unused and in its original packaging.
Return procedure for LM3671MF-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3671MF-3.3 Tags
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