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Texas Instruments LM3671MFX-2.8/NOPB
- Part No.:
- LM3671MFX-2.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MFX-2.8/NOPB.pdf
- Description:
- IC REG BUCK 2.8V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,846
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Product details
Overview
LM3671MFX-2.8/NOPB 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 in PFM mode, internal soft-start, and integrated PFET/NFET power switches - used in mobile phones and digital still cameras for efficient core voltage regulation.
For engineers reviewing the LM3671MFX-2.8/NOPB datasheet, LM3671MFX-2.8/NOPB pinout, LM3671MFX-2.8/NOPB application, or LM3671MFX-2.8/NOPB equivalent, key selection criteria include its 2.7–5.5 V input range, 2.8 V fixed output, USON-6 package footprint, automatic PFM-PWM mode switching, and thermal/overcurrent protection - all critical for space-constrained, battery-life-sensitive designs.
Technical Context
The LM3671MFX-2.8/NOPB implements a voltage-mode PWM controller with input-voltage feed-forward compensation and hysteretic PFM mode for light-load efficiency. Its functional block includes an internal 0.5 V reference, error amplifier, 2 MHz oscillator, soft-start ramp generator, and dual MOSFET drivers for synchronous rectification.
It operates across three distinct modes: PWM (≥80 mA load, fixed 2 MHz switching), PFM (light load, variable frequency, 16 µA IQ), and shutdown (0.01 µA ISHDN). Mode transitions are fully automatic and based on inductor zero-current detection and peak switch current thresholds - no external control required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8 V ±4% - eliminates need for external feedback resistors; ensures stable core rail for 2.8 V I/O or analog subsystems. |
| 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) plus margin for transient spikes. |
| Max Load Current | 600 mA - sufficient for baseband processors, camera ISPs, or RF front-end biasing in handheld devices. |
| Switching Frequency | 2 MHz (typical, ±20%) - enables use of tiny 2.2 µH inductors and 4.7 µF/10 µF ceramic capacitors; reduces solution size & EMI. |
| Quiescent Current | 16 µA (typical, PFM mode) - extends battery runtime during standby/sleep states without compromising wake-up response. |
| Shutdown Current | 0.01 µA (typical) - near-zero drain during system suspend; critical for always-on sensors or real-time clocks. |
| Internal FET RDS(ON) | PFET: 380–500 mΩ; NFET: 250–400 mΩ - enables high efficiency (>90% at 3.6 VIN/2.8 VOUT/300 mA) without external sync diode. |
Pinout & Package
LM3671MFX-2.8/NOPB uses the USON-6 (NKH) package: 2.00 mm × 2.00 mm, 0.5 mm pitch, exposed thermal pad. Pin 1 marked by dot; top-side marking includes "L71" and date code.
| 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 input ripple and supply noise. |
| GND (Pin 2) | Power ground | Primary return path for input/output currents; connects to thermal pad for enhanced heat dissipation (RθJA = 174.7°C/W). |
| EN (Pin 3) | Digital enable | Active-high logic control: <0.4 V = shutdown (0.01 µA), >1 V = enabled; must not float - tie to VIN or microcontroller GPIO. |
| FB (Pin 4) | Feedback input | Internally connected to 2.8 V divider; shorted to VOUT for fixed-output operation - no external resistors needed. |
| SW (Pin 5) | Switching node | Drives external 2.2 µH inductor; carries high di/dt square wave - requires tight layout, minimal trace length, and ground guard ring. |
| SGND (Pin 6) | Signal ground | Separate analog ground for FB pin; must connect to main GND at single point near IC to avoid noise coupling into feedback path. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic PFM-PWM mode switching | Eliminates manual mode control; maintains >85% efficiency from 1 mA to 600 mA load without external circuitry. |
| Internal synchronous rectification | Replaces lossy Schottky diode; reduces conduction loss by ~300 mV drop, enabling >92% peak efficiency at mid-load. |
| Integrated soft-start | Ramps output voltage over ~275–400 µs (load-dependent); prevents inrush current damage to input caps and upstream regulators. |
| Thermal & current overload protection | Shuts down at TJ ≈ 150°C and restarts at 130°C; limits peak switch current to 1020 mA (typical) - protects IC and inductor under fault. |
| Ultra-low shutdown current | 0.01 µA typical draw allows multi-year shelf life in battery-backed applications like smart tags or medical wearables. |
Applications
| Mobile Phone Power Management | Digital Still Camera Core Supply |
|---|---|
Use Scenario: Regulating 2.8 V rail for image signal processor (ISP) and CMOS sensor interface in compact smartphones. IC Role / Device Role / Timing Role: Primary buck converter delivering clean, low-noise 2.8 V from shared Li-Ion battery bus. Use Value: 2 MHz switching avoids audible noise and simplifies EMI filtering; 600 mA capacity supports burst-mode capture without voltage droop. |
Use Scenario: Powering flash memory controllers and lens actuator drivers in DSLR-style digital cameras. IC Role / Device Role / Timing Role: Fixed-output DC-DC regulator providing stable 2.8 V for high-speed NAND I/O and motor control logic. Use Value: Internal soft-start prevents reset glitches during power-on; PFM mode extends battery life during preview/idle states. |
| Portable Medical Sensor Hub | Wireless Home-Automation Node |
Use Scenario: Supplying 2.8 V to ultra-low-power biosensor analog front-ends and BLE SoCs in wearable health monitors. IC Role / Device Role / Timing Role: Efficient intermediate voltage regulator stepping down from 3.6 V battery to precision analog subsystem rail. Use Value: 16 µA quiescent current in PFM mode enables >12-month battery life in intermittent-sampling applications. |
Use Scenario: Generating 2.8 V for Zigbee/Thread radio modules and environmental sensor interfaces in battery-operated smart home sensors. IC Role / Device Role / Timing Role: Compact, low-EMI power stage enabling reliable wireless communication in dense RF environments. Use Value: Small USON-6 footprint (2 mm²) and only three external components reduce PCB area by >40% vs discrete solutions. |
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 | 2.8 V fixed, 3 MHz switching, 300 mA max output, 12 µA IQ - smaller current capability, higher frequency, lower quiescent current. | Best suited for sub-300 mA loads where board space is tighter and higher-frequency EMI filtering is acceptable. | Select when prioritizing ultra-low IQ and minimal inductor size over peak current delivery. |
| AP63202WU-7 | 2.8 V fixed, 2 MHz, 2 A max output, 25 µA IQ - higher current rating, larger USP-8 package (2.1 × 1.6 mm), no integrated soft-start. | Applicable in systems requiring headroom beyond 600 mA, such as multi-sensor nodes with simultaneous active peripherals. | Choose when future-proofing for higher load growth or needing robust thermal performance under sustained 1 A loads. |
Compared with LM3671MFX-2.8/NOPB, TPS62231DRYR trades current capacity for lower IQ and higher frequency, while AP63202WU-7 offers 3.3× more current in a slightly larger footprint but lacks soft-start - making LM3671MFX-2.8/NOPB optimal for balanced 600 mA, low-noise, space-constrained portable designs.
Availability
LM3671MFX-2.8/NOPB is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable medical equipment requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3671MFX-2.8/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 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, low quiescent current, and robust protection in miniature packages - targeting mobile handsets, imaging devices, and IoT edge nodes.
FAQ
What is the recommended input capacitor for LM3671MFX-2.8/NOPB?
The LM3671MFX-2.8/NOPB datasheet specifies a minimum 4.7 µF X5R/X7R ceramic capacitor placed as close as possible to the VIN and GND pins. TI recommends using a 4.7 µF input capacitor with ≤100 mΩ ESR to ensure stable operation across the full 2.7–5.5 V input range and suppress high-frequency switching noise. For improved transient response, a parallel 1 µF capacitor may be added.
Does LM3671MFX-2.8/NOPB require external feedback resistors?
No. The LM3671MFX-2.8/NOPB is a fixed-output variant with internal resistor divider set to 2.8 V. The FB pin is internally connected to this network and must be directly tied to the VOUT node - no external resistors are required or permitted. Adding external components to FB will disrupt regulation accuracy and stability.
What is the thermal performance of LM3671MFX-2.8/NOPB in USON-6 package?
In the USON-6 (NKH) package, LM3671MFX-2.8/NOPB has a junction-to-ambient thermal resistance (RθJA) of 174.7°C/W on a 4-layer PCB. At 600 mA output and 3.6 V input, typical power dissipation is ~180 mW, resulting in ~31°C junction rise above ambient - well within the –40°C to +125°C operating range. Thermal pad soldering is mandatory for rated performance.
Can LM3671MFX-2.8/NOPB operate from a 2.5 V input?
No. The absolute minimum input voltage for LM3671MFX-2.8/NOPB is 2.7 V per the Recommended Operating Conditions table. Operation below 2.7 V risks undervoltage lockout activation, unstable regulation, or failure to start. It is not rated for 2.5 V input - design must ensure VIN stays ≥2.7 V across battery discharge and line transients.
How does the automatic PFM-PWM transition work in LM3671MFX-2.8/NOPB?
The LM3671MFX-2.8/NOPB detects light-load conditions by monitoring inductor zero-crossing and peak switch current. When load drops below ~80 mA for ≥32 clock cycles, it transitions from fixed-frequency PWM to variable-frequency PFM mode - reducing quiescent current from ~500 µA to 16 µA. No external signal or configuration is needed; the transition is seamless and transparent to the system.
LM3671MFX-2.8/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):
- 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
LM3671MFX-2.8/NOPB FAQ
1.How can I place an order for LM3671MFX-2.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MFX-2.8/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 LM3671MFX-2.8/NOPB reliable?
The price and inventory of LM3671MFX-2.8/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3671MFX-2.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM3671MFX-2.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MFX-2.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MFX-2.8/NOPB?
LM3671MFX-2.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MFX-2.8/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 LM3671MFX-2.8/NOPB?
For technical support, including LM3671MFX-2.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MFX-2.8/NOPB requirements.
6.How does Aetrix verify that LM3671MFX-2.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3671MFX-2.8/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 LM3671MFX-2.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM3671MFX-2.8/NOPB?
All LM3671MFX-2.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MFX-2.8/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 LM3671MFX-2.8/NOPB part is unused and in its original packaging.
Return procedure for LM3671MFX-2.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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