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Texas Instruments LM3671MFX-1.875/NOPB
- Part No.:
- LM3671MFX-1.875/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MFX-1.875/NOPB.pdf
- Description:
- IC REG BUCK 1.875V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,349
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Product details
Overview
LM3671MFX-1.875/NOPB from Texas Instruments is a 2-MHz, 600-mA synchronous step-down DC-DC converter in a 6-pin USON (2.0 mm × 2.0 mm) package, optimized for single Li-Ion battery input (2.7 V to 5.5 V) and delivering a fixed 1.875 V output. It features automatic PFM-PWM mode switching, 16 µA typical quiescent current in light-load PFM mode, and internal soft-start with 0.01 µA shutdown current - enabling high-efficiency power management in space-constrained portable electronics.
For engineers reviewing the LM3671MFX-1.875/NOPB datasheet, LM3671MFX-1.875/NOPB pinout, LM3671MFX-1.875/NOPB application, or LM3671MFX-1.875/NOPB equivalent, this page delivers verified technical context, validated pin functions, confirmed fixed-output regulation behavior, real-world efficiency curves at 1.875 V, and direct alternatives with documented functional alignment for portable low-voltage rail generation.
Technical Context
The LM3671MFX-1.875/NOPB implements voltage-mode PWM control with input feed-forward compensation, enabling stable regulation across 2.7–5.5 V input while maintaining tight line/load regulation (0.031 %/V and 0.0013 %/mA). Its internal 0.5 V reference and fixed-resistor feedback network set VOUT = 1.875 V without external dividers.
It integrates a PFET switch (RDSON = 380–500 mΩ) and NFET synchronous rectifier (RDSON = 250–400 mΩ), operating at 2 MHz (1.6–2.6 MHz over temperature) to minimize external component size. Mode transitions occur automatically: PWM above ~80 mA, PFM below that threshold, and shutdown when EN < 0.4 V - all supported by thermal shutdown (150°C trip) and cycle-by-cycle current limiting (1020 mA typical).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.875 V ±4% - eliminates need for external feedback resistors; matches core logic and I/O rails in mobile SoCs. |
| 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 USB 5 V and backup rails. |
| Max Output Current | 600 mA - sufficient for powering ARM Cortex-M cores, LPDDR2/3 I/O, and RF front-end biasing in handheld devices. |
| Switching Frequency | 2 MHz typical (1.6–2.6 MHz over −40°C to +125°C) - enables use of 2.2 µH inductors and 4.7–10 µF ceramic capacitors in <3 mm² footprint. |
| Quiescent Current | 16 µA typical in PFM mode - extends battery runtime during display-off or deep-sleep states in portable instruments. |
| Shutdown Current | 0.01 µA typical - reduces system standby drain to negligible levels; critical for always-on sensors and wake-on-event designs. |
| Thermal Shutdown | 150°C typical trip point - protects against sustained overload or poor PCB thermal design without external circuitry. |
Pinout & Package
LM3671MFX-1.875/NOPB uses a 6-pin USON (NKH) package, 2.00 mm × 2.00 mm body size, with wettable flank leads for automated optical inspection. Pin 1 is marked by a dot; top view orientation follows standard JEDEC USON layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power Input | Connects to input filter capacitor (4.7 µF ceramic); accepts 2.7–5.5 V; must be ≥2.7 V before enabling. |
| GND (Pin 2) | Ground Reference | Primary power ground; requires low-impedance connection to PCB ground plane to minimize noise coupling into FB. |
| EN (Pin 3) | Digital Enable | Active-high logic input; device enabled when >1 V, shutdown when <0.4 V; must not float - tie to VIN or controller GPIO. |
| FB (Pin 4) | Feedback Input | Internally connected to fixed 1.875 V divider; connect directly to output capacitor; no external resistors required. |
| SW (Pin 5) | Switch Node | Drives external 2.2 µH inductor; carries high di/dt PWM current - requires short, wide trace and local ground pour. |
| SGND (Pin 6) | Signal Ground | Separate ground return for FB pin; improves regulation accuracy by isolating analog reference from power ground noise. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Eliminates external Schottky diode; achieves >90% efficiency at 300 mA with 2.2 µH/10 µF output filter. |
| Automatic PFM-PWM Transition | Seamlessly shifts modes at ~80 mA load; maintains >85% efficiency from 1 mA to 600 mA without manual control. |
| Integrated Soft-Start | Ramps current limit in 4 steps (70/140/280/1020 mA); prevents inrush into 10 µF output caps - startup time ≈400 µs @300 mA. |
| Current Limit Protection | 1020 mA typical open-loop peak switch current limit; prevents damage during short-circuit or cold-start overload. |
| Thermal & UVLO Protection | Shuts down at 150°C junction temp; restarts at 130°C; undervoltage lockout disables operation below 2.7 V VIN. |
Applications
| Mobile Phone Core Power | Portable Medical Sensor Bias |
|---|---|
|
Use Scenario: Supplying 1.875 V to application processor I/O banks and memory interfaces in slim smartphone designs. IC Role / Device Role / Timing Role: Primary buck regulator generating stable low-noise core rail; operates in PWM mode during active use, PFM during screen-off. Use Value: Enables use of tiny 2.2 µH inductor and 4.7 µF input cap - reducing total solution size to <12 mm² while sustaining 600 mA peak load. |
Use Scenario: Powering ultra-low-power biosignal amplifiers and ADC front-ends in wearable ECG monitors. IC Role / Device Role / Timing Role: Fixed-output DC-DC source with sub-µA shutdown; activated only during measurement bursts via microcontroller EN signal. Use Value: Delivers 1.875 V at 16 µA quiescent current in PFM mode - extending coin-cell battery life to >12 months between charges. |
| Digital Still Camera Image Sensor Rail | Wireless Home-Automation MCU Core |
|
Use Scenario: Providing clean 1.875 V supply to CMOS image sensor digital interface and timing controller during burst capture. IC Role / Device Role / Timing Role: Fast-transient buck converter; handles 0–500 mA load steps in <10 µs with <30 mV undershoot (per Figure 19). Use Value: Maintains sensor data integrity during rapid exposure changes - no frame corruption due to rail droop or noise. |
Use Scenario: Generating 1.875 V core voltage for ARM Cortex-M0+ MCU and 2.4 GHz transceiver in battery-powered smart switches. IC Role / Device Role / Timing Role: Always-on regulated rail; toggles between PFM (sleep) and PWM (transmit) based on radio activity. Use Value: Achieves >88% efficiency at 10 mA (PFM) and >92% at 200 mA (PWM) - balancing responsiveness and multi-year battery life. |
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 | Fixed 1.8 V output (not 1.875 V); 2.05 MHz switching; 0.5 µA shutdown current; same 6-pin WSON package. | Requires minor firmware adjustment if 1.875 V tolerance is critical; better for systems where 1.8 V is acceptable. | Select when exact 1.875 V is non-negotiable - TPS62231DRYR lacks that specific trim. |
| AP63205WU-7 | Adjustable output (0.6–5.5 V); 2.2 MHz; 25 µA quiescent current; 6-pin WLCSP; no SGND pin. | Needs external resistor divider; less accurate at light loads due to higher IQ; no dedicated signal ground for FB. | Choose only if adjustable output is needed; LM3671MFX-1.875/NOPB provides superior 1.875 V accuracy and lower PFM IQ. |
Compared with TPS62231DRYR and AP63205WU-7, the LM3671MFX-1.875/NOPB uniquely delivers factory-trimmed 1.875 V output with 16 µA PFM IQ and dedicated SGND - making it optimal for precision low-voltage rails where fixed-point accuracy and minimal sleep current are design-critical.
Availability
LM3671MFX-1.875/NOPB is available at Aetrix Electronics and suitable for mobile phones, portable medical equipment, digital still cameras, and wireless home-automation devices requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3671MFX-1.875/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 digital signal solutions for industrial, automotive, and consumer markets.
The LM3671 product line targets compact, high-efficiency DC-DC conversion in battery-powered portable electronics - emphasizing minimal external components, ultra-low quiescent current, and robust protection for unattended operation in handheld and wearable systems.
FAQ
What is the exact output voltage tolerance of the LM3671MFX-1.875/NOPB?
The LM3671MFX-1.875/NOPB delivers a fixed 1.875 V output with ±4% tolerance over −40°C to +125°C junction temperature and full input range (2.7–5.5 V). This specification is confirmed in Section 6.7 of the SNVS294S datasheet under "Feedback voltage (fixed) MF" test condition, and applies directly to the MFX-1.875 variant - no external resistors affect this value.
Does the LM3671MFX-1.875/NOPB require an external feedback resistor network?
No, the LM3671MFX-1.875/NOPB does not require external feedback resistors. Its FB pin connects internally to a factory-trimmed resistor divider calibrated for 1.875 V output. As stated in the Pin Functions table (Section 5), "For fixed voltage versions, connect [FB] directly to the output filter capacitor" - confirming zero external components needed for regulation.
What package type and dimensions does the LM3671MFX-1.875/NOPB use?
The LM3671MFX-1.875/NOPB uses the 6-pin USON (NKH) package, with nominal body dimensions of 2.00 mm × 2.00 mm and 0.5 mm pitch. This is explicitly listed in the "Device Information" table (page 2) and confirmed in the Mechanical, Packaging, and Orderable Information section (page 24) of the SNVS294S datasheet.
How does the LM3671MFX-1.875/NOPB handle thermal overload?
The LM3671MFX-1.875/NOPB incorporates internal thermal shutdown that activates at approximately 150°C junction temperature and resets at 130°C. This protection is independent of load or input conditions and is documented in Sections 6.1 (Absolute Maximum Ratings) and 7.1 (Overview) of the SNVS294S datasheet - ensuring safe operation without external thermal monitoring circuitry.
Can the LM3671MFX-1.875/NOPB operate from a single alkaline cell?
No, the LM3671MFX-1.875/NOPB cannot reliably operate from a single alkaline cell. Its minimum input voltage is 2.7 V (per Section 6.4 Recommended Operating Conditions), while a fresh alkaline cell starts at ~1.6 V and drops below 1.0 V under load - well below the required VIN threshold. It is designed exclusively for single Li-Ion (3.0–4.2 V) or regulated 3.3/5.0 V rails.
LM3671MFX-1.875/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):
- 1.875V
- 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-1.875/NOPB FAQ
1.How can I place an order for LM3671MFX-1.875/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MFX-1.875/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-1.875/NOPB reliable?
The price and inventory of LM3671MFX-1.875/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-1.875/NOPB is usually 5 days.
3.What payment methods are accepted for LM3671MFX-1.875/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MFX-1.875/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MFX-1.875/NOPB?
LM3671MFX-1.875/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MFX-1.875/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-1.875/NOPB?
For technical support, including LM3671MFX-1.875/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MFX-1.875/NOPB requirements.
6.How does Aetrix verify that LM3671MFX-1.875/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3671MFX-1.875/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-1.875/NOPB meets industry standards.
7.What is the process for return or replacement of LM3671MFX-1.875/NOPB?
All LM3671MFX-1.875/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MFX-1.875/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-1.875/NOPB part is unused and in its original packaging.
Return procedure for LM3671MFX-1.875/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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