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Texas Instruments LM3671MF-1.2/NOPB
- Part No.:
- LM3671MF-1.2/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MF-1.2/NOPB.pdf
- Description:
- IC REG BUCK 1.2V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:12,693
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Product details
Overview
LM3671MF-1.2/NOPB from Texas Instruments is a fixed-output 1.2 V, 600-mA synchronous step-down DC-DC converter optimized for single Li-Ion battery-powered portable electronics. It operates from 2.7 V to 5.5 V input, delivers 2 MHz fixed-frequency PWM switching with automatic PFM mode transition below ~80 mA load, and achieves 16 µA typical quiescent current in light-load operation - enabling extended battery life in mobile phones and handheld instruments.
For engineers reviewing the LM3671MF-1.2/NOPB datasheet, LM3671MF-1.2/NOPB pinout, LM3671MF-1.2/NOPB application, or LM3671MF-1.2/NOPB equivalent, key selection considerations include its USON-6 package footprint, internal 0.5 V reference with ±4% feedback voltage tolerance, 380 mΩ PFET/250 mΩ NFET RDS(on), thermal shutdown at 150°C (typ), and requirement for only three external components: one 2.2 µH inductor and two ceramic capacitors.
Technical Context
The LM3671MF-1.2/NOPB implements voltage-mode control with input feed-forward compensation to maintain stable regulation across 2.7–5.5 V input and 1.2 V output. Its integrated PFET/NFET synchronous rectifier eliminates external diode losses, while the 2 MHz oscillator enables compact 2.2 µH inductor and low-ESR ceramic capacitor usage.
Functional mode transitions are fully autonomous: PWM mode dominates above ~80 mA load for low-noise, constant-frequency operation; PFM mode engages below that threshold to reduce quiescent current to 16 µA (typ) and extend runtime; shutdown mode draws just 0.01 µA (typ) when EN < 0.4 V. Soft-start limits inrush via stepped current-limit ramp (70 → 140 → 280 → 1020 mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.2 V ±4% over −40°C to +125°C - ensures stable core voltage for low-power microcontrollers and sensors. |
| Max Output Current | 600 mA continuous - supports moderate-power RF modules and display drivers without external heatsinking. |
| 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 regulated 3.3 V/5 V rails. |
| Switching Frequency | 2 MHz (typ), 1.6–2.6 MHz (min/max) - enables use of sub-3 mm × 3 mm inductors and reduces EMI filtering complexity. |
| Quiescent Current | 16 µA (typ) in PFM mode - extends battery life in standby/sleep states of portable medical and IoT devices. |
| Shutdown Current | 0.01 µA (typ) - minimizes leakage drain during long-term storage or system hibernation. |
| RDS(on) (PFET/NFET) | 380 mΩ / 250 mΩ at VIN = 3.6 V - enables >90% peak efficiency at mid-load with minimal thermal rise in USON-6 package. |
Pinout & Package
LM3671MF-1.2/NOPB uses the 6-pin USON (NKH) package: 2.00 mm × 2.00 mm body, 0.5 mm pitch, wettable flank terminals. Thermal resistance RθJA = 174.7°C/W on 4-layer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Connects to input filter capacitor; accepts 2.7–5.5 V; must be ≥2.7 V before enabling to avoid UVLO lockout. |
| GND | Power ground | Primary return path for input/output currents; requires low-inductance connection to minimize switching noise. |
| EN | Digital enable | Active-high logic input; device enabled when >1 V, disabled when <0.4 V; must not float - tie to VIN or controller GPIO. |
| FB | Feedback input | Internally connected to fixed 1.2 V divider; shorted directly to VOUT - no external resistors required for this variant. |
| SW | Switching node | Drives external inductor; carries high di/dt PWM current - requires tight layout with minimal trace length and ground pour. |
| SGND | Signal ground | Separate feedback ground pin; must connect to GND near FB pin to prevent sensing error from power-ground IR drop. |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode, reducing conduction loss by >30% vs asynchronous buck at 1.2 V output. |
| Auto PFM-PWM mode switching | Seamlessly transitions between 2 MHz PWM (low-noise) and variable-frequency PFM (ultra-low IQ) based on real-time load demand. |
| Integrated soft-start | Staged current-limit ramp prevents input rail collapse during startup into large output capacitance (e.g., 10 µF). |
| Thermal & overload protection | Thermal shutdown triggers at 150°C (typ); cycle-by-cycle current limit trips at 1020 mA (typ) to protect switch FETs and inductor. |
| Minimal BOM requirement | Only three external passive components needed: 2.2 µH shielded inductor, 4.7 µF input ceramic, 10 µF output ceramic. |
Applications
| Mobile Phone Power Rail | Portable Medical Sensor Node |
|---|---|
|
Use Scenario: Supplying 1.2 V core voltage to an ARM Cortex-M4 MCU and BLE radio transceiver in a compact smartphone subassembly. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated 1.2 V at up to 600 mA with 2 MHz switching to minimize size and EMI impact on RF sections. Use Value: Enables use of tiny 2.2 µH inductor and 0402/0603 ceramic caps, reducing total solution area to <12 mm² while maintaining >92% efficiency at 300 mA. |
Use Scenario: Powering ultra-low-power ECG front-end ASIC and flash memory in a disposable wearable patch monitor. IC Role / Device Role / Timing Role: Efficient 1.2 V supply with 16 µA PFM quiescent current and 0.01 µA shutdown, synchronized to sensor sampling intervals. Use Value: Extends single CR2032 battery life from 7 to >14 days in active monitoring mode by minimizing idle current and eliminating external diode loss. |
| Digital Still Camera Image Processor | Handheld Transaction Terminal |
|
Use Scenario: Providing clean 1.2 V core power to a 12-bit image signal processor during burst capture sequences. IC Role / Device Role / Timing Role: High-transient-response buck converter with automatic PFM→PWM mode switching to handle rapid load steps from 1 mA to 500 mA. Use Value: Maintains output voltage within ±30 mV during 100 mA/µs load transients due to fast control loop and synchronous rectification. |
Use Scenario: Generating 1.2 V for secure element and contactless smartcard interface IC in a PCI-compliant payment terminal. IC Role / Device Role / Timing Role: Safety-enhanced DC-DC supply with thermal shutdown and current limiting, operating from 3.3 V main rail derived from USB-C PD. Use Value: Meets IEC 62368-1 thermal limits under sustained 450 mA load without derating, thanks to USON-6 package's 174.7°C/W RθJA. |
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 1.2 V, 600 mA, 3–6 MHz adjustable frequency, 17 µA IQ, SOT-23-5 package (2.9 × 1.6 mm). | Higher switching frequency allows smaller inductor but increases EMI sensitivity; lacks SGND pin for precision feedback. | Prefer when board space permits larger package and design prioritizes frequency flexibility over feedback accuracy. |
| AP63202WU-7 | Fixed 1.2 V, 2 A, 2 MHz, 25 µA IQ, WLCSP-6 package (1.5 × 1.5 mm), no SGND pin. | Higher current rating and smaller footprint, but wider output tolerance (±5%) and no dedicated signal ground improves noise immunity. | Prefer for cost-sensitive, higher-current applications where 1.2 V ±5% is acceptable and layout constraints favor WLCSP. |
Compared with TPS62231DRYR and AP63202WU-7, LM3671MF-1.2/NOPB offers superior feedback accuracy via dedicated SGND and tighter ±4% output tolerance - critical for noise-sensitive analog subsystems - while maintaining identical 600 mA capability and 2 MHz operation in the smallest USON-6 footprint.
Availability
LM3671MF-1.2/NOPB is available at Aetrix Electronics and suitable for mobile phones, portable medical equipment, and digital still cameras requiring stable component supply, consistent parametric performance, and long-term production continuity.
Supply support for LM3671MF-1.2/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 connectivity technologies, with decades of expertise in power management ICs for portable and industrial systems.
The LM3671 product line was designed specifically for space-constrained, battery-powered portable electronics requiring high-efficiency, low-quiescent-current DC-DC conversion with minimal external components - targeting mobile communications, handheld instrumentation, and wearable devices.
FAQ
What is the recommended input capacitor for LM3671MF-1.2/NOPB?
The LM3671MF-1.2/NOPB datasheet specifies a 4.7 µF ceramic input capacitor (CIN) placed close to the VIN and GND pins. This value provides sufficient high-frequency decoupling for the 2 MHz switching frequency and limits input ripple to <50 mV under 600 mA load. X5R or X7R dielectrics in 0603 or 0805 case sizes are recommended for stable capacitance across temperature and bias.
Does LM3671MF-1.2/NOPB require external feedback resistors?
No. The LM3671MF-1.2/NOPB is the fixed-output 1.2 V variant - its internal resistor divider connects directly to the FB pin, so no external resistors are needed. The FB pin must be connected directly to the output capacitor's VOUT node. Using external resistors would disrupt regulation and is not supported for this part number.
What is the thermal shutdown behavior of LM3671MF-1.2/NOPB?
The LM3671MF-1.2/NOPB activates thermal shutdown at approximately 150°C junction temperature (typical) and resumes operation once the junction cools to ~130°C. During shutdown, the device halts switching and draws only 0.01 µA. This protection is internal and does not require external circuitry - it safeguards against sustained overload or poor PCB thermal design.
Can LM3671MF-1.2/NOPB operate from a 2.5 V input?
No. The absolute minimum input voltage for LM3671MF-1.2/NOPB is 2.7 V per the Recommended Operating Conditions table. At 2.5 V, the device enters undervoltage lockout (UVLO) and remains disabled even if EN is high. Stable operation requires VIN ≥2.7 V; for 2.5 V input systems, a different regulator such as the TPS62740 (1.8–5.5 V input) must be selected.
What is the purpose of the SGND pin on LM3671MF-1.2/NOPB?
The SGND (signal ground) pin on LM3671MF-1.2/NOPB provides a dedicated low-noise return path for the feedback amplifier, isolating it from high-current power ground paths. It must be connected to the main GND plane at a single point near the FB pin - not at the power inductor or output capacitor - to prevent IR drop from corrupting the 0.5 V internal reference sensing and ensure ±4% output accuracy.
LM3671MF-1.2/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):
- 1.2V
- 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-1.2/NOPB FAQ
1.How can I place an order for LM3671MF-1.2/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MF-1.2/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-1.2/NOPB reliable?
The price and inventory of LM3671MF-1.2/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-1.2/NOPB is usually 5 days.
3.What payment methods are accepted for LM3671MF-1.2/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MF-1.2/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MF-1.2/NOPB?
LM3671MF-1.2/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MF-1.2/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-1.2/NOPB?
For technical support, including LM3671MF-1.2/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MF-1.2/NOPB requirements.
6.How does Aetrix verify that LM3671MF-1.2/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3671MF-1.2/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-1.2/NOPB meets industry standards.
7.What is the process for return or replacement of LM3671MF-1.2/NOPB?
All LM3671MF-1.2/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MF-1.2/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-1.2/NOPB part is unused and in its original packaging.
Return procedure for LM3671MF-1.2/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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