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Texas Instruments LM3671MFX-1.2/NOPB
- Part No.:
- LM3671MFX-1.2/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3671MFX-1.2/NOPB.pdf
- Description:
- IC REG BUCK 1.2V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM3671MFX-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 LM3671MFX-1.2/NOPB datasheet, LM3671MFX-1.2/NOPB pinout, LM3671MFX-1.2/NOPB application, or LM3671MFX-1.2/NOPB equivalent, key selection criteria 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 compatibility with only three external components: one 2.2 µH inductor and two ceramic capacitors.
Technical Context
The LM3671MFX-1.2/NOPB implements voltage-mode control with input-voltage feed-forward compensation to maintain stable regulation across 2.7–5.5 V input range. Its integrated PFET/NFET power stage enables synchronous rectification, eliminating external diode losses and supporting high efficiency at low output voltages like 1.2 V.
It features dual-mode operation: fixed 2 MHz PWM for load currents ≥80 mA ensures low-noise, predictable transient response; hysteretic PFM engages at lighter loads to reduce quiescent current to 16 µA (typ) while maintaining regulation within ±0.6–1.7% of nominal output. Soft-start limits inrush current 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% (FB pin internally connected to 0.5 V reference; no external divider required) |
| Max output current | 600 mA continuous - supports processor cores, RF ICs, and memory subsystems in space-constrained portable designs |
| Input voltage range | 2.7 V to 5.5 V - compatible with single Li-Ion (2.7–4.2 V) and regulated 3.3 V/5 V rails |
| Switching frequency | 2 MHz (typ), 1.6–2.6 MHz (min/max over temp) - enables use of tiny 2.2 µH inductors and 10 µF ceramic output capacitors |
| Quiescent current | 16 µA (typ) in PFM mode - extends battery runtime during standby/sleep states in always-on peripherals |
| Shutdown current | 0.01 µA (typ) - eliminates battery drain when system is fully powered down |
| RDS(ON) (PFET/NFET) | 380 mΩ / 250 mΩ at VIN = 3.6 V - minimizes conduction loss and improves full-load efficiency (>90% typical at 3.6 VIN/1.2 VOUT/300 mA) |
Pinout & Package
LM3671MFX-1.2/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 "MFX" and date code.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Connects to input filter capacitor (4.7 µF ceramic); must be ≥2.7 V for startup; supplies internal bias and power switches |
| GND (Pin 2) | Power ground | Primary return path for input capacitor, inductor, and internal FETs; requires low-impedance PCB connection to thermal pad |
| EN (Pin 3) | Digital enable | Active-high logic input; device enabled at VEN ≥ 1 V, disabled at VEN ≤ 0.4 V; must not float - tie to VIN or controller GPIO |
| FB (Pin 4) | Feedback input | Internally connected to 0.5 V reference for fixed 1.2 V output; no external resistor network required; connects directly to VOUT |
| SW (Pin 5) | Switching node | Drives external 2.2 µH inductor; carries high di/dt pulsed current; requires short, low-inductance trace to minimize EMI and voltage spikes |
| SGND (Pin 6) | Signal ground | Separate analog ground for FB pin; must connect to main GND plane under thermal pad to avoid noise coupling into feedback path |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode, reducing BOM count and improving efficiency by 8–12% at 1.2 V/300 mA vs. asynchronous design |
| Automatic PFM-PWM mode switching | Seamlessly transitions at ~80 mA load without external control; maintains regulation while optimizing IQ across full load range |
| Integrated soft-start | Staged current-limit ramp prevents input capacitor inrush; achieves 275–400 µs startup time depending on COUT and load |
| Thermal and overload protection | Thermal shutdown activates at TJ = 150°C (typ); cycle-by-cycle current limit trips at 1020 mA (typ) to protect FETs and inductor |
| Ultra-low shutdown current | 0.01 µA (typ) - reduces annual battery self-discharge to <0.1% in long-term storage applications |
Applications
| Mobile Phone Core Power | Wireless Audio SoC Supply |
|---|---|
|
Use Scenario: Powers ARM Cortex-A series application processor core rail requiring stable 1.2 V at up to 500 mA peak current during burst processing. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated core voltage; operates in PWM mode during active CPU cycles and transitions to PFM during idle periods. Use Value: Enables >90% efficiency at 3.6 VIN/1.2 VOUT/300 mA while maintaining <±15 mV load regulation - critical for preventing processor brownouts and thermal throttling. |
Use Scenario: Supplies 1.2 V to Bluetooth/Wi-Fi combo chip baseband and RF sections in compact earbuds and wearables. IC Role / Device Role / Timing Role: System-level power management IC providing clean, low-noise supply; leverages 2 MHz switching to avoid interference with 2.4 GHz ISM band. Use Value: Delivers 16 µA quiescent current in PFM mode - extends battery life by 30+ hours in standby versus non-synchronous alternatives. |
| Digital Still Camera Sensor Bias | Automotive Infotainment Display Logic |
|
Use Scenario: Generates 1.2 V for CMOS image sensor digital logic and interface circuitry in compact point-and-shoot cameras. IC Role / Device Role / Timing Role: Fixed-output DC-DC converter with fast transient response; handles rapid load steps from sensor readout bursts. Use Value: Achieves <10 µs recovery time from 50 mA → 300 mA load step - prevents image corruption due to supply droop during frame capture. |
Use Scenario: Provides 1.2 V logic supply for display controller ASICs in automotive-grade head units operating from 12 V battery via intermediate 3.3 V rail. IC Role / Device Role / Timing Role: Secondary buck stage downstream of primary regulator; qualified per AEC-Q100 Grade 1 (−40°C to +125°C ambient). Use Value: Maintains ±4% output accuracy over full temperature range and input ripple - ensures reliable HDMI/LVDS interface timing margins. |
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 MHz switching, 17 µA IQ, WSON-6 (2.0 × 2.0 mm) | Higher switching frequency allows smaller inductor (1.0 µH); lacks PFM mode - higher light-load IQ (25 µA) | Preferred where board area is constrained and light-load efficiency is secondary to size reduction |
| AP63202WU-7 | Fixed 1.2 V, 2 A, 2.2 MHz, 22 µA IQ, TSOT23-6 (2.9 × 1.6 mm) | Higher current rating and larger SOT-23 footprint; no integrated soft-start; requires external compensation | Selected when future-proofing for higher-current derivatives or when thermal margin demands larger package |
Compared with LM3671MFX-1.2/NOPB, TPS62231DRYR offers smaller magnetics but sacrifices light-load efficiency, while AP63202WU-7 trades compact USON packaging for higher current headroom and less integrated feature set - making LM3671MFX-1.2/NOPB optimal for cost-sensitive, battery-limited 600 mA applications demanding minimal external components and ultra-low standby current.
Availability
LM3671MFX-1.2/NOPB is available at Aetrix Electronics and suitable for mobile phones, wireless audio devices, and digital still cameras requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3671MFX-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 company headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and silicon technologies for industrial, automotive, and consumer markets.
The LM3671 product line delivers highly integrated, low-quiescent-current DC-DC converters targeting battery-powered portable electronics - emphasizing minimal external component count, small footprint, and intelligent power management across load conditions.
FAQ
What is the recommended input capacitor for LM3671MFX-1.2/NOPB?
The LM3671MFX-1.2/NOPB datasheet specifies a 4.7 µF X5R/X7R ceramic capacitor placed as close as possible to the VIN and GND pins. This value provides sufficient charge reservoir for the 2 MHz switching frequency and limits input voltage ripple to <50 mV peak-to-peak under 600 mA load transients. Larger values (e.g., 10 µF) may improve hold-up time but are not required for basic operation of LM3671MFX-1.2/NOPB.
Does LM3671MFX-1.2/NOPB require an external feedback resistor network?
No. The LM3671MFX-1.2/NOPB is a fixed-output variant with internal resistor divider connected to its 0.5 V reference, so the FB pin is internally tied to generate precisely 1.2 V output. External resistors are unnecessary and must not be added - doing so would disrupt regulation and potentially damage the FB comparator inside LM3671MFX-1.2/NOPB.
What thermal considerations apply to LM3671MFX-1.2/NOPB in USON-6 package?
The LM3671MFX-1.2/NOPB in USON-6 (NKH) has RθJA = 174.7°C/W on a 4-layer board. To maintain TJ ≤125°C at 600 mA, ambient temperature must stay ≤65°C with proper thermal pad soldering and 2+ thermal vias to inner ground planes. Derating is required above 60°C ambient - e.g., max load drops to ~400 mA at 85°C ambient per dissipation ratings in LM3671MFX-1.2/NOPB datasheet.
Can LM3671MFX-1.2/NOPB operate from a 2.5 V input source?
No. The LM3671MFX-1.2/NOPB has a minimum recommended input voltage of 2.7 V per datasheet Section 6.4. Operation below 2.7 V risks undervoltage lockout activation, unstable regulation, or failure to start. For 2.5 V input systems, consider TI's TPS62865 or alternative buck regulators rated down to 2.0 V - LM3671MFX-1.2/NOPB is not specified for reliable function at 2.5 V.
How does the soft-start function behave during repeated enable/disable cycles of LM3671MFX-1.2/NOPB?
The LM3671MFX-1.2/NOPB initiates soft-start only on the first rising edge of EN after VIN reaches ≥2.7 V. Subsequent toggles of EN (e.g., rapid on/off cycling) do not re-trigger soft-start - the device resumes regulation immediately using existing output capacitor charge. This behavior prevents unnecessary delay in dynamic power sequencing scenarios involving LM3671MFX-1.2/NOPB.
LM3671MFX-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
LM3671MFX-1.2/NOPB FAQ
1.How can I place an order for LM3671MFX-1.2/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671MFX-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 LM3671MFX-1.2/NOPB reliable?
The price and inventory of LM3671MFX-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 LM3671MFX-1.2/NOPB is usually 5 days.
3.What payment methods are accepted for LM3671MFX-1.2/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671MFX-1.2/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671MFX-1.2/NOPB?
LM3671MFX-1.2/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671MFX-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 LM3671MFX-1.2/NOPB?
For technical support, including LM3671MFX-1.2/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671MFX-1.2/NOPB requirements.
6.How does Aetrix verify that LM3671MFX-1.2/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3671MFX-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 LM3671MFX-1.2/NOPB meets industry standards.
7.What is the process for return or replacement of LM3671MFX-1.2/NOPB?
All LM3671MFX-1.2/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3671MFX-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 LM3671MFX-1.2/NOPB part is unused and in its original packaging.
Return procedure for LM3671MFX-1.2/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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