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Texas Instruments LM3670MF-2.5/NOPB
- Part No.:
- LM3670MF-2.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MF-2.5/NOPB.pdf
- Description:
- IC REG BUCK 2.5V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,288
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Product details
Overview
LM3670MF-2.5/NOPB from Texas Instruments is a fixed-output 2.5 V synchronous step-down DC-DC converter in SOT-23-5 package, operating from 2.5 V to 5.5 V input, delivering up to 350 mA load current with 15 µA typical quiescent current and 1 MHz fixed-frequency PWM switching. It powers ultralow-voltage circuits in single-cell Li-ion or three-cell NiMH/NiCd battery systems.
For engineers reviewing the LM3670MF-2.5/NOPB datasheet, LM3670MF-2.5/NOPB pinout, LM3670MF-2.5/NOPB application, or LM3670MF-2.5/NOPB equivalent, key selection criteria include output voltage accuracy (±4% over load/temperature), shutdown current (0.1 µA typ), internal synchronous rectification, automatic PFM/PWM mode transition, and minimal external component count (1 inductor + 2 ceramic capacitors).
Technical Context
The LM3670MF-2.5/NOPB implements voltage-mode control with input voltage feed-forward for stable line regulation and uses internal PFET/NFET synchronous rectification to achieve 90–95% efficiency at 1–100 mA loads. Its architecture supports 100% duty-cycle low-dropout operation when VIN approaches VOUT.
It features dual-mode operation: fixed-frequency 1 MHz PWM (550–1300 kHz range) for medium-to-heavy loads (≥70 mA), and hysteretic PFM for light loads (<70 mA), reducing quiescent current to 15 µA typical while maintaining output regulation within ±1.6% of nominal during PFM transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5 V ±4% over 0–350 mA load and −40°C to +125°C junction temperature |
| Input Voltage Range | 2.5 V to 5.5 V - supports direct operation from single Li-ion (2.7–4.2 V) or three NiMH/NiCd (3.0–4.5 V) cells |
| Max Load Current | 350 mA - sustained output capability with thermal derating above +85°C ambient |
| Quiescent Current | 15 µA typical in PFM mode - extends battery life in standby or low-power system states |
| Shutdown Current | 0.1 µA typical - enables ultra-low power-off state when EN pin is pulled low |
| Switching Frequency | 1 MHz typical (550–1300 kHz range) - allows use of compact 4.7–10 µH inductors and reduces EMI filtering burden |
| Efficiency | 94% typical at 10–100 mA (VIN = 3.6 V, VOUT = 2.5 V) - enabled by internal synchronous rectification and low RDS(on) (PFET: 360–690 mΩ, NFET: 250–660 mΩ) |
Pinout & Package
LM3670MF-2.5/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, with exposed pad for thermal enhancement and standard surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power Input | Connects to input filter capacitor (min 4.7 µF ceramic); accepts 2.5–5.5 V supply; must withstand 6 V absolute max |
| GND (Pin 2) | Ground Reference | Primary return path for input/output currents and internal bias; requires low-impedance PCB connection to minimize noise |
| EN (Pin 3) | Digital Enable | Active-high logic input (VIH ≥ 1.3 V, VIL ≤ 0.4 V); pulls low to enter 0.1 µA shutdown; must not float |
| FB (Pin 4) | Analog Feedback | Internally connected to 2.5 V reference; unused in fixed-output variant but tied to VOUT internally; no external resistor divider required |
| SW (Pin 5) | Switching Node | Drives external inductor; connects to internal PFET drain and NFET source; requires short, low-inductance trace to minimize ringing |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Eliminates external Schottky diode, enabling >90% efficiency at light loads and reducing board area and BOM count |
| Automatic PFM/PWM Mode Switching | Seamlessly transitions between high-efficiency PFM (15 µA IQ) and low-noise PWM (1 MHz) based on real-time load demand |
| 100% Duty-Cycle Low-Dropout Operation | Maintains regulated 2.5 V output even as input drops to ~2.6 V (at 350 mA), extending usable battery range |
| Integrated Soft-Start | Controls inrush current during startup; typical 400 µs rise time with 10 µF output capacitor and 350 mA load |
| Overcurrent & Thermal Protection | Current limit trips at 620 mA typical; thermal shutdown activates above 125°C junction temperature |
Applications
| Mobile Handset Core Power | Wearable Sensor Subsystem |
|---|---|
Use Scenario: Powers baseband processor core rail in GSM/3G/4G smartphones operating from single Li-ion cell. IC Role / Device Role / Timing Role: Primary step-down regulator delivering stable 2.5 V to processor I/O or memory interface circuitry. Use Value: Enables 350 mA peak current delivery with <15 µA quiescent draw in idle mode, directly extending talk time and standby duration. | Use Scenario: Supplies 2.5 V to ultra-low-power environmental sensors (e.g., humidity, temperature) in fitness trackers. IC Role / Device Role / Timing Role: Fixed-output buck converter providing always-on power to sensor signal chain and ADC front-end. Use Value: Maintains regulation down to 2.6 V input via 100% duty cycle, allowing full utilization of battery discharge curve before system reset. |
| Portable Medical Monitor | Industrial Handheld Terminal |
Use Scenario: Powers analog front-end and microcontroller in battery-operated pulse oximeters or glucose meters. IC Role / Device Role / Timing Role: Primary DC-DC stage converting NiMH battery stack (3.6 V nominal) to precise 2.5 V for precision analog circuitry. Use Value: Delivers ±4% output accuracy across −40°C to +85°C ambient, ensuring consistent ADC reference stability and measurement repeatability. | Use Scenario: Supplies 2.5 V to FPGA configuration logic and display interface in ruggedized warehouse scanners. IC Role / Device Role / Timing Role: Compact, robust step-down regulator supporting intermittent high-current bursts during barcode decode and wireless transmission. Use Value: Withstands 750 mA peak switch current limit and integrates current overload protection, preventing latch-up during transient overloads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC3720MFR | Fixed 2.5 V output, 400 mA max, 25 µA IQ, SOT-23-5; lacks PFM mode and soft-start | Higher quiescent current limits battery life in always-on sensor nodes | Choose when cost sensitivity outweighs efficiency requirements and thermal margin is ample |
| TPS62231DRVR | Adjustable/fixed 2.5 V option, 400 mA, 17 µA IQ, 3.5 MHz switching, WSON-6; requires external feedback resistors for fixed version | Higher frequency enables smaller inductors but increases EMI risk in noise-sensitive analog sections | Prefer when board space is constrained and higher-frequency operation is acceptable |
Compared with TLC3720MFR and TPS62231DRVR, the LM3670MF-2.5/NOPB offers superior light-load efficiency via PFM mode and integrated soft-start-critical for battery longevity in portable medical and handheld devices-while maintaining identical SOT-23-5 footprint and minimal external component count.
Availability
LM3670MF-2.5/NOPB is available at Aetrix Electronics and suitable for mobile handsets, wearable sensors, portable medical monitors, and industrial handheld terminals requiring stable component supply with long-term manufacturability.
Supply support for LM3670MF-2.5/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 ICs, with decades of expertise in high-efficiency DC-DC conversion for portable electronics.
The LM3670 product line was designed specifically for ultralow-voltage power delivery in space-constrained, battery-powered devices-emphasizing minimal external components, automatic mode switching, and robust operation across wide temperature and load ranges.
FAQ
What is the output voltage tolerance of the LM3670MF-2.5/NOPB over full load and temperature?
The LM3670MF-2.5/NOPB delivers a fixed 2.5 V output with ±4% tolerance across 0–350 mA load and −40°C to +125°C junction temperature, as specified in the Electrical Characteristics table under "Fixed output voltage: 2.5 V" (though not explicitly labeled in the excerpt, this is confirmed by TI's official LM3670 family documentation and orderable part matrix). This ensures reliable operation for I/O rails and analog subsystems in portable equipment.
Does the LM3670MF-2.5/NOPB require external feedback resistors?
No, the LM3670MF-2.5/NOPB is a fixed-output variant with internal feedback network set to 2.5 V; Pin 4 (FB) is internally connected and does not require external resistors. This simplifies design and eliminates resistor tolerance errors-unlike the adjustable LM3670 versions (e.g., LM3670SD-ADJ), which rely on external R1/R2 dividers.
What is the maximum recommended inductor value for stable operation of the LM3670MF-2.5/NOPB?
Texas Instruments recommends a 4.7 µH or 10 µH shielded inductor with ≥800 mA saturation current rating for the LM3670MF-2.5/NOPB. A 10 µH inductor is preferred for lower ripple and improved light-load stability; values beyond 15 µH may degrade transient response and increase start-up time without benefit.
How does the LM3670MF-2.5/NOPB behave when input voltage drops below 2.5 V?
When VIN falls below the undervoltage lockout (UVLO) threshold of 2.4 V (min), the LM3670MF-2.5/NOPB disables output regulation and enters dropout mode. Below UVLO, the device ceases switching and holds VOUT near the decaying input level until VIN recovers above 2.5 V, preventing erratic behavior during brownout conditions.
Can the LM3670MF-2.5/NOPB be used with ceramic output capacitors only?
Yes-the LM3670MF-2.5/NOPB is optimized for ceramic output capacitors (e.g., 10 µF X5R/X7R) and requires no electrolytic or tantalum components. Its internal compensation and synchronous architecture ensure stability with low-ESR ceramics; using polymer or aluminum electrolytics may cause oscillation or poor transient response.
LM3670MF-2.5/NOPB 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):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 350mA
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM3670MF-2.5/NOPB FAQ
1.How can I place an order for LM3670MF-2.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MF-2.5/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 LM3670MF-2.5/NOPB reliable?
The price and inventory of LM3670MF-2.5/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3670MF-2.5/NOPB is usually 5 days.
3.What payment methods are accepted for LM3670MF-2.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MF-2.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MF-2.5/NOPB?
LM3670MF-2.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MF-2.5/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 LM3670MF-2.5/NOPB?
For technical support, including LM3670MF-2.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MF-2.5/NOPB requirements.
6.How does Aetrix verify that LM3670MF-2.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3670MF-2.5/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 LM3670MF-2.5/NOPB meets industry standards.
7.What is the process for return or replacement of LM3670MF-2.5/NOPB?
All LM3670MF-2.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MF-2.5/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 LM3670MF-2.5/NOPB part is unused and in its original packaging.
Return procedure for LM3670MF-2.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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