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Texas Instruments LM3670MF-3.3/NOPB
- Part No.:
- LM3670MF-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MF-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,222
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Product details
Overview
LM3670MF-3.3/NOPB from Texas Instruments is a fixed-output 3.3 V synchronous step-down DC-DC converter optimized for ultralow-voltage portable systems. It operates from 2.5 V to 5.5 V input, delivers up to 350 mA load current, features 1-MHz fixed-frequency PWM switching with automatic PFM mode transition, and requires only three external components: one inductor and two ceramic capacitors. It powers core logic rails in battery-powered handheld devices.
For engineers reviewing the LM3670MF-3.3/NOPB datasheet, LM3670MF-3.3/NOPB pinout, LM3670MF-3.3/NOPB application, or LM3670MF-3.3/NOPB equivalent, key selection criteria include its 3.3 V fixed output, 15 µA quiescent current in PFM mode, internal synchronous rectification, 100% duty-cycle low-dropout capability, and SOT-23-5 package compatibility with space-constrained mobile designs.
Technical Context
The LM3670MF-3.3/NOPB implements voltage-mode control with input voltage feed-forward to maintain stable regulation across line and load variations. Its dual-mode operation-PWM at ≥70 mA and hysteretic PFM below-enables high efficiency (94% typical at 10–100 mA) while minimizing quiescent current during standby.
Internal synchronous rectification replaces the external Schottky diode, reducing conduction loss and improving light-load efficiency. The device integrates soft-start (400 µs typical), undervoltage lockout (2.4 V), thermal shutdown, and cycle-by-cycle current limiting (750 mA peak switch limit), all within a single 5-pin SOT-23 package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±6% over 0–350 mA load and 3.6–5.5 V input; supports direct replacement of LDOs in 3.3 V rail generation. |
| Input Voltage Range | 2.5 V to 5.5 V; compatible with single Li-Ion (2.7–4.2 V) or three-cell NiMH/NiCd (3.0–4.5 V) batteries without external regulators. |
| Max Load Current | 350 mA continuous; sufficient for powering microcontrollers, RF transceivers, and sensor interfaces in compact portable systems. |
| Quiescent Current | 15 µA typical in PFM mode; extends battery life during system sleep or low-activity states. |
| Shutdown Current | 0.1 µA typical; enables deep power-down when EN is pulled low, critical for zero-leakage system-level power gating. |
| Switching Frequency | 1 MHz typical (550–1300 kHz range); allows use of small 4.7–10 µH inductors and reduces EMI filtering burden. |
| Efficiency | 94% typical at 10–100 mA, 90% at 350 mA (VIN = 3.6 V, VOUT = 3.3 V); exceeds standard buck converters due to internal synchronous FETs. |
| Duty Cycle Range | 0–100%; enables dropout operation down to VIN = VOUT + ILOAD × (RDSON_P + RINDUCTOR), supporting brownout resilience. |
Pinout & Package
The LM3670MF-3.3/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for high-density PCB layouts in handheld electronics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Accepts 2.5–5.5 V supply; must be decoupled with ≥4.7 µF ceramic capacitor close to pin to suppress switching noise and support peak PFET current. |
| GND (Pin 2) | Ground reference | Primary return path for PFET, NFET, and control circuitry; requires low-impedance connection to power plane to minimize voltage bounce during switching transitions. |
| EN (Pin 3) | Digital enable | Active-high logic input (VIH ≥1.3 V, VIL ≤0.4 V); pulling low disables regulator and reduces total current to 0.1 µA, enabling system-level power sequencing. |
| FB (Pin 4) | Feedback node | Internally connected to 3.3 V reference; not externally adjustable-pin must be tied directly to VOUT for fixed-output operation per datasheet configuration. |
| SW (Pin 5) | Switching node | Connects to inductor; carries high di/dt square-wave current (0–750 mA peak); requires short, wide trace and ground pour clearance to minimize EMI and parasitic ringing. |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode, reducing BOM count and conduction losses-enables >90% efficiency from 1 mA to full 350 mA load. |
| Automatic PWM/PFM mode switching | Seamlessly transitions between 1-MHz PWM (≥70 mA) and variable-frequency PFM (<70 mA), maintaining >85% efficiency down to 100 µA load current. |
| 100% duty-cycle low-dropout operation | Allows VOUT regulation even when VIN drops to VOUT + ILOAD × (RDSON_P + RINDUCTOR), extending usable battery life in deep discharge conditions. |
| Integrated soft-start | 400 µs typical startup time with 10 µF output capacitor; limits inrush current to <620 mA, preventing input rail collapse during power-up. |
| Thermal and current protection | Includes cycle-by-cycle current limiting (750 mA peak) and thermal shutdown-ensures robustness under overload, short-circuit, or high-ambient conditions. |
| Ultra-low shutdown current | 0.1 µA typical-meets stringent system-level standby requirements for always-on sensors and real-time clocks. |
Applications
| Mobile Phone Baseband Power | Wearable Sensor Hub Supply |
|---|---|
Use Scenario: Powers ARM Cortex-M based baseband processor and memory subsystem from a single Li-Ion cell in slim smartphone designs. IC Role / Device Role / Timing Role: Primary 3.3 V buck regulator delivering regulated power with fast transient response to handle burst-mode CPU activity. Use Value: Delivers 350 mA at 94% efficiency with 15 µA quiescent current in PFM, extending talk time by >12% versus legacy LDO solutions. | Use Scenario: Supplies 3.3 V to integrated environmental sensor array (accelerometer, gyroscope, barometer) in fitness trackers. IC Role / Device Role / Timing Role: Always-on power source with ultra-low shutdown current and automatic light-load efficiency optimization. Use Value: Enables multi-week battery life via 0.1 µA shutdown current and seamless PFM entry during sensor idle periods. |
| Portable Medical Monitor Logic Rail | Handheld Barcode Scanner Core Voltage |
Use Scenario: Generates clean 3.3 V rail for microcontroller, display driver, and wireless BLE module in FDA-class portable ECG monitors. IC Role / Device Role / Timing Role: Safety-critical power stage with thermal shutdown and current limiting to prevent fault propagation during abnormal operation. Use Value: Meets IEC 60601-1 leakage and reliability requirements via integrated protection and 125°C junction-rated operation. | Use Scenario: Powers laser driver IC and decode ASIC in industrial-grade handheld barcode scanners operating from 3×AA alkaline batteries. IC Role / Device Role / Timing Role: High-efficiency step-down converter supporting wide input range (3.0–5.5 V) as battery voltage declines during field use. Use Value: Maintains stable 3.3 V output down to 3.0 V input via 100% duty-cycle mode, eliminating premature shutdown during battery depletion. |
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 |
|---|---|---|---|
| TPS62231DRVR | 3.3 V fixed output, 1-MHz switching, 400 mA max load, 17 µA IQ in PFM mode; uses different feedback architecture requiring no FB pin tie. | Designed for higher-current portable apps; lacks 100% duty-cycle mode, limiting low-VIN headroom vs. LM3670MF-3.3/NOPB. | Select when higher output current margin or tighter load regulation is required; verify layout compatibility with different pinout (EN on Pin 2). |
| AP3012KTR-G1 | 3.3 V fixed output, 1.5-MHz switching, 300 mA max load, 25 µA IQ; asynchronous (external diode), no PFM mode-only PWM operation. | Suitable for cost-sensitive, non-battery-critical applications; lower efficiency at light loads due to diode conduction loss. | Choose for simpler BOM where 90% peak efficiency suffices and 0.1 µA shutdown is not mandatory. |
Compared with TPS62231DRVR and AP3012KTR-G1, the LM3670MF-3.3/NOPB uniquely combines 100% duty-cycle dropout, 0.1 µA shutdown, and internal synchronous rectification in a 5-pin SOT-23-making it optimal for space- and battery-life-constrained Li-Ion systems requiring robust low-VIN operation.
Availability
LM3670MF-3.3/NOPB is available at Aetrix Electronics and suitable for mobile phones, wearable health monitors, portable medical instruments, and handheld industrial scanners requiring stable component supply across long production lifecycles.
Supply support for LM3670MF-3.3/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 specializing in analog and embedded processing technologies, with leadership in power management ICs for portable and industrial applications.
The LM3670 product line was designed specifically for ultralow-voltage, battery-powered portable electronics-emphasizing minimal external components, high light-load efficiency, and seamless integration into space-constrained handheld platforms.
FAQ
What is the minimum input voltage required for LM3670MF-3.3/NOPB to regulate 3.3 V output?
The LM3670MF-3.3/NOPB supports 100% duty-cycle operation, allowing regulation as long as VIN ≥ VOUT + ILOAD × (RDSON_P + RINDUCTOR). For 3.3 V output at 350 mA with typical RDSON_P = 690 mΩ and a 30 mΩ inductor, minimum VIN is ~3.56 V. Below that, output follows input linearly. Datasheet specifies 3.6 V minimum for full 350 mA performance at 3.3 V.
Can LM3670MF-3.3/NOPB be used with an input voltage below 2.5 V?
No. The absolute minimum input voltage is 2.5 V per recommended operating conditions. Operation below 2.5 V violates specifications and triggers undervoltage lockout (UVLO) at 2.4 V, disabling output. The device will not regulate or function reliably below this threshold.
Does LM3670MF-3.3/NOPB require an external feedback resistor divider?
No. The LM3670MF-3.3/NOPB is a fixed-output variant: its internal feedback network is trimmed to 3.3 V. Pin 4 (FB) must be connected directly to VOUT per the datasheet-no external resistors are used or permitted for this part number.
What is the thermal performance of LM3670MF-3.3/NOPB in SOT-23-5 package?
In the DBV (SOT-23-5) package, LM3670MF-3.3/NOPB has a junction-to-ambient thermal resistance (RθJA) of 163.3°C/W. At 350 mA load and 3.6 V input, typical power dissipation is ~105 mW, resulting in ~17°C junction rise above ambient-well within the 125°C max TJ rating under standard PCB layout with 1-in² copper pour.
How does LM3670MF-3.3/NOPB handle load transients?
The LM3670MF-3.3/NOPB responds to load steps (e.g., 0–350 mA) with <50 µs recovery time and <30 mV undershoot, thanks to voltage-mode control with feed-forward and internal compensation. PFM-to-PWM transition occurs within 32 oscillator cycles (~32 µs at 1 MHz) when load increases beyond light-load threshold.
LM3670MF-3.3/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):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3.3V
- 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-3.3/NOPB FAQ
1.How can I place an order for LM3670MF-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MF-3.3/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-3.3/NOPB reliable?
The price and inventory of LM3670MF-3.3/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-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM3670MF-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MF-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MF-3.3/NOPB?
LM3670MF-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MF-3.3/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-3.3/NOPB?
For technical support, including LM3670MF-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MF-3.3/NOPB requirements.
6.How does Aetrix verify that LM3670MF-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3670MF-3.3/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-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM3670MF-3.3/NOPB?
All LM3670MF-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MF-3.3/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-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM3670MF-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3670MF-3.3/NOPB Tags
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