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Texas Instruments LM3670MFX-1.8/NOPB
- Part No.:
- LM3670MFX-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MFX-1.8/NOPB.pdf
- Description:
- IC REG BUCK 1.8V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,276
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Product details
Overview
LM3670MFX-1.8/NOPB from Texas Instruments is a fixed-output 1.8 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 with automatic PFM mode switching, and achieves 94% typical efficiency at 100 mA. It powers core logic rails in battery-powered handheld devices requiring stable low-noise regulation.
For engineers reviewing the LM3670MFX-1.8/NOPB datasheet, LM3670MFX-1.8/NOPB pinout, LM3670MFX-1.8/NOPB application, or LM3670MFX-1.8/NOPB equivalent, key selection criteria include its 15 µA quiescent current in PFM mode, 0.1 µA shutdown current, internal synchronous rectification, 100% duty-cycle low-dropout capability, and minimal external component count (one inductor + two ceramic capacitors).
Technical Context
The LM3670MFX-1.8/NOPB uses voltage-mode control with input voltage feed-forward to maintain tight line regulation across its 2.5–5.5 V input range. Its integrated PFET/NFET synchronous rectifier eliminates external diode losses, enabling high efficiency (≥90%) from 1 mA to 350 mA loads.
It implements three functional modes: fixed-frequency 1-MHz PWM for medium-to-heavy loads (≥70 mA), hysteretic PFM for ultra-low-quiescent operation (<30 µA) at light loads, and shutdown mode (0.1 µA) triggered by EN < 0.4 V. Soft-start limits inrush current, while undervoltage lockout disables output below 2.4 V VIN.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±3% (0 mA–350 mA load, 2.5–5.5 V input) |
| Input Voltage Range | 2.5 V to 5.5 V - supports single Li-Ion or triple NiMH/NiCd cells |
| Max Load Current | 350 mA - sufficient for baseband processors, memory I/O, and sensor subsystems |
| Quiescent Current | 15 µA typical in PFM mode - extends battery life during standby/sleep states |
| Switching Frequency | 1 MHz typical (550–1300 kHz range) - enables use of compact 4.7–10 µH inductors |
| Shutdown Current | 0.1 µA typical - minimizes battery drain when system is powered off |
| Efficiency | 94% typical at 100 mA (VIN = 3.6 V, VOUT = 1.8 V) - reduces thermal load in space-constrained PCBs |
| Duty Cycle | 100% - maintains regulation down to VIN = VOUT + ILOAD × (RDSON_P + RINDUCTOR) |
Pinout & Package
The LM3670MFX-1.8/NOPB is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm body size), optimized for high-density portable layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power Input | Connects to input filter capacitor; accepts 2.5–5.5 V supply; powers internal bias and switches |
| GND (Pin 2) | Ground Reference | Primary return path for power, feedback, and enable circuits; must be low-impedance |
| EN (Pin 3) | Digital Enable | Active-high logic input; ≥1.3 V enables regulation; ≤0.4 V forces shutdown (0.1 µA IQ) |
| FB (Pin 4) | Analog Feedback | Internally connected to 1.8 V reference; monitors output via direct connection to VOUT in fixed versions |
| SW (Pin 5) | Switching Node | Drives external inductor; connects to internal PFET drain and NFET source; requires low-inductance layout |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Eliminates external Schottky diode; improves efficiency by 8–12% vs. asynchronous designs at 10–100 mA loads |
| Automatic PWM/PFM Mode Switching | Seamlessly transitions between 1-MHz PWM (≥70 mA) and burst-mode PFM (<70 mA) without external control |
| 100% Duty-Cycle Low-Dropout Operation | Maintains 1.8 V output even as input decays to ~2.0 V under 100 mA load, extending usable battery range |
| Integrated Soft-Start | 400 µs typical startup time with 10 µF COUT; limits inrush current to ≤620 mA, preventing input rail collapse |
| Overcurrent & Thermal Protection | Peak switch current limit of 620 mA (typical); thermal shutdown activates above 125°C junction temperature |
Applications
| Mobile Phone Core Rail | Handheld Instrument Logic Supply |
|---|---|
Use Scenario: Powers ARM-based application processor core voltage (VDD_CORE) in dual-mode GSM/UMTS smartphones operating from single-cell Li-Ion battery. IC Role / Device Role / Timing Role: Primary step-down regulator delivering stable 1.8 V at up to 350 mA with fast transient response to CPU DVFS events. Use Value: 94% efficiency at 100 mA reduces thermal dissipation in sealed handset enclosures; 15 µA PFM IQ extends standby time beyond 7 days. | Use Scenario: Supplies 1.8 V to microcontroller I/O banks and precision ADC reference circuitry in portable multimeters and data loggers. IC Role / Device Role / Timing Role: Low-noise, low-ripple power source ensuring <0.5% ADC gain error and stable digital interface timing. Use Value: 1-MHz switching frequency places noise spectrum above sensitive analog bands; internal soft-start prevents measurement offset during power-up. |
| PDA Application Processor I/O | Battery-Powered Sensor Hub |
Use Scenario: Generates 1.8 V for SDIO, USB PHY, and display interface I/O in legacy Palm OS PDAs using triple NiMH batteries. IC Role / Device Role / Timing Role: Fixed-output buck converter interfacing between battery stack and high-speed digital peripherals. Use Value: Only three external components (10 µH inductor + 4.7 µF CIN + 10 µF COUT) simplify BOM and reduce PCB area by >40% vs. discrete solutions. | Use Scenario: Powers BLE SoC, environmental sensors (temp/humidity/pressure), and flash memory in wireless IoT nodes powered by CR2032 coin cell. IC Role / Device Role / Timing Role: Ultra-low-IQ step-down regulator enabling multi-year battery life in intermittent-sensing applications. Use Value: 0.1 µA shutdown current and 15 µA PFM IQ allow >5-year operation on single coin cell at 1-sample-per-minute duty cycle. |
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 | 1.8 V fixed, 300 mA max, 2.05–6.5 V input, 27 µA IQ in PFM, 5-pin WSON (1.5 × 1.5 mm) | Higher input range but lower current rating; smaller footprint but requires tighter layout for thermal management | Preferred for space-constrained designs where input may exceed 5.5 V or where WSON thermal performance is validated |
| AP3012K5-18 | 1.8 V fixed, 300 mA max, 2.5–5.5 V input, 40 µA IQ, no PFM mode, SOT-23-5 | Lacks automatic PFM; higher quiescent current; no soft-start; identical pinout but different FB network behavior | Suitable only for cost-sensitive, non-battery-critical applications where 40 µA IQ is acceptable and soft-start is not required |
Compared with TPS62231DRYR and AP3012K5-18, the LM3670MFX-1.8/NOPB offers superior light-load efficiency (15 µA vs. 27/40 µA), integrated soft-start, and proven robustness in high-volume mobile designs - making it optimal for battery-life-critical portable systems requiring reliable 350 mA delivery.
Availability
LM3670MFX-1.8/NOPB is available at Aetrix Electronics and suitable for mobile phones, handheld instruments, and battery-powered sensor hubs requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3670MFX-1.8/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 leadership in power management ICs.
The LM3670 series was designed specifically for ultralow-voltage portable electronics - delivering high-efficiency, minimal-component DC-DC conversion from single-cell batteries to sub-2 V logic rails.
FAQ
What is the minimum input voltage required for LM3670MFX-1.8/NOPB to regulate 1.8 V at 350 mA?
The minimum input voltage depends on load current and component resistances. For LM3670MFX-1.8/NOPB at 350 mA, VIN_MIN ≈ VOUT + ILOAD × (RDSON_P + RINDUCTOR). With RDSON_P = 690 mΩ (max) and a typical 0.2 Ω inductor, VIN_MIN ≈ 1.8 V + 0.35 A × 0.89 Ω ≈ 2.11 V - but the device enforces 2.4 V UVLO, so practical minimum is 2.5 V per spec.
Does LM3670MFX-1.8/NOPB require an external feedback resistor divider?
No. The LM3670MFX-1.8/NOPB is a fixed-output variant with internal feedback network set to 1.8 V. Pin 4 (FB) is internally connected to the 0.5 V reference and output node; no external resistors are needed - unlike the adjustable LM3670MF/NOPB version.
Can LM3670MFX-1.8/NOPB operate with a 4.7 µH inductor instead of 10 µH?
Yes. The LM3670MFX-1.8/NOPB supports both 4.7 µH and 10 µH inductors per TI's typical application schematics. A 4.7 µH inductor increases peak inductor current and ripple but allows faster transient response; ensure saturation current rating exceeds 750 mA and DCR remains <0.3 Ω for efficiency.
What is the purpose of the SW pin on LM3670MFX-1.8/NOPB, and what layout guidance applies?
The SW pin on LM3670MFX-1.8/NOPB is the switching node connecting the internal PFET drain and NFET source to the external inductor. It carries high di/dt square-wave current; layout requires shortest possible trace, direct connection to inductor pad, ground plane clearance underneath, and avoidance of sensitive analog traces nearby to minimize EMI coupling.
How does LM3670MFX-1.8/NOPB handle overcurrent conditions?
The LM3670MFX-1.8/NOPB implements cycle-by-cycle peak current limiting with a typical threshold of 620 mA. During overload, it clamps switch current, reducing effective duty cycle and causing output voltage droop. If sustained, thermal shutdown activates above 125°C junction temperature - protecting both LM3670MFX-1.8/NOPB and external components.
LM3670MFX-1.8/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):
- 1.8V
- 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
LM3670MFX-1.8/NOPB FAQ
1.How can I place an order for LM3670MFX-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MFX-1.8/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 LM3670MFX-1.8/NOPB reliable?
The price and inventory of LM3670MFX-1.8/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3670MFX-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM3670MFX-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MFX-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MFX-1.8/NOPB?
LM3670MFX-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MFX-1.8/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 LM3670MFX-1.8/NOPB?
For technical support, including LM3670MFX-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MFX-1.8/NOPB requirements.
6.How does Aetrix verify that LM3670MFX-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3670MFX-1.8/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 LM3670MFX-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM3670MFX-1.8/NOPB?
All LM3670MFX-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MFX-1.8/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 LM3670MFX-1.8/NOPB part is unused and in its original packaging.
Return procedure for LM3670MFX-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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