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Texas Instruments LM3674MFX-1.8/NOPB
- Part No.:
- LM3674MFX-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3674MFX-1.8/NOPB.pdf
- Description:
- IC REG BUCK 1.8V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,055
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Product details
Overview
LM3674MFX-1.8/NOPB from Texas Instruments is a fixed-output 1.8 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 up to 600 mA load current, features 2 MHz fixed-frequency PWM operation, internal soft-start, and 0.01 µA shutdown current - enabling compact, high-efficiency power delivery in space-constrained mobile applications like smartphones and digital cameras.
For engineers reviewing the LM3674MFX-1.8/NOPB datasheet, LM3674MFX-1.8/NOPB pinout, LM3674MFX-1.8/NOPB application, or LM3674MFX-1.8/NOPB equivalent, key selection criteria include its 1.8 V fixed output, SOT-23-5 package footprint, 2 MHz switching frequency enabling small external components (2.2 µH inductor, 4.7 µF CIN, 10 µF COUT), synchronous rectification for >90% efficiency at mid-load, and thermal/current protection for robust operation in battery-powered systems.
Technical Context
The LM3674MFX-1.8/NOPB implements voltage-mode PWM control with input voltage feed-forward to maintain tight line regulation across its 2.7–5.5 V input range. Its internal 0.5 V reference and fixed feedback network set the regulated 1.8 V output without external resistors.
It integrates a PFET high-side switch (500 mΩ typical RDS(ON)) and NFET synchronous rectifier (400 mΩ typical RDS(ON)), operating at 2 MHz (1.6–2.6 MHz over temperature) to minimize inductor and capacitor size while maintaining stable regulation under dynamic load transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% - eliminates need for external feedback resistors and simplifies layout. |
| Max Output Current | 600 mA - supports core logic rails and peripheral ICs in portable devices. |
| Input Voltage Range | 2.7 V to 5.5 V - compatible with single Li-Ion (3.0–4.2 V) and USB-powered (5 V) systems. |
| Switching Frequency | 2 MHz typical - enables use of tiny 2.2 µH shielded inductors and low-ESR ceramic capacitors. |
| Shutdown Current | 0.01 µA typical - extends battery life during system sleep modes. |
| Efficiency | >90% at 300 mA (VIN = 3.6 V, VOUT = 1.8 V) - reduces thermal load and improves runtime. |
| Protection Features | Thermal shutdown, cycle-by-cycle current limit (1020 mA typ), undervoltage lockout - ensures safe operation under fault conditions. |
Pinout & Package
LM3674MFX-1.8/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for high-density PCB layouts and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Accepts 2.7–5.5 V supply; requires local 4.7 µF ceramic decoupling capacitor. |
| GND (Pin 2) | Ground reference | Primary return path for input, output, and internal circuitry; must be low-impedance connection. |
| EN (Pin 3) | Enable control | Logic-high (>1 V) enables regulation; <0.4 V forces shutdown (0.01 µA quiescent). |
| FB (Pin 4) | Feedback input | Internally connected to fixed 1.8 V divider; no external components required for this variant. |
| SW (Pin 5) | Switching node | Drives external 2.2 µH inductor; carries high di/dt - requires short, wide trace and ground plane clearance. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated NFET replaces Schottky diode, reducing conduction loss and improving efficiency by ~8–12% vs asynchronous designs. |
| Internal soft-start | Gradually ramps switch current limit (70 → 140 → 280 → 1020 mA) to limit inrush current and prevent input rail droop during startup. |
| 2 MHz fixed-frequency PWM | Enables use of sub-3 mm × 3 mm inductors and avoids AM radio band interference; supports fast transient response. |
| Thermal & overload protection | Auto-recovery thermal shutdown and cycle-by-cycle current limiting prevent damage during sustained overload or poor heatsinking. |
| Low-noise operation | No external compensation required; stable with standard X5R/X7R ceramic capacitors; minimal EMI due to controlled slew rates. |
Applications
| Smartphone Core Power | Digital Camera Sensor Rail |
|---|---|
Use Scenario: Powers application processor I/O or memory interface in compact smartphones using single-cell Li-Ion battery. IC Role / Device Role / Timing Role: Primary 1.8 V buck regulator delivering clean, regulated power with fast load-step response. Use Value: Enables 2.2 µH inductor + 10 µF ceramic output capacitor solution, reducing board area by >40% vs lower-frequency alternatives. | Use Scenario: Supplies image sensor digital core in DSLR or mirrorless camera bodies where low noise and stable voltage are critical. IC Role / Device Role / Timing Role: Fixed 1.8 V point-of-load regulator with low output ripple (<25 mVPP) and thermal foldback during burst capture. Use Value: Internal synchronous FETs and 2 MHz switching suppress audible coil whine and meet CISPR-22 Class B EMI limits without shielding. |
| Portable HDD Controller | WLAN Baseband SoC |
Use Scenario: Provides 1.8 V supply to 2.5-inch portable hard disk drive controller IC during spin-up and data transfer phases. IC Role / Device Role / Timing Role: High-current (600 mA peak) buck converter with current-limit protection to handle motor-induced load surges. Use Value: 1020 mA cycle-by-cycle current limit prevents latch-up during HDD spindle motor startup transients. | Use Scenario: Powers WLAN baseband SoC in tablets and hotspots requiring stable 1.8 V rail across varying RF transmit duty cycles. IC Role / Device Role / Timing Role: Efficient, low-quiescent-power DC-DC converter supporting deep-sleep states with 0.01 µA shutdown current. Use Value: Maintains >85% efficiency down to 10 mA load, extending battery life during idle and beacon intervals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRVR | 1.8 V fixed, 600 mA, 3 MHz switching, 0.02 µA shutdown, same SOT-23-5 package | Higher frequency allows smaller inductor (1 µH); tighter output accuracy (±1.5%) but higher cost | Preferred when board space is constrained and higher precision is required. |
| AP3012KTR-G1 | 1.8 V fixed, 500 mA, 1.5 MHz, 1.5 µA shutdown, SOT-23-5 | Lower max current and frequency; simpler design but reduced efficiency at 600 mA | Suitable for cost-sensitive, lower-power applications where 500 mA suffices. |
Compared with LM3674MFX-1.8/NOPB, TPS62231DRVR offers higher switching frequency and tighter regulation at the expense of higher BOM cost, while AP3012KTR-G1 trades current capability and efficiency for lower unit price - making LM3674MFX-1.8/NOPB the balanced choice for mainstream 600 mA, 1.8 V portable power rails.
Availability
LM3674MFX-1.8/NOPB is available at Aetrix Electronics and suitable for smartphone power management, digital camera sensor supplies, portable HDD controllers, and WLAN baseband SoC applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3674MFX-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 power management technologies, with decades of expertise in high-efficiency DC-DC conversion for portable electronics.
The LM3674 product line was designed specifically for ultra-compact, battery-powered devices requiring high-efficiency, low-noise, fixed-output step-down regulation - targeting mobile phones, PDAs, MP3 players, and digital still cameras.
FAQ
What is the recommended input and output capacitor configuration for LM3674MFX-1.8/NOPB?
The LM3674MFX-1.8/NOPB requires a 4.7 µF X5R/X7R ceramic capacitor on VIN (placed within 2 mm of Pin 1) and a 10 µF X5R/X7R ceramic capacitor on VOUT (placed adjacent to Pin 4 and Pin 5). These values ensure stable operation, low input ripple, and <25 mVPP output ripple at full load. The LM3674MFX-1.8/NOPB datasheet specifies minimum values of 2.2 µF (VIN, 3 V bias) and 5.75 µF (VOUT, 1.8 V bias) across temperature and DC bias.
Does LM3674MFX-1.8/NOPB require external feedback resistors?
No. The LM3674MFX-1.8/NOPB is the fixed 1.8 V version - its internal resistor divider sets the output voltage, so no external FB resistors are needed. Pin 4 (FB) is internally connected and must be left unconnected externally. This differs from the LM3674-ADJ variant, which requires R1/R2 to program VOUT. The LM3674MFX-1.8/NOPB simplifies design and improves accuracy by eliminating resistor tolerance effects.
What thermal performance can be expected from LM3674MFX-1.8/NOPB in a standard 2-layer PCB layout?
In a standard 2-layer PCB with 1 oz copper and no thermal vias, the LM3674MFX-1.8/NOPB has a junction-to-ambient thermal resistance (RθJA) of 250°C/W. At 600 mA load and 3.6 V input, power dissipation is ~360 mW, resulting in ~90°C junction rise above ambient - well within the 125°C maximum rating. For continuous 600 mA operation, TI recommends a 4-layer board (RθJA = 130°C/W) or thermal vias under the exposed pad (if present - though SOT-23-5 DBV has no thermal pad).
How does the soft-start function operate in LM3674MFX-1.8/NOPB?
The LM3674MFX-1.8/NOPB implements hardware-based soft-start by progressively increasing the internal switch current limit in four steps: 70 mA → 140 mA → 280 mA → 1020 mA (typical). This occurs only when EN transitions high *after* VIN reaches ≥2.7 V. Soft-start duration depends on output capacitance and load - e.g., 350 µs with 10 µF COUT and 300 mA load. This prevents input rail collapse and inrush stress on the LM3674MFX-1.8/NOPB and upstream power sources.
Is LM3674MFX-1.8/NOPB compatible with lead-free reflow soldering processes?
Yes. The LM3674MFX-1.8/NOPB is rated for lead-free reflow with a maximum peak solder temperature of 260°C for 10 seconds, per JEDEC J-STD-020. Its SOT-23-5 (DBV) package uses matte tin plating and meets RoHS Directive 2011/65/EU. The device is qualified for MSL Level 1 (unlimited floor life at ≤30°C/85% RH), eliminating bake requirements prior to assembly. TI confirms full compatibility with standard Pb-free reflow profiles including IPC/JEDEC J-STD-020D.
LM3674MFX-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):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 600mA
- Frequency - Switching:
- 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM3674MFX-1.8/NOPB FAQ
1.How can I place an order for LM3674MFX-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3674MFX-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 LM3674MFX-1.8/NOPB reliable?
The price and inventory of LM3674MFX-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 LM3674MFX-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM3674MFX-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3674MFX-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3674MFX-1.8/NOPB?
LM3674MFX-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3674MFX-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 LM3674MFX-1.8/NOPB?
For technical support, including LM3674MFX-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3674MFX-1.8/NOPB requirements.
6.How does Aetrix verify that LM3674MFX-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3674MFX-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 LM3674MFX-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM3674MFX-1.8/NOPB?
All LM3674MFX-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3674MFX-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 LM3674MFX-1.8/NOPB part is unused and in its original packaging.
Return procedure for LM3674MFX-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3674MFX-1.8/NOPB Tags
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