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Texas Instruments LM3674MF-1.8
- Part No.:
- LM3674MF-1.8
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3674MF-1.8.pdf
- Description:
- IC REG BUCK 1.8V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,340
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Product details
Overview
LM3674MF-1.8 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 systems (2.7–5.5 V input). It integrates PFET/NFET switches, operates at 2 MHz (typical), delivers >90% efficiency at 300 mA with 2.2 µH inductor and ceramic capacitors, and supports mobile phone core logic rail regulation.
For engineers reviewing the LM3674MF-1.8 datasheet, LM3674MF-1.8 pinout, LM3674MF-1.8 application, or LM3674MF-1.8 equivalent, key selection criteria include its 2-MHz fixed-frequency PWM operation, 0.01 µA shutdown current, internal 0.5-V reference, SOT-23-5 package footprint, and compatibility with low-ESR ceramic input/output capacitors (4.7 µF/10 µF).
Technical Context
The LM3674MF-1.8 employs voltage-mode PWM control with input voltage feed-forward to achieve tight line regulation (0.083%/V) and load regulation (0.0010%/mA). Its internal 0.5-V reference sets output via fixed resistor divider, eliminating external feedback components required in adjustable variants.
It integrates a 380 mΩ (typ) PFET switch and 250 mΩ (typ) NFET synchronous rectifier, enabling high efficiency without external diodes. Thermal shutdown, current limiting (1020 mA typ), and undervoltage lockout ensure robust operation across −30°C to 125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% over load/temperature - eliminates external feedback resistors and simplifies layout. |
| Max Load Current | 600 mA continuous - sufficient for ARM Cortex-A/M cores, baseband processors, and memory I/O rails. |
| Switching Frequency | 2 MHz typical (1.6–2.6 MHz range) - enables use of small 2.2 µH shielded inductors and reduces EMI filtering burden. |
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-Ion (fully charged to depleted) and USB-powered portable systems. |
| Shutdown Current | 0.01 µA typical - extends battery life during system sleep modes without external enable sequencing. |
| Internal Reference | 0.5 V ±4% - defines output accuracy and enables precise fixed-voltage variants like LM3674MF-1.8. |
| Thermal Protection | 125°C junction limit with automatic recovery - prevents latch-up during transient overload or poor PCB thermal design. |
Pinout & Package
SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, gull-wing leads, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Accepts 2.7–5.5 V; requires local 4.7 µF ceramic capacitor to suppress switching noise and supply peak PFET current. |
| GND (Pin 2) | Ground reference | Primary return path for PFET, NFET, and feedback circuitry; must be low-impedance connection to power plane. |
| EN (Pin 3) | Digital enable | Active-high logic input; <0.4 V disables device (0.01 µA IQ); >1 V enables; 1 µA max input current avoids pull-up burden. |
| FB (Pin 4) | Feedback sense | Internally connected to 1.8 V output divider; not user-accessible in fixed versions - ties directly to regulated output node. |
| SW (Pin 5) | Switching node | Drives external 2.2 µH inductor; carries high di/dt square wave - requires short, wide trace and ground pour clearance. |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and improving full-load efficiency by ≥8% vs asynchronous designs. |
| 2-MHz fixed-frequency PWM | Enables compact BOM with 2.2 µH inductor and 10 µF/4.7 µF ceramic caps - no ferrite beads or large electrolytics needed. |
| Integrated soft-start | Staged current limit (70/140/280/1020 mA) prevents inrush into 10 µF output cap - start-up time <350 µs at 300 mA load. |
| 0.5-V precision internal reference | Ensures 1.8 V output accuracy within ±4% across temperature and line/load variations - no calibration required. |
| Thermal + current protection | Auto-recovering shutdown at 125°C junction or 1020 mA peak switch current - protects IC and inductor under fault conditions. |
Applications
| Mobile Phone Core Rail | WLAN Baseband Power |
|---|---|
Use Scenario: Powers ARM-based application processor core (e.g., Qualcomm Snapdragon, MediaTek MT series) requiring stable 1.8 V at up to 600 mA. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated core voltage with fast transient response to dynamic CPU load changes. Use Value: Achieves >92% efficiency at 300 mA with 2.2 µH inductor, minimizing thermal rise in space-constrained handset PCBs. | Use Scenario: Supplies 1.8 V to IEEE 802.11a/b/g/n WLAN transceiver ICs (e.g., TI WL183x, QCA QCA9377) during active transmit/receive bursts. IC Role / Device Role / Timing Role: High-frequency buck converter maintaining output stability during 500 mA pulsed loads with <20 mV undershoot. Use Value: 2-MHz switching enables small LC filter (2.2 µH + 10 µF) that meets spectral mask requirements without added shielding. |
| Portable Digital Camera Sensor | MP3 Player Audio Codec |
Use Scenario: Provides clean 1.8 V bias to CMOS image sensor analog front-end (AFE) and column ADC in compact digital still cameras. IC Role / Device Role / Timing Role: Low-noise DC-DC source with <10 mVpp ripple (at 100 kHz BW) to prevent fixed-pattern noise in sensor output. Use Value: Internal synchronous rectification and ceramic-only filtering reduce switching artifacts - no audible buzz in video playback. | Use Scenario: Powers stereo audio codec (e.g., TI PCM3002, AKM AK4552) requiring low-noise 1.8 V for DAC/ADC sections in flash-based MP3 players. IC Role / Device Role / Timing Role: Efficient, quiet power stage supporting 100+ hours of playback on single Li-Ion cell. Use Value: 0.01 µA shutdown current preserves battery charge during pause mode - critical for >1-week standby life. |
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 | 2.25-MHz fixed frequency, 600-mA output, 0.05-µA shutdown, but requires external feedback resistors even for fixed 1.8 V. | Higher light-load efficiency due to DCS-Control topology; less suitable for cost-sensitive designs needing zero-resistor BOM. | Select TPS62231DRVR only if ultra-low IQ (<1 µA) in deep sleep or tighter load regulation (<0.0005%/mA) is mandatory. |
| AP63201WU-18 | 2-MHz, 600-mA, SOT-23-5, but uses external compensation and lacks integrated soft-start - requires additional 2–3 passive components. | Lower BOM cost per unit, but increases layout complexity and validation effort for production release. | Choose AP63201WU-18 only when procurement constraints require non-TI sourcing and engineering bandwidth exists for compensation tuning. |
Compared with TPS62231DRVR and AP63201WU-18, the LM3674MF-1.8 offers the simplest implementation (no feedback resistors, no compensation network) and lowest design risk for cost-sensitive, volume portable electronics - trading minor IQ and regulation improvements for guaranteed first-pass success.
Availability
LM3674MF-1.8 is available at Aetrix Electronics and suitable for mobile phones, WLAN modules, digital cameras, and MP3 players requiring stable component supply with consistent parametric performance and long-term lifecycle support.
Supply support for LM3674MF-1.8 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, specializing in analog, embedded processing, and silicon innovation for industrial, automotive, and consumer markets.
The LM3674 product line delivers highly integrated, low-external-component DC-DC converters targeting battery-powered portable electronics where board space, efficiency, and rapid time-to-market are critical design constraints.
FAQ
What is the recommended input and output capacitor configuration for LM3674MF-1.8?
The LM3674MF-1.8 requires a 4.7 µF X5R/X7R ceramic capacitor (6.3 V rating) placed adjacent to the VIN pin, and a 10 µF X5R/X7R ceramic capacitor (6.3 V rating) at the VOUT node. These values are validated for stable 2-MHz operation with <20 mVpp ripple under 600-mA load. Case sizes of 0805 are preferred; Y5V dielectrics must be avoided due to DC bias degradation.
Does LM3674MF-1.8 support 100% duty-cycle operation for low-dropout scenarios?
No - the LM3674MF-1.8 is a fixed-frequency PWM buck converter and does not support 100% duty-cycle LDO mode. That capability is exclusive to the LM3674-ADJ variant. The LM3674MF-1.8 maintains regulation down to VIN = 2.7 V, but below ~2.2 V input, output collapses as duty cycle approaches maximum and internal PFET RDS(on) limits headroom.
What is the thermal resistance (RθJA) of LM3674MF-1.8 in standard PCB layouts?
The LM3674MF-1.8 in SOT-23-5 (DBV) package has a junction-to-ambient thermal resistance of 130°C/W on a 4-layer PCB with 2-in² copper pour, and 250°C/W on a 2-layer board. Derating is required above 60°C ambient: at 85°C TA, maximum continuous power dissipation drops to 310 mW (4-layer) or 160 mW (2-layer) per the datasheet's dissipation ratings table.
Can LM3674MF-1.8 replace LM3674MF-1.5 or LM3674MF-3.3 in an existing design?
No - LM3674MF-1.8 is a fixed 1.8 V output variant with internal feedback divider; it is not pin-compatible or functionally interchangeable with other fixed-output versions (e.g., LM3674MF-1.5, LM3674MF-3.3). Output voltage is laser-trimmed during test and cannot be adjusted. Swapping requires verifying all downstream 1.8 V logic tolerances and revalidating transient response.
What protection features are integrated into LM3674MF-1.8?
The LM3674MF-1.8 integrates four hardware protections: (1) thermal shutdown at 125°C junction temperature with auto-recovery; (2) cycle-by-cycle peak current limiting at 1020 mA (typical); (3) undervoltage lockout disabling operation below VIN = 2.7 V; and (4) 0.01 µA shutdown current in EN = low state. No external components are needed to activate these functions.
LM3674MF-1.8 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):
- 2.7V
- 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
LM3674MF-1.8 FAQ
1.How can I place an order for LM3674MF-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3674MF-1.8 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 LM3674MF-1.8 reliable?
The price and inventory of LM3674MF-1.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3674MF-1.8 is usually 5 days.
3.What payment methods are accepted for LM3674MF-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3674MF-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3674MF-1.8?
LM3674MF-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3674MF-1.8 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 LM3674MF-1.8?
For technical support, including LM3674MF-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3674MF-1.8 requirements.
6.How does Aetrix verify that LM3674MF-1.8 is sourced from the original manufacturer or authorized distributors?
All LM3674MF-1.8 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 LM3674MF-1.8 meets industry standards.
7.What is the process for return or replacement of LM3674MF-1.8?
All LM3674MF-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM3674MF-1.8, 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 LM3674MF-1.8 part is unused and in its original packaging.
Return procedure for LM3674MF-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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