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Texas Instruments LM3674MF-1.5/NOPB
- Part No.:
- LM3674MF-1.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3674MF-1.5/NOPB.pdf
- Description:
- IC REG BUCK 1.5V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,092
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Product details
Overview
LM3674MF-1.5/NOPB from Texas Instruments is a fixed-output 1.5 V, 600-mA synchronous step-down DC-DC converter optimized for single Li-Ion battery-powered systems (2.7 V–5.5 V input). It integrates PFET/NFET switches, operates at 2 MHz fixed frequency, delivers >90% efficiency at 300 mA with 2.2 µH inductor and ceramic capacitors, and is used in mobile phone core logic power rails.
For engineers reviewing the LM3674MF-1.5/NOPB datasheet, LM3674MF-1.5/NOPB pinout, LM3674MF-1.5/NOPB application, or LM3674MF-1.5/NOPB equivalent, key selection criteria include its 0.01 µA shutdown current, internal 0.5 V reference, thermal/overcurrent protection, and SOT-23-5 footprint compatibility with space-constrained portable designs.
Technical Context
The LM3674MF-1.5/NOPB uses 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 feeds an error amplifier that modulates the 2 MHz oscillator's duty cycle via a ramp generator and PWM comparator.
It implements internal synchronous rectification using a 380 mΩ (typ) PFET switch and 250 mΩ (typ) NFET rectifier, enabling high efficiency at low output voltages. Protection includes cycle-by-cycle current limiting (1020 mA typical), thermal shutdown, undervoltage lockout, and soft-start with stepped current limit (70/140/280/1020 mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - supports full discharge curve of single Li-Ion cell without dropout |
| Output Voltage | Fixed 1.5 V ±4% - internally trimmed; no external feedback resistors required |
| Max Output Current | 600 mA - sustained across full input range and temperature (−30°C to 125°C) |
| Switching Frequency | 2 MHz (typ), 1.6–2.6 MHz (min/max) - enables use of tiny 2.2 µH inductor and 10 µF/4.7 µF ceramic caps |
| Shutdown Current | 0.01 µA (typ) - minimizes battery drain in standby mode of portable devices |
| Feedback Reference | 0.5 V (internal) - sets output via precision bandgap; enables accurate 1.5 V regulation (VOUT = 3 × VREF) |
| Thermal Protection | Junction shutdown at 125°C - prevents damage during overload or poor PCB thermal design |
Pinout & Package
SOT-23-5 package (2.90 mm × 1.60 mm body size) with exposed pad not electrically connected; standard JEDEC MO-178AC footprint; RoHS-compliant, lead-free (NOPB suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Connects to input filter capacitor (4.7 µF); must be ≥2.7 V for enable; supplies internal circuitry and PFET switch |
| GND (Pin 2) | Ground reference | Common return path for input/output currents and internal bias; requires low-impedance PCB pour |
| EN (Pin 3) | Digital enable | Active-high logic input; device enabled when >1 V, shutdown when <0.4 V; 0.01 µA input current |
| FB (Pin 4) | Feedback sense | Internally connected to 1.5 V output divider; fixed version ties internal resistors - no external components needed |
| SW (Pin 5) | Switching node | Drain of internal PFET and source of NFET; connects to inductor; carries high di/dt square wave (2 MHz) |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated 380 mΩ PFET + 250 mΩ NFET eliminates external Schottky loss, enabling >92% efficiency at 1.5 V/300 mA |
| 2 MHz fixed-frequency PWM | Enables compact BOM: only 2.2 µH inductor + 10 µF COUT + 4.7 µF CIN required; reduces EMI compared to lower-frequency alternatives |
| Internal soft-start | Staged current limit (70→140→280→1020 mA) prevents inrush into large output caps; 240–350 µs start-up time typical |
| Thermal & current protection | Auto-recovery thermal shutdown + cycle-by-cycle current limit (1020 mA typ) protect IC and inductor under fault conditions |
| Ultra-low shutdown current | 0.01 µA typical draw extends battery life in always-on portable systems during deep sleep modes |
Applications
| Mobile Phone Core Power | MP3 Player Audio Codec Supply |
|---|---|
Use Scenario: Powers ARM Cortex-A series application processor cores requiring stable 1.5 V rail from a 3.6 V Li-Ion battery. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 1.5 V with fast transient response to handle CPU burst loads. Use Value: 2 MHz switching minimizes output voltage droop during 100 mA → 400 mA load steps; efficiency >89% sustains runtime. | Use Scenario: Supplies clean 1.5 V to stereo audio DAC/ADC in flash-based MP3 players with 3.7 V nominal battery. IC Role / Device Role / Timing Role: Low-noise DC-DC converter providing low-ripple power to analog audio circuitry. Use Value: Synchronous architecture and ceramic caps yield <15 mVpp ripple; thermal shutdown prevents overheating during extended playback. |
| Portable Hard Disk Drive Interface | Digital Still Camera Image Sensor Bias |
Use Scenario: Generates 1.5 V for SATA or PATA interface logic in 2.5″ portable HDD enclosures powered by USB or battery. IC Role / Device Role / Timing Role: High-current buck converter supporting 500 mA peak interface loads with minimal board area. Use Value: 600 mA capability handles HDD spin-up surges; SOT-23-5 footprint saves space vs. larger packages. | Use Scenario: Provides precise 1.5 V bias to CMOS image sensor analog front-end in compact digital cameras. IC Role / Device Role / Timing Role: Fixed-output voltage regulator ensuring stable sensor reference despite battery voltage sag. Use Value: ±4% output tolerance and 0.083%/V line regulation maintain sensor SNR across 2.7–5.5 V input range. |
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 | 1.5 V fixed, 600 mA, 3 MHz, 0.02 µA shutdown, but requires external compensation | Better light-load efficiency; higher frequency allows smaller inductor but increases EMI sensitivity | Choose for ultra-compact layouts where 3 MHz operation and tighter light-load regulation are critical |
| AP3012KTR-G1 | 1.5 V fixed, 500 mA, 1.5 MHz, 1.5 µA shutdown, no thermal shutdown | Lower cost; lacks thermal protection and has 100 mA lower current rating | Acceptable for low-power, thermally benign environments where cost outweighs robustness |
Compared with TPS62231DRVR and AP3012KTR-G1, the LM3674MF-1.5/NOPB offers integrated thermal protection and simpler layout (no external compensation), making it more suitable for unattended portable systems requiring reliability over minimal BOM count.
Availability
LM3674MF-1.5/NOPB is available at Aetrix Electronics and suitable for mobile phones, MP3 players, portable hard disk drives, and digital still cameras requiring stable component supply with consistent parametric performance and long-term lifecycle support.
Supply support for LM3674MF-1.5/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 designing analog ICs, embedded processors, and system solutions for industrial, automotive, and personal electronics markets.
The LM3674 product line targets space-constrained portable devices needing high-efficiency, low-voltage DC-DC conversion from single-cell batteries - emphasizing small footprint, low quiescent current, and robust protection.
FAQ
What is the recommended input and output capacitor configuration for LM3674MF-1.5/NOPB?
The LM3674MF-1.5/NOPB requires a 4.7 µF X5R/X7R ceramic capacitor on VIN and a 10 µF X5R/X7R ceramic capacitor on VOUT, both rated ≥6.3 V. These values are validated for stability and ripple suppression across the full 2.7–5.5 V input range and up to 600 mA load. Place CIN within 2 mm of VIN/GND pins and COUT adjacent to FB/GND to minimize loop inductance. The LM3674MF-1.5/NOPB datasheet specifies these as minimum values for reliable operation.
Does LM3674MF-1.5/NOPB require external feedback resistors?
No. The LM3674MF-1.5/NOPB is the fixed 1.5 V output variant with internal resistor divider connected to the FB pin; no external R1/R2 network is needed. This simplifies layout and eliminates resistor tolerance errors affecting output accuracy. The internal 0.5 V reference and 3× gain ensure 1.5 V ±4% regulation. Using external resistors would conflict with the fixed-output topology and is not supported for the LM3674MF-1.5/NOPB.
What protection features does LM3674MF-1.5/NOPB include?
The LM3674MF-1.5/NOPB integrates cycle-by-cycle current limiting (1020 mA typical), thermal shutdown (125°C junction), undervoltage lockout, and soft-start. It also achieves 0.01 µA shutdown current to preserve battery life. These protections operate autonomously without external components. During overload, the LM3674MF-1.5/NOPB enters timed current-limit mode to safely decay inductor current, preventing damage to itself or the external inductor.
Can LM3674MF-1.5/NOPB operate with a 2.5 V input?
No. The LM3674MF-1.5/NOPB has a minimum recommended input voltage of 2.7 V per TI's operating conditions. At 2.5 V, the internal PFET may not fully enhance, causing excessive conduction loss, thermal stress, and potential dropout or instability. The datasheet explicitly defines 2.7 V as the lower bound for reliable 1.5 V regulation. For sub-2.7 V inputs, consider LDOs or buck-boost converters - the LM3674MF-1.5/NOPB is not rated for 2.5 V operation.
What is the thermal resistance (RθJA) of LM3674MF-1.5/NOPB in standard PCB layout?
The LM3674MF-1.5/NOPB has a junction-to-ambient thermal resistance of 250°C/W on a 2-layer PCB and 130°C/W on a 4-layer PCB per TI's characterization. These values assume standard JEDEC test boards with 1-in² copper pours on top/bottom layers (2-layer) or internal ground/power planes (4-layer). Actual RθJA depends on PCB copper area, vias to inner layers, and airflow; derate power accordingly using TA-MAX = TJ-MAX – (RθJA × PD-MAX). The LM3674MF-1.5/NOPB's 125°C max junction temperature defines safe operating limits.
LM3674MF-1.5/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):
- 1.5V
- 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-1.5/NOPB FAQ
1.How can I place an order for LM3674MF-1.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3674MF-1.5/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 LM3674MF-1.5/NOPB reliable?
The price and inventory of LM3674MF-1.5/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3674MF-1.5/NOPB is usually 5 days.
3.What payment methods are accepted for LM3674MF-1.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3674MF-1.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3674MF-1.5/NOPB?
LM3674MF-1.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3674MF-1.5/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 LM3674MF-1.5/NOPB?
For technical support, including LM3674MF-1.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3674MF-1.5/NOPB requirements.
6.How does Aetrix verify that LM3674MF-1.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3674MF-1.5/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 LM3674MF-1.5/NOPB meets industry standards.
7.What is the process for return or replacement of LM3674MF-1.5/NOPB?
All LM3674MF-1.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3674MF-1.5/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 LM3674MF-1.5/NOPB part is unused and in its original packaging.
Return procedure for LM3674MF-1.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3674MF-1.5/NOPB Tags
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MC34063ABD-TR
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TPS561201DDCR
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MC33063ADR
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