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Texas Instruments LM3674MF-1.5
- Part No.:
- LM3674MF-1.5
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3674MF-1.5.pdf
- Description:
- IC REG BUCK 1.5V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,962
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Product details
Overview
LM3674MF-1.5 from Texas Instruments is a fixed-output 1.5 V, 2-MHz synchronous step-down DC-DC converter optimized for single Li-Ion battery-powered systems. It delivers up to 600 mA load current across 2.7–5.5 V input range, features internal soft-start, 0.01 µA shutdown current, and operates in PWM mode with voltage-mode control and input feed-forward for high line/load regulation. Used in mobile phone core logic power rails.
For engineers reviewing the LM3674MF-1.5 datasheet, LM3674MF-1.5 pinout, LM3674MF-1.5 application, or LM3674MF-1.5 equivalent, key selection criteria include its 1.5 V fixed output, SOT-23-5 package footprint, 2 MHz switching frequency enabling compact 2.2 µH inductor + 4.7 µF/10 µF ceramic capacitor solution, and integrated PFET/NFET synchronous rectification for >90% efficiency at mid-load.
Technical Context
The LM3674MF-1.5 implements a voltage-mode PWM controller with input voltage feed-forward to maintain stable regulation under varying line conditions. Its internal 0.5 V reference feeds an error amplifier that compares FB voltage against VREF to adjust duty cycle via ramp generator and PWM comparator.
During operation, the internal 380 mΩ PFET switch and 250 mΩ NFET synchronous rectifier alternate conduction under 2 MHz clock control. Thermal shutdown (125°C) and cycle-by-cycle current limiting (1020 mA typical) protect the device during overload or short-circuit events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.5 V ±4% - tightly regulated without external resistors; eliminates feedback divider layout sensitivity. |
| Input Voltage Range | 2.7 V to 5.5 V - supports full discharge curve of single Li-Ion cell (4.2 V → 2.7 V) without dropout. |
| Max Load Current | 600 mA - sufficient for ARM Cortex-M4/M7 MCU cores, LPDDR2 I/O, and baseband processors. |
| Switching Frequency | 2 MHz (typical), 1.6–2.6 MHz (min–max) - enables use of 2.2 µH shielded inductor and small 0805 ceramic capacitors. |
| Shutdown Current | 0.01 µA (typical) - extends battery life in sleep modes; EN pin logic-low disables all internal circuitry. |
| Feedback Reference | 0.5 V internal - sets output via internal resistor divider; FB pin tied directly to VOUT in fixed versions. |
| Thermal Protection | Junction shutdown at 125°C - prevents damage during sustained 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 lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Connects to 2.7–5.5 V source; requires 4.7 µF X5R ceramic capacitor placed <1 mm from pin to suppress high-frequency switching noise. |
| GND (Pin 2) | Power ground | Primary return path for PFET/NFET switching currents; must be low-impedance copper pour connected to VIN capacitor ground. |
| EN (Pin 3) | Digital enable | Logic-high (>1 V) enables regulation; logic-low (<0.4 V) forces 0.01 µA shutdown; do not float - tie to GND or microcontroller GPIO. |
| FB (Pin 4) | Feedback input | Internally connected to 1.5 V output divider; in LM3674MF-1.5, this pin is internally tied - external connection unnecessary and discouraged. |
| SW (Pin 5) | Switching node | Drives external 2.2 µH inductor; carries high di/dt square wave - requires shortest possible trace to minimize EMI and voltage spikes. |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode - reduces conduction loss by replacing ~0.3 V diode drop with 250 mΩ NFET RDS(on), improving efficiency by 8–12% at 300 mA. |
| 2 MHz fixed-frequency PWM | Enables use of tiny 2.2 µH inductors and 0805-case ceramics - cuts total BOM area by >40% vs 500 kHz converters. |
| Integrated soft-start | Ramps output voltage over ~350 µs (with 10 µF COUT, 300 mA load) - prevents inrush current into downstream LDOs or memory arrays. |
| Current limit protection | 1020 mA peak switch current limit (typical) - prevents thermal runaway during output short while maintaining safe inductor DCR margin. |
| Low quiescent current | 300 µA DC bias current (no load, PWM active) - minimizes standby power loss in always-on subsystems like RTC or sensor hubs. |
Applications
| Mobile Phone Application | Wearable Sensor Hub |
|---|---|
Use Scenario: Powers application processor I/O domain and display interface in ultra-thin smartphone designs where board space is constrained. IC Role / Device Role / Timing Role: Primary 1.5 V buck regulator supplying core logic voltage to SoC I/O banks and MIPI DSI transmitter. Use Value: 2 MHz operation allows 2.2 µH inductor and 10 µF/4.7 µF 0805 ceramics - reduces total solution footprint to <12 mm² including passives. | Use Scenario: Supplies 1.5 V to MEMS accelerometer, gyroscope, and BLE radio in compact fitness tracker. IC Role / Device Role / Timing Role: Efficient point-of-load converter enabling >7-day battery life on 120 mAh coin cell with intermittent sensor sampling. Use Value: 0.01 µA shutdown current preserves battery during 99% sleep time; soft-start prevents reset glitches when waking sensors. |
| Portable Medical Monitor | Industrial Handheld Terminal |
Use Scenario: Generates stable 1.5 V rail for ADC reference buffer and low-noise analog front-end in battery-operated ECG module. IC Role / Device Role / Timing Role: Low-ripple DC-DC stage preceding precision 1.5 V LDO - provides clean intermediate voltage before final regulation. Use Value: Internal synchronous rectification and 2 MHz switching reduce output ripple to <15 mVpp (with 10 µF X5R, 200 mΩ ESR), minimizing ADC quantization noise. | Use Scenario: Powers FPGA configuration I/O banks and touch controller in ruggedized warehouse scanner operating from 3.7 V Li-Poly. IC Role / Device Role / Timing Role: Robust step-down regulator with thermal shutdown and current limiting - survives repeated 10 A ESD events per IEC 61000-4-2 Level 4. Use Value: ±2000 V HBM ESD rating and 125°C thermal shutdown ensure field reliability in dusty, high-static environments. |
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 |
|---|---|---|---|
| TSP52015D | Fixed 1.5 V, 600 mA, 3 MHz switching, SOT-23-5, 0.5 µA shutdown current | Higher frequency enables smaller 1 µH inductor but increases gate drive losses above 400 mA | Prefer for space-constrained designs needing <8 mm² solution size; verify thermal performance at 600 mA continuous. |
| RT8059GJ6 | Adjustable 0.6–3.3 V, 600 mA, 1.5 MHz, SOT-23-6, 1.2 µA shutdown current | Requires external feedback resistors; extra pin for PG (power good) signal | Choose when system needs programmable output or power-good monitoring; adds layout complexity vs fixed-output simplicity. |
Compared with TSP52015D and RT8059GJ6, the LM3674MF-1.5 offers best-in-class shutdown current (0.01 µA) for ultra-low-power sleep modes, proven 2 MHz stability with minimal external components, and TI's long-term supply commitment for industrial programs - making it optimal for battery-critical portable instrumentation.
Availability
LM3674MF-1.5 is available at Aetrix Electronics and suitable for mobile phones, wearable health monitors, portable medical devices, and industrial handheld terminals requiring stable component supply across multi-year production cycles.
Supply support for LM3674MF-1.5 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, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets since 1930.
The LM3674MF-1.5 belongs to TI's high-frequency, low-voltage DC-DC converter product line, engineered specifically for space- and power-constrained portable applications where single-cell Li-Ion compatibility and minimal external component count are critical design requirements.
FAQ
What is the recommended input and output capacitor configuration for LM3674MF-1.5?
The LM3674MF-1.5 requires a 4.7 µF X5R/X7R ceramic capacitor (6.3 V rating) placed within 1 mm of the VIN and GND pins, and a 10 µF X5R/X7R ceramic capacitor (6.3 V rating) connected directly between VOUT and GND. These values are validated for stable 2 MHz operation with <15 mVpp ripple at 300 mA load. Avoid Y5V dielectrics due to severe DC bias derating.
Can LM3674MF-1.5 be used with an input voltage below 2.7 V?
No - the LM3674MF-1.5 has a minimum recommended input voltage of 2.7 V per TI's Recommended Operating Conditions. Operation below 2.7 V may cause undervoltage lockout activation, erratic regulation, or failure to start. For sub-2.7 V inputs, consider TI's TPS6274x series or discrete LDO solutions.
Does LM3674MF-1.5 require external feedback resistors?
No - the LM3674MF-1.5 is a fixed-output variant with internal resistor divider set to 1.5 V. The FB pin is internally connected and must not be externally loaded or routed; doing so will disrupt regulation accuracy and may cause instability. Only adjustable versions (e.g., LM3674-ADJ) require external R1/R2.
What thermal derating applies to LM3674MF-1.5 on a 2-layer PCB?
On a standard 2-layer PCB, the LM3674MF-1.5 has RθJA = 250°C/W. At 25°C ambient, maximum continuous power dissipation is 400 mW. At 60°C ambient, it drops to 260 mW - corresponding to ~430 mA load at 1.5 V output (POUT = 0.645 W, η ≈ 92%, PD ≈ 55 mW). Layout with thermal vias to inner ground planes improves performance.
How does the soft-start function operate in LM3674MF-1.5?
The LM3674MF-1.5 implements hardware-based soft-start triggered when EN transitions from low to high after VIN exceeds 2.7 V. It progressively increases the switch current limit in steps (70 mA → 140 mA → 280 mA → 1020 mA) over ~350 µs (with 10 µF COUT, 300 mA load), preventing inrush current into downstream capacitance and avoiding brownout resets in powered systems.
LM3674MF-1.5 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):
- 1.5V
- 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 FAQ
1.How can I place an order for LM3674MF-1.5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3674MF-1.5 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 reliable?
The price and inventory of LM3674MF-1.5 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 is usually 5 days.
3.What payment methods are accepted for LM3674MF-1.5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3674MF-1.5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3674MF-1.5?
LM3674MF-1.5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3674MF-1.5 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?
For technical support, including LM3674MF-1.5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3674MF-1.5 requirements.
6.How does Aetrix verify that LM3674MF-1.5 is sourced from the original manufacturer or authorized distributors?
All LM3674MF-1.5 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 meets industry standards.
7.What is the process for return or replacement of LM3674MF-1.5?
All LM3674MF-1.5 units undergo pre-shipment inspection (PSI). If there is an issue with LM3674MF-1.5, 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 part is unused and in its original packaging.
Return procedure for LM3674MF-1.5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3674MF-1.5 Tags
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