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Texas Instruments LM3674MFX-1.875/NOPB
- Part No.:
- LM3674MFX-1.875/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3674MFX-1.875/NOPB.pdf
- Description:
- IC REG BUCK 1.875V 600MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,549
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Product details
Overview
LM3674MFX-1.875/NOPB from Texas Instruments is a fixed-output, 1.875 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 phones and digital cameras.
For engineers reviewing the LM3674MFX-1.875/NOPB datasheet, LM3674MFX-1.875/NOPB pinout, LM3674MFX-1.875/NOPB application, or LM3674MFX-1.875/NOPB equivalent, key selection considerations include its fixed 1.875 V output, SOT-23-5 package footprint, 2-MHz switching frequency enabling use of tiny 2.2 µH inductors and 10 µF ceramic output capacitors, and integrated synchronous rectification for >90% efficiency at mid-load in portable systems.
Technical Context
The LM3674MFX-1.875/NOPB 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 and fixed feedback divider set the regulated output precisely to 1.875 V without external resistors.
It integrates a 380 mΩ PFET switch and 250 mΩ NFET synchronous rectifier, enabling high efficiency across 10–600 mA loads. Thermal shutdown, current-limit protection (1020 mA typical), and undervoltage lockout ensure robust operation under fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.875 V ±4% - eliminates need for external feedback resistors and simplifies layout for stable low-noise core supply. |
| Max Output Current | 600 mA - supports processor cores, memory I/O, and RF subsystems in handheld devices without external boost stages. |
| Input Voltage Range | 2.7 V to 5.5 V - fully compatible with single-cell Li-Ion (3.0–4.2 V) and USB-powered (5 V) operation. |
| Switching Frequency | 2 MHz (typical), 1.6–2.6 MHz (min–max) - enables use of small 2.2 µH shielded inductors and 10 µF X5R ceramic capacitors. |
| Shutdown Current | 0.01 µA (typical) - minimizes battery drain during system sleep modes in always-on portable applications. |
| Feedback Reference | 0.5 V internal - sets output via internal resistor divider; no external components required for fixed-voltage variants. |
| Thermal Protection | 125°C junction shutdown - 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-free (NOPB).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Accepts 2.7–5.5 V; requires local 4.7 µF ceramic decoupling capacitor placed adjacent to pin for low-ESR input filtering. |
| GND (Pin 2) | Ground reference | Primary return path for input/output currents and IC substrate; must connect to low-impedance ground plane. |
| EN (Pin 3) | Digital enable | Active-high logic control; device enabled when >1 V, disabled when <0.4 V; 0.01 µA leakage ensures minimal standby drain. |
| FB (Pin 4) | Feedback input | Internally connected to fixed 1.875 V divider; not user-accessible - no external resistor network needed for this variant. |
| SW (Pin 5) | Switching node | Drives external inductor; carries high di/dt square wave; requires short, low-inductance trace to minimize EMI and voltage spikes. |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and improving full-load efficiency by ~8–12% vs. asynchronous designs. |
| 2-MHz fixed-frequency PWM | Enables use of sub-3 mm × 3 mm inductors and avoids AM radio band interference; supports fast transient response. |
| Integrated soft-start | Ramps output voltage over ~240–350 µs (depending on load/capacitance), limiting inrush current and preventing input rail collapse. |
| Current limit & thermal shutdown | 1020 mA peak switch current limit and 125°C thermal cutoff protect against short-circuit, overtemperature, and inductor saturation faults. |
| Low quiescent current | 300 µA typical operating IQ and 0.01 µA shutdown current extend battery life in intermittent-use portable devices. |
Applications
| Mobile Phone Core Supply | Digital Camera Sensor Bias |
|---|---|
Use Scenario: Powers ARM Cortex-A series application processors requiring stable 1.875 V core voltage from a single Li-Ion cell. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated core power; operates in continuous conduction mode at 2 MHz. Use Value: Enables compact 2.2 µH + 10 µF solution footprint while maintaining <15 mV output ripple under 500 mA dynamic load steps. |
Use Scenario: Supplies image sensor analog front-end (AFE) and ADC reference rails in DSLR and mirrorless camera modules. IC Role / Device Role / Timing Role: Low-noise, fixed-output DC-DC converter providing clean bias for precision analog signal chains. Use Value: Delivers 1.875 V with <0.5% line/load regulation and <25 mV peak-to-peak ripple - meeting sensor SNR requirements without LDO post-regulation. |
| WLAN Baseband SoC Power | Portable HDD Controller Supply |
Use Scenario: Powers IEEE 802.11ac baseband SoCs in smartphones and tablets where burst-mode RF transmission demands fast load transient response. IC Role / Device Role / Timing Role: High-frequency buck converter supplying SoC I/O and PLL domains; switches at 2 MHz for rapid loop response. Use Value: Achieves <10 µs recovery time from 100→600 mA load steps due to high bandwidth control loop and synchronous architecture. |
Use Scenario: Supplies 1.875 V to 2.5 V controller ICs in 2.5-inch portable hard disk drives powered from USB 5 V or battery packs. IC Role / Device Role / Timing Role: Efficient intermediate voltage regulator stepping down from 5 V or 3.3 V to match controller logic thresholds. Use Value: Maintains >88% efficiency at 400 mA load, reducing thermal stress in sealed drive enclosures and extending runtime per charge 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 |
|---|---|---|---|
| TPS62231DRVR | 1.8 V fixed output (±1%), 3-MHz switching, 0.03 µA shutdown, but only 300 mA max output current. | Lower current capability limits use to ultra-low-power microcontrollers or sensors - not suitable for 600 mA SoC cores. | Select when lower quiescent current and higher frequency are prioritized over output current headroom. |
| AP3012KTR-G1 | Adjustable output (0.6–5 V), 1.5-MHz switching, 600 mA rating, but uses external feedback resistors and lacks integrated soft-start. | Requires additional BOM components and layout area; less optimal for space-constrained fixed-voltage designs. | Select when output voltage flexibility or cost sensitivity outweighs the benefit of pin-compatible simplicity. |
Compared with TPS62231DRVR and AP3012KTR-G1, the LM3674MFX-1.875/NOPB provides the only combination of 600 mA capability, fixed 1.875 V output, 2-MHz operation, and zero external feedback components - making it uniquely suited for compact, high-reliability core power in portable imaging and communications devices.
Availability
LM3674MFX-1.875/NOPB is available at Aetrix Electronics and suitable for mobile phone power management, digital camera sensor biasing, and WLAN baseband SoC supply applications requiring stable component supply, consistent parametric performance, and long-term production continuity.
Supply support for LM3674MFX-1.875/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 LM3674MFX-1.875/NOPB belongs to TI's low-voltage, high-frequency buck converter product line, designed specifically to replace linear regulators in battery-powered devices where efficiency, size, and thermal performance are critical.
FAQ
What is the output voltage tolerance of the LM3674MFX-1.875/NOPB?
The LM3674MFX-1.875/NOPB delivers a nominal 1.875 V output with a guaranteed tolerance of ±4% over temperature (−30°C to 125°C) and line/load conditions, as specified in the Electrical Characteristics table of the SNVS405G datasheet. This tolerance is achieved using an internal 0.5 V reference and precision laser-trimmed feedback resistors - no external calibration is required. The LM3674MFX-1.875/NOPB maintains this accuracy without user adjustment across its full 2.7–5.5 V input range and 0–600 mA load range.
Can the LM3674MFX-1.875/NOPB be used with a 2.2 µH inductor and 10 µF output capacitor?
Yes - the LM3674MFX-1.875/NOPB is explicitly validated for use with a 2.2 µH inductor (e.g., Coilcraft DO3314-222MX) and 10 µF X5R ceramic output capacitor (e.g., Murata GRM21BR60J106K), as shown in the Typical Application Circuit (Figure 19) and confirmed in Section 8.2.1.2.1 of the SNVS405G datasheet. These values yield <15 mV output ripple at 500 mA and ensure stable operation across temperature and input voltage variations. The LM3674MFX-1.875/NOPB's 2-MHz switching frequency makes this compact passive set feasible.
Does the LM3674MFX-1.875/NOPB require external feedback resistors?
No - the LM3674MFX-1.875/NOPB is a fixed-output variant with internal feedback resistors configured for 1.875 V. Pin 4 (FB) is internally connected and not accessible for external adjustment; therefore, no external R1/R2 divider is needed or supported. This distinguishes it from the LM3674-ADJ version, which requires external resistors to set the output. The LM3674MFX-1.875/NOPB simplifies design, reduces BOM count, and improves reliability by eliminating feedback component tolerances and layout sensitivity.
What is the maximum ambient temperature for continuous 600 mA operation of the LM3674MFX-1.875/NOPB?
At 600 mA load and 3.6 V input, the LM3674MFX-1.875/NOPB can operate continuously up to 60°C ambient temperature on a standard 2-layer PCB (RθJA = 250°C/W), based on its 125°C maximum junction temperature and 260 mW power dissipation rating at TA = 60°C (Section 6.5, SNVS405G). For 85°C ambient operation, a 4-layer board (RθJA = 130°C/W) is required to maintain safe junction temperature. Thermal derating curves are provided in Figure 7 of the datasheet.
How does the LM3674MFX-1.875/NOPB handle short-circuit conditions?
The LM3674MFX-1.875/NOPB responds to output short-circuit with cycle-by-cycle current limiting (1020 mA typical trip point) followed by thermal shutdown if sustained. During overload, the device enters timed current-limit mode: the NFET remains on longer to allow inductor current decay, preventing runaway. If junction temperature exceeds 125°C, thermal shutdown disables switching until cooldown. Recovery is automatic upon fault removal and temperature reduction. This dual-protection scheme is documented in Sections 7.3.2.2 and 7.4 of the SNVS405G datasheet.
LM3674MFX-1.875/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):
- 1.875V
- 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-1.875/NOPB FAQ
1.How can I place an order for LM3674MFX-1.875/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3674MFX-1.875/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-1.875/NOPB reliable?
The price and inventory of LM3674MFX-1.875/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-1.875/NOPB is usually 5 days.
3.What payment methods are accepted for LM3674MFX-1.875/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3674MFX-1.875/NOPB transactions.
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4.How is shipping managed for LM3674MFX-1.875/NOPB?
LM3674MFX-1.875/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3674MFX-1.875/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-1.875/NOPB?
For technical support, including LM3674MFX-1.875/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3674MFX-1.875/NOPB requirements.
6.How does Aetrix verify that LM3674MFX-1.875/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3674MFX-1.875/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-1.875/NOPB meets industry standards.
7.What is the process for return or replacement of LM3674MFX-1.875/NOPB?
All LM3674MFX-1.875/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3674MFX-1.875/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-1.875/NOPB part is unused and in its original packaging.
Return procedure for LM3674MFX-1.875/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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