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Texas Instruments LM3671LC-1.8
- Part No.:
- LM3671LC-1.8
- Manufacturer:
- Texas Instruments
- Package:
- 6-UFDFN
- Datasheet:
-
LM3671LC-1.8.pdf
- Description:
- IC REG BUCK 1.8V 600MA 6USON
- Quantity:
- Payment:
- Shipping:
Inventory:2,380
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Product details
Overview
LM3671LC-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 portable electronics. It operates from 2.7 V to 5.5 V input, delivers 2 MHz fixed-frequency PWM switching with automatic PFM mode transition below ~80 mA load, and achieves 16 µA typical quiescent current in light-load operation - enabling extended battery life in mobile phones and digital cameras.
For engineers reviewing the LM3671LC-1.8 datasheet, LM3671LC-1.8 pinout, LM3671LC-1.8 application, or LM3671LC-1.8 equivalent, key selection criteria include its 1.8 V fixed output accuracy (±4%), internal synchronous rectification, thermal shutdown protection at 150°C, and compatibility with only three external components: one 2.2 µH inductor and two ceramic capacitors.
Technical Context
The LM3671LC-1.8 implements voltage-mode control with input-voltage feed-forward compensation to maintain stable regulation across 2.7–5.5 V input range. Its integrated PFET/NFET power stage enables synchronous rectification, eliminating external diode losses and supporting high efficiency at low output voltages.
Operation spans three modes: 2 MHz PWM for loads ≥80 mA, hysteretic PFM for light loads (16 µA IQ), and shutdown (0.01 µA ISHDN). Soft-start limits inrush current via stepped current-limit ramping (70/140/280/1020 mA), and internal 0.5 V reference sets output via fixed resistor divider embedded in the LC variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% - eliminates external feedback resistors and simplifies layout for space-constrained portable designs. |
| Max Output Current | 600 mA - supports core logic rails and I/O supplies in smartphones, PDAs, and portable medical devices. |
| Input Voltage Range | 2.7 V to 5.5 V - compatible with single-cell Li-Ion (fully charged to 4.2 V) and regulated 3.3 V/5 V system rails. |
| Switching Frequency | 2 MHz (typical) - enables use of ultra-small 2.2 µH inductors and 4.7 µF/10 µF ceramic capacitors, reducing solution footprint. |
| Quiescent Current | 16 µA (typical, PFM mode) - extends battery runtime during standby or low-activity states without manual enable control. |
| Shutdown Current | 0.01 µA (typical) - ensures negligible battery drain when system is powered off via EN pin assertion. |
| Internal Reference | 0.5 V - provides stable feedback reference for output regulation; used directly by internal error amplifier in fixed-output variants. |
Pinout & Package
LM3671LC-1.8 is packaged in a 6-pin USON (NKH) package measuring 2.00 mm × 2.00 mm, with wettable flanks for automated optical inspection. Thermal resistance RθJA is 174.7°C/W on a 4-layer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Connects to input filter capacitor; accepts 2.7–5.5 V supply - must be decoupled with ≥4.7 µF ceramic capacitor near pin. |
| GND | Power Ground | Primary return path for input/output currents; requires low-inductance connection to PCB ground plane. |
| EN | Digital Enable | Active-high logic control: >1 V enables regulation; <0.4 V forces shutdown; must not float - tie to VIN or microcontroller GPIO. |
| FB | Feedback Input | Internally connected to fixed 1.8 V divider; no external resistors required - simplifies BOM and layout vs. adjustable versions. |
| SW | Switch Node | Drives external 2.2 µH inductor; carries high dv/dt switching waveform - requires tight loop area with GND and minimal trace length. |
| SGND | Signal Ground | Separate feedback ground pin; connects internally to FB reference - improves regulation accuracy by isolating analog sensing from power return noise. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Synchronous Rectification | Eliminates external Schottky diode, reduces conduction loss, and improves full-load efficiency by up to 12% vs. asynchronous buck converters. |
| Automatic PFM-PWM Mode Switching | Seamlessly transitions between high-efficiency light-load PFM (16 µA IQ) and low-noise PWM (2 MHz) without external control or configuration. |
| Internal Soft-Start | Prevents input inrush current spikes during power-up by ramping switch current limit in four steps (70 → 140 → 280 → 1020 mA). |
| Thermal Shutdown Protection | Disables switching at 150°C junction temperature and resumes operation at 130°C - prevents permanent damage under sustained overload or poor heatsinking. |
| Only Three External Components | Requires just one 2.2 µH inductor and two ceramic capacitors (CIN = 4.7 µF, COUT = 10 µF), minimizing bill-of-materials and PCB area. |
Applications
| Mobile Phone Power Rail | Digital Still Camera Core Supply |
|---|---|
Use Scenario: Powers baseband processor I/O and memory interface circuits requiring stable 1.8 V from a single Li-Ion cell. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated 1.8 V at up to 600 mA with fast transient response to burst-mode processing loads. Use Value: 2 MHz switching enables compact 2.2 µH inductor placement near SoC, while PFM mode extends standby time by maintaining 16 µA quiescent draw. | Use Scenario: Supplies image sensor interface and ISP core logic in compact digital cameras operating from 3.6 V nominal battery. IC Role / Device Role / Timing Role: Fixed-output buck converter providing low-noise 1.8 V rail with <±4% tolerance across temperature and line variations. Use Value: Internal 0.5 V reference and factory-trimmed feedback network ensure output accuracy without calibration, reducing production test complexity. |
| Portable Medical Sensor Module | Wireless Home-Automation Controller |
Use Scenario: Powers low-power microcontroller and analog front-end in battery-operated wearable ECG or SpO₂ monitors. IC Role / Device Role / Timing Role: High-efficiency DC-DC regulator converting 3.0–4.2 V battery voltage to precise 1.8 V for mixed-signal ICs with strict noise and current consumption requirements. Use Value: 0.01 µA shutdown current preserves battery charge over months of storage; thermal shutdown ensures safe operation during enclosure overheating. | Use Scenario: Supplies 1.8 V logic rail for Zigbee/Thread SoCs and RF transceivers in compact smart-home hubs and sensors. IC Role / Device Role / Timing Role: Compact, low-EMI step-down converter supporting intermittent transmit bursts and long idle periods. Use Value: 2 MHz fixed frequency avoids AM radio band interference; small USON package (2.0 × 2.0 mm) fits within tight 10 mm² board area constraints. |
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, 600 mA, 3 MHz switching, 19 µA IQ - higher frequency but slightly higher quiescent current. | Optimized for ultra-thin profiles using 1 µH inductor; lacks SGND pin, potentially reducing light-load regulation accuracy. | Select when board space is constrained to <1.5 mm height and 3 MHz allows smaller magnetics - verify noise sensitivity in analog sections. |
| AP63202WU-18 | 1.8 V fixed output, 2 A capability, 2.2 MHz, 25 µA IQ - higher current rating and wider input range (2.5–5.5 V). | Targeted at industrial IoT nodes needing headroom for future firmware expansion; larger 2.5 × 2.5 mm WLCSP package. | Choose when future-proofing for >600 mA peak loads or requiring operation down to 2.5 V input - accept 9 µA higher IQ for robustness. |
Compared with TPS62231DRVR and AP63202WU-18, the LM3671LC-1.8 offers superior light-load efficiency (16 µA IQ), dedicated SGND for precision feedback, and smallest footprint (2.0 × 2.0 mm USON), making it optimal for cost-sensitive, battery-limited portable designs where 600 mA is sufficient.
Availability
LM3671LC-1.8 is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable medical equipment requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.
Supply support for LM3671LC-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, designing and manufacturing analog ICs, embedded processors, and DLP technology for industrial, automotive, and consumer markets.
The LM3671 product line delivers highly integrated, low-quiescent-current DC-DC buck converters specifically engineered for space- and power-constrained portable electronics powered by single-cell Li-Ion batteries.
FAQ
What is the output voltage tolerance of the LM3671LC-1.8 across temperature and line variations?
The LM3671LC-1.8 guarantees a fixed 1.8 V output with ±4% tolerance over the full operating temperature range (–40°C to +125°C) and input voltage range (2.7 V to 5.5 V). This specification is verified per the electrical characteristics table in the official TI datasheet SNVS294S, where VFB for LC-grade parts is specified as ±4% - directly determining output accuracy since the internal feedback divider is factory-trimmed.
Can the LM3671LC-1.8 operate from a 2.5 V input source?
No, the LM3671LC-1.8 has a minimum recommended input voltage of 2.7 V per the datasheet's Recommended Operating Conditions table. Operation below 2.7 V may cause undervoltage lockout activation or unstable regulation, as the internal reference and control circuitry require sufficient headroom to function correctly.
Does the LM3671LC-1.8 require an external feedback resistor network?
No, the LM3671LC-1.8 does not require external feedback resistors. The "LC" suffix denotes the fixed 1.8 V output variant, which integrates a precision internal resistor divider tied to the 0.5 V internal reference. The FB pin is internally connected and must be left unconnected externally - unlike the adjustable LM3671-ADJ version.
What thermal protection features does the LM3671LC-1.8 include?
The LM3671LC-1.8 incorporates thermal shutdown protection that disables switching when junction temperature reaches approximately 150°C (typical) and re-enables operation once temperature falls to ~130°C. This feature is implemented in hardware and requires no external components - protecting both the IC and surrounding circuitry during sustained overload or inadequate PCB thermal design.
Is the LM3671LC-1.8 pin-compatible with other LM3671 variants like LM3671MF-1.8 or LM3671TL-1.8?
Yes, all LM3671 fixed-output variants - including LM3671LC-1.8, LM3671MF-1.8, and LM3671TL-1.8 - share identical pinout, package outline, and electrical interface across USON, SOT-23, and DSBGA packages. Differences lie solely in grade-specific parameters: LC offers ±4% output tolerance, MF ±2.5%, and TL ±4% with tighter line/load regulation specs - all functionally interchangeable in the same footprint.
LM3671LC-1.8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-UFDFN
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-USON (2x2)
LM3671LC-1.8 FAQ
1.How can I place an order for LM3671LC-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671LC-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 LM3671LC-1.8 reliable?
The price and inventory of LM3671LC-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 LM3671LC-1.8 is usually 5 days.
3.What payment methods are accepted for LM3671LC-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671LC-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671LC-1.8?
LM3671LC-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671LC-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 LM3671LC-1.8?
For technical support, including LM3671LC-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671LC-1.8 requirements.
6.How does Aetrix verify that LM3671LC-1.8 is sourced from the original manufacturer or authorized distributors?
All LM3671LC-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 LM3671LC-1.8 meets industry standards.
7.What is the process for return or replacement of LM3671LC-1.8?
All LM3671LC-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM3671LC-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 LM3671LC-1.8 part is unused and in its original packaging.
Return procedure for LM3671LC-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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