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Texas Instruments LM3671LC-1.8/NOPB
- Part No.:
- LM3671LC-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-UFDFN
- Datasheet:
-
LM3671LC-1.8/NOPB.pdf
- Description:
- IC REG BUCK 1.8V 600MA 6USON
- Quantity:
- Payment:
- Shipping:
Inventory:10,000
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Product details
Overview
LM3671LC-1.8/NOPB 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/NOPB datasheet, LM3671LC-1.8/NOPB pinout, LM3671LC-1.8/NOPB application, or LM3671LC-1.8/NOPB equivalent, key selection considerations include its USON-6 package footprint, internal 0.5 V reference, 1020 mA peak switch current limit, thermal shutdown at 150°C (typ), and compatibility with only three external components: one 2.2 µH inductor and two ceramic capacitors.
Technical Context
The LM3671LC-1.8/NOPB implements voltage-mode control with input-voltage feed-forward 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 like 1.8 V.
It features dual-mode operation: fixed 2 MHz PWM for load currents ≥80 mA ensures low-noise, predictable transient response; hysteretic PFM engages at lighter loads to reduce quiescent current to 16 µA (typ) while maintaining regulation within ±4% of 1.8 V output. Soft-start limits inrush current via stepped current-limit ramp (70 → 140 → 280 → 1020 mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% over −40°C to +125°C - ensures stable core logic supply for ASICs/FPGAs without external feedback resistors. |
| Max Output Current | 600 mA continuous - supports moderate-power subsystems such as camera ISPs or RF front-ends in handheld devices. |
| Switching Frequency | 2 MHz (typ), 1.6–2.6 MHz (min/max) - enables use of compact 2.2 µH inductors and reduces EMI fundamental frequency above AM band. |
| Quiescent Current | 16 µA (typ) in PFM mode - extends battery runtime during standby or display-off states in portable instruments. |
| Shutdown Current | 0.01 µA (typ) - minimizes battery drain when system is fully powered down. |
| Input Voltage Range | 2.7 V to 5.5 V - compatible with single-cell Li-ion (2.7–4.2 V), USB 5 V, or regulated 3.3 V rails. |
| Internal Reference | 0.5 V - sets feedback threshold; for LM3671LC-1.8/NOPB, internal resistor divider fixes VOUT = 1.8 V = 0.5 V × (1 + R1/R2). |
Pinout & Package
LM3671LC-1.8/NOPB uses the USON-6 (NKH) package: 2.00 mm × 2.00 mm body, 0.5 mm pitch, wettable flank terminals. Thermal resistance RθJA = 174.7°C/W on 4-layer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Accepts 2.7–5.5 V; must be decoupled with ≥4.7 µF ceramic capacitor close to pin to suppress switching noise and support peak current delivery. |
| GND (Pin 2) | Power ground | Primary return path for high-frequency switch current; requires low-inductance connection to PCB ground plane. |
| EN (Pin 3) | Digital enable | Active-high logic input; device enabled when >1 V, shutdown when <0.4 V; must not float - tie to VIN or controller GPIO with pull-up if unused. |
| FB (Pin 4) | Feedback input | Internally connected to fixed 1.8 V divider; shorted to VOUT for regulation - no external resistors required. |
| SW (Pin 5) | Switch node | Drives external 2.2 µH inductor; carries high dv/dt square wave - requires tight layout, minimal trace length, and guard ring to reduce EMI. |
| SGND (Pin 6) | Signal ground | Separate analog ground for FB reference; must connect to main GND at single point near IC to avoid noise coupling into feedback path. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and improving full-load efficiency by ~8–12% vs asynchronous buck. |
| Automatic PFM-PWM mode switching | Seamlessly transitions between high-efficiency light-load PFM and low-noise PWM without external control - simplifies firmware and improves dynamic response. |
| Internal soft-start | Staged 70/140/280/1020 mA current-limit ramp prevents output overshoot and inrush stress on input capacitor and load. |
| Thermal shutdown protection | Engages at 150°C (typ), disengages at 130°C (typ) - protects IC and PCB during sustained overload or poor heatsinking. |
| Only three external components | Requires just one 2.2 µH inductor and two ceramic caps (CIN, COUT) - minimizes BOM count, board area, and design validation effort. |
Applications
| Mobile Phone Power Rail | Digital Still Camera Core Supply |
|---|---|
Use Scenario: Powers baseband processor I/O or memory interface in slim smartphone designs using single Li-Ion cell. IC Role / Device Role / Timing Role: Primary 1.8 V buck regulator delivering up to 600 mA with 2 MHz switching to minimize filter size and meet EMI limits. Use Value: Enables compact layout with 2.2 µH inductor and 10 µF output cap; PFM mode extends standby time by reducing IQ to 16 µA. | Use Scenario: Supplies image signal processor (ISP) core voltage in battery-operated digital cameras. IC Role / Device Role / Timing Role: Fixed 1.8 V step-down converter providing clean, regulated power with fast load transient response during burst capture. Use Value: 2 MHz PWM ensures rapid recovery from 10–90% load steps (<5 µs); internal soft-start prevents ISP reset during power-on. |
| Portable Medical Sensor Module | Wireless Home-Automation Controller |
Use Scenario: Powers low-power microcontroller and analog front-end in wearable ECG or SpO₂ sensor. IC Role / Device Role / Timing Role: Efficient 1.8 V source operating across full battery discharge curve (4.2 V → 2.7 V input). Use Value: Maintains >85% efficiency from 10 mA to 600 mA load; shutdown current <0.01 µA preserves battery during multi-week storage. | Use Scenario: Supplies 1.8 V rail to Zigbee/Thread SoC and flash memory in battery-powered smart switches/sensors. IC Role / Device Role / Timing Role: Always-on buck converter supporting intermittent radio transmission and deep-sleep MCU states. Use Value: PFM mode sustains 16 µA quiescent draw during 99% sleep duty cycle; thermal shutdown prevents overheating in enclosed enclosures. |
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 | Fixed 1.8 V, 600 mA, 3–6 MHz adjustable frequency, 17 µA IQ, SOT-23-6 package. | Higher switching frequency allows smaller inductors but increases EMI filtering complexity; lacks PFM mode - less efficient below 50 mA. | Prefer for space-constrained layouts needing <1.5 µH inductors; avoid where ultra-low IQ in standby is critical. |
| AP63202WU-18 | Fixed 1.8 V, 2 A, 2 MHz, 25 µA IQ, WLCSP-6 package; includes spread-spectrum clocking. | Higher current rating and integrated spread spectrum reduce EMI peaks; larger 2 A capability adds cost and thermal margin beyond need for 600 mA apps. | Choose when future-proofing for higher loads or stringent CISPR-22 Class B emissions compliance is required. |
Compared with TPS62231DRVR and AP63202WU-18, LM3671LC-1.8/NOPB offers the best balance of ultra-low light-load IQ (16 µA), proven PFM-PWM seamless transition, and minimal external component count - making it optimal for cost-sensitive, battery-life-critical portable designs at ≤600 mA.
Availability
LM3671LC-1.8/NOPB is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable medical equipment requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3671LC-1.8/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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and silicon technology for industrial, automotive, and consumer markets.
The LM3671 product line delivers highly integrated, low-quiescent-current DC-DC converters targeting battery-powered portable electronics - designed to maximize runtime, minimize board area, and simplify power architecture with minimal external components.
FAQ
What is the recommended input capacitor for LM3671LC-1.8/NOPB?
The LM3671LC-1.8/NOPB datasheet specifies a minimum 4.7 µF X5R/X7R ceramic capacitor at the VIN pin, placed as close as possible to pins 1 (VIN) and 2 (GND). TI recommends using a 4.7–10 µF capacitor with ≤100 mΩ ESL to handle high-frequency ripple current and prevent input voltage droop during 2 MHz switching transitions. Larger values improve hold-up time but do not affect regulation stability.
Does LM3671LC-1.8/NOPB require an external feedback resistor network?
No, LM3671LC-1.8/NOPB does not require external feedback resistors. It is a fixed-output variant with an internal resistor divider configured for 1.8 V output. The FB pin (Pin 4) connects directly to the output capacitor for regulation - unlike the adjustable LM3671MF-ADJ version, which requires external R1/R2 to set VOUT.
What thermal derating applies to LM3671LC-1.8/NOPB at 85°C ambient?
At 85°C ambient temperature, the LM3671LC-1.8/NOPB's maximum power dissipation is derated to 242 mW (per datasheet Table 6.6), based on its USON-6 RθJA of 174.7°C/W. This corresponds to ~400 mA max continuous load at 1.8 V output under worst-case conditions - designers should verify junction temperature using TJ = TA + (PDISS × RθJA) and ensure TJ remains ≤125°C.
How does LM3671LC-1.8/NOPB behave during input voltage brownout?
The LM3671LC-1.8/NOPB incorporates undervoltage lockout (UVLO) that disables switching when VIN falls below ~2.5 V (typical turn-on threshold is 2.7 V). Below this, the device enters shutdown mode with 0.01 µA current draw. It will not attempt regulation or deliver output current until VIN rises above the UVLO threshold and EN is asserted - preventing unstable operation or output collapse during battery depletion.
Can LM3671LC-1.8/NOPB drive a 10 µF output capacitor safely during startup?
Yes, LM3671LC-1.8/NOPB safely drives a 10 µF output capacitor thanks to its internal soft-start circuit. The device ramps the switch current limit in four stages (70 → 140 → 280 → 1020 mA), limiting inrush current and preventing output overshoot. Typical startup time with 10 µF COUT and 300 mA load is 400 µs - well within safe limits for ceramic capacitors and downstream logic.
LM3671LC-1.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-UFDFN
- 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):
- 1.8V
- 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/NOPB FAQ
1.How can I place an order for LM3671LC-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3671LC-1.8/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 LM3671LC-1.8/NOPB reliable?
The price and inventory of LM3671LC-1.8/NOPB 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/NOPB is usually 5 days.
3.What payment methods are accepted for LM3671LC-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3671LC-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3671LC-1.8/NOPB?
LM3671LC-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3671LC-1.8/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 LM3671LC-1.8/NOPB?
For technical support, including LM3671LC-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3671LC-1.8/NOPB requirements.
6.How does Aetrix verify that LM3671LC-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3671LC-1.8/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 LM3671LC-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM3671LC-1.8/NOPB?
All LM3671LC-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3671LC-1.8/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 LM3671LC-1.8/NOPB part is unused and in its original packaging.
Return procedure for LM3671LC-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3671LC-1.8/NOPB Tags
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