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Texas Instruments LM3679URX-1.8/NOPB
- Part No.:
- LM3679URX-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 5-XFBGA, DSBGA
- Datasheet:
-
LM3679URX-1.8/NOPB.pdf
- Description:
- IC REG BUCK 1.8V 350MA 5DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:3,646
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Product details
Overview
LM3679URX-1.8/NOPB from Texas Instruments is a 3 MHz, 350 mA synchronous step-down DC-DC converter optimized for ultra-low-profile portable applications powered by a single Li-Ion cell (2.5 V to 5.5 V input). It delivers a fixed 1.8 V output with ±2.5% regulation accuracy in PWM mode and integrates internal PFET/NFET switches, soft-start, and thermal/overcurrent protection - enabling compact power solutions under 0.55 mm total height.
For engineers reviewing the LM3679URX-1.8/NOPB datasheet, LM3679URX-1.8/NOPB pinout, LM3679URX-1.8/NOPB application, or LM3679URX-1.8/NOPB equivalent, key selection considerations include its 16 µA typical quiescent current in PFM mode, automatic PWM/PFM transition at ~42 mA (VIN = 3.6 V), 0.01 µA shutdown current, 5-bump DSBGA YZR package, and compatibility with low-profile external components including 1.0 µH inductors and dual 4.7 µF ceramic output capacitors.
Technical Context
The LM3679URX-1.8/NOPB employs voltage-mode control with input voltage feed-forward to maintain stable line regulation across 2.5–5.5 V input. Its integrated synchronous rectification uses a 350 mΩ PFET and 150 mΩ NFET (typ at VIN = 3.6 V) to achieve >90% efficiency at 300 mA load and 1.8 V output.
Operation dynamically shifts between 3 MHz fixed-frequency PWM mode (≥80 mA load) and variable-frequency PFM mode (<80 mA), reducing IQ to 16 µA (typ) while maintaining output voltage within ±2.5% during light-load conditions. Shutdown is activated via EN pin logic low (<0.4 V), reducing supply current to 0.01 µA (typ).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V with ±2.5% regulation accuracy in PWM mode - ensures stable core voltage for 1.8 V I/O or processor domains. |
| Input Voltage Range | 2.5 V to 5.5 V - supports direct operation from single-cell Li-Ion batteries without pre-regulation. |
| Max Load Current | 350 mA continuous - sufficient for baseband processors, RF transceivers, or camera modules in mobile handsets. |
| Switching Frequency | 3 MHz (typ), 2.5–3.5 MHz (min–max) - enables use of sub-1 mm-height 1.0 µH shielded inductors and 0603 ceramic capacitors. |
| Quiescent Current | 16 µA (typ) in PFM mode - extends battery life during standby or idle states in portable instruments. |
| Shutdown Current | 0.01 µA (typ) - minimizes leakage during system sleep, critical for always-on sensors or real-time clocks. |
| Feedback Voltage | 0.5 V internal reference - sets output via resistor divider; fixed 1.8 V version eliminates external feedback network. |
| Thermal Protection | Engages at TJ ≈ 150°C (typ), disengages at TJ ≈ 130°C - prevents permanent damage during sustained high-power operation. |
Pinout & Package
LM3679URX-1.8/NOPB is housed in a lead-free 5-bump DSBGA YZR package (0.6 mm height, 1.0 mm × 1.4 mm footprint) with non-solder-mask-defined (NSMD) pads and 300 µm solder balls. The package supports ultra-thin PCB designs and requires precision reflow per TI Application Note SNVA009.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (A1) | Power input | Connects directly to input filter capacitor; accepts 2.5–5.5 V; must be decoupled within 2 mm for EMI suppression. |
| GND (A3) | Ground reference | Primary return path for PFET/NFET switching currents; requires low-inductance connection to power plane. |
| EN (C1) | Enable control | Active-high logic input; device enabled at >1.0 V, shutdown at <0.4 V; must not float - tie to MCU GPIO or pull-up. |
| FB (C3) | Feedback node | Not used in fixed-output LM3679URX-1.8/NOPB; internally connected to 0.5 V reference - no external resistor divider required. |
| SW (B2) | Switching node | Drives external inductor; carries high di/dt square wave (0–VIN); requires short, wide trace and ground guard ring to minimize EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic PWM/PFM mode switching | Eliminates manual mode control; transitions seamlessly at ~42 mA (VIN = 3.6 V), optimizing efficiency across full load range. |
| Integrated synchronous rectification | Reduces conduction loss vs. external Schottky diode; enables >90% efficiency at 300 mA with 1.8 V output. |
| Internal soft-start | Staged current limit (200/400/600/920 mA) limits inrush into 10 µF output capacitance - prevents input rail sag during startup. |
| Low-profile solution support | Validated with YPD package + LQM21PN1R0MC0 inductor + dual JMK107BJ475K capacitors for ≤0.55 mm total height. |
| Comprehensive protection | Includes cycle-by-cycle current limiting (920 mA typ), thermal shutdown (150°C), and undervoltage lockout (2.5 V min). |
Applications
| Mobile Handset Core Power | Digital Still Camera Sensor Bias |
|---|---|
Use Scenario: Powering application processor I/O banks and memory interfaces in slim smartphone designs where board height is constrained to <0.6 mm. IC Role / Device Role / Timing Role: Primary 1.8 V buck regulator delivering up to 350 mA with automatic light-load efficiency optimization. Use Value: Enables use of 0603 capacitors and 1.0 µH inductors to meet mechanical height targets without sacrificing transient response or regulation accuracy. | Use Scenario: Supplying image sensor analog and digital rails in compact digital cameras requiring stable 1.8 V with minimal ripple during burst capture. IC Role / Device Role / Timing Role: Fixed-output DC-DC converter providing low-noise, tightly regulated 1.8 V with <2.5% tolerance across temperature and load. Use Value: Delivers >90% efficiency at 200 mA while maintaining <10 mVpp output ripple using dual 4.7 µF X5R ceramics - suppressing sensor noise artifacts. |
| Portable WLAN Module Power | MP3 Player Audio Codec Supply |
Use Scenario: Powering IEEE 802.11b/g/n RF transceivers in handheld wireless clients where battery runtime and thermal dissipation are critical. IC Role / Device Role / Timing Role: High-efficiency step-down regulator operating in PFM mode during receive standby and PWM during transmit bursts. Use Value: Achieves 16 µA quiescent current in PFM mode and fast PWM-to-PFM transition (<10 µs) to preserve signal integrity during channel switching. | Use Scenario: Supplying audio codec and flash memory in battery-powered MP3 players requiring long playback time and silent operation. IC Role / Device Role / Timing Role: Low-noise 1.8 V power source with integrated soft-start and thermal protection for unattended consumer devices. Use Value: Prevents audible pop/click during power-on via controlled 300 µs startup ramp and eliminates thermal derating concerns up to +85°C ambient. |
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 | 3 MHz, 300 mA, fixed 1.8 V; 12 µA IQ in PFM; 2.05–6.0 V input; 6-pin WSON package (2.0 × 2.0 mm). | Larger footprint and height; lacks integrated soft-start; requires external feedback for adjustable versions. | Preferred when board space allows larger package and higher input voltage margin is needed beyond 5.5 V. |
| AP63201WU-18 | 2.5–5.5 V input; 2 A max; fixed 1.8 V; 25 µA IQ; 1.5 MHz switching; 6-bump WLCSP (1.2 × 0.8 mm). | Higher current capability but lower switching frequency; larger package size; no PFM/PWM auto-switching. | Selected when future-proofing for higher load growth or when 1.5 MHz operation better fits system EMI requirements. |
Compared with LM3679URX-1.8/NOPB, TPS62231DRVR offers wider input range but larger footprint and no soft-start, while AP63201WU-18 provides higher current headroom at the cost of reduced switching frequency and absence of intelligent mode transition - making LM3679URX-1.8/NOPB optimal for ultra-thin, battery-sensitive 350 mA applications.
Availability
LM3679URX-1.8/NOPB is available at Aetrix Electronics and suitable for mobile handset core power, digital still camera sensor bias, portable WLAN module power, and MP3 player audio codec supply requiring stable component supply, consistent parametric performance, and long-term lifecycle support.
Supply support for LM3679URX-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 leader specializing in analog, embedded processing, and power management technologies, with over 90 years of innovation in high-reliability, energy-efficient IC design.
The LM3679URX-1.8/NOPB belongs to TI's ultra-low-profile DC-DC converter product line, engineered specifically for space-constrained portable electronics - emphasizing minimal height, automatic efficiency optimization, and seamless integration with miniature passive components.
FAQ
What is the maximum output current capability of the LM3679URX-1.8/NOPB?
The LM3679URX-1.8/NOPB delivers up to 350 mA continuous output current across its full 2.5–5.5 V input range and −30°C to +125°C junction temperature range. At 300 mA, it maintains ≥90% efficiency with 1.8 V output and 3.6 V input. Performance is validated using recommended external components including LQM21PN1R0MC0 inductor and dual JMK107BJ475K capacitors.
Does the LM3679URX-1.8/NOPB require external feedback resistors?
No. The LM3679URX-1.8/NOPB is a fixed-output variant with internal feedback tied to a 0.5 V reference, configured for 1.8 V output. Unlike adjustable versions (e.g., LM3679TL), it does not require external resistors on the FB pin - simplifying layout and reducing BOM count.
How does the LM3679URX-1.8/NOPB manage efficiency at light loads?
The LM3679URX-1.8/NOPB automatically transitions from 3 MHz PWM mode to variable-frequency PFM mode below ~42 mA (at VIN = 3.6 V), reducing quiescent current to 16 µA (typ). This preserves battery life in standby without compromising regulation - output remains within ±2.5% of 1.8 V during PFM operation.
What package type is used for the LM3679URX-1.8/NOPB?
The LM3679URX-1.8/NOPB uses a lead-free 5-bump DSBGA YZR package (1.0 mm × 1.4 mm, 0.6 mm height) with NSMD pads and 300 µm solder balls. It is distinct from the thinner YPD variant and requires precise reflow per TI Application Note SNVA009 for reliable assembly.
Can the LM3679URX-1.8/NOPB operate from a 2.5 V input?
Yes - the LM3679URX-1.8/NOPB operates down to 2.5 V input, supporting single-cell Li-Ion batteries at end-of-discharge. However, maximum output current is reduced to 300 mA at 2.5 V input; full 350 mA capability requires VIN ≥ 2.7 V. Startup is guaranteed only when EN is asserted after VIN exceeds 2.5 V.
LM3679URX-1.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 5-XFBGA, DSBGA
- 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):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 350mA
- Frequency - Switching:
- 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 5-DSBGA (1.47x1.02)
LM3679URX-1.8/NOPB FAQ
1.How can I place an order for LM3679URX-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3679URX-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 LM3679URX-1.8/NOPB reliable?
The price and inventory of LM3679URX-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 LM3679URX-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM3679URX-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3679URX-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3679URX-1.8/NOPB?
LM3679URX-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3679URX-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 LM3679URX-1.8/NOPB?
For technical support, including LM3679URX-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3679URX-1.8/NOPB requirements.
6.How does Aetrix verify that LM3679URX-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3679URX-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 LM3679URX-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM3679URX-1.8/NOPB?
All LM3679URX-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3679URX-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 LM3679URX-1.8/NOPB part is unused and in its original packaging.
Return procedure for LM3679URX-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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