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Texas Instruments LM3676SDX-1.8
- Part No.:
- LM3676SDX-1.8
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LM3676SDX-1.8.pdf
- Description:
- IC REG BUCK 1.8V 600MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,820
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Product details
Overview
LM3676SDX-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 2.9 V to 5.5 V input, delivers 2 MHz fixed-frequency PWM or auto PFM/PWM mode switching, and achieves 16 µA typical quiescent current in light-load PFM mode - enabling extended battery life in mobile phones and digital cameras.
For engineers reviewing the LM3676SDX-1.8 datasheet, LM3676SDX-1.8 pinout, LM3676SDX-1.8 application, or LM3676SDX-1.8 equivalent, key selection criteria include its 8-pin WSON package, internal synchronous rectification, MODE pin-controlled efficiency optimization, and compatibility with only three external components (2.2 µH inductor + two ceramic capacitors).
Technical Context
The LM3676SDX-1.8 implements voltage-mode control with input voltage feed-forward to maintain stable regulation across 2.9–5.5 V input range. Its integrated PFET/NFET power stage supports up to 600 mA output with RDSON(P) = 380 mΩ (typ) and RDSON(N) = 250 mΩ (typ), enabling high efficiency at low output voltages.
Mode selection is hardware-driven: MODE pin >1.0 V forces continuous 2 MHz PWM operation; <0.4 V enables automatic PFM/PWM transition based on load (e.g., PFM below ~100 mA at VIN = 3.6 V). Feedback uses a precision 0.5 V internal reference, with fixed 1.8 V output achieved via internal resistor divider - eliminating external resistors required in the adjustable version.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% - internally trimmed; no external feedback resistors needed. |
| Max Output Current | 600 mA - sustained across full input range (2.9–5.5 V) and junction temperature (−30°C to +125°C). |
| Switching Frequency | 2 MHz (typ), 1.6–2.6 MHz (min–max) - enables use of compact 2.2 µH inductor and 4.7 µF/10 µF ceramic capacitors. |
| Quiescent Current | 16 µA (typ) in PFM mode - extends battery runtime during standby or light-load operation. |
| Shutdown Current | 0.01 µA (typ) - near-zero power draw when EN pin <0.4 V. |
| Input Voltage Range | 2.9 V to 5.5 V - matches single-cell Li-Ion battery discharge profile (fully compatible from 3.0 V nominal down to 2.9 V cutoff). |
| Protection Features | Thermal shutdown (150°C typ), current limit (1020 mA typ), undervoltage lockout - ensures robust operation under fault conditions. |
Pinout & Package
LM3676SDX-1.8 is housed in an 8-lead non-pullback WSON package (Package Number NGQ0008A), measuring 2.0 mm × 2.0 mm × 0.75 mm, with exposed thermal pad for enhanced power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 PGND | Power Ground | High-current return path for internal PFET/NFET switches; must be connected to low-impedance ground plane. |
| 2 SW | Switch Node | Connection point between internal PFET drain and NFET source; ties directly to inductor and diode-free output path. |
| 3 MODE | Mode Control Input | Digital-selectable operation: >1.0 V = forced PWM; <0.4 V = auto PFM/PWM; floating prohibited. |
| 4 FB | Feedback Input | Internally connected to fixed 1.8 V divider; no external connection required for this variant. |
| 5 EN | Enable Input | Logic-controlled startup/shutdown: >1.0 V = active; <0.4 V = 0.01 µA shutdown; floating prohibited. |
| 6 NC | No Connect | Unbonded pin; must remain unconnected and floating - no PCB trace or pull-up/down. |
| 7 SGND | Signal Ground | Reference for FB, MODE, and EN inputs; should be routed separately from PGND and joined at single point. |
| 8 VIN | Input Supply | Primary power input (2.9–5.5 V); requires local 4.7 µF ceramic capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Eliminates external Schottky diode; reduces conduction loss and improves efficiency by >10% at 1.8 V/300 mA vs. asynchronous designs. |
| Auto PFM/PWM Mode Switching | Seamlessly transitions between high-efficiency PFM (16 µA IQ) at light loads and low-noise PWM (2 MHz) above ~100 mA - no firmware or external logic required. |
| Integrated Soft Start | Gradually ramps switch current limit (70 → 140 → 280 → 1020 mA) during EN assertion - prevents inrush current and output overshoot into 10 µF COUT. |
| Only Three External Components | Requires just one 2.2 µH inductor and two ceramic capacitors (4.7 µF CIN, 10 µF COUT) - minimizes BOM count, board area, and layout complexity. |
| Thermal & Overcurrent Protection | Thermal shutdown activates at TJ ≈ 150°C (typ); cycle-by-cycle current limit trips at 1020 mA (typ) - protects IC and system during short-circuit or overload events. |
Applications
| Mobile Phones | MP3 Players |
|---|---|
Use Scenario: Powering baseband processor core voltage rail in slim-profile smartphones operating from single Li-Ion cell. IC Role / Device Role / Timing Role: Primary 1.8 V buck regulator delivering up to 600 mA with dynamic load response to CPU burst activity. Use Value: Auto PFM/PWM mode maintains >85% efficiency from 1 mA standby to 400 mA peak, extending talk time without requiring system-level mode coordination. | Use Scenario: Supplying DSP and audio codec in portable music players with tight space constraints. IC Role / Device Role / Timing Role: Fixed 1.8 V power source with 2 MHz switching enabling ultra-compact 2.2 µH inductor placement near SoC. Use Value: Internal soft start prevents pop noise during playback startup; 16 µA quiescent current preserves battery over multi-day idle periods. |
| Digital Still Cameras | WLAN Modules |
Use Scenario: Powering image sensor interface and ISP in compact digital cameras with rapid on/off cycling. IC Role / Device Role / Timing Role: Fast-enabling 1.8 V supply synchronized to camera shutter command via EN pin. Use Value: 0.01 µA shutdown current eliminates battery drain during storage; 400 µs typical startup time (with 10 µF COUT + 300 mA load) supports responsive capture. | Use Scenario: Regulating 1.8 V I/O supply for IEEE 802.11b/g/n transceivers in handheld IoT devices. IC Role / Device Role / Timing Role: Low-noise, high-PWM-mode regulator minimizing RF interference during data transmission bursts. Use Value: Forced PWM mode (via MODE pin) ensures consistent 2 MHz switching - simplifying EMI filtering and avoiding frequency modulation artifacts in sensitive RF bands. |
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 V input, 3.6 MHz switching, 17 µA IQ - higher frequency but narrower input range. | Requires ≥3 V input; unsuitable for Li-Ion cells below 3.0 V; better for 3.3 V rail-derived systems. | Select if system uses regulated 3.3 V input and needs smaller inductor; avoid for direct Li-Ion battery input. |
| AP63202-W5-7 | Fixed 1.8 V, 2 A, 2.5–5.5 V input, 2 MHz, 22 µA IQ - higher current rating, same footprint-compatible WDFN package. | Over-specified current capability adds cost and size; thermal performance differs due to different package construction. | Choose only if future design scaling to >600 mA is certain; otherwise LM3676SDX-1.8 offers optimal cost/size/efficiency balance. |
Compared with TPS62231DRVR and AP63202-W5-7, the LM3676SDX-1.8 uniquely supports full Li-Ion battery voltage range (2.9–5.5 V) while maintaining 16 µA quiescent current and minimal external component count - making it the most integrated solution for space-constrained, battery-life-sensitive portable designs.
Availability
LM3676SDX-1.8 is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and WLAN modules requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3676SDX-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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-efficiency DC-DC conversion.
The LM3676 product line was designed specifically for ultra-low-power portable electronics powered by single-cell Li-Ion batteries, emphasizing minimal external components, adaptive efficiency modes, and robust protection in miniature WSON packaging.
FAQ
What is the recommended input capacitor for LM3676SDX-1.8?
The LM3676SDX-1.8 requires a minimum 4.7 µF X7R/X5R ceramic capacitor rated for ≥6.3 V, placed directly adjacent to the VIN pin. This value ensures stable operation across 2.9–5.5 V input and suppresses high-frequency switching noise. The datasheet specifies 2.2 µF as absolute minimum at 3 V bias, but 4.7 µF is the validated design value used in all TI reference layouts for LM3676SDX-1.8.
Does LM3676SDX-1.8 require external feedback resistors?
No, LM3676SDX-1.8 does not require external feedback resistors. It is a fixed-output variant with internal resistor divider set to 1.8 V, and the FB pin is pre-connected internally. External resistors are only needed for the LM3676SDX-ADJ version. Connecting external components to FB on LM3676SDX-1.8 may disrupt regulation accuracy.
How does the MODE pin affect efficiency in LM3676SDX-1.8?
When the MODE pin is pulled low (<0.4 V), LM3676SDX-1.8 enters auto PFM/PWM mode, achieving 16 µA typical quiescent current at light loads (e.g., <100 mA), maximizing battery life. When pulled high (>1.0 V), it operates in forced 2 MHz PWM mode, delivering lower output ripple and superior transient response at medium-to-heavy loads - allowing system designers to trade noise performance for efficiency based on real-time requirements.
What is the maximum allowable ambient temperature for continuous 600 mA operation of LM3676SDX-1.8?
At TA = 85°C, the LM3676SDX-1.8 can sustain 600 mA output only with adequate PCB copper area and thermal vias under the exposed pad. The datasheet specifies 714 mW maximum power dissipation at TA = 85°C on a 4-layer board (θJA = 56°C/W). Exceeding this requires derating - e.g., max load drops to ~450 mA at TA = 85°C with standard layout. Junction temperature must remain ≤125°C.
Can LM3676SDX-1.8 be used with input voltages below 2.9 V?
No, LM3676SDX-1.8 is not specified to operate below 2.9 V. The device incorporates undervoltage lockout (UVLO) that disables switching until VIN reaches 2.9 V. Attempting to power it from <2.9 V - such as deeply discharged Li-Ion cells - results in no output regulation and potential instability. TI explicitly recommends holding EN low until VIN ≥2.9 V, as stated in the Operation Description section of the LM3676SDX-1.8 datasheet.
LM3676SDX-1.8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- 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):
- 2.9V
- 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:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WSON (3x3)
LM3676SDX-1.8 FAQ
1.How can I place an order for LM3676SDX-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3676SDX-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 LM3676SDX-1.8 reliable?
The price and inventory of LM3676SDX-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 LM3676SDX-1.8 is usually 5 days.
3.What payment methods are accepted for LM3676SDX-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3676SDX-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3676SDX-1.8?
LM3676SDX-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3676SDX-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 LM3676SDX-1.8?
For technical support, including LM3676SDX-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3676SDX-1.8 requirements.
6.How does Aetrix verify that LM3676SDX-1.8 is sourced from the original manufacturer or authorized distributors?
All LM3676SDX-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 LM3676SDX-1.8 meets industry standards.
7.What is the process for return or replacement of LM3676SDX-1.8?
All LM3676SDX-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM3676SDX-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 LM3676SDX-1.8 part is unused and in its original packaging.
Return procedure for LM3676SDX-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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