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Texas Instruments LM3676SDX-3.3
- Part No.:
- LM3676SDX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LM3676SDX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 600MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,035
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Product details
Overview
LM3676SDX-3.3 from Texas Instruments is a fixed-output 3.3 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-3.3 datasheet, LM3676SDX-3.3 pinout, LM3676SDX-3.3 application, or LM3676SDX-3.3 equivalent, key selection criteria include its 8-pin WSON package, internal synchronous rectification, MODE/EN logic-level control interface, 0.5 V internal reference, and thermal/overcurrent protection - all critical for compact, high-efficiency power rail design in space-constrained portable systems.
Technical Context
The LM3676SDX-3.3 implements voltage-mode PWM control with input voltage feed-forward for stable line regulation across 2.9–5.5 V input. Its integrated PFET/NFET synchronous rectifier pair enables high efficiency at low output voltages, with RDSON(P) = 380 mΩ (typ) and RDSON(N) = 250 mΩ (typ).
Operation is governed by two dedicated control pins: EN enables/disables the regulator with 0.4 V/1.0 V logic thresholds, while MODE selects forced PWM (>1.0 V) or auto PFM/PWM (<0.4 V). The FB pin connects directly to the output capacitor for fixed 3.3 V regulation, referencing an internal 0.5 V bandgap.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% - no external feedback resistors required; regulated via internal 0.5 V reference and FB pin connection to VOUT. |
| Max Output Current | 600 mA - sustained over 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 small 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 in portable devices. |
| Shutdown Current | 0.01 µA (typ) - achieved when EN < 0.4 V; ensures near-zero system leakage during powered-off states. |
| Input Voltage Range | 2.9 V to 5.5 V - matches single-cell Li-Ion battery discharge profile and supports USB-powered operation. |
| Protection Features | Thermal shutdown (150°C typ), cycle-by-cycle current limit (1020 mA typ), and undervoltage lockout - prevents damage under fault or brownout conditions. |
Pinout & Package
LM3676SDX-3.3 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; drives external inductor; requires tight layout to minimize EMI. |
| 3 MODE | Mode Control Input | Logic-controlled selection: <0.4 V → auto PFM/PWM; >1.0 V → forced PWM; floating prohibited. |
| 4 FB | Feedback Input | Direct connection to VOUT for fixed 3.3 V regulation; internal resistor divider enabled; no external components needed. |
| 5 EN | Enable Input | Active-high enable: <0.4 V → shutdown (0.01 µA IQ); >1.0 V → normal operation; floating prohibited. |
| 6 NC | No Connect | Unbonded pin; must remain unconnected and floating; no PCB trace or solder mask required. |
| 7 SGND | Signal Ground | Reference for FB, MODE, and EN inputs; should be tied to PGND at single point near IC for noise immunity. |
| 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 at 3.3 V output, especially under medium-to-heavy loads. |
| Auto PFM/PWM Mode Switching | Seamlessly transitions between high-efficiency PFM (16 µA IQ) at light load and low-noise PWM (2 MHz) above ~100 mA - optimizing battery life and EMI simultaneously. |
| Integrated Soft-Start | Gradually ramps switch current limit (70→140→280→1020 mA) during EN assertion, limiting inrush current into 10 µF output capacitor and preventing input rail collapse. |
| Only Three External Components | Requires only one 2.2 µH inductor and two ceramic capacitors (4.7 µF CIN, 10 µF COUT) - minimizes BOM count and board area in space-critical designs. |
| Thermal & Overcurrent Protection | Internal thermal shutdown (150°C) and cycle-by-cycle peak current limit (1020 mA typ) safeguard device and system during overload, short-circuit, or poor heatsinking conditions. |
Applications
| Mobile Phone Power Management | Digital Still Camera Core Rail |
|---|---|
Use Scenario: Powers baseband processor, display interface, and RF transceiver in slim smartphone designs using single Li-Ion cell. IC Role / Device Role / Timing Role: Primary 3.3 V buck regulator delivering up to 600 mA with dynamic load response to burst-mode CPU activity. Use Value: 2 MHz switching enables ultra-compact 2.2 µH inductor placement; 16 µA PFM IQ extends standby time beyond 7 days on 1000 mAh battery. | Use Scenario: Supplies image sensor interface, memory controller, and LCD driver in compact digital cameras with rapid on/off cycling. IC Role / Device Role / Timing Role: Fixed 3.3 V core supply with fast transient response to flash LED activation and sensor readout bursts. Use Value: Auto PFM/PWM mode reduces average supply current by 65% vs. forced PWM during viewfinder idle state, preserving battery for photo capture. |
| WLAN Module Baseband Supply | Portable Instrument MCU Rail |
Use Scenario: Provides clean, regulated 3.3 V to IEEE 802.11b/g/n baseband ICs in handheld hotspot or IoT gateway modules. IC Role / Device Role / Timing Role: Low-noise 2 MHz PWM mode maintains spectral purity during packet transmission; soft-start prevents RF interference at power-up. Use Value: Internal synchronous rectification achieves >90% efficiency at 300 mA, reducing thermal load in sealed plastic enclosures without heatsinks. | Use Scenario: Powers ARM Cortex-M microcontroller and analog front-end in battery-operated test equipment like handheld DMMs or data loggers. IC Role / Device Role / Timing Role: Primary system rail with shutdown capability (EN pin) enabling deep-sleep modes consuming <1 µA total system current. Use Value: 0.01 µA shutdown current allows multi-year operation on coin-cell backup; thermal shutdown protects against ambient temperature excursions in field use. |
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 |
|---|---|---|---|
| TPS62231DRYR | 3.3 V fixed, 600 mA, 3–6 V input, 3.6 MHz switching, 19 µA IQ in PFM - higher frequency but narrower input range. | Requires ≥3 V input; unsuitable for Li-Ion cells below 3.0 V; better for USB-powered systems. | Select TPS62231DRYR if system input stays ≥3.0 V and board space permits smaller 1 µH inductor. |
| AP3012KTR-G1 | 3.3 V fixed, 300 mA, 2.5–5.5 V input, 1.5 MHz switching, 40 µA IQ - lower current rating and higher quiescent current. | Limited to ≤300 mA loads; less suitable for processors or RF ICs requiring >400 mA peak current. | Choose AP3012KTR-G1 only for cost-sensitive, low-power peripherals where 300 mA headroom suffices. |
Compared with LM3676SDX-3.3, TPS62231DRYR offers faster transient response due to higher 3.6 MHz frequency but sacrifices Li-Ion compatibility below 3.0 V; AP3012KTR-G1 provides broader input range but lacks the 600 mA capability and ultra-low 16 µA IQ needed for premium portable battery life.
Availability
LM3676SDX-3.3 is available at Aetrix Electronics and suitable for mobile phone power management, digital still camera core rails, WLAN module baseband supplies, and portable instrument MCU rails requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3676SDX-3.3 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 and battery-powered systems.
The LM3676 product line was designed specifically for space-constrained, battery-operated portable electronics - delivering high integration, ultra-low quiescent current, and robust protection in miniature WSON packages for mobile phones, PDAs, and digital imaging devices.
FAQ
What is the recommended input capacitor for LM3676SDX-3.3?
A 4.7 µF X7R/X5R ceramic capacitor rated for ≥6.3 V DC is recommended for LM3676SDX-3.3. It must be placed as close as possible to the VIN and PGND pins to minimize high-frequency loop inductance. The minimum acceptable value is 2.2 µF at 3 V DC bias, but 4.7 µF ensures stable operation across temperature, voltage, and capacitance tolerance variations in real-world LM3676SDX-3.3 deployments.
Does LM3676SDX-3.3 require external feedback resistors to set the 3.3 V output?
No, LM3676SDX-3.3 does not require external feedback resistors. It is a fixed-output variant with internal resistor divider configured for 3.3 V regulation. The FB pin connects directly to the VOUT node, referencing the internal 0.5 V bandgap. External resistors are only needed for the adjustable LM3676SDX-ADJ version - not for LM3676SDX-3.3.
How does the MODE pin affect efficiency and noise performance in LM3676SDX-3.3?
When MODE is pulled high (>1.0 V), LM3676SDX-3.3 operates in forced PWM mode - delivering lowest output voltage ripple and best load regulation, but with higher 35 µA typical IQ. When MODE is pulled low (<0.4 V), it enters auto PFM/PWM mode - dropping IQ to 16 µA at light loads while maintaining PWM at >100 mA, balancing efficiency and noise. Leaving MODE floating is prohibited and may cause erratic behavior in LM3676SDX-3.3.
What thermal considerations apply to LM3676SDX-3.3 in continuous 600 mA operation?
In continuous 600 mA operation at 3.3 V output and 3.6 V input, LM3676SDX-3.3 dissipates ~0.18 W. With θJA = 56°C/W (4-layer board), junction temperature rise is ~10°C above ambient. To maintain TJ ≤125°C, ambient must stay ≤115°C - but derating is advised above 85°C ambient. Use the exposed thermal pad, connect PGND/SGND to large copper pour, and avoid enclosing LM3676SDX-3.3 in sealed enclosures without airflow.
Can LM3676SDX-3.3 be used with input voltages below 2.9 V?
No, LM3676SDX-3.3 is not specified to operate below 2.9 V input. Undervoltage lockout disables regulation when VIN falls below this threshold, and attempting operation risks unstable output or failure to start. For Li-Ion batteries discharging below 2.9 V, consider pairing LM3676SDX-3.3 with a fuel gauge or system-level cutoff, or select a converter with wider input range such as TPS61099 - but LM3676SDX-3.3 itself must be operated strictly within 2.9–5.5 V.
LM3676SDX-3.3 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):
- 3.3V
- 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-3.3 FAQ
1.How can I place an order for LM3676SDX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3676SDX-3.3 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-3.3 reliable?
The price and inventory of LM3676SDX-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3676SDX-3.3 is usually 5 days.
3.What payment methods are accepted for LM3676SDX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3676SDX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3676SDX-3.3?
LM3676SDX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3676SDX-3.3 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-3.3?
For technical support, including LM3676SDX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3676SDX-3.3 requirements.
6.How does Aetrix verify that LM3676SDX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM3676SDX-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM3676SDX-3.3?
All LM3676SDX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM3676SDX-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM3676SDX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3676SDX-3.3 Tags
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