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Texas Instruments LM3676SD-ADJ
- Part No.:
- LM3676SD-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LM3676SD-ADJ.pdf
- Description:
- IC REG BUCK ADJ 600MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,884
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Product details
Overview
LM3676SD-ADJ from Texas Instruments is a 2-MHz, 600-mA synchronous step-down DC-DC converter in an 8-lead WSON package, designed for Li-Ion-powered portable electronics. It delivers adjustable output voltage (1.1 V to 3.3 V) from 2.9 V–5.5 V input, features automatic PFM/PWM mode switching, 16 µA quiescent current in light-load PFM mode, and internal soft-start-enabling efficient power management in mobile phones and digital cameras.
For engineers reviewing the LM3676SD-ADJ datasheet, LM3676SD-ADJ pinout, LM3676SD-ADJ application, or LM3676SD-ADJ equivalent, key selection criteria include its adjustable feedback architecture (0.5 V reference), MODE/EN logic thresholds (0.4 V / 1.0 V), thermal shutdown behavior (150 °C trip), 2.2 µH inductor requirement, and compatibility with only three external components (inductor + two ceramics).
Technical Context
The LM3676SD-ADJ employs voltage-mode PWM control with input voltage feed-forward for stable line regulation and integrates synchronous PFET/NFET switches with typical RDS(ON) of 380 mΩ (P) and 250 mΩ (N). Its dual-mode operation-forced PWM (>100 mA load or MODE >1.0 V) and auto PFM-PWM (<100 mA)-is governed by internal comparators monitoring SW node zero-crossing and peak current limits.
Feedback is referenced to a precision 0.5 V internal bandgap; output voltage is set externally via resistor divider (R1/R2) on FB pin. The device supports LDO-like 100% duty-cycle operation near dropout, with minimum input voltage determined by ILOAD × (RDS(ON) + RINDUCTOR) + VOUT, and includes undervoltage lockout below 2.9 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.9 V to 5.5 V - supports single-cell Li-Ion battery operation without pre-regulation. |
| Output Current Capability | 600 mA max - sustained across full input range and ambient temperature (−30 °C to +125 °C). |
| Switching Frequency | 2 MHz typical (1.6–2.6 MHz) - enables use of compact 2.2 µH inductor and low-ESR ceramic capacitors. |
| Quiescent Current | 16 µA typical in PFM mode - extends battery life during standby or light-load operation. |
| Feedback Reference Voltage | 0.5 V ±4% - sets output voltage via external R1/R2 divider; enables 1.1 V–3.3 V adjustment range. |
| Shutdown Current | 0.01 µA typical - ensures minimal leakage when EN < 0.4 V, critical for system-level power gating. |
| Current Limit Threshold | 1020 mA typical (open-loop) - protects against overload and short-circuit conditions with thermal foldback. |
Pinout & Package
LM3676SD-ADJ is housed in an 8-lead non-pullback WSON package (Package Number NGQ0008A, 2.0 mm × 2.0 mm, 0.5 mm pitch), optimized for high-density portable PCB layouts with exposed thermal pad.
| 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 | Switching Node | Connection point between internal PFET drain and NFET source; routes high-frequency AC current to external inductor. |
| 3: MODE | Mode Control Input | Logic-controlled pin: <0.4 V enables auto PFM/PWM; >1.0 V forces continuous PWM; floating prohibited. |
| 4: FB | Feedback Input | Analog input sensing output voltage via external resistor divider; disables internal fixed-voltage divider in ADJ version. |
| 5: VIN | Power Supply Input | Primary DC input (2.9–5.5 V); requires local 4.7 µF ceramic capacitor placed adjacent to pin. |
| 6: NC | No Connect | Internally unconnected; must remain floating-no PCB trace or solder connection permitted. |
| 7: SGND | Signal Ground | Reference for EN, MODE, and FB pins; isolated from PGND to minimize noise coupling into feedback path. |
| 8: EN | Enable Input | Active-high enable: <0.4 V disables device (0.01 µA shutdown); >1.0 V activates regulation; floating prohibited. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Eliminates external Schottky diode; reduces conduction loss and improves efficiency at low VOUT (e.g., 1.5 V). |
| Automatic PFM/PWM Transition | Seamlessly shifts between high-efficiency PFM (16 µA IQ) and low-noise PWM (2 MHz fixed freq) based on load current. |
| Integrated Soft-Start | Staged current limit ramp-up (70 → 140 → 280 → 1020 mA) prevents inrush current and output overshoot at startup. |
| Thermal & Overcurrent Protection | Thermal shutdown engages at ~150 °C; cycle-by-cycle current limiting trips at 1020 mA typical to protect IC and inductor. |
| Adjustable Output Architecture | 0.5 V reference + external R1/R2 allows precise VOUT tuning from 1.1 V to 3.3 V with stability compensation guidance provided. |
Applications
| Mobile Phone Power Rail | Digital Still Camera Core Logic |
|---|---|
Use Scenario: Regulating main SoC core voltage (1.2–1.8 V) from single Li-Ion cell in slim smartphone designs. IC Role / Device Role / Timing Role: Primary buck converter delivering up to 600 mA with dynamic PFM/PWM mode switching during burst-mode CPU activity. Use Value: 16 µA quiescent current in PFM mode extends standby time; 2 MHz switching avoids AM radio band interference. |
Use Scenario: Powering image sensor interface and ISP logic in compact digital cameras requiring clean, low-noise supply. IC Role / Device Role / Timing Role: Adjustable-output DC-DC supplying 1.5 V or 2.5 V to CMOS sensor front-end with tight ripple tolerance. Use Value: Forced PWM mode eliminates PFM-induced frequency variation, ensuring stable timing for high-speed pixel readout. |
| WLAN Module Baseband | Portable Hard Disk Drive Controller |
Use Scenario: Generating 1.8 V or 3.3 V for Wi-Fi/BT baseband ICs in handheld IoT devices with aggressive power budget. IC Role / Device Role / Timing Role: Efficient intermediate rail converter enabling fast wake-from-sleep transitions via EN pin control. Use Value: 0.01 µA shutdown current minimizes system leakage; MODE pin allows firmware-controlled efficiency/noise trade-off. |
Use Scenario: Supplying 2.5 V or 3.3 V to HDD controller ASIC during spin-up and data transfer phases. IC Role / Device Role / Timing Role: High-current (≥500 mA) buck regulator supporting transient-heavy loads with thermal foldback protection. Use Value: 600 mA capability and 1020 mA current limit prevent brownout during motor start; thermal shutdown avoids permanent damage. |
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 output; 3-MHz switching; 400-mA rating; smaller 6-pin WSON package. | Lacks adjustable output and MODE pin control; suited for space-constrained fixed-voltage rails only. | Select TPS62231DRVR only if output voltage is fixed and load ≤400 mA; LM3676SD-ADJ preferred for design flexibility. |
| TPS62260DRVR | Adjustable output (0.6–5.5 V); 2.25-MHz switching; 600-mA rating; integrated soft-start and power-good. | Includes PG pin and tighter VREF accuracy (±1%); higher BOM cost but enhanced system monitoring capability. | Choose TPS62260DRVR when power-good signaling or ±1% output accuracy is required; LM3676SD-ADJ offers lower cost and proven PFM efficiency. |
Compared with TPS62231DRVR and TPS62260DRVR, the LM3676SD-ADJ provides unique value in ultra-low-quiescent PFM operation (16 µA) and explicit MODE pin control-making it optimal for battery-sensitive portable systems where adaptive efficiency outweighs need for power-good or tighter reference tolerance.
Availability
LM3676SD-ADJ is available at Aetrix Electronics and suitable for mobile phone power rails, digital camera core logic, WLAN module baseband supplies, and portable hard disk drive controllers requiring stable component supply and long-term production continuity.
Supply support for LM3676SD-ADJ 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 electronics.
The LM3676 product line was engineered specifically for Li-Ion-powered portable devices demanding compact size, ultra-low IQ, and seamless light-to-heavy load efficiency-targeting mobile phones, PDAs, MP3 players, and digital imaging equipment.
FAQ
What is the minimum input voltage required for LM3676SD-ADJ to regulate a 1.5 V output at 300 mA?
The minimum input voltage depends on load current, PFET RDS(ON), and inductor DCR. For LM3676SD-ADJ with 300 mA load, typical RDS(ON) = 380 mΩ, and assuming 50 mΩ inductor resistance, VINMIN ≈ 1.5 V + 300 mA × (0.38 Ω + 0.05 Ω) = 2.79 V. However, the datasheet specifies 2.9 V as absolute minimum operating voltage due to internal bias requirements-so 2.9 V is the guaranteed functional floor for LM3676SD-ADJ.
How does the MODE pin affect efficiency and noise performance in LM3676SD-ADJ?
In LM3676SD-ADJ, pulling MODE >1.0 V forces continuous PWM mode-delivering lowest output voltage ripple and best line/load regulation but higher light-load IQ (~35 µA). Pulling MODE <0.4 V enables auto PFM/PWM mode, reducing IQ to 16 µA at light loads and extending battery life, at the cost of variable switching frequency and slightly higher ripple. The choice directly trades noise performance for efficiency in LM3676SD-ADJ designs.
Can LM3676SD-ADJ operate in 100% duty cycle, and what are the implications?
Yes, LM3676SD-ADJ supports 100% duty cycle (LDO-like operation) when VIN approaches VOUT, enabling regulation down to VIN = VOUT + ILOAD × (RDS(ON) + RINDUCTOR). In this state, the PFET remains fully on, eliminating switching losses but increasing output ripple to ~25 mV peak-to-peak. This mode is useful for maintaining output during battery discharge, and is explicitly supported in the LM3676SD-ADJ datasheet.
What external components are mandatory for basic LM3676SD-ADJ operation?
Three components are mandatory for LM3676SD-ADJ: a 2.2 µH shielded inductor (saturation current ≥1200 mA), a 4.7 µF X7R/X5R ceramic input capacitor placed adjacent to VIN, and a 10 µF ceramic output capacitor. For the ADJ version, two feedback resistors (R1/R2) are also required to set VOUT; R2 is typically 200 kΩ to minimize divider current while maintaining noise immunity in LM3676SD-ADJ circuits.
Does LM3676SD-ADJ include thermal protection, and how does it behave?
Yes, LM3676SD-ADJ incorporates thermal shutdown protection that activates at ~150 °C junction temperature and releases at ~130 °C. During overtemperature events, the device halts switching, holds EN and MODE states, and draws only shutdown current (0.01 µA) until cooling occurs. This behavior is fully specified in the Absolute Maximum Ratings and Operating Ratings sections of the LM3676SD-ADJ datasheet and prevents permanent damage under sustained overload or poor PCB thermal design.
LM3676SD-ADJ 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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.9V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.1V
- Voltage - Output (Max):
- 3.3V
- 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)
LM3676SD-ADJ FAQ
1.How can I place an order for LM3676SD-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3676SD-ADJ 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 LM3676SD-ADJ reliable?
The price and inventory of LM3676SD-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3676SD-ADJ is usually 5 days.
3.What payment methods are accepted for LM3676SD-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3676SD-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3676SD-ADJ?
LM3676SD-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3676SD-ADJ 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 LM3676SD-ADJ?
For technical support, including LM3676SD-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3676SD-ADJ requirements.
6.How does Aetrix verify that LM3676SD-ADJ is sourced from the original manufacturer or authorized distributors?
All LM3676SD-ADJ 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 LM3676SD-ADJ meets industry standards.
7.What is the process for return or replacement of LM3676SD-ADJ?
All LM3676SD-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM3676SD-ADJ, 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 LM3676SD-ADJ part is unused and in its original packaging.
Return procedure for LM3676SD-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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