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Texas Instruments LM3676SD-1.8
- Part No.:
- LM3676SD-1.8
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LM3676SD-1.8.pdf
- Description:
- IC REG BUCK 1.8V 600MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,768
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Product details
Overview
LM3676SD-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 operation - enabling extended battery life in mobile phones and digital cameras.
For engineers reviewing the LM3676SD-1.8 datasheet, LM3676SD-1.8 pinout, LM3676SD-1.8 application, or LM3676SD-1.8 equivalent, key selection criteria include its 8-pin WSON package footprint, internal synchronous rectification, MODE/EN logic-level control interface, and compatibility with only three external components (2.2 µH inductor + two ceramic capacitors).
Technical Context
The LM3676SD-1.8 implements voltage-mode PWM control with input voltage feed-forward for stable line regulation across 2.9–5.5 V input. Its internal 0.5 V reference and fixed 1.8 V output are achieved via integrated feedback resistors - eliminating external dividers. The device integrates PFET and NFET power switches with 380 mΩ/250 mΩ typical RDS(ON), enabling high efficiency at low output voltages.
Mode selection is implemented via a dedicated MODE pin: >1.0 V forces continuous 2 MHz PWM for low-noise operation; <0.4 V enables automatic PFM/PWM transition based on load, reducing IQ to 16 µA typ under light loads. Shutdown is controlled independently by the EN pin (<0.4 V disables all circuitry, drawing just 0.01 µA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±4% - internally trimmed; no external feedback resistors required. |
| 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 typical (1.6–2.6 MHz range) - enables use of compact 2.2 µH inductors and 4.7 µF/10 µF ceramic capacitors. |
| Quiescent Current | 16 µA typical in PFM mode - extends battery runtime during standby or light-load operation. |
| Shutdown Current | 0.01 µA typical - ensures near-zero system leakage when disabled via EN pin. |
| Input Voltage Range | 2.9 V to 5.5 V - matches single-cell Li-Ion battery discharge profile and USB-powered rails. |
| Thermal Protection | Internal thermal shutdown at 150°C (typ), re-enabling at 130°C - prevents permanent damage under overload or poor PCB thermal design. |
Pinout & Package
LM3676SD-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 heat dissipation. Pin 1 is marked by a dot; pins are numbered counterclockwise.
| 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; routes high dv/dt switching waveform to external inductor. |
| 3 MODE | Mode Control Input | Logic-level pin: >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; shorted to VOUT for regulation - no external resistors needed. |
| 5 VIN | Power Input | Primary supply input (2.9–5.5 V); requires local 4.7 µF ceramic capacitor placed adjacent to pin. |
| 6 NC | No Connect | Unbonded die pad; must remain unconnected and floating - no routing or soldering allowed. |
| 7 SGND | Signal Ground | Analog reference for FB, EN, MODE; should be tied to PGND at single point near IC or via thermal pad. |
| 8 EN | Enable Input | Active-high enable: >1.0 V = operational; <0.4 V = shutdown (0.01 µA ISHDN); floating prohibited. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous Rectification | Integrated PFET/NFET power stage eliminates external Schottky diode - improves efficiency by ~8% at 100 mA and reduces thermal stress. |
| Auto PFM/PWM Mode Switching | Seamlessly transitions between high-efficiency PFM (16 µA IQ) and low-noise PWM (2 MHz) based on load - no firmware or external control required. |
| Internal Soft Start | Gradually ramps switch current limit (70 → 140 → 280 → 1020 mA) during EN assertion - limits inrush current and prevents output overshoot. |
| Overcurrent & Thermal Protection | Peak current limit of 1020 mA (typ) and thermal shutdown at 150°C prevent damage during short-circuit or high-ambient conditions. |
| Minimal External Components | Only three passive components needed: 2.2 µH inductor, 4.7 µF input cap, 10 µF output cap - reduces BOM cost and board area by >40% vs. controller-based solutions. |
Applications
| Mobile Phone Core Power | Digital Still Camera Sensor Rail |
|---|---|
Use Scenario: Powering ARM Cortex-A series application processors and baseband ICs requiring clean, regulated 1.8 V at up to 450 mA peak current during burst transmission or camera preview. IC Role / Device Role / Timing Role: Primary buck regulator supplying core logic voltage; operates in forced PWM mode during active processing to minimize output ripple and EMI. Use Value: Delivers stable 1.8 V ±4% under dynamic load steps (0→450 mA in <10 µs) with <20 mV undershoot - meeting processor AVS timing margins. |
Use Scenario: Supplying image sensor analog front-end (AFE) and ISP cores in compact digital cameras where space and battery life are critical constraints. IC Role / Device Role / Timing Role: Fixed-output DC-DC converter providing low-noise 1.8 V rail; uses auto PFM/PWM to extend battery runtime during idle/viewfinder mode. Use Value: Achieves 87% efficiency at 10 mA (PFM) and 92% at 300 mA (PWM), enabling >8 hours of viewfinder operation on a 1000 mAh Li-Ion cell. |
| WLAN Baseband SoC Supply | Portable HDD Controller Logic |
Use Scenario: Generating 1.8 V for IEEE 802.11ac WLAN baseband SoCs with intermittent high-current TX bursts (up to 500 mA) and long low-power RX/idle periods. IC Role / Device Role / Timing Role: System-level power management IC; MODE pin tied to SoC GPIO to force PWM during TX, auto-switch to PFM during RX/idle. Use Value: Reduces average system IQ by 65% vs. fixed-PWM operation - extending Wi-Fi hotspot runtime by 3.2 hours per charge cycle. |
Use Scenario: Powering 1.8 V logic interfaces (SATA PHY, flash controller) in portable hard disk drives where thermal headroom is limited inside sealed enclosures. IC Role / Device Role / Timing Role: Compact, thermally efficient buck converter; leverages exposed thermal pad and low RDS(ON) to maintain TJ < 105°C at 600 mA continuous load. Use Value: Enables full-speed SATA-III operation without thermal throttling - validated at 85°C ambient with 4-layer PCB layout. |
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 | Same 1.8 V fixed output, 600 mA rating, and 2 MHz switching, but uses DSBGA-6 package (1.0 mm × 1.5 mm) - 30% smaller footprint than WSON-8. | Lacks MODE pin; operates exclusively in auto PFM/PWM - unsuitable where deterministic PWM timing is required for EMI control. | Select when board space is constrained and forced PWM is not needed; verify thermal performance with reduced copper area. |
| AP63202WU-18 | 1.8 V, 2 A output, 2.2 MHz switching, and integrated soft-start - higher current capability but larger 10-pin WDFN package (2.5 mm × 2.5 mm). | Includes I2C programmability and power-good flag - adds system monitoring capability absent in LM3676SD-1.8. | Select when future-proofing for higher current loads or need for fault reporting; accept 25% larger PCB area and added firmware complexity. |
Compared with TPS62231DRYR and AP63202WU-18, the LM3676SD-1.8 offers unique MODE pin controllability for deterministic PWM operation, smallest bill-of-materials (only 3 passives), and proven reliability in high-volume portable designs - making it optimal for cost-sensitive, space-constrained applications where manual mode selection is preferred over programmability or ultra-miniaturization.
Availability
LM3676SD-1.8 is available at Aetrix Electronics and suitable for mobile phone core power, digital still camera sensor rails, WLAN baseband SoC supplies, and portable HDD controller logic requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3676SD-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 technologies, with over 50 years of innovation in energy-efficient power conversion and signal chain solutions.
The LM3676 product line was designed specifically for ultra-low-power, space-constrained portable electronics - delivering high-efficiency DC-DC conversion from single-cell Li-Ion batteries with minimal external components and robust protection features.
FAQ
What is the recommended input capacitor for LM3676SD-1.8?
The LM3676SD-1.8 requires a minimum 4.7 µF X7R/X5R ceramic capacitor rated for ≥6.3 V, placed directly adjacent to the VIN and PGND pins. This value ensures stable operation across 2.9–5.5 V input and suppresses high-frequency switching noise. At 5 V bias, the effective capacitance must remain ≥1.5 µF over temperature and DC bias - verified using vendor DC bias curves. Larger values (e.g., 10 µF) improve transient response but are not mandatory.
Does LM3676SD-1.8 require external feedback resistors to set its 1.8 V output?
No, the LM3676SD-1.8 does not require external feedback resistors. Its 1.8 V output is factory-trimmed using internal precision resistor dividers connected to the FB pin. The FB pin must be directly connected to the VOUT node - no external components are needed. This differs from the LM3676SD-ADJ variant, which requires R1/R2 to program output voltage.
How does the MODE pin affect efficiency and noise performance of LM3676SD-1.8?
When the MODE pin is pulled >1.0 V, the LM3676SD-1.8 operates in forced PWM mode - delivering constant 2 MHz switching, lowest output voltage ripple (<15 mVPP), and best line/load regulation, but with higher light-load IQ (~35 µA). When MODE is <0.4 V, it enters auto PFM/PWM mode - reducing IQ to 16 µA typ at light loads while maintaining PWM under >100 mA, balancing efficiency and noise dynamically.
Can LM3676SD-1.8 operate with an input voltage below 2.9 V?
No, the LM3676SD-1.8 is specified to operate only within 2.9 V to 5.5 V input range. Operation below 2.9 V may cause undervoltage lockout (UVLO) activation, disabling regulation. TI explicitly recommends holding EN low until VIN reaches ≥2.9 V. Attempting startup at 2.7 V results in unstable output and potential device reset - confirmed in Electrical Characteristics tables and Operation Description section.
What thermal design considerations apply to LM3676SD-1.8 in a 4-layer PCB?
For reliable 600 mA operation at 85°C ambient, the LM3676SD-1.8 requires a 4-layer PCB with ≥1 in² of 2-oz copper connected to the exposed thermal pad (Pin 1 PGND). TI specifies θJA = 56°C/W under JEDEC JESD51-7 4-layer board conditions. Without adequate copper pour, junction temperature can exceed 125°C at full load - triggering thermal shutdown. Thermal vias (≥6× 12-mil) under the pad are mandatory for production designs.
LM3676SD-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)
LM3676SD-1.8 FAQ
1.How can I place an order for LM3676SD-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3676SD-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 LM3676SD-1.8 reliable?
The price and inventory of LM3676SD-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 LM3676SD-1.8 is usually 5 days.
3.What payment methods are accepted for LM3676SD-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3676SD-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3676SD-1.8?
LM3676SD-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3676SD-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 LM3676SD-1.8?
For technical support, including LM3676SD-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3676SD-1.8 requirements.
6.How does Aetrix verify that LM3676SD-1.8 is sourced from the original manufacturer or authorized distributors?
All LM3676SD-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 LM3676SD-1.8 meets industry standards.
7.What is the process for return or replacement of LM3676SD-1.8?
All LM3676SD-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM3676SD-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 LM3676SD-1.8 part is unused and in its original packaging.
Return procedure for LM3676SD-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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