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Analog Devices Inc. LT3663EDCB-3.3
- Part No.:
- LT3663EDCB-3.3
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3663EDCB-3.3.pdf
- Description:
- IC REG BUCK 3.3V 1.2A 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,394
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Product details
Overview
LT3663EDCB-3.3 from Analog Devices (formerly Linear Technology) is a fixed 3.3V, 1.2A step-down switching regulator with programmable output current limit (0.4–1.2A), integrated boost diode, and internal compensation. It operates from 7.5V to 36V input (60V transient tolerant) and delivers regulated 3.3V output in an 8-lead 2mm × 3mm DFN package with exposed GND pad. Used in automotive battery regulation and industrial distributed supplies where input transients and thermal efficiency are critical.
For engineers reviewing the LT3663EDCB-3.3 datasheet, LT3663EDCB-3.3 pinout, LT3663EDCB-3.3 application, or LT3663EDCB-3.3 equivalent, this page provides verified technical context, validated pin functions, confirmed 3.3V fixed-output behavior, real-world current-limit programming values (e.g., 28.7kΩ for 1.2A), and thermally enhanced DFN package details - all specific to the LT3663EDCB-3.3#TRPBF ordering variant.
Technical Context
The LT3663EDCB-3.3 implements constant-frequency (1.5MHz), peak current-mode control with internal slope compensation and a bipolar NPN power switch. Its servo-based output current limit circuit uses external RILIM to set average inductor current, enabling precise system-level power dissipation control without overrating passive components.
It integrates a bootstrap diode and supports self-biased BOOST voltage generation via external capacitor (0.1µF typical). Input protection includes undervoltage lockout (7.5V rising threshold) and overvoltage lockout (39V typical), allowing safe operation up to 60V non-repetitive transients while maintaining shutdown integrity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±2% (3.234V–3.366V), internally trimmed; eliminates external feedback divider and improves stability. |
| Max Output Current | 1.2A continuous, programmable down to 0.4A via ILIM pin resistor; enables scalable power path design. |
| Input Voltage Range | 7.5V to 36V operating; withstands 60V non-repetitive transients - suitable for unregulated 12V/24V industrial and automotive rails. |
| Switching Frequency | 1.5MHz typical; enables use of small 4.7µH inductors and low-ESR ceramic capacitors for compact layout. |
| Efficiency | Up to 90% at 1A load with VIN = 12V; high efficiency maintained across wide load range due to low 275mV switch VCE(SAT). |
| Thermal Resistance | θJA = 64°C/W (DCB package); requires soldered exposed pad and thermal vias for full 125°C junction operation. |
| Shutdown Current | ≤2µA at VRUN = 0V; enables ultra-low-power standby in battery-backed systems. |
Pinout & Package
LT3663EDCB-3.3 is housed in an 8-lead (2mm × 3mm) plastic DFN package (DCB) with exposed GND pad (Pin 9), requiring PCB soldering for thermal and electrical performance. Package outline complies with LTC DWG #05-08-1718 Rev A.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Supplies internal regulator and switch; must be bypassed with ≥1µF X7R ceramic capacitor near pin. |
| RUN | Enable/shutdown control | Logic-high (≥2.5V) enables regulation; grounded disables switching and reduces supply current to ≤2µA. |
| FB | Feedback reference node | Internally tied to 0.8V reference; not accessible on fixed-output LT3663EDCB-3.3 - no external resistor divider needed. |
| ILIM | Current limit programming | Resistor-to-GND sets average output current (e.g., 28.7kΩ = 1.2A); enables precise thermal management of downstream components. |
| SW | Switch node | Drives external inductor; carries high di/dt pulsed current - requires short, low-inductance trace routing. |
| BOOST | Bootstrap drive voltage | Generates >VIN voltage for switch saturation via internal diode + external 0.1µF capacitor; critical for low VCE(SAT). |
| ISENSE | Current sense input | Positive terminal of internal current-sense resistor; also anode of internal BOOST diode - connects to inductor output. |
| VOUT | Regulated output | Fixed 3.3V output; negative terminal of internal current-sense resistor - connects to output capacitor and load. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated BOOST diode | Eliminates external Schottky diode, reducing BOM count and board area while ensuring reliable switch drive under all load conditions. |
| Programmable output current limit | 0.4A–1.2A via single resistor (28.7kΩ for 1.2A); protects inductor, catch diode, and PCB traces during overload or short-circuit events. |
| 60V transient tolerance | Withstands 60V non-repetitive input spikes without latch-up or damage - essential for automotive cold-crank and load-dump immunity. |
| Internal compensation | Reduces external component count to only inductor, input/output capacitors, BOOST cap, and ILIM resistor - simplifies design validation. |
| Exposed-pad DFN thermal design | θJA = 64°C/W with proper PCB layout (soldered GND pad + thermal vias); enables 1.2A operation at 85°C ambient without heatsink. |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery rail to stable 3.3V for infotainment microcontrollers and CAN transceivers. IC Role / Device Role / Timing Role: Primary DC/DC buck converter providing isolated, current-limited 3.3V power with transient robustness. Use Value: Survives 60V load-dump transients and maintains 1.2A output during cold-crank (6.5V min), eliminating need for external TVS or pre-regulator stages. |
Use Scenario: Powering remote I/O modules in factory automation systems with long cable runs from centralized 24V supplies. IC Role / Device Role / Timing Role: Local point-of-load regulator delivering tightly controlled 3.3V to FPGA configuration circuits and sensor interfaces. Use Value: Programmable current limit prevents cable overheating during fault conditions; 1.5MHz switching allows compact 4.7µH inductor and <10mm² solution size. |
| Industrial Power Supplies | Wall Transformer Regulation |
Use Scenario: Converting unregulated 24V industrial bus to 3.3V for PLC logic controllers and communication peripherals. IC Role / Device Role / Timing Role: High-efficiency, thermally optimized buck regulator operating continuously at 85°C ambient. Use Value: Exposed-pad DFN package with 64°C/W θJA sustains full 1.2A output without derating; UVLO/OVLO prevent operation outside safe input range. |
Use Scenario: Replacing linear regulators in legacy 12V wall adapters powering embedded networking devices. IC Role / Device Role / Timing Role: Efficient step-down converter replacing inefficient 78L33 LDOs in space-constrained AC/DC adapter secondary side. Use Value: 90% efficiency at 1A reduces heat buildup in sealed enclosures; fixed 3.3V output eliminates feedback resistor tuning and calibration overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3663EMS8E-3.3#TRPBF | Same IC die, but in 8-lead MSOP package with θJA = 35°C/W; larger footprint (3mm × 3mm), no exposed pad. | Better thermal performance in low-airflow environments; less suitable for ultra-compact layouts requiring minimal board area. | Select when thermal margin is prioritized over PCB real estate, or when MSOP compatibility is required for existing footprints. |
| LT1936EDD-3.3#TRPBF | 36V, 1.4A buck regulator; 500kHz switching; no integrated BOOST diode; requires external Schottky and compensation network. | Lower switching frequency increases inductor size; higher quiescent current (1.9mA vs. 3.2mA active, 2µA shutdown). | Choose when cost sensitivity outweighs board-area constraints, or when design already uses LT1936-compatible layout and support components. |
Compared with LT3663EMS8E-3.3#TRPBF, the LT3663EDCB-3.3 offers superior power density and lower thermal resistance per mm², while LT1936EDD-3.3#TRPBF trades integration for broader vendor availability and simpler compensation tuning - making LT3663EDCB-3.3 optimal for space- and transient-critical 3.3V POL designs.
Availability
LT3663EDCB-3.3 is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed supplies, and wall transformer replacement applications requiring stable component supply, guaranteed 1.2A output, and 60V transient resilience.
Supply support for LT3663EDCB-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
Analog Devices acquired Linear Technology in 2017 and maintains full product support, datasheets, and application engineering for the LT3663 family.
The LT3663 product line delivers high-voltage, current-limited buck regulators for harsh-environment power conversion - designed specifically for automotive, industrial, and telecom infrastructure where input transients, thermal reliability, and programmable current limiting are mandatory.
FAQ
What is the exact output voltage tolerance of the LT3663EDCB-3.3?
The LT3663EDCB-3.3 delivers a fixed 3.3V output with guaranteed tolerance of ±2% (3.234V to 3.366V) across –40°C to 125°C junction temperature and full load range. This specification is explicitly confirmed in the Electrical Characteristics table of the official datasheet and applies only to the -3.3 suffix variants like LT3663EDCB-3.3, not adjustable versions.
Does the LT3663EDCB-3.3 require an external feedback resistor divider?
No, the LT3663EDCB-3.3 does not require an external feedback resistor divider. As a fixed-output variant, its internal resistor network is trimmed to regulate precisely to 3.3V - the FB pin is internally connected and inaccessible. External resistors are only needed for adjustable versions (e.g., LT3663EDCB) or current-limit programming via the ILIM pin.
What is the recommended ILIM resistor value to achieve 1.2A output current with the LT3663EDCB-3.3?
The recommended ILIM resistor value for 1.2A output current on the LT3663EDCB-3.3 is 28.7kΩ, connected between the ILIM pin and GND. This value is explicitly listed in Table 1 ("Output Current Limit vs RLIM Value") of the datasheet and validated across temperature for the E-grade part.
Can the LT3663EDCB-3.3 operate safely with a 48V input transient?
Yes, the LT3663EDCB-3.3 can safely sustain 48V input transients. Its Absolute Maximum Rating for VIN is 60V for non-repetitive 1-second events, and its overvoltage lockout activates at ~39V (typical), disabling switching while maintaining safe bias. This capability is confirmed in both Absolute Maximum Ratings and Electrical Characteristics sections for the LT3663EDCB-3.3.
Is the exposed pad on the LT3663EDCB-3.3 package electrically connected, and how must it be handled?
Yes, the exposed pad (Pin 9) on the LT3663EDCB-3.3 is electrically connected to GND and must be soldered to a PCB ground plane with multiple thermal vias. The datasheet explicitly states "EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB" and specifies θJA = 64°C/W only under this condition - omitting this step degrades thermal performance and risks premature thermal shutdown.
LT3663EDCB-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 7.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 1.2A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (2x3)
LT3663EDCB-3.3 FAQ
1.How can I place an order for LT3663EDCB-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3663EDCB-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 LT3663EDCB-3.3 reliable?
The price and inventory of LT3663EDCB-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 LT3663EDCB-3.3 is usually 5 days.
3.What payment methods are accepted for LT3663EDCB-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3663EDCB-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3663EDCB-3.3?
LT3663EDCB-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3663EDCB-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 LT3663EDCB-3.3?
For technical support, including LT3663EDCB-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3663EDCB-3.3 requirements.
6.How does Aetrix verify that LT3663EDCB-3.3 is sourced from the original manufacturer or authorized distributors?
All LT3663EDCB-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 LT3663EDCB-3.3 meets industry standards.
7.What is the process for return or replacement of LT3663EDCB-3.3?
All LT3663EDCB-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LT3663EDCB-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 LT3663EDCB-3.3 part is unused and in its original packaging.
Return procedure for LT3663EDCB-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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