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Analog Devices Inc. LT3663EDCB-5
- Part No.:
- LT3663EDCB-5
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3663EDCB-5.pdf
- Description:
- IC REG BUCK 5V 1.2A 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,825
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Product details
Overview
LT3663EDCB-5 from Analog Devices (formerly Linear Technology) is a fixed 5V, 1.2A step-down switching regulator with programmable output current limit, wide 7.5V–36V input range, integrated boost diode, and internal compensation. It operates at 1.5MHz fixed frequency in peak current mode and is used in automotive battery regulation and industrial distributed supplies where transient robustness to 60V and thermal efficiency are critical.
For engineers reviewing the LT3663EDCB-5 datasheet, LT3663EDCB-5 pinout, LT3663EDCB-5 application, or LT3663EDCB-5 equivalent, key selection criteria include its 5V fixed output, 0.4A–1.2A programmable current limit via ILIM resistor, 275mV switch VCE(SAT) at 1A, thermal shutdown, and exposed-pad DFN package for low θJA = 64°C/W.
Technical Context
The LT3663EDCB-5 implements constant-frequency peak current mode control with internal slope compensation and an internally compensated error amplifier (G1) that regulates FB to 0.8V. Its servo-based output current limit circuit uses ISENSE and ILIM to enforce average inductor current limits independent of load voltage.
Startup and high-efficiency operation rely on the BOOST pin, driven by an internal Schottky diode and external capacitor to generate >VIN gate drive - enabling full saturation of the internal NPN switch. Input protection includes undervoltage lockout (7.5V rising) and overvoltage lockout (39V typical), with safe 60V transient tolerance while disabled.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.5% (guaranteed over –40°C to 125°C junction temperature) |
| Max Output Current | 1.2A continuous (programmable down to 0.4A via ILIM resistor) |
| Input Voltage Range | 7.5V to 36V operating; withstands nonrepetitive 60V transients |
| Switching Frequency | 1.5MHz typical (±10% variation); enables compact 6.8µH inductor and low-profile layout |
| Switch VCE(SAT) | 275mV at 1A - reduces conduction loss and improves efficiency at high load |
| Feedback Reference | 0.800V ±2% at FB pin - sets output via internal resistor divider (no external resistors required) |
| Thermal Resistance | θJA = 64°C/W (DCB package with soldered exposed pad to PCB ground plane) |
Pinout & Package
LT3663EDCB-5 is housed in an 8-lead (2mm × 3mm) plastic DFN package with exposed GND pad (Pin 9), requiring soldering to PCB for thermal and electrical performance. Package code: DCB; marking: LFMY; temperature grade: E (–40°C to 125°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Supplies internal regulator and switch; bypass with ≥1µF ceramic capacitor close to pin |
| RUN | Enable/shutdown control | Logic-high ≥2.5V enables operation; grounded disables with 0.01–2µA shutdown current |
| FB | Feedback reference node | Internally regulated to 0.800V; no external divider needed for fixed 5V version |
| ILIM | Current limit programming | Resistor-to-GND sets average output current limit (28.7kΩ = 1.2A for LT3663EDCB-5) |
| SW | Switch node | Connects to inductor, catch diode, and boost capacitor; carries high di/dt pulsed current |
| BOOST | Bootstrap drive supply | Internally connected to cathode of boost diode; must be >2.3V above SW for optimal switch saturation |
| ISENSE | Current sense input | Anode of internal boost diode; connects to positive terminal of output current sense resistor |
| VOUT | Output return path | Negative terminal of internal current sense resistor; ties to output capacitor negative |
| GND (exposed pad) | Power and signal ground | Must be soldered to large PCB ground plane with thermal vias; primary thermal path |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost diode | Eliminates external Schottky diode in standard 5V applications, reducing BOM count and board area |
| Programmable current limit | Enables precise system-level power dissipation control and allows use of smaller-rated inductors/diodes |
| Wide input voltage range | Supports unregulated 12V/24V industrial rails and automotive batteries without pre-regulation |
| Thermally enhanced DFN | Exposed pad + θJA = 64°C/W enables 1.2A operation at 85°C ambient without heatsink |
| Internal compensation | Reduces external component count and eliminates loop stability tuning during design |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
Use Scenario: Regulating 12V–24V vehicle battery rail to stable 5V for infotainment microcontrollers and CAN transceivers under cold-crank and load-dump conditions. IC Role / Device Role / Timing Role: Primary 5V buck converter with 60V transient tolerance and thermal shutdown protecting downstream logic. Use Value: Eliminates need for external TVS or pre-regulator; maintains regulation during 25ms 60V transients per ISO 7637-2. | Use Scenario: Providing isolated 5V rails across multi-board industrial PLC backplanes where input voltage varies due to cable drop and shared supply impedance. IC Role / Device Role / Timing Role: Local point-of-load regulator with programmable current limit to prevent bus collapse during local overload events. Use Value: Current limiting prevents upstream fuse blowing and enables graceful degradation instead of system-wide shutdown. |
| Industrial Sensor Hub Power | Wall Transformer Regulation |
Use Scenario: Powering 5V sensor signal chains (ADCs, op-amps, digital isolators) in factory-floor condition monitoring nodes fed from 24V DIN-rail supplies. IC Role / Device Role / Timing Role: Fixed-output buck regulator with low-noise switching and tight line/load regulation for precision analog front-ends. Use Value: 1.5MHz operation minimizes EMI coupling into adjacent analog traces; 0.8V FB reference enables <1% output drift over temperature. | Use Scenario: Replacing linear regulators in legacy 12V wall adapters powering USB peripherals, IoT gateways, or PoE-powered devices requiring clean 5V. IC Role / Device Role / Timing Role: High-efficiency step-down converter replacing inefficient 7805-style solutions in space-constrained enclosures. Use Value: >90% efficiency at 1A reduces thermal stress in sealed plastic housings and extends adapter lifetime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMS8E-5 | Same 5V fixed output, but 1.2MHz sync. buck with MOSFET drivers; requires external high-side/low-side FETs | Higher efficiency at light loads (Burst Mode™), but needs 4 external FETs and more layout effort | Select when >95% efficiency at 10mA–100mA is critical and board space allows discrete FETs |
| LT1936EMS8E-5 | 5V fixed, 1.4A, 500kHz; no integrated boost diode; higher quiescent current (1.9mA vs. 3.2mA active) | Limited to ≤36V input; lacks 60V transient rating and programmable current limit | Select for cost-sensitive, lower-frequency designs where transient immunity is not required |
Compared with LTC3630EMS8E-5 and LT1936EMS8E-5, LT3663EDCB-5 uniquely combines 60V transient tolerance, integrated boost diode, and programmable current limiting in a single 2mm×3mm DFN - making it optimal for ruggedized 5V POL applications where reliability and minimal BOM are prioritized over ultra-low IQ or synchronous efficiency.
Availability
LT3663EDCB-5 is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed supplies, and wall transformer replacement applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT3663EDCB-5 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, documentation, and manufacturing continuity for all Linear ICs including the LT3663 family.
The LT3663 product line was designed for high-reliability industrial and automotive DC/DC conversion where input transients, thermal constraints, and system-level power limiting are critical - emphasizing ruggedness, integration, and ease of use over ultra-low-power features.
FAQ
What is the output voltage accuracy of the LT3663EDCB-5 over temperature?
The LT3663EDCB-5 delivers 5.0V output with ±1.5% total accuracy over the full –40°C to 125°C junction temperature range. This includes initial tolerance, line regulation, load regulation, and temperature drift - verified per the Electrical Characteristics table in the official datasheet. The LT3663EDCB-5 achieves this using a trimmed 0.800V internal feedback reference and matched on-chip resistor divider.
Does the LT3663EDCB-5 require external compensation components?
No, the LT3663EDCB-5 is fully internally compensated. Its error amplifier (G1) and VC node include a pole-zero network optimized for stability with standard output capacitor ESR ranges. No external compensation capacitors or resistors are needed - simplifying layout and eliminating loop-tuning iterations. This applies specifically to the LT3663EDCB-5 fixed 5V variant as confirmed in the Functional Block Diagram and Applications Information sections.
What is the recommended ILIM resistor value for the LT3663EDCB-5 to achieve its rated 1.2A output current?
The LT3663EDCB-5 is configured for 1.2A output current limit using a 28.7kΩ resistor from ILIM to GND. This value is explicitly listed in Table 1 ("Output Current Limit vs RLIM Value") and used in the 5V Typical Application schematic (TA07). Deviating from 28.7kΩ will scale the current limit proportionally - e.g., 36.5kΩ yields 1.0A, per the datasheet's linear programming relationship.
Can the LT3663EDCB-5 operate with input voltages below 7.5V?
No - the LT3663EDCB-5 has a guaranteed minimum operating VIN of 7.5V (rising UVLO threshold). Below this, the internal regulator cannot sustain bias, and switching ceases. Attempting operation at 6V or lower will result in unregulated output and potential instability. For sub-7.5V inputs, consider the LT3630 or LTC3630 families, which support down to 3.6V.
Is the exposed pad (Pin 9) of the LT3663EDCB-5 electrically connected to GND?
Yes - the exposed pad (Pin 9) of the LT3663EDCB-5 is internally connected to GND and must be soldered to a PCB ground plane. The datasheet explicitly states "EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB" in both Pin Configuration diagrams and the Package Description. Failure to connect it degrades thermal performance and may cause premature thermal shutdown under load.
LT3663EDCB-5 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):
- 5V
- 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-5 FAQ
1.How can I place an order for LT3663EDCB-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3663EDCB-5 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-5 reliable?
The price and inventory of LT3663EDCB-5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3663EDCB-5 is usually 5 days.
3.What payment methods are accepted for LT3663EDCB-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3663EDCB-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3663EDCB-5?
LT3663EDCB-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3663EDCB-5 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-5?
For technical support, including LT3663EDCB-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3663EDCB-5 requirements.
6.How does Aetrix verify that LT3663EDCB-5 is sourced from the original manufacturer or authorized distributors?
All LT3663EDCB-5 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-5 meets industry standards.
7.What is the process for return or replacement of LT3663EDCB-5?
All LT3663EDCB-5 units undergo pre-shipment inspection (PSI). If there is an issue with LT3663EDCB-5, 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-5 part is unused and in its original packaging.
Return procedure for LT3663EDCB-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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