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Analog Devices Inc. LTC3621IDCB-3.3#TRPBF
- Part No.:
- LTC3621IDCB-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 6-WFDFN Exposed Pad
- Datasheet:
-
LTC3621IDCB-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 1A 6DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,461
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Product details
Overview
LTC3621IDCB-3.3#TRPBF from Analog Devices is a 17V, 1A synchronous step-down regulator in a 6-lead DFN (2mm × 3mm) package, delivering fixed 3.3V output with ±1% accuracy, 2.25MHz switching frequency, and ultralow 3.5µA quiescent current - optimized for battery-powered industrial sensors and automotive infotainment power rails.
For engineers reviewing the LTC3621IDCB-3.3#TRPBF datasheet, LTC3621IDCB-3.3#TRPBF pinout, LTC3621IDCB-3.3#TRPBF application, or LTC3621IDCB-3.3#TRPBF equivalent, key selection criteria include dropout operation down to VIN = VOUT, Burst Mode® efficiency at microamp loads, PGOOD monitoring capability (in MS8E only), and thermal performance in the thermally enhanced DFN package.
Technical Context
The LTC3621IDCB-3.3#TRPBF implements a constant-frequency peak current mode architecture with internal compensation and 800µs soft-start. It operates across 2.7V–17V input while maintaining regulation at full 1A load even as VIN approaches 3.3V, enabled by high-duty-cycle slope compensation and 1.6A peak current limit.
Its MODE/SYNC pin supports three operating modes: Burst Mode® (MODE/SYNC = INTVCC) for <3.5µA IQ, pulse-skipping (MODE/SYNC = GND) for minimal output ripple, and forced continuous mode (1V < MODE/SYNC < VINTVCC – 1.2V) for EMI-sensitive applications - all without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1% over –40°C to 125°C junction temperature - eliminates external feedback divider and ensures stable rail for MCU I/O or CAN transceivers. |
| Switching Frequency | 2.25MHz ±20% - enables use of compact 2.2µH inductors and reduces EMI fundamental below 30MHz for Class B compliance. |
| Quiescent Current | 3.5µA in Burst Mode® - extends battery life in always-on emergency radios or telematics modules during sleep states. |
| Input Voltage Range | 2.7V to 17V - supports direct connection to 12V automotive batteries including cold-crank (6.5V) and load-dump (18V) transients (with external clamping). |
| Output Current | 1A continuous - sufficient to power dual-core ARM Cortex-M7 MCUs with peripherals active, with thermal derating above 85°C ambient. |
| Thermal Resistance | θJA = 64°C/W (DFN package, 2-layer board) - requires exposed pad soldered to PCB ground plane for reliable 1A operation at 125°C ambient. |
| Reference Accuracy | 0.6V ±1% internal reference - ensures 3.3V output tolerance remains within ±33mV across voltage, temperature, and line/load conditions. |
Pinout & Package
Package: 6-lead (2mm × 3mm) plastic DFN with exposed thermal pad (Pin 7 = GND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connection point for external inductor; carries high di/dt square wave - must minimize loop area to reduce EMI and voltage overshoot. |
| VIN (Pin 2) | Main input supply | Accepts 2.7V–17V; powers internal LDO (INTVCC) and gate drivers - requires local 10µF ceramic bypass capacitor placed adjacent to pin. |
| RUN (Pin 3) | Enable control | Active-high logic input; pulls regulator out of shutdown when >1.0V - must not be left floating; tied to VIN or microcontroller GPIO. |
| FB (Pin 4) | Feedback input | Internally connected to fixed 3.3V output divider - no external resistors needed; monitors regulation via 0.6V reference amplifier. |
| INTVCC (Pin 5) | Internal LDO output | 3.6V regulated supply for gate drivers and logic - bypass with ≥1µF ceramic capacitor to GND to prevent instability during load transients. |
| MODE/SYNC (Pin 6) | Operating mode select | Configures Burst Mode®, pulse-skipping, or forced continuous operation; also accepts external clock (±40% sync range) for EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow quiescent current | 3.5µA in Burst Mode® enables >1-year battery life in coin-cell–powered IoT sensors at 10µA average system load. |
| Full dropout operation | Maintains regulation with VIN as low as 3.3V at full 1A load - critical for automotive stop-start systems where battery sags to 6V–8V. |
| Internal compensation | Eliminates external compensation network - reduces BOM count and layout sensitivity while ensuring stability with standard ceramic output capacitors. |
| Overtemperature protection | Thermal shutdown activates at TJ > 150°C and auto-restarts after cooldown - prevents permanent damage during sustained overload or poor heatsinking. |
| 2.25MHz fixed frequency | Enables use of sub-3mm height inductors and reduces solution footprint by >40% vs 500kHz alternatives - ideal for space-constrained portable medical devices. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node |
|---|---|
Use Scenario: Powering display interface ICs and audio codecs in head units under wide battery voltage variation (6V–16V) and thermal stress (-40°C to 105°C). IC Role / Device Role / Timing Role: Primary 3.3V buck converter supplying digital logic rails with PGOOD signaling to host processor for fault detection. Use Value: 2.25MHz operation avoids AM radio band interference; 3.5µA IQ extends standby time during vehicle ignition-off periods. | Use Scenario: Providing regulated 3.3V to low-power wireless sensor transceivers (e.g., LoRaWAN, NB-IoT) deployed in remote field locations with primary lithium-thionyl chloride batteries. IC Role / Device Role / Timing Role: Always-on power management IC enabling multi-year operation via ultralow IQ and efficient light-load conversion. Use Value: Burst Mode® maintains >85% efficiency at 100µA load - directly translates to >7-year battery life at 10-second wake-up intervals. |
| Emergency Radio Supply | Embedded Computing Rail |
Use Scenario: Delivering clean 3.3V to SDR-based emergency broadcast receivers operating from 9V alkaline or rechargeable Li-ion packs with deep discharge capability. IC Role / Device Role / Timing Role: Main DC/DC converter supporting dynamic load steps from 10µA (sleep) to 500mA (transmit burst) without brownout. Use Value: Forced continuous mode option eliminates output ripple during RF transmission, preventing data corruption in narrowband receivers. | Use Scenario: Generating 3.3V for FPGA configuration memory, Ethernet PHYs, and USB controllers in fanless edge computing gateways. IC Role / Device Role / Timing Role: High-current point-of-load regulator with thermal-aware design for conduction-cooled enclosures. Use Value: Exposed-pad DFN package achieves 64°C/W θJA - sustains 1A output at 70°C ambient without airflow, reducing system cooling cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3.0V–17V input, 3.3V fixed, 2.25MHz, 3.5µA IQ - but rated only to 85°C ambient and lacks VIN OVP. | Suitable for commercial-grade portable instruments; not qualified for automotive or extended-temp industrial use. | Select when cost sensitivity outweighs AEC-Q100 requirement and ambient stays below 70°C. |
| MAX17503GCU+T | 4.5V–60V input, adjustable output, 2.2MHz, 12µA IQ - wider VIN but higher IQ and no fixed 3.3V variant. | Preferred for high-voltage industrial PLCs; requires external feedback resistors and compensation. | Choose when input exceeds 17V or adjustable output is needed; avoid if minimizing BOM and layout complexity is critical. |
Compared with TPS62130ARGTR and MAX17503GCU+T, the LTC3621IDCB-3.3#TRPBF uniquely combines AEC-Q100 qualification, guaranteed 125°C operation, fixed 3.3V output with zero external components, and identical 2.25MHz/3.5µA specs - making it the only drop-in solution for thermally demanding automotive and industrial designs requiring minimal validation effort.
Availability
LTC3621IDCB-3.3#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor nodes, emergency radio supplies, and embedded computing requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3621IDCB-3.3#TRPBF 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.
The LTC3621 product line delivers high-efficiency, ultralow-IQ synchronous buck regulators for battery-critical and thermally constrained applications - designed specifically for automotive subsystems, portable medical devices, and always-on IoT endpoints.
FAQ
What is the maximum output current capability of the LTC3621IDCB-3.3#TRPBF?
The LTC3621IDCB-3.3#TRPBF delivers up to 1A continuous output current at ambient temperatures ≤85°C with proper PCB thermal design. Derating applies above 85°C: at 125°C ambient, maximum sustainable current drops to ~750mA due to thermal limits. The device features overtemperature protection that disables switching if junction temperature exceeds 150°C, and resumes automatically upon cooldown. This rating is validated per the datasheet's electrical characteristics table under "ILIM Peak Current Limit" for I-grade parts.
Does the LTC3621IDCB-3.3#TRPBF require external feedback resistors?
No, the LTC3621IDCB-3.3#TRPBF does not require external feedback resistors. It is a fixed-output variant with internally trimmed resistive divider setting VOUT = 3.3V ±1%. The FB pin is pre-connected to the internal divider network - unlike adjustable versions (e.g., LTC3621IDCB#TRPBF), no external R1/R2 network is needed, simplifying layout and reducing BOM count. This is confirmed in the "ORDER INFORMATION" table and "PIN FUNCTIONS" section of the datasheet.
Can the LTC3621IDCB-3.3#TRPBF synchronize to an external clock?
Yes, the LTC3621IDCB-3.3#TRPBF can synchronize its 2.25MHz switching frequency to an external clock applied to the MODE/SYNC pin. The sync range is ±40% of the nominal frequency (i.e., 1.35MHz to 3.15MHz). Upon detection, the part enters forced continuous mode and locks to the external signal within 2–3 cycles. This feature is explicitly documented in the "FEATURES" list and "Frequency Sync Capability" section of the datasheet.
What is the purpose of the exposed thermal pad on the LTC3621IDCB-3.3#TRPBF DFN package?
The exposed thermal pad (Pin 7) on the LTC3621IDCB-3.3#TRPBF DFN package serves as the primary thermal and electrical ground path. It must be soldered to a PCB copper pour connected to system ground to achieve the specified θJA = 64°C/W and ensure reliable 1A operation. Leaving it unconnected degrades thermal performance by >30°C/W and risks thermal shutdown under load. This requirement is mandated in the "PIN CONFIGURATION" diagram and "ABSOLUTE MAXIMUM RATINGS" footnote.
How does the LTC3621IDCB-3.3#TRPBF behave during input undervoltage or overvoltage conditions?
The LTC3621IDCB-3.3#TRPBF incorporates dedicated protection circuits: VIN undervoltage lockout (UVLO) disables regulation below 2.7V (with 250mV hysteresis), while VIN overvoltage lockout (OVLO) suspends switching above 19V (with 300mV hysteresis). After OVLO recovery, the part executes full soft-start. These thresholds are guaranteed over temperature and are listed in the "ELECTRICAL CHARACTERISTICS" table under VUVLO and VOVLO parameters.
LTC3621IDCB-3.3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 6-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 17V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 1A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-DFN (2x3)
LTC3621IDCB-3.3#TRPBF FAQ
1.How can I place an order for LTC3621IDCB-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3621IDCB-3.3#TRPBF 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 LTC3621IDCB-3.3#TRPBF reliable?
The price and inventory of LTC3621IDCB-3.3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3621IDCB-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3621IDCB-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3621IDCB-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3621IDCB-3.3#TRPBF?
LTC3621IDCB-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3621IDCB-3.3#TRPBF 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 LTC3621IDCB-3.3#TRPBF?
For technical support, including LTC3621IDCB-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3621IDCB-3.3#TRPBF requirements.
6.How does Aetrix verify that LTC3621IDCB-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3621IDCB-3.3#TRPBF 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 LTC3621IDCB-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3621IDCB-3.3#TRPBF?
All LTC3621IDCB-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3621IDCB-3.3#TRPBF, 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 LTC3621IDCB-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LTC3621IDCB-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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