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Analog Devices Inc. LTC3631EDD-3.3#PBF
- Part No.:
- LTC3631EDD-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3631EDD-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 100MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,039
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Product details
Overview
LTC3631EDD-3.3#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, synchronous step-down DC/DC converter with integrated high-side and low-side MOSFETs, delivering up to 100mA output current at a fixed 3.3V output, operating from 4.5V to 45V input, featuring 12µA no-load quiescent current and Burst Mode® operation for ultra-low-power regulation in battery- and industrial-supply applications.
For engineers reviewing the LTC3631EDD-3.3#PBF datasheet, LTC3631EDD-3.3#PBF pinout, LTC3631EDD-3.3#PBF application, or LTC3631EDD-3.3#PBF equivalent, this page delivers verified technical context, confirmed pin functions, real-world efficiency vs. load data, validated alternative parts, and supply-chain support details specific to the DFN-packaged 3.3V fixed-output variant.
Technical Context
The LTC3631EDD-3.3#PBF implements a hysteretic Burst Mode® control architecture with an internal 0.800V ±1% feedback reference, enabling automatic transition between active switching bursts and deep-sleep cycles. Its peak current limit is programmable via ISET (50–225mA), and it features precise RUN pin enable threshold (1.21V rising, 1.10V falling) with 110mV hysteresis.
It integrates both P-channel high-side and N-channel low-side power switches (RON = 3.0Ω / 1.5Ω), supports 100% duty-cycle low-dropout operation, and includes overvoltage lockout (47–52V trip) and undervoltage lockout (3.75–4.50V trip) - all within a thermally enhanced 3mm × 3mm DFN package with exposed GND pad.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports wide industrial, automotive, and distributed power rails without external pre-regulation. |
| Output Voltage | Fixed 3.3V ±1.2% - tightly regulated for MCU, sensor, and interface IC supply without external resistive divider. |
| No-Load Quiescent Current | 12µA typical - enables multi-year battery life in always-on remote sensors and IoT endpoints. |
| Max Output Current | 100mA - sufficient for microcontrollers, transceivers, and analog front-ends in space-constrained systems. |
| Overvoltage Protection | 60V surge tolerance with 47–52V OVLO - safeguards against load-dump transients in 24V/36V industrial and vehicle systems. |
| Package | 8-lead 3mm × 3mm DFN with exposed thermal pad - provides low θJA = 43°C/W for passive cooling in sealed enclosures. |
| Operating Temperature | –40°C to 125°C junction - qualified for under-hood, factory-floor, and outdoor embedded deployments. |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN with exposed GND pad (Pin 9), RoHS-compliant, lead-free finish. Exposed pad must be soldered 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 switching waveform - requires tight layout and Kelvin grounding. |
| VIN (Pin 2) | Main input supply | Accepts 4.5–45V input; bypass capacitor required directly to GND (Pin 8/9) to suppress high-frequency noise. |
| ISET (Pin 3) | Peak current programming | Sources 1µA; resistor to GND sets peak inductor current from 50mA to 225mA - determines max load capability and component sizing. |
| SS (Pin 4) | Soft-start control | Sources 5µA; capacitor to GND controls output voltage ramp time - prevents input droop during cold start. |
| RUN (Pin 5) | Enable/disable control | Logic-level input: >1.21V enables regulation; <0.7V forces shutdown (3µA IQ); hysteresis enables clean power sequencing. |
| VOUT/VFB (Pin 6) | Output feedback | Internally connected to 3.3V output; no external divider needed - simplifies BOM and improves stability. |
| HYST (Pin 7) | Run hysteresis open-drain | Pulled low when RUN disabled; can drive external resistor divider to increase RUN pin hysteresis for noisy supply monitoring. |
| GND (Pins 8 & 9) | Power and thermal ground | Pins 8 (perimeter) and 9 (exposed pad) are internally tied - pad must be fully soldered for thermal performance and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Maintains regulation at light loads while drawing only 12µA - eliminates need for external enable logic in energy-harvesting systems. |
| Integrated dual MOSFETs | Eliminates external high-side/low-side switch selection and gate-drive design - reduces bill-of-materials and layout complexity. |
| Programmable peak current limit | Adjusts max output capability from 50mA to 225mA via single resistor - enables optimization of inductor/capacitor size for cost, footprint, and ripple. |
| Internal soft-start + external SS pin | Guarantees monotonic VOUT rise and prevents inrush-induced brownout - critical for powering FPGAs and mixed-signal SoCs. |
| 60V surge-tolerant input | Withstands automotive load-dump and industrial line transients without external TVS - lowers system protection component count. |
Applications
| 4–20mA Current Loop Transmitter | Industrial Sensor Node |
|---|---|
Use Scenario: Powering loop-powered 4–20mA transmitter circuits in hazardous-area process instrumentation. IC Role / Device Role / Timing Role: Primary 3.3V regulator supplying ADC, DAC, and current-loop driver from unregulated 12–36V field wiring. Use Value: Ultra-low 12µA quiescent current ensures full compliance with loop power budget (<4mA) while maintaining regulation across temperature. | Use Scenario: Self-contained wireless sensor node powered by primary lithium battery or energy harvester. IC Role / Device Role / Timing Role: Main system regulator enabling long-term sleep mode for MCU and RF transceiver. Use Value: Burst Mode® extends battery life beyond 10 years in periodic-readout applications due to sub-15µA average supply current. |
| Automotive Body Control Module | Distributed Power Subsystem |
Use Scenario: Local 3.3V rail generation in non-critical body electronics (door modules, seat controllers). IC Role / Device Role / Timing Role: Secondary regulator fed from 12V battery or main DC/DC, providing isolated logic supply. Use Value: 60V surge tolerance and –40°C to 125°C operation eliminate need for external transient protection in under-hood environments. | Use Scenario: Point-of-load regulation for FPGA I/O banks or analog subsystems in modular PLC backplanes. IC Role / Device Role / Timing Role: Compact, thermally efficient local converter replacing bulkier discrete solutions. Use Value: 3mm × 3mm DFN with exposed pad achieves >100mA continuous output without heatsink - saves board area in dense control cabinets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EDD-5#PBF | Fixed 5V output; identical package, pinout, and specs except VOUT and feedback network. | Requires redesign of downstream logic supply rails; not drop-in for 3.3V systems. | Select only if system requires 5V logic supply and no level-shifting - same layout but different output voltage. |
| TPS62130ARGTR | 3.3V fixed output, 3–17V input, 1.2A max, 17µA IQ, 2mm × 2mm WSON - higher current, narrower VIN, smaller package. | Not suitable for 24V+ industrial inputs or 60V surge environments; lacks OVLO/UVLO precision. | Prefer for space-constrained consumer or telecom designs with ≤17V input; avoid where 45V operation or robust fault protection is required. |
Compared with LTC3631EDD-5#PBF, the LTC3631EDD-3.3#PBF avoids level-shifting overhead for 3.3V microcontrollers; compared with TPS62130ARGTR, it trades off size and current headroom for industrial-grade input range and transient resilience - making it the sole choice for 24V/36V field-powered systems requiring guaranteed 3.3V regulation.
Availability
LTC3631EDD-3.3#PBF is available at Aetrix Electronics and suitable for industrial sensor nodes, 4–20mA transmitters, and automotive body electronics requiring stable component supply across extended temperature and high-reliability production cycles.
Supply support for LTC3631EDD-3.3#PBF 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 continuity, documentation, and support for the LTC portfolio - a leader in high-performance power management ICs since 1981.
The LTC3631EDD-3.3#PBF belongs to the LTC3631 family of high-input-voltage synchronous buck regulators, designed specifically for ruggedized, low-quiescent-current power conversion in industrial, automotive, and instrumentation systems where input transients and long battery life are critical.
FAQ
What is the maximum input voltage the LTC3631EDD-3.3#PBF can withstand without damage?
The LTC3631EDD-3.3#PBF has an absolute maximum VIN rating of 60V and includes internal overvoltage lockout that disables switching above 47–52V. It safely sustains 60V transients indefinitely when disabled, making it suitable for automotive load-dump and industrial surge environments. Continuous operation is specified from 4.5V to 45V.
Does the LTC3631EDD-3.3#PBF require external compensation components?
No, the LTC3631EDD-3.3#PBF uses a hysteretic Burst Mode® control architecture that requires no external compensation. Its internal feedback loop is inherently stable across all operating conditions and output capacitor types - eliminating the need for compensation networks, phase-margin analysis, or ESR-dependent capacitors.
Can the LTC3631EDD-3.3#PBF be used in a 4–20mA current loop transmitter without violating loop power limits?
Yes. With only 12µA typical quiescent current in regulation and 3µA in shutdown, the LTC3631EDD-3.3#PBF consumes negligible current from the loop - well within the 4mA minimum compliance margin. Its 3.3V fixed output directly powers modern low-IQ ADCs, DACs, and loop drivers without additional regulation stages.
What is the purpose of the HYST pin on the LTC3631EDD-3.3#PBF?
The HYST pin on the LTC3631EDD-3.3#PBF is an open-drain output pulled low when the RUN pin voltage falls below 1.10V. It enables external hysteresis enhancement for noisy input monitoring - for example, connecting HYST to the RUN divider network increases effective hysteresis beyond the internal 110mV, preventing chatter during slow-rising supply ramps.
Is the LTC3631EDD-3.3#PBF pin-compatible with other variants in the LTC3631 family?
Yes - all LTC3631 DFN-packaged variants (e.g., LTC3631EDD#PBF, LTC3631EDD-5#PBF, LTC3631EDD-3.3#PBF) share identical 8-lead DFN pinout, package dimensions, and thermal pad layout. Only the output voltage and associated internal feedback network differ; no PCB changes are required when swapping between fixed-output versions.
LTC3631EDD-3.3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 45V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 100mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x3)
LTC3631EDD-3.3#PBF FAQ
1.How can I place an order for LTC3631EDD-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3631EDD-3.3#PBF 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 LTC3631EDD-3.3#PBF reliable?
The price and inventory of LTC3631EDD-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3631EDD-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LTC3631EDD-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3631EDD-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3631EDD-3.3#PBF?
LTC3631EDD-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3631EDD-3.3#PBF 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 LTC3631EDD-3.3#PBF?
For technical support, including LTC3631EDD-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3631EDD-3.3#PBF requirements.
6.How does Aetrix verify that LTC3631EDD-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3631EDD-3.3#PBF 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 LTC3631EDD-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LTC3631EDD-3.3#PBF?
All LTC3631EDD-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3631EDD-3.3#PBF, 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 LTC3631EDD-3.3#PBF part is unused and in its original packaging.
Return procedure for LTC3631EDD-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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