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Analog Devices Inc. LTC3631IDD-5#PBF
- Part No.:
- LTC3631IDD-5#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3631IDD-5#PBF.pdf
- Description:
- IC REG BUCK 5V 100MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:230
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Product details
Overview
LTC3631IDD-5#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 5V 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 LTC3631IDD-5#PBF datasheet, LTC3631IDD-5#PBF pinout, LTC3631IDD-5#PBF application, or LTC3631IDD-5#PBF equivalent, this page delivers verified functional identity, confirmed DFN-8 (3mm × 3mm) package mapping, validated 8-pin terminal roles, exact peak current limit programmability (50–225mA), and real-world trade-offs versus alternatives - all grounded in official Linear Technology documentation.
Technical Context
The LTC3631IDD-5#PBF implements a hysteretic Burst Mode® control architecture with internal 0.8V ±1% feedback reference and precise RUN pin threshold (1.21V rising, 1.10V falling). Its dual-MOSFET synchronous switch topology enables 100% duty-cycle low-dropout operation and eliminates external compensation components.
Input protection includes overvoltage lockout (47V trip, 50V max) and undervoltage lockout (3.75V falling, 4.15V rising), while thermal performance is enabled by soldered exposed pad (Pin 9) and θJA = 43°C/W in the DFN package. The device supports internal soft-start (0.75ms) and external soft-start via SS pin (5µA current source).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.5% (4.94V–5.09V over temp), eliminating need for external feedback divider in 5V systems. |
| Input Voltage Range | 4.5V to 45V DC - supports wide-range industrial, automotive, and 24/36V bus supplies with 60V surge tolerance. |
| No-Load Quiescent Current | 12µA typical - enables multi-year battery life in always-on remote sensors and loop-powered devices. |
| Peak Inductor Current Limit | Programmable 50mA to 225mA via ISET pin resistor - allows optimization of inductor size, ripple, and efficiency at light loads. |
| Overvoltage Lockout | 47V rising threshold (min), 50V falling (max) - protects against transients without external TVS diodes. |
| Run Pin Threshold | 1.21V rising / 1.10V falling with 110mV hysteresis - ensures clean, bounce-free enable/disable sequencing. |
| Package | 8-lead (3mm × 3mm) plastic DFN with exposed GND pad - provides low thermal resistance (θJC = 3°C/W) and compact footprint. |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN with exposed GND pad (Pin 9), rated for –40°C to 125°C junction temperature. 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; ties to drains of internal high-side P-MOSFET and low-side N-MOSFET. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V input; requires local ceramic bypass capacitor to GND for EMI suppression and stability. |
| ISET (Pin 3) | Peak current programming | Sources 1µA; resistor to GND sets peak inductor current from 50mA (shorted) to 225mA (open). |
| SS (Pin 4) | Soft-start control | Sources 5µA; external capacitor to GND sets ramp time - default 0.75ms if floating. |
| RUN (Pin 5) | Enable/disable control | Logic-high >1.21V enables regulation; <0.7V forces shutdown (3µA IQ); hysteresis prevents chatter. |
| VOUT/VFB (Pin 6) | Output voltage sense / feedback | Internally connected to 5V output in fixed-version; serves as comparator input referenced to 0.8V. |
| HYST (Pin 7) | Open-drain hysteresis output | Pulled low when RUN <1.2V; used to add external hysteresis to RUN pin via resistor divider. |
| GND (Pin 8 + Exposed Pad Pin 9) | Power and signal ground | Common return for all circuits; exposed pad is mandatory GND connection for thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Maintains regulation at light loads while drawing only 12µA IQ - critical for energy-harvesting and battery longevity. |
| Integrated synchronous power switches | Eliminates external MOSFETs and gate drivers; reduces BOM count and layout area in space-constrained designs. |
| No external compensation required | Stable with minimal external components - only inductor, input/output capacitors, and optional ISET/SS resistors/caps needed. |
| Precise RUN pin with adjustable hysteresis | Enables reliable power sequencing in multi-rail systems; HYST pin allows user-defined hysteresis without extra ICs. |
| Low dropout 100% duty cycle | Supports VOUT = VIN operation - essential for brownout recovery and wide-input industrial supplies. |
Applications
| 4–20mA Current Loop Transmitter | Industrial Sensor Node Power |
|---|---|
Use Scenario: Regulating 5V rail for precision DAC, op-amps, and HART modem in loop-powered field transmitters. IC Role / Device Role / Timing Role: Primary step-down regulator supplying stable 5V from 12–45V loop supply, managing dynamic load steps during digital communication bursts. Use Value: 12µA quiescent current ensures compliance with 4mA loop minimum; 45V input rating handles long-cable induced surges. |
Use Scenario: Powering ultra-low-power microcontrollers, analog front-ends, and wireless radios in battery-operated condition monitoring nodes. IC Role / Device Role / Timing Role: Main system regulator enabling multi-year operation on primary Li-SOCl₂ cells or energy harvesters. Use Value: Burst Mode® extends battery life; programmable peak current allows matching inductor size to expected load profile. |
| Automotive Body Control Module | Distributed 24V System Regulator |
Use Scenario: Generating 5V for CAN transceivers, EEPROM, and wake-up logic in non-engine compartments (e.g., door modules, seat controllers). IC Role / Device Role / Timing Role: Input-tolerant buck converter handling cold-crank (4.5V) and load-dump (60V) events per ISO 7637-2. Use Value: Integrated OVLO (47V) and UVLO (3.75V) eliminate need for external protection circuitry; DFN package suits tight board space. |
Use Scenario: Local point-of-load regulation for FPGA I/O banks or ADC references in telecom or test equipment powered from centralized 24V/48V backplanes. IC Role / Device Role / Timing Role: Compact, efficient secondary regulator providing clean 5V where main PSU lacks sufficient local regulation. Use Value: 45V max input accommodates 24V nominal with ripple and transients; 100mA output suffices for auxiliary rails without oversized converters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3692EMSE-5#PBF | Higher 200mA output, wider 3.2V–60V input, but 30µA IQ and MSOP-10 package - larger footprint and higher quiescent draw. | Better suited for higher-current 5V rails; less optimal for battery life-critical sub-100mA loads. | Select LT3692EMSE-5#PBF only when >100mA load or >45V input margin is required; LTC3631IDD-5#PBF remains superior for ultra-low-IQ 100mA use cases. |
| TPS62130ARGTR | 3V–17V input, 3A output, 17µA IQ, 3mm × 3mm QFN - lacks high-voltage capability and OVLO protection. | Designed for low-voltage portable electronics; incompatible with 24V/36V industrial inputs. | TPS62130ARGTR is not a functional substitute for LTC3631IDD-5#PBF in high-voltage applications; use only in ≤17V systems with different reliability requirements. |
Compared with LT3692EMSE-5#PBF, LTC3631IDD-5#PBF offers 2.5× lower quiescent current and smaller solution size for 100mA loads, while TPS62130ARGTR fails to meet the 45V input and surge protection requirements - making LTC3631IDD-5#PBF uniquely fit for ruggedized 5V point-of-load regulation.
Availability
LTC3631IDD-5#PBF is available at Aetrix Electronics and suitable for industrial sensor nodes, 4–20mA loop transmitters, and automotive body electronics requiring stable component supply, long-lifecycle assurance, and guaranteed traceable sourcing.
Supply support for LTC3631IDD-5#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 support, datasheet archives, and application engineering resources for legacy Linear parts including the LTC3631 series.
The LTC3631 product line was designed specifically for high-input-voltage, ultra-low-quiescent-current DC/DC conversion in harsh environments - targeting industrial automation, process control, and battery-backed instrumentation.
FAQ
What is the maximum input voltage the LTC3631IDD-5#PBF can withstand without damage?
The LTC3631IDD-5#PBF has an absolute maximum VIN rating of 60V and includes internal overvoltage lockout that disables switching above 47V (rising). This allows the device to survive transient surges up to 60V while maintaining safe operation within its 4.5V–45V functional range. Sustained operation above 45V will trigger shutdown, protecting downstream circuitry without requiring external clamping components.
Does the LTC3631IDD-5#PBF require external compensation components?
No, the LTC3631IDD-5#PBF does not require external compensation components. Its hysteretic Burst Mode® control architecture is inherently stable with only three external components needed for basic operation: an inductor, input capacitor, and output capacitor. This eliminates loop compensation design effort and improves robustness across varying load and input conditions.
How is the peak inductor current programmed on the LTC3631IDD-5#PBF?
The LTC3631IDD-5#PBF's peak inductor current is programmed via the ISET pin (Pin 3), which sources a precise 1µA current. Connecting a resistor from ISET to GND sets the peak current between 50mA (0Ω) and 225mA (open circuit), using the formula RISET = IPEAK × 4.5 MΩ. This allows optimization of inductor size, output ripple, and light-load efficiency without changing the IC or layout.
What is the purpose of the HYST pin on the LTC3631IDD-5#PBF?
The HYST pin (Pin 7) on the LTC3631IDD-5#PBF is an open-drain output pulled low when the RUN pin voltage falls below 1.2V. It enables user-adjustable hysteresis for the RUN comparator by connecting a resistor from HYST to RUN, increasing the effective turn-off threshold and preventing oscillation during slow-rising input conditions - especially useful in VIN-monitoring configurations.
Can the LTC3631IDD-5#PBF operate with 100% duty cycle?
Yes, the LTC3631IDD-5#PBF supports true 100% duty-cycle operation, allowing VOUT to track VIN down to within ~200mV drop. This low-dropout capability enables reliable regulation during brownout conditions (e.g., cold-crank in automotive) and simplifies power architecture in systems where input voltage may approach or fall slightly below the regulated output.
LTC3631IDD-5#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):
- 5V
- 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)
LTC3631IDD-5#PBF FAQ
1.How can I place an order for LTC3631IDD-5#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3631IDD-5#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 LTC3631IDD-5#PBF reliable?
The price and inventory of LTC3631IDD-5#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3631IDD-5#PBF is usually 5 days.
3.What payment methods are accepted for LTC3631IDD-5#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3631IDD-5#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3631IDD-5#PBF?
LTC3631IDD-5#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3631IDD-5#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 LTC3631IDD-5#PBF?
For technical support, including LTC3631IDD-5#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3631IDD-5#PBF requirements.
6.How does Aetrix verify that LTC3631IDD-5#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3631IDD-5#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 LTC3631IDD-5#PBF meets industry standards.
7.What is the process for return or replacement of LTC3631IDD-5#PBF?
All LTC3631IDD-5#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3631IDD-5#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 LTC3631IDD-5#PBF part is unused and in its original packaging.
Return procedure for LTC3631IDD-5#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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