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Analog Devices Inc. LTC3631EDD#TRPBF
- Part No.:
- LTC3631EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3631EDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 100MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:6,624
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Product details
Overview
LTC3631EDD#TRPBF 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 from a 4.5V–45V input. It operates in Burst Mode® with 12µA no-load quiescent current, features programmable peak current limit (50–225mA), and maintains regulation down to 0% duty cycle for low-dropout operation. It is used in industrial control supplies and battery-operated devices requiring robust, ultra-low-power regulation.
For engineers reviewing the LTC3631EDD#TRPBF datasheet, LTC3631EDD#TRPBF pinout, LTC3631EDD#TRPBF application, or LTC3631EDD#TRPBF equivalent, key selection criteria include its 45V max input rating, internal overvoltage lockout (60V surge tolerant), 0.8V ±1% feedback reference, adjustable soft-start via SS pin, and compatibility with fixed 3.3V/5V or adjustable output configurations using external resistive dividers.
Technical Context
The LTC3631EDD#TRPBF employs a hysteretic Burst Mode® control architecture with an internal 0.800V feedback reference and 5mV comparator hysteresis, enabling automatic transition between active switching and sleep cycles. Its peak current comparator is offset-programmable via ISET pin (1µA sourced), allowing precise tuning of inductor current limits from 50mA to 225mA.
Startup is managed by a precise RUN pin threshold (1.21V rising, 1.10V falling) with 110mV hysteresis, while HYST pin provides open-drain logic signaling for external hysteresis extension. The device integrates shoot-through prevention logic, reverse current detection, and internal soft-start (0.75ms default), all implemented without external compensation components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports wide-range industrial and automotive inputs; survives 60V transients via integrated OVLO. |
| Output Current | Up to 100mA - maximum average load current; limited by peak current setting (max 225mA) and architecture (IOUT(AVG) ≤ 0.5 × IPEAK). |
| Quiescent Current | 12µA typical in Burst Mode - enables multi-year battery life in always-on sensor nodes and portable instruments. |
| Feedback Reference | 0.800V ±1% - precision reference enables accurate output regulation across temperature and line variations. |
| Peak Current Limit | Programmable 50–225mA via ISET resistor - allows optimization of inductor size, ripple, and efficiency for specific load profiles. |
| Soft-Start | Internal 0.75ms + external capacitor option - prevents input droop during power-up; SS pin sources 5µA for linear ramp control. |
| Overvoltage Lockout | 47V rising / 45V falling - protects internal switches during load dump or supply surges without external clamping. |
Pinout & Package
The LTC3631EDD#TRPBF is housed in an 8-lead, 3mm × 3mm plastic DFN package with exposed thermal pad (Pin 9 = GND), optimized for high power density and thermal performance (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connection point for external inductor; ties drains of internal high-side P-MOSFET and low-side N-MOSFET. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V; requires local ceramic bypass capacitor to GND for stable switching operation. |
| 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 for controlled VOUT rise and reduced input stress. |
| RUN (Pin 5) | Enable/disable control | Active-high logic: >1.21V enables regulation; <0.7V forces shutdown (3µA IQ); 110mV hysteresis prevents chatter. |
| VOUT/VFB (Pin 6) | Output feedback | Connects to output for fixed versions; for adjustable versions, forms divider with external resistors to 0.8V reference. |
| HYST (Pin 7) | Run hysteresis indicator | Open-drain output pulled low when RUN < 1.2V; usable to extend RUN pin hysteresis with external resistor to VIN. |
| GND (Pin 8 & Exposed Pad Pin 9) | Ground reference | Primary ground return and thermal path; exposed pad must be soldered to PCB ground plane for electrical integrity and thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| No external compensation required | Integrated control loop eliminates need for loop compensation network - reduces BOM count and layout sensitivity. |
| Low dropout operation | 100% duty cycle capability - maintains regulation even as input voltage approaches output voltage (e.g., 5.5V → 5V). |
| Internal overvoltage monitor | Lockout at 47V rising - protects against 60V transients without external TVS, simplifying front-end protection design. |
| Precise RUN pin threshold | 1.21V rising / 1.10V falling - enables reliable power sequencing and brown-out detection in multi-rail systems. |
| Three-component fixed-output solution | Only inductor, input cap, and output cap needed - minimizes footprint and cost for 3.3V/5V variants. |
Applications
| Industrial Control Supplies | 4–20mA Current Loops |
|---|---|
Use Scenario: Powering analog sensor transmitters in hazardous-area PLC I/O modules with 24V DC field bus. IC Role / Device Role / Timing Role: Primary isolated or non-isolated 5V/3.3V regulator supplying op-amps, ADCs, and loop drivers. Use Value: 12µA quiescent current extends system uptime during brownouts; 45V input range accommodates long cable drops and field surges. |
Use Scenario: Providing stable bias for 4–20mA transmitter circuitry in process instrumentation (e.g., pressure, flow sensors). IC Role / Device Role / Timing Role: High-efficiency, low-noise local supply for current-sense amplifiers and DAC output stages. Use Value: Burst Mode® operation eliminates switching noise near sensitive analog signal paths; programmable peak current minimizes inductor size in space-constrained enclosures. |
| Portable Instruments | Battery-Operated Devices |
Use Scenario: Regulating power for handheld multimeters, gas detectors, or portable data loggers powered by two AA/AAA cells or Li-ion. IC Role / Device Role / Timing Role: Main DC/DC converter stepping down from 3.0–4.2V (Li-ion) or 2.4–3.0V (alkaline) to 3.3V for MCU and sensors. Use Value: 12µA no-load IQ preserves battery capacity during standby; low-profile DFN (0.75mm height) fits thin handheld form factors. |
Use Scenario: Power management in remote wireless sensors (e.g., Zigbee, LoRaWAN nodes) operating from primary lithium batteries (CR2032, AA). IC Role / Device Role / Timing Role: Always-on regulator maintaining real-time clock, wake-up logic, and RF transceiver bias between transmissions. Use Value: 3µA shutdown current (via RUN pin) enables years of shelf life; wide input range supports aging battery discharge curves without premature cutoff. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3652IMSE#TRPBF | 42V max input, 2A output, constant-current/constant-voltage battery charger architecture; no programmable peak current limit. | Designed for Li-ion/Pb-acid charging; lacks Burst Mode® and ultra-low IQ for always-on regulation. | Select only if battery charging functionality is required; not suitable as direct replacement for standalone regulation. |
| TPS561201DRCT | 17V max input, 1.2A output, 22µA IQ, requires external compensation; no overvoltage lockout or RUN hysteresis. | Lower voltage range limits use in industrial 24V/48V systems; higher IQ increases battery drain in long-life applications. | Consider for cost-sensitive, lower-input-voltage designs where 45V tolerance and sub-15µA IQ are not critical. |
Compared with LT3652IMSE#TRPBF and TPS561201DRCT, the LTC3631EDD#TRPBF uniquely combines 45V input tolerance, 12µA Burst Mode® IQ, programmable peak current, and integrated OVLO - making it optimal for ultra-low-power, high-voltage industrial and portable regulation where reliability under surge and longevity are primary concerns.
Availability
LTC3631EDD#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, 4–20mA current loops, portable instruments, battery-operated devices, and automotive power systems requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LTC3631EDD#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 acquired Linear Technology in 2017 and maintains its legacy of high-performance power management ICs with rigorous testing and long-term product support.
The LTC3631EDD#TRPBF belongs to Linear's high-voltage monolithic DC/DC converter family, designed specifically for rugged, low-quiescent-current regulation in harsh environments including factory automation, test equipment, and energy-harvesting systems.
FAQ
What is the maximum input voltage the LTC3631EDD#TRPBF can withstand without damage?
The LTC3631EDD#TRPBF has an absolute maximum VIN rating of 60V and incorporates internal overvoltage lockout that disables switching above 47V (rising). This allows the device to survive automotive load-dump transients and industrial power surges while protecting internal MOSFETs - no external TVS diode is required for 60V events. Operation remains within specification from 4.5V to 45V.
How does the LTC3631EDD#TRPBF achieve 12µA quiescent current?
The LTC3631EDD#TRPBF achieves 12µA typical quiescent current through Burst Mode® operation: during light loads, it enters sleep cycles where internal power switches, comparators, and gate drivers are disabled. Only essential bias circuitry remains active, drawing minimal current from VIN. This architecture maintains output regulation while minimizing average supply current - critical for battery longevity in always-on applications.
Can the LTC3631EDD#TRPBF be used with an adjustable output voltage?
Yes, the LTC3631EDD#TRPBF supports adjustable output via the VOUT/VFB pin. Connect an external resistive divider from VOUT to GND such that the voltage at VOUT/VFB equals 0.800V. The device's internal 0.8V ±1% reference ensures accurate regulation across temperature and line conditions. Fixed 3.3V and 5V variants (e.g., LTC3631EDD-3.3#TRPBF) are also available for simplified designs.
What is the function of the HYST pin on the LTC3631EDD#TRPBF?
The HYST pin on the LTC3631EDD#TRPBF is an open-drain logic output pulled low when the RUN pin voltage falls below 1.2V, indicating disabled operation. It is not an input - it signals RUN status and can be used with an external pull-up resistor to extend RUN pin hysteresis (e.g., to prevent oscillation during slow-rising input rails). It does not accept external drive or set thresholds.
Does the LTC3631EDD#TRPBF require external compensation components?
No, the LTC3631EDD#TRPBF uses a hysteretic control architecture with internal compensation - no external RC networks or type-II/type-III compensators are needed. This simplifies design, improves stability across component tolerances, and reduces bill-of-materials cost. The device regulates accurately with only three external components for fixed-output configurations: inductor, input capacitor, and output capacitor.
LTC3631EDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 45V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 45V
- 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#TRPBF FAQ
1.How can I place an order for LTC3631EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3631EDD#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 LTC3631EDD#TRPBF reliable?
The price and inventory of LTC3631EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3631EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3631EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3631EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3631EDD#TRPBF?
LTC3631EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3631EDD#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 LTC3631EDD#TRPBF?
For technical support, including LTC3631EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3631EDD#TRPBF requirements.
6.How does Aetrix verify that LTC3631EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3631EDD#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 LTC3631EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3631EDD#TRPBF?
All LTC3631EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3631EDD#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 LTC3631EDD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3631EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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