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Analog Devices Inc. LTC3631IMS8E#PBF
- Part No.:
- LTC3631IMS8E#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3631IMS8E#PBF.pdf
- Description:
- IC REG BUCK ADJ 100MA 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,096
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Product details
Overview
LTC3631IMS8E#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 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 during 60V input surges via overvoltage lockout.
For engineers reviewing the LTC3631IMS8E#PBF datasheet, LTC3631IMS8E#PBF pinout, LTC3631IMS8E#PBF application, or LTC3631IMS8E#PBF equivalent, this page provides verified technical context for industrial control supplies, 4–20mA current loops, battery-operated instrumentation, and automotive power systems requiring robust wide-input regulation with minimal standby power.
Technical Context
The LTC3631IMS8E#PBF implements a hysteretic burst-mode control architecture with an internal 0.800V ±1% feedback reference and 5mV hysteresis, enabling automatic transition between active switching bursts and ultra-low-power sleep cycles. Its peak-current-limited operation uses a user-programmable ISET pin (1µA current source) to set trip thresholds from 50mA to 225mA, directly determining maximum average output current (up to 112mA).
Input protection includes undervoltage lockout (UVLO: 3.75V–4.50V) and overvoltage lockout (OVLO: 47V–52V), allowing safe exposure to 60V transients. The RUN pin enables precise start-up control (1.17V–1.25V rising threshold, 110mV hysteresis), while the HYST pin provides open-drain logic output for external hysteresis extension - critical for stable operation in noisy industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports direct connection to 12V/24V/36V industrial buses and automotive batteries with surge tolerance up to 60V. |
| Output Current | 100mA - sufficient for powering microcontrollers, sensors, and analog front-ends in distributed systems without external boost stages. |
| No-Load Quiescent Current | 12µA - enables multi-year battery life in portable instruments and remote sensors operating intermittently. |
| Feedback Reference Voltage | 0.800V ±1% - enables accurate output regulation across temperature and line variations using standard resistor dividers. |
| Peak Current Limit Range | 50mA to 225mA - adjustable via ISET-to-GND resistor to optimize efficiency and component size for specific load profiles. |
| Switching Architecture | Burst Mode® with hysteretic control - eliminates need for external compensation and delivers >85% efficiency at 1mA load. |
| Package Thermal Resistance | θJA = 40°C/W (MS8E) - enables 100mA continuous operation at +85°C ambient without forced airflow or heatsinking. |
Pinout & Package
Package: 8-lead plastic MSOP (MS8E), 3mm × 3mm footprint, 0.75mm height, exposed pad (Pin 9) tied to GND 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 current - requires tight layout and Kelvin grounding. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V input; bypassed with ceramic capacitor to GND (Pin 8) to suppress high-frequency noise and supply ripple. |
| ISET (Pin 3) | Peak current programming | 1µA current source sets peak inductor current limit (50–225mA); resistor to GND determines trade-off between efficiency and component size. |
| SS (Pin 4) | Soft-start control | 5µA current source charges external capacitor to control output voltage ramp rate - prevents input droop during cold start. |
| RUN (Pin 5) | Enable/disable control | Logic-level input with 1.21V rising threshold; below 0.7V forces shutdown (3µA IQ), enabling system-level power sequencing. |
| VOUT/VFB (Pin 6) | Output feedback | Connects to regulated output (fixed versions) or resistive divider (adjustable version); referenced to internal 0.800V comparator. |
| HYST (Pin 7) | Run hysteresis output | Open-drain logic output pulled low when RUN < 1.2V - used to add external hysteresis for stable VIN monitoring in noisy rails. |
| GND (Pin 8) | Power ground | Primary ground return path; must be connected to PCB ground plane alongside exposed pad (Pin 9) for optimal thermal performance. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous power switches | Eliminates external MOSFETs and gate drivers - reduces BOM count to only three components for fixed-output configurations. |
| Programmable peak current limit | Enables optimization of inductor and capacitor sizing for target load range, reducing board area and cost in low-current applications. |
| Internal soft-start + external SS pin | Guarantees controlled startup with <1ms internal ramp or user-defined longer ramp - prevents overshoot and input supply collapse. |
| Precise RUN pin threshold with hysteresis | Ensures reliable enable/disable behavior in fluctuating input conditions - eliminates chatter during brown-out recovery. |
| Overvoltage lockout up to 60V | Protects downstream circuitry from load-dump transients in automotive and industrial 24V systems without external TVS clamping. |
Applications
| 4–20mA Current Loops | Industrial Control Supplies |
|---|---|
|
Use Scenario: Powering loop-powered field transmitters in process automation where supply is derived from 4–20mA loop voltage (typically 12–36V). IC Role / Device Role / Timing Role: Primary DC/DC regulator converting loop voltage to stable 3.3V or 5V for sensor signal conditioning and ADC reference. Use Value: 12µA quiescent current ensures minimum loop compliance voltage drop, preserving full 4–20mA dynamic range under all operating conditions. |
Use Scenario: Providing isolated auxiliary power for PLC I/O modules, valve positioners, and HART modems in factory-floor environments. IC Role / Device Role / Timing Role: Main step-down regulator handling wide-input industrial bus voltages (24V ±20%) with transient immunity. Use Value: 60V surge tolerance and UVLO/OVLO protection eliminate need for external protection circuitry, simplifying design and improving reliability. |
| Portable Instruments | Battery-Operated Devices |
|
Use Scenario: Power management in handheld multimeters, gas detectors, and portable data loggers powered by two or three alkaline cells (3–4.5V) or Li-ion (3.0–4.2V). IC Role / Device Role / Timing Role: Efficient buck converter extending battery runtime while maintaining regulation as cell voltage decays. Use Value: Burst Mode® operation sustains >80% efficiency down to 100µA load - critical for sleep-mode longevity in always-on sensing nodes. |
Use Scenario: Supplying clean 3.3V to microcontrollers and wireless SoCs (e.g., BLE, LoRa) in asset trackers and smart sensors. IC Role / Device Role / Timing Role: Primary power stage regulating from primary battery (e.g., CR2032, AA, or Li-SOCl₂) to system rail. Use Value: Adjustable peak current limit allows matching inductor selection to battery ESR and capacity - minimizing voltage sag during transmit bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMS8E#PBF | Same silicon, E-grade (-40°C to 85°C) vs I-grade (-40°C to 125°C); identical electrical specs and pinout. | Suitable for commercial/industrial environments with lower ambient temperature requirements. | Select when full industrial temperature range is not required - offers same performance at lower cost. |
| LT8609SIS8E#PBF | Higher 2A output, 3V–42V input, 2.5µA IQ, but requires external compensation and lacks programmable peak current limit. | Better for higher-current applications; less suitable for ultra-low-IQ or fine-tuned low-current optimization. | Choose when >100mA output or tighter input range (3V–42V) is needed - not a drop-in replacement due to different control architecture. |
Compared with LTC3631EMS8E#PBF, the LTC3631IMS8E#PBF guarantees full -40°C to +125°C operation for harsh environments, while LT8609SIS8E#PBF trades programmability and simplicity for higher current capability - making LTC3631IMS8E#PBF optimal for precision low-power industrial regulation.
Availability
LTC3631IMS8E#PBF is available at Aetrix Electronics and suitable for 4–20mA current loops, industrial control supplies, and battery-operated devices requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC3631IMS8E#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 continues its legacy of high-performance analog and power management ICs with rigorous qualification and long-term product support.
The LTC3631IMS8E#PBF belongs to Linear's high-voltage monolithic buck converter family, designed specifically for rugged industrial, automotive, and instrumentation applications demanding wide input range, low quiescent current, and integrated protection.
FAQ
What is the operating temperature range for the LTC3631IMS8E#PBF?
The LTC3631IMS8E#PBF is specified and guaranteed over the full industrial junction temperature range of –40°C to +125°C. This rating is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section of the official datasheet, where all "l"-marked parameters apply across this range. The MS8E package's θJA of 40°C/W enables reliable 100mA operation at +85°C ambient with standard PCB copper area.
Does the LTC3631IMS8E#PBF require external compensation components?
No, the LTC3631IMS8E#PBF uses a hysteretic burst-mode control architecture that does not require external compensation. Its internal feedback loop is inherently stable across all input voltages, output loads, and output capacitor types - eliminating the need for compensation networks, phase-margin analysis, or ESR-dependent output capacitors.
How is the output voltage set on the LTC3631IMS8E#PBF?
The LTC3631IMS8E#PBF is an adjustable-output converter: its VOUT/VFB pin (Pin 6) connects to an external resistive divider that scales the output voltage to match the internal 0.800V ±1% reference. Fixed-output variants (e.g., LTC3631IMS8E-3.3#PBF) have internal dividers; the IMS8E#PBF part number indicates the bare die version requiring external configuration.
What protection features does the LTC3631IMS8E#PBF include?
The LTC3631IMS8E#PBF integrates input undervoltage lockout (UVLO: 3.75V–4.50V), overvoltage lockout (OVLO: 47V–52V), and short-circuit limiting via hysteretic control. It withstands 60V input surges indefinitely in shutdown mode and features reverse-current blocking to prevent output-to-input backfeed during fault conditions.
Can the LTC3631IMS8E#PBF operate with 100% duty cycle?
Yes, the LTC3631IMS8E#PBF supports 100% duty cycle low-dropout operation - meaning it can maintain regulation even when VIN approaches VOUT. This is enabled by its synchronous architecture and internal P-channel high-side switch, allowing seamless transition into dropout without output collapse or pulse-skipping artifacts.
LTC3631IMS8E#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- 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-MSOP-EP
LTC3631IMS8E#PBF FAQ
1.How can I place an order for LTC3631IMS8E#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3631IMS8E#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 LTC3631IMS8E#PBF reliable?
The price and inventory of LTC3631IMS8E#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3631IMS8E#PBF is usually 5 days.
3.What payment methods are accepted for LTC3631IMS8E#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3631IMS8E#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3631IMS8E#PBF?
LTC3631IMS8E#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3631IMS8E#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 LTC3631IMS8E#PBF?
For technical support, including LTC3631IMS8E#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3631IMS8E#PBF requirements.
6.How does Aetrix verify that LTC3631IMS8E#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3631IMS8E#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 LTC3631IMS8E#PBF meets industry standards.
7.What is the process for return or replacement of LTC3631IMS8E#PBF?
All LTC3631IMS8E#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3631IMS8E#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 LTC3631IMS8E#PBF part is unused and in its original packaging.
Return procedure for LTC3631IMS8E#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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