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Analog Devices Inc. LTC3638MPMSE#PBF
- Part No.:
- LTC3638MPMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Datasheet:
-
LTC3638MPMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:105
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Product details
Overview
LTC3638MPMSE#PBF from Analog Devices (formerly Linear Technology) is a high-efficiency, wide-input 140V step-down DC/DC regulator with integrated P-channel MOSFET, delivering up to 250mA output current, operating from 4V to 140V input, featuring 12µA no-load quiescent current and programmable peak current limit for optimized light-load efficiency - used in avionics power supplies requiring extended temperature operation.
For engineers reviewing the LTC3638MPMSE#PBF datasheet, LTC3638MPMSE#PBF pinout, LTC3638MPMSE#PBF application, or LTC3638MPMSE#PBF equivalent, key selection considerations include its –55°C to 150°C operating junction temperature range, programmable 1.8V/3.3V/5V/fixed or adjustable output, Burst Mode® operation for ultra-low IQ, and parallelability via FBO pin for higher-current systems.
Technical Context
The LTC3638MPMSE#PBF implements a hysteretic Burst Mode® control architecture with internal P-channel MOSFET switch, enabling 100% duty cycle dropout operation and inherent short-circuit protection through variable-frequency switching dependent on VIN, VOUT, and inductor value. Its feedback comparator uses a precise 0.800V ±1% reference with 5mV hysteresis for stable regulation across load transients.
Startup is managed by a dedicated RUN pin with 1.21V enable threshold and 110mV hysteresis, coupled with internal 1ms soft-start (extendable externally via SS pin capacitor); overvoltage lockout is independently configurable via OVLO pin with 1.21V trip threshold, and peak current is set via ISET pin using a resistor-to-GND network scaling linearly from 40mA to 500mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 140V - supports direct regulation from unregulated industrial, automotive, or avionic bus voltages without pre-regulation. |
| Max Output Current | 250mA - average output limited to half the programmable peak inductor current (up to 500mA), ensuring safe thermal margin at full load. |
| Quiescent Current | 12µA typical in Burst Mode® sleep - enables multi-year battery life in always-on remote sensors or backup power systems. |
| Feedback Reference | 0.800V ±1% - enables accurate adjustable output down to 0.8V or fixed 1.8V/3.3V/5V via VPRG1/VPRG2 pin strapping. |
| Operating Temp Range | –55°C to 150°C junction - qualified for extended-temperature military, aerospace, and downhole industrial applications. |
| Switch On-Resistance | 1.8Ω typical - low RDS(on) minimizes conduction loss at high input voltages and moderate loads. |
| Peak Current Range | 40mA to 500mA programmable via ISET - allows optimization of inductor size, output ripple, and light-load efficiency per application. |
Pinout & Package
The LTC3638MPMSE#PBF is housed in a thermally enhanced 16-lead plastic MSOP package (MSE16 variant) with four missing pins (pins 2, 4, 13, 15), featuring an exposed pad (Pin 17) that must be soldered to PCB ground for rated thermal performance (θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Switch Node | Drain of internal P-channel MOSFET; connects to inductor and catch diode cathode - carries high dv/dt switching waveform. |
| VIN (3) | Main Input Supply | Accepts 4V–140V input; requires local 1µF/250V ceramic bypass capacitor to GND for stability and EMI suppression. |
| FBO (5) | Feedback Comparator Output | Open-drain output (20µA pull-up, 70Ω pull-down) for master-slave paralleling of multiple LTC3638MPMSE#PBF units. |
| VPRG2 / VPRG1 (6,7) | Output Voltage Selection | Strap pins to GND or SS to select 1.8V, 3.3V, 5V fixed outputs or enable adjustable mode - eliminates external resistors for common voltages. |
| GND (8,16,17) | Ground Return | Three ground connections including exposed thermal pad (Pin 17) - mandatory soldering ensures thermal derating compliance at 150°C. |
| VFB (9) | Feedback Input | Compares divided output voltage against 0.800V reference; directly tied to VOUT in fixed-output mode or to resistor divider in adjustable mode. |
| SS (10) | Soft-Start Control | Capacitor-to-GND sets ramp time (1ms per 6.25nF); internal 50µA/5µA current source enables controlled startup and transient recovery. |
| ISET (11) | Peak Current Programming | Resistor-to-GND sets peak inductor current from 40mA to 500mA; floating = max, shorted = min - determines max output current and ripple tradeoff. |
| OVLO (12) | Overvoltage Lockout Input | Resistive divider from VIN sets disable threshold (1.21V rising); prevents operation during input transients above safe level. |
| RUN (14) | Enable/UVLO Control | Resistive divider enables operation above 1.21V (110mV hysteresis); below 0.7V forces shutdown with 1.4µA IQ - replaces external supervisor IC. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Reduces no-load IQ to 12µA while maintaining regulation - critical for energy-harvesting and battery-backed systems. |
| Programmable Peak Current Limit | Adjusts max inductor current from 40mA to 500mA via single resistor - enables optimization of inductor size, efficiency, and output ripple. |
| Parallelable Architecture | FBO pin allows synchronous current sharing across multiple LTC3638MPMSE#PBF units - scales output current linearly without external controllers. |
| Wide Input Range with UVLO/OVLO | Dual independent voltage monitors (RUN and OVLO pins) provide precise, resistor-programmable input window - eliminates need for discrete supervisors. |
| 100% Duty Cycle Dropout | P-channel MOSFET enables continuous conduction at low VIN/VOUT ratios - maintains regulation down to VIN ≈ VOUT with minimal dropout loss. |
Applications
| Avionics Power Conversion | Industrial Control Supplies |
|---|---|
Use Scenario: Regulating 28V or 115VAC-derived 140V DC bus to 3.3V for flight data recorders and sensor interfaces in commercial aircraft. IC Role / Device Role / Timing Role: Primary non-isolated step-down regulator providing clean, low-noise 3.3V rail with guaranteed operation from –55°C to +150°C. Use Value: Eliminates need for external UVLO/OVLO circuitry and enables direct connection to high-voltage avionic buses while meeting DO-160 lightning surge immunity requirements. |
Use Scenario: Powering PLC I/O modules and fieldbus transceivers from unregulated 24V–72V DC industrial rails subject to brownouts and surges. IC Role / Device Role / Timing Role: High-reliability buck converter with programmable current limit and robust thermal management for harsh factory-floor environments. Use Value: Sustains regulation during 4V undervoltage events and shuts down cleanly above 140V transients - reduces system-level protection component count by 3+ parts. |
| Downhole Oil & Gas Sensors | Medical Imaging Subsystems |
Use Scenario: Generating 5V bias for MEMS pressure sensors and telemetry radios deployed in oil well drill strings at 150°C ambient. IC Role / Device Role / Timing Role: Extended-temperature DC/DC regulator with low IQ and high input voltage tolerance for battery- or turbine-powered downhole tools. Use Value: Qualified for –55°C to +150°C operation with no derating - enables single-supply design without heater-cooler subsystems or thermal shielding. |
Use Scenario: Providing isolated 1.8V logic supply for FPGA-based image processing boards in portable ultrasound and X-ray equipment. IC Role / Device Role / Timing Role: Low-noise, low-ripple buck regulator supporting high-speed digital logic with tight voltage tolerance (±1%) and fast transient response. Use Value: Adjustable output and precise 0.800V reference ensure stable core voltage under dynamic FPGA load changes - improves signal integrity and reduces bit error rate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3638HMSE#PBF | Same architecture and pinout; rated for –40°C to +150°C (vs. –55°C to +150°C for LTC3638MPMSE#PBF). | Lacks extended low-temperature qualification; unsuitable for cryogenic or space-grade cold-soak testing. | Select LTC3638MPMSE#PBF when operation below –40°C is required; otherwise LTC3638HMSE#PBF offers cost advantage. |
| LTC3638IMSE#PBF | Same functionality; rated for –40°C to +125°C junction temperature - lower max temp and no extended cold rating. | Not qualified for military/aerospace thermal cycling profiles; limited to commercial/industrial ambient conditions. | Choose only for cost-sensitive, non-extended-temp applications where full –55°C to +150°C range is unnecessary. |
Compared with LTC3638HMSE#PBF and LTC3638IMSE#PBF, the LTC3638MPMSE#PBF uniquely supports operation down to –55°C while maintaining full 150°C upper limit - making it the sole option for systems requiring validated performance across the full military-grade temperature spectrum.
Availability
LTC3638MPMSE#PBF is available at Aetrix Electronics and suitable for avionics power conversion, downhole instrumentation, and medical imaging subsystems requiring stable component supply across extended temperature extremes and long production lifecycles.
Supply support for LTC3638MPMSE#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, datasheets, and application engineering for all Linear-branded power management ICs.
The LTC3638MPMSE#PBF belongs to Linear's high-voltage monolithic buck regulator family, designed specifically for ruggedized power conversion in aerospace, industrial, and medical systems where wide input range, ultra-low quiescent current, and extended temperature reliability are mandatory.
FAQ
What is the operating temperature range of the LTC3638MPMSE#PBF?
The LTC3638MPMSE#PBF is tested and guaranteed over a junction temperature range of –55°C to +150°C. This extended range exceeds standard industrial and automotive grades, making it suitable for military, aerospace, and downhole applications where extreme thermal environments are encountered. The device incorporates overtemperature protection that disables switching above ~180°C and restarts after cooling below ~160°C.
How does the LTC3638MPMSE#PBF achieve ultra-low quiescent current?
The LTC3638MPMSE#PBF achieves 12µA typical quiescent current through Burst Mode® operation: during light loads, it enters a sleep cycle where the internal power switch and comparators are disabled, drawing only bias current. A burst of switching cycles resumes only when output voltage droop triggers the feedback comparator. This architecture avoids continuous switching losses, enabling multi-year battery life in always-on systems powered by the LTC3638MPMSE#PBF.
Can multiple LTC3638MPMSE#PBF devices be paralleled, and how?
Yes, the LTC3638MPMSE#PBF supports current sharing via its FBO (feedback comparator output) pin. Connect the FBO pin of a master LTC3638MPMSE#PBF to the VFB pins of one or more slave LTC3638MPMSE#PBF units. This forces all devices to regulate to the same feedback threshold, enabling synchronized operation and linear current scaling - e.g., two units deliver up to 500mA total output current without external clock synchronization or current-sense resistors.
What is the purpose of the ISET pin on the LTC3638MPMSE#PBF?
The ISET pin on the LTC3638MPMSE#PBF programs the peak inductor current limit from 40mA to 500mA using a resistor-to-GND network. Since maximum average output current equals half the peak current, this pin directly sets the device's current capability. It also enables tradeoffs: lower peak current reduces output ripple and allows smaller inductors, while higher values improve transient response - all configurable without changing feedback components or layout.
Does the LTC3638MPMSE#PBF require external compensation components?
No, the LTC3638MPMSE#PBF uses a hysteretic control architecture with internal compensation, eliminating the need for external Type-II or Type-III compensation networks. This simplifies design, reduces BOM count, and improves reliability - especially in high-voltage applications where compensation capacitor voltage ratings and leakage become critical. Stability is inherent to the Burst Mode® topology and does not depend on output capacitor ESR.
LTC3638MPMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 140V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 140V
- Current - Output:
- 250mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC3638MPMSE#PBF FAQ
1.How can I place an order for LTC3638MPMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3638MPMSE#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 LTC3638MPMSE#PBF reliable?
The price and inventory of LTC3638MPMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3638MPMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3638MPMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3638MPMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3638MPMSE#PBF?
LTC3638MPMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3638MPMSE#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 LTC3638MPMSE#PBF?
For technical support, including LTC3638MPMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3638MPMSE#PBF requirements.
6.How does Aetrix verify that LTC3638MPMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3638MPMSE#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 LTC3638MPMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3638MPMSE#PBF?
All LTC3638MPMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3638MPMSE#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 LTC3638MPMSE#PBF part is unused and in its original packaging.
Return procedure for LTC3638MPMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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