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Analog Devices Inc. LTC3638HMSE#PBF
- Part No.:
- LTC3638HMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Datasheet:
-
LTC3638HMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,263
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Product details
Overview
LTC3638HMSE#PBF from Analog Devices (formerly Linear Technology) is a high-efficiency, wide-input 4V–140V monolithic step-down DC/DC regulator with integrated 1.8Ω P-channel MOSFET switch, delivering up to 250mA output current. It features Burst Mode® operation for 12µA no-load quiescent current, programmable peak current limit (40–575mA), and precise 0.8V ±1% feedback reference - enabling robust power conversion in avionics, industrial control, and battery-operated systems with high input voltage transients.
For engineers reviewing the LTC3638HMSE#PBF datasheet, LTC3638HMSE#PBF pinout, LTC3638HMSE#PBF application, or LTC3638HMSE#PBF equivalent, key selection considerations include its 140V absolute max input rating, –40°C to 150°C junction temperature range (H-grade), programmable OVLO/RUN thresholds, parallelable FBO output, and thermally enhanced 16-lead MSE package with exposed GND pad.
Technical Context
The LTC3638HMSE#PBF implements a hysteretic Burst Mode® control architecture with internal P-channel MOSFET, where regulation is maintained by alternating burst cycles (switching active) and sleep cycles (only 12µA IQ). Its feedback comparator compares VFB to a trimmed 0.8V reference, triggering bursts when VFB falls 5mV below threshold.
Peak inductor current is set via ISET pin using a resistor-to-GND (40–575mA range), directly determining maximum average output current (½ × IPEAK). The RUN and OVLO pins provide independent, precision-programmable enable and overvoltage lockout functions with 110mV hysteresis, while FBO enables master-slave current sharing across multiple units.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 140V - supports direct regulation from unregulated HV rails like PoE++, automotive batteries, or industrial 48V/96V systems. |
| Max Output Current | 250mA - achievable only when peak current limit is set ≥500mA; actual sustained load depends on thermal design and ambient conditions. |
| Quiescent Current | 12µA typical in Burst Mode sleep - enables multi-year battery life in always-on remote sensors or low-power IoT nodes. |
| Feedback Reference | 0.800V ±1% - enables accurate adjustable output down to 0.8V or fixed 1.8V/3.3V/5V via VPRG pins without external resistors. |
| Switch RDS(on) | 1.8Ω typical - limits conduction loss at 250mA; combined with Burst Mode, delivers >80% efficiency at 1mA load (VIN=48V→5V). |
| Operating Temp Range | –40°C to 150°C junction - H-grade qualification ensures reliability in under-hood automotive, downhole tools, and high-temp industrial enclosures. |
| Package Thermal θJA | 40°C/W - requires exposed pad soldered to PCB ground plane to sustain 250mA continuous output at elevated ambient temperatures. |
Pinout & Package
The LTC3638HMSE#PBF is housed in a thermally enhanced 16-lead MSE (MSOP variant with four missing pins) package. The exposed pad (Pin 17) is GND and must be soldered to the PCB ground plane for rated thermal performance (θJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Switch node | Drain of internal P-MOSFET; connects to inductor and catch diode cathode - carries high di/dt switching current. |
| VIN (3) | Main supply input | Accepts 4V–140V; 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); used to synchronize multiple LTC3638s in parallel for higher current. |
| VPRG2/VPRG1 (6,7) | Output voltage select | Logic inputs that configure internal feedback divider for 1.8V, 3.3V, 5V, or adjustable mode - eliminates external resistors for fixed outputs. |
| GND (8,16,17) | Ground reference | Pins 8 & 16 are signal GND; Pin 17 is exposed thermal pad - all must connect to low-impedance PCB ground plane. |
| VFB (9) | Feedback input | Compares output voltage (via external divider or direct connection) to 0.8V reference - determines regulation accuracy and transient response. |
| SS (10) | Soft-start control | Capacitor-to-GND sets ramp time (1ms per 6.25nF); internal 1ms default if floating - prevents input droop during startup. |
| ISET (11) | Peak current programming | Resistor-to-GND sets peak inductor current (40–575mA); open = max, shorted = min - directly scales max output current and ripple. |
| OVLO (12) | Overvoltage lockout | Resistor-divider input; disables switching above 1.21V (≈140V input) - protects against input transients without external circuitry. |
| RUN (14) | Enable/disable control | Resistor-divider input; enables at 1.21V rising, disables at 1.10V falling - provides precise UVLO and system-level power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Reduces no-load IQ to 12µA while maintaining regulation - critical for energy harvesting and battery longevity. |
| Programmable peak current limit | Adjusts IPEAK from 40mA to 575mA via single resistor - optimizes inductor size, output ripple, and light-load efficiency. |
| Integrated 1.8Ω P-MOSFET | Eliminates external high-voltage switch and gate driver - simplifies layout and improves reliability in 140V systems. |
| Parallelable FBO output | Enables current sharing across multiple LTC3638HMSE#PBF units - scales output to 500mA+ without redesigning magnetics. |
| Thermally enhanced MSE package | Exposed GND pad + 40°C/W θJA - sustains 250mA output at 125°C ambient with proper PCB copper area. |
Applications
| Avionics Power Supply | Industrial Control System |
|---|---|
Use Scenario: Regulating 28V or 115VAC-derived 140V DC bus to 5V for flight data recorders and sensor interfaces in harsh EMI/thermal environments. IC Role / Device Role / Timing Role: Primary non-isolated step-down regulator with built-in OVLO and thermal protection - replaces discrete HV buck controllers requiring external MOSFETs and compensation. Use Value: 140V absolute max rating and –40°C to 150°C operation ensure uninterrupted function during aircraft cold-soak and high-altitude thermal cycling. | Use Scenario: Powering PLC I/O modules and fieldbus transceivers from unregulated 48V or 96V industrial DC rails subject to load dump transients. IC Role / Device Role / Timing Role: High-voltage point-of-load regulator with programmable RUN/OVLO thresholds - provides fault-tolerant enable sequencing and transient immunity. Use Value: Internal soft-start and 12µA sleep current prevent brownouts during hot-swap events and extend backup battery runtime. |
| Portable Medical Instrument | Automotive Telematics Unit |
Use Scenario: Converting primary Li-ion battery stack (up to 42V) or supercapacitor bank (up to 140V) to stable 3.3V for microcontroller and wireless SoC in handheld diagnostics devices. IC Role / Device Role / Timing Role: Efficient, low-noise buck converter with adjustable output and minimal external components - reduces BOM count and board space in compact enclosures. Use Value: 0.8V ±1% reference and Burst Mode enable <1% output deviation across 10µA–250mA load range - ensures ADC accuracy and RF stability. | Use Scenario: Regulating 12V/24V automotive battery (with load dump up to 140V) to 5V for GPS, cellular modem, and CAN controller in telematics control units. IC Role / Device Role / Timing Role: Robust front-end DC/DC with integrated UVLO/OVLO and 150°C H-grade rating - withstands ISO 7637-2 pulse 5a/b and under-hood thermal stress. Use Value: Programmable peak current and parallel FBO support scalable power delivery as modem complexity increases - avoids full hardware redesign. |
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 |
|---|---|---|---|
| LTC3637HMSE#PBF | Same pinout and package; lacks FBO pin and parallel capability; lower max IPEAK (400mA vs 575mA). | Suitable for single-rail 200mA applications where current sharing is unnecessary. | Select LTC3637HMSE#PBF only if FBO functionality and >200mA output are not required - saves cost but sacrifices scalability. |
| MAX5033BASA+ | 36V max input (vs 140V); 250mA output; no programmable OVLO/RUN; 100µA IQ (vs 12µA). | Limited to low-voltage industrial or telecom applications without HV transients. | Choose MAX5033BASA+ only for ≤36V systems where ultra-low IQ and HV tolerance are not needed - avoid for automotive/avionics. |
Compared with LTC3637HMSE#PBF and MAX5033BASA+, the LTC3638HMSE#PBF uniquely combines 140V input tolerance, 12µA quiescent current, FBO-based current sharing, and H-grade 150°C operation - making it the sole option for scalable, ultra-low-power, high-temperature HV buck conversion.
Availability
LTC3638HMSE#PBF is available at Aetrix Electronics and suitable for avionics power supplies, industrial control systems, and automotive telematics units requiring stable component supply across extended temperature and high-reliability lifecycles.
Supply support for LTC3638HMSE#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 its legacy of high-performance analog and power management ICs with rigorous testing and long-term product support.
The LTC3638HMSE#PBF belongs to Linear's high-voltage monolithic DC/DC regulator family, designed specifically for reliable power conversion in systems with wide-input, high-transient, and extended-temperature requirements - such as aerospace, downhole, and transportation electronics.
FAQ
What is the maximum input voltage the LTC3638HMSE#PBF can safely handle?
The LTC3638HMSE#PBF has an absolute maximum input voltage rating of 140V. It operates continuously from 4V to 140V, and its programmable OVLO pin allows disabling switching above a user-defined threshold (e.g., 120V) to protect downstream circuitry during transients. Sustained operation at 140V requires adherence to thermal limits and proper PCB layout with the exposed pad soldered to GND.
How does the LTC3638HMSE#PBF achieve 12µA quiescent current?
The LTC3638HMSE#PBF achieves 12µA typical quiescent current through Burst Mode® operation: during light loads, it enters a sleep cycle where the internal power switch and current comparators are disabled, leaving only essential bias circuitry active. This ultra-low IQ is maintained while holding output regulation via charge stored in the output capacitor - a key enabler for battery-powered and energy-harvesting applications.
Can multiple LTC3638HMSE#PBF ICs be connected in parallel to increase output current?
Yes, the LTC3638HMSE#PBF supports parallel operation via its FBO (Feedback Comparator Output) pin. Connecting the FBO of a master unit to the VFB pins of slave units forces synchronized burst timing and equal current sharing. This configuration scales total output current linearly (e.g., two units deliver 500mA), preserving regulation accuracy and thermal balance without external current-sharing circuitry.
What is the purpose of the VPRG1 and VPRG2 pins on the LTC3638HMSE#PBF?
The VPRG1 and VPRG2 pins on the LTC3638HMSE#PBF configure the internal feedback divider to select fixed output voltages - shorting VPRG1 to SS and VPRG2 to GND yields 5V; VPRG1 to GND and VPRG2 to SS yields 3.3V; both to SS yields 1.8V; both to GND enables adjustable mode (0.8V–VIN). This eliminates external resistors for common outputs, reducing component count and noise sensitivity while maintaining 0.8V ±1% reference accuracy.
Does the LTC3638HMSE#PBF require external compensation components?
No, the LTC3638HMSE#PBF uses a hysteretic Burst Mode® control architecture that is inherently stable and requires no external compensation components. Its loop stability is determined by internal comparator hysteresis and passive component selection (inductor, input/output capacitors), simplifying design and eliminating tuning effort - a significant advantage over voltage-mode or current-mode controllers needing complex RC networks.
LTC3638HMSE#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:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC3638HMSE#PBF FAQ
1.How can I place an order for LTC3638HMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3638HMSE#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 LTC3638HMSE#PBF reliable?
The price and inventory of LTC3638HMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3638HMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3638HMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3638HMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3638HMSE#PBF?
LTC3638HMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3638HMSE#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 LTC3638HMSE#PBF?
For technical support, including LTC3638HMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3638HMSE#PBF requirements.
6.How does Aetrix verify that LTC3638HMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3638HMSE#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 LTC3638HMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3638HMSE#PBF?
All LTC3638HMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3638HMSE#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 LTC3638HMSE#PBF part is unused and in its original packaging.
Return procedure for LTC3638HMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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