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Analog Devices Inc. LTC3638EMSE#TRPBF
- Part No.:
- LTC3638EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Datasheet:
-
LTC3638EMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,220
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Product details
Overview
LTC3638EMSE#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, wide-input 140V step-down DC/DC regulator with integrated P-channel MOSFET switch, delivering up to 250mA output current, operating from 4V to 140V input, featuring 12µA quiescent current in Burst Mode® and programmable peak current limit (40–575mA). It is used in avionics power supplies where high-voltage transient tolerance and ultra-low no-load power are critical.
For engineers reviewing the LTC3638EMSE#TRPBF datasheet, LTC3638EMSE#TRPBF pinout, LTC3638EMSE#TRPBF application, or LTC3638EMSE#TRPBF equivalent, key selection criteria include input voltage range (4–140V), adjustable/programmable output (0.8V–VIN), precise RUN/OVLO thresholds (±110mV hysteresis), thermal performance in MSOP-16 (θJA = 40°C/W), and parallel operation capability via FBO pin.
Technical Context
The LTC3638EMSE#TRPBF employs Burst Mode® control architecture with hysteretic feedback, enabling high efficiency across 1µA–250mA load range by alternating between active burst cycles and low-power sleep mode. Its internal P-channel MOSFET supports 100% duty cycle for dropout operation down to VIN ≈ VOUT.
It integrates programmable overvoltage lockout (OVLO) and undervoltage lockout (UVLO) via resistor dividers on OVLO and RUN pins, with independent 1.21V rising/1.10V falling thresholds and 110mV hysteresis. The feedback comparator uses a precision 0.800V ±1% reference and supports fixed outputs (1.8V/3.3V/5V) or adjustable configuration via external resistive divider.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 140V - enables direct regulation from unregulated industrial, automotive, or avionics bus voltages without pre-regulation. |
| Max Output Current | 250mA - determined as half the programmable peak inductor current (up to 575mA), ensuring stable continuous operation under full load. |
| Quiescent Current | 12µA typical in Burst Mode® - sustains regulated output at no load while minimizing standby power in battery- or energy-harvesting systems. |
| Feedback Reference | 0.800V ±1% - provides accurate output voltage setting in adjustable mode; enables <1% output error with standard 1% resistors. |
| Peak Current Limit | 40mA to 575mA (programmable via ISET pin) - allows optimization of inductor size, output ripple, and light-load efficiency for specific load profiles. |
| Thermal Resistance | θJA = 40°C/W, θJC = 10°C/W - requires exposed pad (Pin 17) soldered to PCB ground plane to achieve rated 125°C junction temperature in ambient. |
| Operating Temp Range | –40°C to 125°C - specified for E-grade version LTC3638EMSE#TRPBF, suitable for industrial and extended-temperature embedded applications. |
Pinout & Package
The LTC3638EMSE#TRPBF is housed in a thermally enhanced, high-voltage-capable 16-lead plastic MSOP package (MSE16) with four missing pins (1, 2, 4, 13), and an exposed GND pad (Pin 17) that must be soldered to the PCB ground plane for thermal compliance.
| 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) enabling master-slave parallel operation of multiple LTC3638EMSE#TRPBF units. |
| VPRG2/VPRG1 (6,7) | Output Voltage Selection | Configure fixed 1.8V/3.3V/5V or adjustable output by grounding or connecting to SS pin; eliminates external feedback resistors in fixed-mode designs. |
| GND (8,16,17) | Ground Reference | Pins 8 and 16 are signal GND; Pin 17 is exposed thermal pad - all must connect to low-impedance PCB ground plane for thermal and noise performance. |
| VFB (9) | Feedback Input | Compares divided output voltage against 0.800V reference; in fixed-output mode, directly tied to VOUT; in adjustable mode, connected to external resistor divider. |
| SS (10) | Soft-Start Control | Capacitor-to-GND sets output ramp time (1ms per 6.25nF); internal 1ms default if floating; resets after UVLO/OVLO events. |
| ISET (11) | Peak Current Programming | Resistor-to-GND sets peak inductor current (40–575mA); 5µA current source (reduced to 1µA in sleep) enables ripple-efficiency tradeoff. |
| OVLO (12) | Overvoltage Lockout Input | Resistor-divider input with 1.21V rising threshold; disables switching during input transients >VIN(MAX); triggers soft-start reset for graceful recovery. |
| RUN (14) | Enable/Undervoltage Control | Resistor-divider input with 1.21V rising / 1.10V falling threshold; enables operation above 1.21V, shuts down below 0.7V (1.4µA IQ). |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Enables 12µA no-load IQ while maintaining regulation - extends battery life in portable instruments and reduces heat in sealed enclosures. |
| Programmable Peak Current Limit | Adjusts switching behavior from 40mA to 575mA via single resistor - optimizes inductor size, output ripple, and light-load efficiency without redesigning control loop. |
| Integrated P-Channel MOSFET | Eliminates external high-side switch and gate driver - simplifies layout, reduces BOM count, and enables 100% duty cycle for low-dropout operation. |
| Parallel Operation Support | FBO pin allows synchronization and current sharing across multiple LTC3638EMSE#TRPBF regulators - scales output current to 500mA+ without external controllers. |
| Precision Thresholds with Hysteresis | RUN and OVLO pins feature 110mV hysteresis - prevents chatter during slow-rising/falling input rails and ensures clean enable/disable transitions in noisy environments. |
Applications
| Avionics Power Distribution | Industrial Sensor Transmitters |
|---|---|
Use Scenario: Regulating 28V or 115VAC-derived 140V DC bus to 3.3V for flight-critical sensors and data acquisition modules in harsh EMI/thermal environments. IC Role / Device Role / Timing Role: Primary non-isolated step-down regulator providing isolated downstream power domains; operates continuously with minimal self-heating. Use Value: 140V absolute max rating and robust OVLO/RUN monitoring ensure survival during lightning-induced transients; 12µA IQ preserves backup battery runtime during aircraft standby. | Use Scenario: Powering 4–20mA loop-powered smart transmitters in oil & gas refineries where input can vary from 12V (battery backup) to 56V (industrial supply) with surge risk. IC Role / Device Role / Timing Role: Main DC/DC converter supplying 5V to microcontroller, ADC, and analog front-end; handles wide input variation without external pre-regulator. Use Value: Programmable UVLO/OVLO prevents operation outside safe input window; adjustable peak current allows optimized efficiency at 10–100mA typical loads. |
| Portable Medical Diagnostics | Automotive Battery Monitoring Systems |
Use Scenario: Generating stable 1.8V and 3.3V rails from a 9–16V Li-ion pack in handheld ultrasound or point-of-care analyzers requiring low audible noise and long battery life. IC Role / Device Role / Timing Role: High-efficiency buck regulator supporting Burst Mode® for intermittent processing bursts and deep-sleep states. Use Value: 12µA IQ extends battery life beyond 72 hours in standby; soft-start and precise RUN threshold prevent brownout resets during cold cranking or battery insertion. | Use Scenario: Powering CAN controller, microcontroller, and voltage monitors from vehicle battery (9–16V nominal) with jump-start tolerance up to 40V and load-dump immunity to 120V. IC Role / Device Role / Timing Role: Primary system regulator delivering 5V to safety-critical ECUs; withstands ISO 7637-2 pulse 5a (120V/50ms) without latch-up. Use Value: 140V input rating and internal OVLO allow direct connection to battery rail; thermal shutdown (180°C) protects during sustained overloads in engine bay mounting. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-input-voltage step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3999EMSE#TRPBF | Higher 60V max input, 1.2A output, fixed 3.3V/5V only; no programmable peak current or adjustable output; requires external compensation. | Targeted at lower-voltage, higher-current LED drivers and isolated bias supplies - lacks 140V capability and flexible feedback. | Select LT3999EMSE#TRPBF only when input stays ≤60V and fixed output suffices; not suitable for avionics or industrial 100V+ rails. |
| MAX5033BASA+T | 100V max input, 250mA output, 100µA IQ, no Burst Mode®, fixed 3.3V/5V/12V outputs only; no OVLO/RUN programmability. | Designed for cost-sensitive industrial power modules - trades ultra-low IQ and wide input for reduced feature set and lower voltage ceiling. | Choose MAX5033BASA+T for simpler, lower-cost 100V designs where 12µA IQ and 140V margin are unnecessary. |
Compared with LT3999EMSE#TRPBF and MAX5033BASA+T, the LTC3638EMSE#TRPBF uniquely combines 140V input rating, 12µA Burst Mode® IQ, programmable peak current, and adjustable output in a single MSOP package - making it irreplaceable for high-reliability, wide-input, low-quiescent applications where thermal headroom and transient resilience are mandatory.
Availability
LTC3638EMSE#TRPBF is available at Aetrix Electronics and suitable for avionics power distribution, industrial sensor transmitters, portable medical diagnostics, and automotive battery monitoring systems requiring stable component supply across extended temperature and high-voltage stress conditions.
Supply support for LTC3638EMSE#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 high-performance power management portfolio with rigorous qualification and long-term product support.
The LTC3638EMSE#TRPBF belongs to Linear's high-voltage monolithic buck regulator family, designed specifically for ruggedized power conversion in aerospace, industrial, and automotive applications where input transients, wide voltage range, and ultra-low standby power are mission-critical.
FAQ
What is the maximum input voltage rating for the LTC3638EMSE#TRPBF?
The LTC3638EMSE#TRPBF has an absolute maximum input voltage rating of 140V, with guaranteed operation from 4V to 140V. This allows direct regulation from high-voltage sources such as avionics 115VAC-derived DC buses or industrial 100V+ supplies without external pre-regulation stages. Exceeding 140V may cause permanent damage per Absolute Maximum Ratings.
How does the LTC3638EMSE#TRPBF achieve 12µA quiescent current?
The LTC3638EMSE#TRPBF 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, reducing VIN supply current to just 12µA while maintaining output regulation via the output capacitor. This behavior is confirmed in Electrical Characteristics (IQ = 12µA typ, Sleep Mode).
Can the LTC3638EMSE#TRPBF be configured for a 1.2V output?
Yes, the LTC3638EMSE#TRPBF supports adjustable output voltages from 0.8V to VIN using an external resistive divider connected to the VFB pin, with a precision 0.800V ±1% internal reference. For 1.2V output, use R1 = 50kΩ and R2 = 100kΩ (or standard 1% values yielding VOUT = 0.8V × (1 + R1/R2)), verified in the Feedback Comparator Threshold section of the datasheet.
What is the purpose of the FBO pin on the LTC3638EMSE#TRPBF?
The FBO (Feedback Comparator Output) pin on the LTC3638EMSE#TRPBF is an open-drain output (20µA pull-up, 70Ω pull-down) that enables parallel operation: connecting the FBO of a master LTC3638EMSE#TRPBF to the VFB pins of slave units synchronizes regulation and shares load current proportionally, scaling total output to 250mA × N devices without external controllers or complex timing circuits.
Is the exposed pad (Pin 17) on the LTC3638EMSE#TRPBF electrically connected?
Yes, the exposed pad (Pin 17) on the LTC3638EMSE#TRPBF is internally connected to GND and must be soldered to the PCB ground plane. This is required to meet thermal specifications (θJA = 40°C/W) and ensure reliable operation at full load and elevated ambient temperatures - failure to connect it risks thermal shutdown or reduced lifetime per the Absolute Maximum Ratings note.
LTC3638EMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC3638EMSE#TRPBF FAQ
1.How can I place an order for LTC3638EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3638EMSE#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 LTC3638EMSE#TRPBF reliable?
The price and inventory of LTC3638EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3638EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3638EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3638EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3638EMSE#TRPBF?
LTC3638EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3638EMSE#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 LTC3638EMSE#TRPBF?
For technical support, including LTC3638EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3638EMSE#TRPBF requirements.
6.How does Aetrix verify that LTC3638EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3638EMSE#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 LTC3638EMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3638EMSE#TRPBF?
All LTC3638EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3638EMSE#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 LTC3638EMSE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3638EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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