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Analog Devices Inc. LTC3638HMSE#TRPBF
- Part No.:
- LTC3638HMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Datasheet:
-
LTC3638HMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,315
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Product details
Overview
LTC3638HMSE#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, wide-input 140V step-down DC/DC regulator with integrated 1.8Ω P-channel MOSFET, delivering up to 250mA output current, featuring 12µA no-load quiescent current and programmable peak current limit (40–575mA). It enables robust power conversion in avionics and industrial control systems where input voltage may range from 4V to 140V.
For engineers reviewing the LTC3638HMSE#TRPBF datasheet, LTC3638HMSE#TRPBF pinout, LTC3638HMSE#TRPBF application, or LTC3638HMSE#TRPBF equivalent, key selection considerations include its –40°C to 150°C operating junction temperature rating, programmable overvoltage lockout via OVLO pin, precise RUN threshold (1.21V rising), internal soft-start, and parallel operation capability via FBO pin for higher current designs.
Technical Context
The LTC3638HMSE#TRPBF employs Burst Mode® operation to maintain high efficiency across ultra-light to full load (1mA–250mA), using a hysteretic feedback comparator referenced to 0.800V ±1% and a programmable peak current comparator whose threshold is set by an external resistor on ISET. Its P-channel synchronous architecture supports 100% duty cycle dropout operation.
Control logic integrates precision undervoltage lockout (UVLO = 3.5V typ.), programmable input overvoltage lockout (OVLO threshold = 1.21V), and thermal shutdown (~180°C). The FBO pin provides open-drain feedback comparator output enabling master-slave paralleling of multiple LTC3638HMSE#TRPBF units without external synchronization circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 140V - supports direct regulation from unregulated industrial, automotive, or avionics bus voltages without pre-regulation. |
| Max Output Current | 250mA - determined as half the programmable peak switch current (up to 575mA), ensuring stable continuous operation under full load. |
| Quiescent Current | 12µA typical in sleep mode - enables multi-year battery life in always-on portable or remote sensor applications. |
| Feedback Reference | 0.800V ±1% - high-precision internal reference enabling accurate output regulation across temperature and line variations. |
| Operating Temp Range | –40°C to +150°C junction - qualified for high-reliability industrial, avionics, and downhole equipment environments. |
| Switch RDS(on) | 1.8Ω - low on-resistance P-channel MOSFET minimizes conduction loss at high input voltages and light loads. |
| Soft-Start Time | 1ms internal default - prevents inrush current and input supply droop during power-up; adjustable via external capacitor on SS pin. |
Pinout & Package
The LTC3638HMSE#TRPBF is housed in a thermally enhanced 16-lead plastic MSOP package (MSE16) with four missing pins (pins 2, 4, 13, 15), featuring an exposed GND pad (pin 17) that must be soldered to PCB for 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 dv/dt switching waveform. |
| VIN (3) | Main Input Supply | Accepts 4V–140V input; requires local ceramic bypass capacitor to GND for stability and EMI suppression. |
| FBO (5) | Feedback Comparator Output | Open-drain output used to parallel multiple LTC3638HMSE#TRPBF units - pulls low when VFB exceeds reference, enabling synchronized regulation. |
| VPRG1/VPRG2 (6,7) | Output Voltage Selection | Configure fixed 1.8V/3.3V/5V or adjustable output by grounding or tying to SS - eliminates external feedback resistors for standard outputs. |
| GND (8,16,17) | Ground Reference | Three ground connections including exposed thermal pad (pin 17); all must be low-impedance to PCB ground plane for thermal and noise performance. |
| VFB (9) | Feedback Input | Compares divided output voltage to 0.800V reference - directly connected to output for fixed-voltage modes; connected to divider for adjustable mode. |
| SS (10) | Soft-Start Control | Capacitor-to-GND sets output ramp time (1ms per 6.25nF); internal 5µA current source ensures controlled start-up without input droop. |
| ISET (11) | Peak Current Programming | Resistor-to-GND sets peak inductor current (40–575mA); floating = max current, shorted = min - directly scales max output current and ripple. |
| OVLO (12) | Overvoltage Lockout Input | Resistive divider from VIN sets disable threshold (1.21V rising); triggers soft-start reset on overvoltage transients - protects downstream circuitry. |
| RUN (14) | Enable/Undervoltage Monitor | Resistive divider sets turn-on threshold (1.21V rising); falling below 1.1V disables regulator - provides precise input UVLO and enable control. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Maintains >80% efficiency at 1mA load while drawing only 12µA supply current - ideal for intermittent-sensing IoT nodes. |
| Programmable Peak Current Limit | Adjustable 40–575mA via single resistor on ISET - optimizes inductor size, output ripple, and efficiency for specific load profiles. |
| Wide Input Range with Programmable OVLO | Operates from 4V to 140V; OVLO pin allows custom overvoltage cutoff (e.g., disable above 80V) - enhances reliability in variable-source systems. |
| Precision RUN Threshold & Hysteresis | 1.21V rising / 1.10V falling with 110mV hysteresis - enables clean, bounce-free enable/disable control and accurate UVLO setting. |
| Parallel Operation Support | FBO pin enables master-slave configuration of multiple LTC3638HMSE#TRPBF - scales output current to 500mA+ without external clock or current-sharing ICs. |
Applications
| Industrial Control Supplies | Avionics Power Systems |
|---|---|
Use Scenario: Powering PLC I/O modules and fieldbus transceivers from 24V–72V DC distribution rails subject to load dump transients. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator providing stable 3.3V or 5V rail for microcontrollers and interface ICs. Use Value: 140V absolute maximum input withstands 100V load-dump spikes; programmable OVLO prevents false triggering during transient events. | Use Scenario: Generating 5V for flight control sensors and data acquisition units in unmanned aerial vehicles (UAVs) powered by 28V or 115VAC-derived DC buses. IC Role / Device Role / Timing Role: High-reliability point-of-load regulator meeting DO-160 Section 22 surge immunity requirements. Use Value: –40°C to +150°C junction rating ensures operation in extreme ambient conditions; low 12µA quiescent current extends battery backup runtime. |
| Medical Imaging Subsystems | Portable Test Instruments |
Use Scenario: Supplying bias voltage to photodiode amplifiers and ADC front-ends in handheld ultrasound or X-ray detectors with battery + boost-derived 48V input. IC Role / Device Role / Timing Role: Low-noise, low-ripple step-down converter delivering regulated 1.8V or 3.3V for precision analog signal chains. Use Value: Adjustable peak current programming reduces output ripple at light loads; 0.800V ±1% reference ensures <±0.5% output accuracy over temperature. | Use Scenario: Power management in handheld multimeters and oscilloscope probes requiring long battery life and stable 5V USB-compatible output. IC Role / Device Role / Timing Role: Primary buck regulator converting 9V–12V alkaline or Li-ion battery stack to regulated 5V system rail. Use Value: 100% duty cycle dropout operation maintains regulation down to VOUT + 0.5V input; internal soft-start prevents display flicker during cold start. |
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 |
|---|---|---|---|
| LTC3637EMSE#TRPBF | Same architecture but rated for –40°C to 125°C; lacks H-grade extended temperature qualification. | Suitable for commercial/industrial environments without extreme thermal stress. | Select when 150°C junction operation is not required and cost sensitivity is higher. |
| MAX5033BASA+ | Fixed 5V output only; 76V max input; 125mA max output; no programmable current limit or OVLO pin. | Limited to lower-power, fixed-output applications with narrower input range. | Choose only for simple 5V/125mA designs where programmability and ruggedness are secondary. |
Compared with LTC3637EMSE#TRPBF and MAX5033BASA+, the LTC3638HMSE#TRPBF uniquely combines 140V input tolerance, 150°C operation, programmable peak current, and parallel capability - making it the sole option for high-reliability, high-temperature, scalable buck regulation in harsh environments.
Availability
LTC3638HMSE#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, avionics power systems, and medical imaging subsystems requiring stable component supply across extended temperature and voltage ranges.
Supply support for LTC3638HMSE#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 qualification and application support.
The LTC3638 product line was designed specifically for high-input-voltage, low-quiescent-current step-down regulation in mission-critical systems where reliability, thermal resilience, and design flexibility are paramount.
FAQ
What is the maximum allowable input voltage for the LTC3638HMSE#TRPBF?
The LTC3638HMSE#TRPBF has an absolute maximum input voltage rating of 140V, with operational functionality guaranteed from 4V to 140V. Exceeding 140V risks permanent damage. Its programmable OVLO pin allows setting a custom overvoltage cutoff (e.g., 80V or 100V) to enhance system safety before reaching the absolute maximum limit. Always observe derating guidelines for long-term reliability at high voltage and temperature.
How does the LTC3638HMSE#TRPBF achieve 12µA quiescent current?
The LTC3638HMSE#TRPBF achieves 12µA typical quiescent current in sleep mode through Burst Mode® operation: the internal power switch and current comparators are disabled between burst cycles, leaving only essential bias circuitry active. During each burst, the 5µA ISET current source ramps up to deliver energy; between bursts, it drops to 1µA. This architecture minimizes average supply current at light loads while maintaining regulation - a key enabler for battery-powered applications using the LTC3638HMSE#TRPBF.
Can the LTC3638HMSE#TRPBF be used in parallel to increase output current?
Yes, the LTC3638HMSE#TRPBF supports parallel operation via its FBO (feedback comparator output) pin. Connecting the FBO pin of a master LTC3638HMSE#TRPBF to the VFB pins of one or more slave devices forces them to regulate synchronously, effectively combining output currents. Each LTC3638HMSE#TRPBF contributes up to 250mA, enabling scalable solutions (e.g., 500mA with two units). No external clock or current-sharing resistors are needed - the FBO pin's open-drain structure handles arbitration inherently.
What is the purpose of the VPRG1 and VPRG2 pins on the LTC3638HMSE#TRPBF?
The VPRG1 and VPRG2 pins on the LTC3638HMSE#TRPBF configure the output voltage without external resistors: grounding both selects adjustable mode (0.8V–VIN); tying VPRG1 to SS and VPRG2 to GND sets 5V; VPRG1 to GND and VPRG2 to SS sets 3.3V; tying both to SS sets 1.8V. This eliminates feedback divider errors and noise susceptibility while simplifying layout - a design advantage unique to the LTC3638HMSE#TRPBF among high-voltage buck regulators.
Does the LTC3638HMSE#TRPBF require external compensation components?
No, the LTC3638HMSE#TRPBF uses a hysteretic current-mode control architecture with internal compensation - no external compensation components (e.g., type-II or type-III networks) are required. Stability is inherent due to the feedback comparator's built-in hysteresis and the relationship between peak inductor current, output voltage, and input voltage. This simplifies design, reduces BOM count, and improves reliability compared to voltage-mode controllers requiring loop compensation.
LTC3638HMSE#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC3638HMSE#TRPBF FAQ
1.How can I place an order for LTC3638HMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3638HMSE#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 LTC3638HMSE#TRPBF reliable?
The price and inventory of LTC3638HMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3638HMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3638HMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3638HMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3638HMSE#TRPBF?
LTC3638HMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3638HMSE#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 LTC3638HMSE#TRPBF?
For technical support, including LTC3638HMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3638HMSE#TRPBF requirements.
6.How does Aetrix verify that LTC3638HMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3638HMSE#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 LTC3638HMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3638HMSE#TRPBF?
All LTC3638HMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3638HMSE#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 LTC3638HMSE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3638HMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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