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Analog Devices Inc. LTC3638IMSE#PBF
- Part No.:
- LTC3638IMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Datasheet:
-
LTC3638IMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,685
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Product details
Overview
LTC3638IMSE#PBF 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 switch, delivering up to 250mA output current, featuring 12µA no-load quiescent current and programmable peak current limit (40–575mA). It enables robust industrial power conversion in avionics, medical devices, and distributed systems where input voltage varies from 4V to 140V.
For engineers reviewing the LTC3638IMSE#PBF datasheet, LTC3638IMSE#PBF pinout, LTC3638IMSE#PBF application, or LTC3638IMSE#PBF equivalent, key selection considerations include its 140V absolute max input rating, programmable overvoltage lockout via OVLO pin, precise 1.21V RUN threshold with hysteresis, and parallel operation support via FBO feedback comparator output.
Technical Context
The LTC3638IMSE#PBF employs Burst Mode® control architecture with hysteretic feedback, enabling ultra-low 12µA sleep-mode supply current while maintaining regulation across load currents from 1mA to 250mA. Its internal P-channel MOSFET supports 100% duty cycle dropout operation, critical for high-VIN-to-low-VOUT conversion.
Peak inductor current is set by an external resistor on ISET (40–575mA range), directly determining maximum average output current (half the peak value). Output voltage is selectable as fixed 1.8V/3.3V/5V or adjustable (0.8V to VIN) using VPRG1/VPRG2 pins and external resistive divider, referenced to a ±1% 0.8V internal bandgap.
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-regulator. |
| Max Output Current | 250mA - achievable only when peak current limit is set ≥500mA; actual max load = 0.5 × IPEAK. |
| Quiescent Current | 12µA typical in sleep mode - enables multi-year battery life in always-on remote sensors or portable instruments. |
| Feedback Reference | 0.800V ±1% - sets precise output accuracy in adjustable mode; enables 0.8V to VIN output range. |
| Switch RDS(ON) | 1.8Ω typical - low conduction loss at high input voltages; enables high efficiency even at 140VIN/5VOUT. |
| Run Threshold | 1.21V rising / 1.10V falling - provides clean, hysteresis-controlled enable/disable with 110mV window for noise immunity. |
| Overvoltage Lockout | 1.21V OVLO threshold - allows programmable input overvoltage protection using external resistor divider. |
Pinout & Package
The LTC3638IMSE#PBF is housed in a thermally enhanced 16-lead plastic MSOP package (MSE16) with four missing pins (pins 2, 4, 13, 15) and an exposed GND pad (pin 17) that must be soldered to PCB ground 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 1µF/250V ceramic bypass capacitor to GND for stability. |
| FBO (5) | Feedback Comparator Output | Open-drain output (20µA pull-up, 70Ω pull-down); enables master-slave parallel operation by connecting to slave VFB pins. |
| VPRG2 (6), VPRG1 (7) | Output Voltage Select | Logic inputs defining fixed output: both GND = adjustable; VPRG1=SS/VPRG2=GND = 5V; VPRG1=GND/VPRG2=SS = 3.3V; both SS = 1.8V. |
| GND (8, 16, 17) | Ground Reference | Three GND connections including exposed thermal pad (pin 17); all must connect to low-impedance PCB ground plane. |
| VFB (9) | Feedback Input | Compares divided output voltage to 0.8V reference; in fixed-output mode, tied directly to VOUT. |
| SS (10) | Soft-Start Control | 5µA current source charges external capacitor; 1ms ramp per 6.25nF; floating defaults to internal 1ms soft-start. |
| ISET (11) | Peak Current Set | 5µA current source to GND sets peak inductor current (40–575mA); short to GND = min, open = max. |
| OVLO (12) | Overvoltage Lockout Input | Disables switching when >1.21V; resumes when <1.10V; used with resistor divider to protect against input transients. |
| RUN (14) | Enable/Shutdown Control | Enables regulation when >1.21V; shuts down to 1.4µA when <0.7V; supports programmable UVLO with resistor divider. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Maintains regulation at light loads with only 12µA supply current, eliminating need for external bias supplies in battery-powered systems. |
| Programmable Peak Current Limit | Adjusts IPEAK from 40mA to 575mA via single resistor on ISET, optimizing inductor size, output ripple, and efficiency for specific load requirements. |
| Parallel Operation Support | FBO pin enables synchronous current sharing across multiple LTC3638IMSE#PBF units, scaling output current linearly without external controllers. |
| Precision Run and OVLO Thresholds | 1.21V/1.10V RUN and OVLO thresholds with 110mV hysteresis provide reliable, noise-immune input voltage monitoring for harsh environments. |
| 100% Duty Cycle Dropout | P-channel MOSFET allows continuous conduction at VIN ≈ VOUT, supporting brownout resilience in industrial control supplies during line sag. |
Applications
| Industrial Control Supplies | Avionics Power Systems |
|---|---|
Use Scenario: Regulating 28V or 115VAC-derived 140V DC bus to 5V/3.3V for PLC I/O modules and sensor interfaces in factory automation. IC Role / Device Role / Timing Role: Primary non-isolated step-down regulator providing isolated logic supply rails with high input transient tolerance. Use Value: Eliminates need for bulky pre-regulators or discrete high-voltage MOSFETs, reducing BOM count and improving MTBF in vibration-prone enclosures. | Use Scenario: Generating stable 3.3V for flight control computers from aircraft 270V DC distribution bus under extreme temperature cycling. IC Role / Device Role / Timing Role: High-reliability point-of-load converter meeting DO-160 Section 22 surge immunity with 140V absolute max rating. Use Value: Withstands 140V transients without latch-up or degradation, and -40°C to 125°C operation ensures functionality across stratospheric to ground-level ambient conditions. |
| Medical Imaging Sensors | Portable Battery-Powered Instruments |
Use Scenario: Powering low-noise analog front-ends and ADCs in handheld ultrasound probes powered by 12V–48V Li-ion packs. IC Role / Device Role / Timing Role: Efficient, low-ripple DC/DC stage supplying precision analog circuitry with minimal EMI impact on sensitive signal paths. Use Value: 12µA quiescent current extends probe runtime between charges; programmable peak current minimizes inductor size for compact form factor. | Use Scenario: Providing regulated 1.8V core voltage for microcontrollers in portable gas detectors operating from two AA cells (up to 3.2V) or USB (5V). IC Role / Device Role / Timing Role: Wide-input buck regulator enabling single design to support multiple battery chemistries and charging sources. Use Value: 4V–140V input range accommodates both low-voltage batteries and higher-voltage adapters, simplifying global product variants and inventory management. |
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 |
|---|---|---|---|
| LTC3637IMSE#PBF | Same pinout and feature set but lacks FBO pin and parallel operation capability; identical 140V/250mA rating and 12µA IQ. | Suitable only for single-rail applications; cannot scale output current via master-slave configuration. | Select LTC3638IMSE#PBF when current scalability or synchronized multi-rail regulation is required. |
| MAX5033BASA+T | 100V max input, 250mA output, 100µA IQ, no programmable peak current or Burst Mode; uses external MOSFET. | Requires external high-voltage MOSFET and compensation network; lower integration increases board area and design complexity. | Choose LTC3638IMSE#PBF for higher input voltage margin, lower quiescent current, and full integration in space-constrained designs. |
Compared with LTC3637IMSE#PBF, the LTC3638IMSE#PBF adds FBO-based parallel operation for current scaling; compared with MAX5033BASA+T, it delivers 40V higher input rating, 90% lower quiescent current, and eliminates external MOSFET and compensation components.
Availability
LTC3638IMSE#PBF is available at Aetrix Electronics and suitable for industrial control supplies, avionics power systems, and portable battery-powered instruments requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3638IMSE#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 high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LTC3638IMSE#PBF belongs to Linear's high-voltage monolithic buck regulator family, designed specifically for ruggedized power conversion in environments where input voltage can exceed 100V and reliability under thermal stress is mission-critical.
FAQ
What is the maximum input voltage rating for the LTC3638IMSE#PBF?
The LTC3638IMSE#PBF has an absolute maximum input voltage rating of 140V, with guaranteed operation from 4V to 140V. This allows direct connection to high-voltage industrial buses, avionics supplies, or rectified AC sources without external clamping or pre-regulation. Exceeding 140V may cause permanent damage, and operation above 125°C junction temperature degrades lifetime reliability.
How does the LTC3638IMSE#PBF achieve 12µA quiescent current?
The LTC3638IMSE#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. The 12µA figure applies at no load and 25°C; actual sleep current rises slightly with temperature but remains below 22µA over the full –40°C to 125°C range.
Can the LTC3638IMSE#PBF be used in parallel to increase output current?
Yes, the LTC3638IMSE#PBF supports parallel operation via its FBO (feedback comparator output) pin. Connecting the FBO of a master LTC3638IMSE#PBF to the VFB pins of one or more slave LTC3638IMSE#PBF units forces current sharing, enabling total output current of 250mA × N. All units must use identical inductors and output capacitors, and share common input/output grounds for stable operation.
What output voltage options does the LTC3638IMSE#PBF support?
The LTC3638IMSE#PBF supports four output configurations: fixed 1.8V, 3.3V, or 5V (selected via VPRG1/VPRG2 pin states), and adjustable output from 0.8V to VIN (with VPRG1/VPRG2 both grounded and external resistive divider on VFB). The feedback reference is 0.800V ±1%, ensuring tight output accuracy in all modes.
Is the LTC3638IMSE#PBF RoHS-compliant and lead-free?
Yes, the LTC3638IMSE#PBF carries the #PBF suffix indicating lead-free finish and full RoHS compliance per EU Directive 2011/65/EU. The part marking "3638" appears on the top surface, and the exposed pad (pin 17) is electrically GND and must be soldered to the PCB ground plane to meet thermal specifications and ensure long-term reliability.
LTC3638IMSE#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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC3638IMSE#PBF FAQ
1.How can I place an order for LTC3638IMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3638IMSE#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 LTC3638IMSE#PBF reliable?
The price and inventory of LTC3638IMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3638IMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3638IMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3638IMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3638IMSE#PBF?
LTC3638IMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3638IMSE#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 LTC3638IMSE#PBF?
For technical support, including LTC3638IMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3638IMSE#PBF requirements.
6.How does Aetrix verify that LTC3638IMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3638IMSE#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 LTC3638IMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3638IMSE#PBF?
All LTC3638IMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3638IMSE#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 LTC3638IMSE#PBF part is unused and in its original packaging.
Return procedure for LTC3638IMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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