LT3748EMS#PBF - 100V Isolated Flyback Controller | Analog Devices
MPN: LT3748EMS#PBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.75 | $4.75 |
| 10 | $4.75 | $47.50 |
| 100 | $4.75 | $475.00 |
| 500 | $4.75 | $2,375.00 |
| 1,000 | $4.75 | $4,750.00 |
LT3748EMS#PBF Overview
A flyback controller is a switching-regulator controller that uses an energy-storage transformer to transfer power across an isolation barrier. The LT3748EMS#PBF belongs to the DC-DC converter and isolated power-supply hierarchy, combining high-voltage input capability, boundary-mode control, and external power-stage design flexibility. Its isolation-capable architecture is useful where the output must be electrically separated from the input source.
Key verified features include a 5V to 100V input operating range, a 100V isolated flyback-controller rating, boundary-mode operation, low-side external N-MOSFET drive, internally regulated 7V gate-drive supply, and load regulation of ±5% over the specified line, load, and temperature ranges. The 16-MSOP package supports compact isolated power modules while leaving the MOSFET and transformer selection to the designer.
The LT3748 is intended for isolated auxiliary supplies, industrial equipment, telecom power systems, data-acquisition equipment, instrumentation, and high-voltage DC-DC converters. The boundary-mode approach can reduce transformer size while maintaining load regulation, but final efficiency, isolation, voltage accuracy, and thermal performance depend on the external transformer, MOSFET, compensation, layout, and output components.
Designers should select an external MOSFET with adequate voltage and current ratings, verify transformer isolation and saturation margins, and keep high-current switching loops compact. The controller’s 100V input capability does not remove the need for surge protection, input filtering, creepage, clearance, and safety validation in the completed isolated converter. This page summarizes verified source information and clearly identifies specifications that require additional data.
Drop-in alternatives for LT3748EMS#PBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LT3748HMS#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LT3748IMS#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LT3748EMS#TRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LT3748EMS#PBF-T
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT3748HMS#TRPBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT3748EMS#PBF Maximum Ratings & Electrical Characteristics
| Product Type | 100V isolated flyback controller IC |
| Input Voltage Range | 5V to 100V |
| Maximum Input Voltage | 100V |
| Switching Topology | Isolated flyback |
| Control Method | Boundary mode |
| Output Configuration | Isolated step-up/step-down capable |
| External Power Stage | Low-side external N-channel MOSFET |
| Internal Gate-Drive Supply | 7V regulated |
| Load Regulation | ±5% over full line, load, and temperature ranges |
| Package | 16-MSOP |
| Mounting Type | Surface mount |
| Isolation Capability | Isolation-capable isolated flyback controller |
| Operating Mode | Boundary mode |
| Load Power Capability | Several tens of watts with suitable external MOSFET and transformer |
| Manufacturer Product Status | Production |
| Switching Frequency | Set by load current and transformer magnetizing inductance |
| Number of Outputs | 1 isolated output |
LT3748EMS#PBF 16-msop Pin Configuration Guide
Pin configuration for LT3748EMS#PBF (16-msop package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for LT3748EMS#PBF.
Refer to the datasheet for full pin configuration.
Typical Applications
LT3748EMS#PBF is suitable for 6 applications: Isolated Industrial Auxiliary Supply, High-Voltage DC-DC Converter, Telecom Power System, Instrumentation and Test Equipment, Data Acquisition and Sensor Gateway, Isolated Gate-Drive or Bias Supply.
Isolated Industrial Auxiliary Supply
The LT3748EMS#PBF fits isolated auxiliary supplies in industrial equipment because it accepts 5V to 100V and uses an isolated flyback topology to transfer power across a safety barrier. Place the controller with a suitably rated external N-channel MOSFET and transformer, then regulate the isolated output through the transformer and feedback network. Its boundary-mode operation lets the switching frequency depend on load current and transformer magnetizing inductance, helping reduce magnetic size while maintaining the manufacturer-stated ±5% load regulation. The design must be checked for worst-case surge voltage, insulation, creepage, clearance, thermal rise, and isolation withstand.
Recommended
High-Voltage DC-DC Converter
Use LT3748EMS#PBF as the control element in a high-input-voltage isolated DC-DC converter when the source may operate near the controller’s 100V capability. Its low-side external N-MOSFET drive and boundary-mode control provide a compact solution for power levels of several tens of watts when the passive and semiconductor design is appropriate. The external MOSFET must withstand the worst-case input voltage plus switching transients, while the transformer must satisfy turns ratio, magnetizing inductance, saturation, leakage-inductance, and isolation requirements. Final regulation and efficiency depend on those choices rather than on the controller alone.
Recommended
Telecom Power System
The LT3748EMS#PBF is applicable to telecom-style isolated power modules where a 48V-class nominal input may be used with a higher transient voltage and where galvanic isolation is required. The 5V to 100V controller range provides design margin over a nominal telecom bus, but the completed converter still needs input surge suppression, reverse-polarity protection as required, filtering, and safety-qualified isolation. Boundary-mode operation supports a small transformer solution, and the external MOSFET allows the switching device to be selected for the module’s power and thermal requirements.
Recommended
Instrumentation and Test Equipment
The LT3748EMS#PBF can generate an isolated auxiliary rail for instrumentation, measurement front ends, and test equipment that require a clean separation from a high-voltage input. The isolated flyback architecture avoids sharing the output return with the primary side, while boundary-mode control helps keep the magnetic solution compact. Design the transformer for the target isolation voltage and working voltage, maintain the required clearance and creepage across the barrier, and verify that feedback components and output capacitors meet the required ripple and transient response. The controller is suitable only when the external power stage is designed for the specified environment.
Recommended
Data Acquisition and Sensor Gateway
An LT3748EMS#PBF-based isolated flyback converter can supply a local isolated rail for data-acquisition equipment, sensor gateways, and field-installed electronics. Its high-input-voltage capability is useful when the converter is fed from a long industrial wiring system where transients are possible. The controller’s external MOSFET and transformer arrangement permits optimization for a required isolated output power of several tens of watts, but the engineering must include input protection, common-mode considerations, galvanic isolation, thermal design, and tested surge immunity. Boundary-mode frequency variation should be checked across the complete line and load range.
Recommended
Isolated Gate-Drive or Bias Supply
The LT3748EMS#PBF can be used in isolated gate-drive or bias-supply subsystems when the target circuit requires a secondary-side supply separated from a high-voltage primary. The controller drives a low-side external N-channel MOSFET from an internally regulated 7V supply, allowing the power stage to be selected for the required isolation and output levels. Because the device is a flyback controller, the transformer turns ratio and feedback network determine the output voltage, while leakage inductance and clamping components influence EMI and switch stress. Validate the design for dielectric withstand, partial-discharge, temperature, and creepage requirements applicable to the target system.
Recommended
Recommended Products Summary
Engineering reference data for LT3748EMS#PBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LT3748HMS#PBF | LT3748IMS#PBF | LT3748EMS#TRPBF | LT3748EMS#PBF-T | LT3748HMS#TRPBF |
|---|---|---|---|---|---|---|
| Package | 16-MSOP | MSOP-16 | MSOP-16 | MSOP-16 | MSOP-16 | MSOP-16 |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
Key Differentiators
- High-input-voltage isolated flyback control (vs LT3748HMS#PBF)
- Boundary-mode operation (vs LT3748IMS#PBF)
- External power-stage flexibility (vs LT3748EMS#TRPBF)
Design Notes
The LT3748EMS#PBF is a controller, not a complete power stage. Select the external N-channel MOSFET for the worst-case input voltage, switching transients, output current, RDS(on), gate charge, avalanche behavior, and thermal rise. Verify the transformer turns ratio and magnetizing inductance against the intended output voltage and power level. Estimated system power cannot be calculated from the controller alone; use the manufacturer application guidance and test the selected transformer, MOSFET, clamp, rectifier, and output network together.
Keep the primary-side switching loop compact by placing the input capacitor, controller, external MOSFET, and transformer primary in the smallest practical loop. Route the gate trace with low parasitic inductance and avoid long shared paths. Keep feedback and compensation nodes away from the drain, switch node, and transformer leakage field. Respect the isolation barrier with verified creepage, clearance, insulation, and component-height rules; a layout that meets low-voltage switching performance may still fail high-voltage isolation requirements.
Do not assume that a related LT3748 ordering suffix is automatically a drop-in replacement. Confirm the exact package drawing, pin names, exposed connections, electrical limits, and ordering code against the current Analog Devices datasheet. Also do not interpret the 100V controller rating as complete 100V system qualification. Add appropriate input surge and transient protection, transformer insulation verification, output filtering, and prototype testing across line, load, and temperature conditions.
Compliance Information
The supplied verified snippets identify the manufacturer, package, topology, voltage range, production status, and product information, but they do not explicitly provide RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals statements. Verify current compliance documents from Analog Devices before release to manufacturing.
