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Analog Devices Inc. LT3748EMS#TRPBF
- Part No.:
- LT3748EMS#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads
- Datasheet:
-
LT3748EMS#TRPBF.pdf
- Description:
- IC REG CTRLR FLYBACK 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,721
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Product details
Overview
LT3748EMS#TRPBF from Analog Devices is a 100V isolated flyback controller IC designed for primary-side regulation in high-power isolated DC/DC converters. It drives an external N-channel MOSFET, operates in boundary mode, supports 5–100V input, delivers up to 25W output (e.g., 12V/2A), and eliminates need for opto-isolators or third-winding feedback.
For engineers reviewing the LT3748EMS#TRPBF datasheet, LT3748EMS#TRPBF pinout, LT3748EMS#TRPBF application, or LT3748EMS#TRPBF equivalent, key selection considerations include its 16-lead MSOP package with four leads removed, 7V internally regulated INTVCC gate driver supply, programmable UVLO and soft-start, and primary-side sensing capability enabling compact telecom and automotive power supplies.
Technical Context
The LT3748EMS#TRPBF implements boundary-mode (critical conduction) control using primary-side flyback waveform sampling to derive isolated output voltage - eliminating opto-isolators and third windings. Its internal error amplifier references a 1.223V bandgap and samples at zero secondary current to ensure precise load regulation.
It features a 1.9A average gate drive source/sink, programmable SENSE current limit threshold (90–110mV), and temperature-compensated RREF bias via TC pin current (27.5µA into 20kΩ). Operating frequency varies dynamically with load and transformer magnetizing inductance, not fixed by external oscillator.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5V to 100V - supports wide-input industrial, telecom, and automotive battery systems without pre-regulation. |
| INTVCC Regulation | 7.0V ±0.2V - powers gate driver and internal circuitry; stable bias enables consistent MOSFET switching performance. |
| Gate Drive Capability | 1.9A avg source/sink - drives large external N-MOSFETs for >25W output power with fast rise/fall times (16ns). |
| SENSE Threshold Range | 90–110mV - sets peak primary current limit; adjustable via VC pin for precise overcurrent protection. |
| EN/UVLO Threshold | 1.223V rising - enables programmable undervoltage lockout using resistor divider from VIN for system-level brownout control. |
| Soft-Start Threshold | 0.65V - controls startup ramp time via external capacitor; prevents inrush current and stabilizes initial regulation. |
| Operating Temp Range | –40°C to +125°C - qualified for industrial and automotive environments (I-grade); junction-limited to 125°C. |
Pinout & Package
LT3748EMS#TRPBF is housed in a 16-lead plastic MSOP package with four leads (2, 4, 13, 15) removed - resulting in a 12-pin functional layout optimized for high-voltage isolation and thermal dissipation (θJA = 90°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main input supply reference | Bypassed locally; supplies start-up circuitry and serves as reference for RFB feedback network. |
| EN/UVLO (Pin 3) | Enable and undervoltage detection | Resistor-divider input sets turn-on threshold (~1.223V); sinks 2.4µA hysteresis current for clean UVLO release. |
| INTVCC (Pin 5) | Internally regulated gate driver supply | 7V output powers GATE driver; may be tied to VIN if ≤20V and no third winding used. |
| GATE (Pin 6) | N-MOSFET gate drive output | Switches between INTVCC and GND; 1.9A avg drive supports fast switching of high-Qg MOSFETs. |
| SENSE (Pin 7) | Primary current sense input | Kelvin-connected to RSENSE source; detects current limit with 90–110mV threshold range. |
| GND (Pins 8, 9) | Power and signal ground reference | Dual ground pins reduce noise coupling; connect directly to low-impedance PCB ground plane. |
| SS (Pin 10) | Soft-start timing control | Sources 5µA to external capacitor; startup begins when voltage reaches ~0.65V. |
| VC (Pin 11) | Error amplifier compensation node | Connect series RC to ground for loop stability; also adjusts SENSE threshold via transconductance. |
| TC (Pin 12) | Temperature compensation current source | Sources 27.5µA into RTC resistor to offset diode VF drift and improve output voltage tempco. |
| RREF (Pin 14) | Reference resistor connection | Accepts 6.04kΩ (±1%) to set feedback gain; internal 1.223V bandgap reference defines output voltage ratio. |
| RFB (Pin 16) | Primary-side feedback input | Connected to MOSFET drain; senses flyback pulse amplitude to derive isolated output voltage without opto-coupler. |
Key Features
| Feature | Design Value |
|---|---|
| Primary-side regulation | Eliminates opto-isolator and third-winding components - reduces BOM cost, board area, and long-term reliability risk from aging LEDs. |
| Boundary mode operation | Enables zero-current switching on secondary side - improves load regulation accuracy and allows smaller magnetics vs CCM designs. |
| Programmable INTVCC control | INTVCC pin can be driven externally or tied to VIN - simplifies biasing when third winding is omitted and input ≤20V. |
| Integrated temperature compensation | TC pin current (27.5µA) into RTC resistor cancels diode forward-voltage drift - maintains <±5% output regulation over –40°C to +125°C. |
| High-voltage robustness | 100V absolute max rating on VIN/RFB pins - supports direct connection to 48V/72V telecom or 12V/24V automotive battery rails with transient margin. |
Applications
| Telecom Isolated Supply | Automotive High-Voltage DC/DC |
|---|---|
Use Scenario: 36–72V input telecom brick delivering 12V/2A to base station control logic. IC Role / Device Role / Timing Role: Primary-side flyback controller performing boundary-mode switching and output voltage regulation via RFB/RREF sampling. Use Value: Achieves 25W output with <±1.5% line/load regulation and eliminates opto-isolator - reducing component count and improving MTBF. |
Use Scenario: 12V battery-powered ADAS camera module requiring isolated 5V rail with AEC-Q100 compliance. IC Role / Device Role / Timing Role: Isolated flyback controller managing startup sequencing, UVLO, and temperature-compensated regulation across automotive temperature range. Use Value: Meets AEC-Q100 Grade I requirements (–40°C to +125°C) and enables compact, high-reliability design without third-winding complexity. |
| Industrial Isolated Power | Military/Harsh-Environment Supply |
Use Scenario: Factory automation PLC with 24–48V input powering isolated 15V analog sensor interface. IC Role / Device Role / Timing Role: Boundary-mode controller regulating output via primary-side flyback waveform sampling under variable load and input conditions. Use Value: Delivers stable output despite wide input range and load transients - no opto-isolator drift or aging effects over 10+ year service life. |
Use Scenario: Avionics subsystem requiring 28V input to 5V/3A isolated output operating at +150°C junction temperature. IC Role / Device Role / Timing Role: High-temp rated flyback controller (LT3748H variant available) maintaining regulation during extended high-temperature soak tests. Use Value: Supports LT3748HMPMS#TRPBF variant rated to –55°C to +150°C - enables deployment in uncooled military enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28911DR | Fixed-frequency DCM controller; no boundary-mode sampling; requires auxiliary winding for VDD and feedback. | Lacks primary-side regulation - needs third winding and additional bias circuitry; lower integration than LT3748EMS#TRPBF. | Choose UCC28911DR only if fixed-frequency EMI profile is required and third-winding implementation is acceptable. |
| MAX17690ATP+ | Current-mode flyback controller with integrated 65V MOSFET; no external switch support; max 65V VIN. | Not suitable for >65V inputs (e.g., 72V telecom); limited to lower-power applications due to integrated FET thermal constraints. | Select MAX17690ATP+ only for space-constrained <15W designs where integrated FET simplifies layout and 65V max input suffices. |
Compared with UCC28911DR and MAX17690ATP+, the LT3748EMS#TRPBF uniquely combines 100V input capability, external MOSFET drive, and true primary-side boundary-mode regulation - enabling higher power, smaller magnetics, and elimination of opto-isolators or third windings in demanding industrial and automotive applications.
Availability
LT3748EMS#TRPBF is available at Aetrix Electronics and suitable for telecom isolated supplies, automotive high-voltage DC/DC converters, and industrial embedded power systems requiring stable component supply and long-term lifecycle support.
Supply support for LT3748EMS#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 is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and aerospace markets.
The LT3748EMS#TRPBF belongs to Analog Devices' Power by Linear™ isolated controller product line, engineered specifically for high-efficiency, high-reliability primary-side regulated flyback converters in harsh environments.
FAQ
What is the maximum input voltage supported by the LT3748EMS#TRPBF?
The LT3748EMS#TRPBF supports an absolute maximum input voltage of 100V on the VIN and RFB pins. Its specified operating input voltage range is 5V to 100V, making it suitable for direct connection to 48V/72V telecom systems and 12V/24V automotive battery rails with transient headroom. Exceeding 100V risks permanent damage per Absolute Maximum Ratings.
Does the LT3748EMS#TRPBF require an opto-isolator or third transformer winding?
No - the LT3748EMS#TRPBF performs primary-side regulation by sampling the flyback pulse waveform at the MOSFET drain (RFB pin), eliminating the need for opto-isolators or third-winding feedback. This reduces component count, improves long-term reliability, and avoids opto-coupler aging and nonlinearity issues inherent in traditional isolated flyback designs.
How is output voltage programmed on the LT3748EMS#TRPBF?
The LT3748EMS#TRPBF sets output voltage using two external resistors: RREF (typically 6.04kΩ) connected to the RREF pin, and RFB connected between the MOSFET drain and RFB pin. The ratio RFB/RREF, multiplied by the internal 1.223V bandgap reference and divided by the transformer turns ratio (NPS), determines VOUT - enabling precise, resistor-based programming without secondary-side components.
What package type and lead count does the LT3748EMS#TRPBF use?
The LT3748EMS#TRPBF uses a 16-lead plastic MSOP package with four leads (2, 4, 13, 15) physically removed - resulting in a 12-pin functional footprint. This configuration enhances creepage/clearance for high-voltage isolation while maintaining compatibility with standard MSOP assembly processes and thermal performance (θJA = 90°C/W).
Is the LT3748EMS#TRPBF qualified for automotive applications?
The LT3748EMS#TRPBF is rated for –40°C to +125°C operating junction temperature and is part of Analog Devices' automotive-qualified portfolio. While the EMS grade itself is industrial-qualified, AEC-Q100-compliant variants (e.g., LT3748IMS#WTRPBF) are available with controlled manufacturing and full automotive reliability reporting - required for functional safety-critical automotive deployments.
LT3748EMS#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Flyback
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 5V ~ 100V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP
LT3748EMS#TRPBF FAQ
1.How can I place an order for LT3748EMS#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3748EMS#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 LT3748EMS#TRPBF reliable?
The price and inventory of LT3748EMS#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3748EMS#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3748EMS#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3748EMS#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3748EMS#TRPBF?
LT3748EMS#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3748EMS#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 LT3748EMS#TRPBF?
For technical support, including LT3748EMS#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3748EMS#TRPBF requirements.
6.How does Aetrix verify that LT3748EMS#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3748EMS#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 LT3748EMS#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3748EMS#TRPBF?
All LT3748EMS#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3748EMS#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 LT3748EMS#TRPBF part is unused and in its original packaging.
Return procedure for LT3748EMS#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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