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Analog Devices Inc. LT3752HFE#WTRPBF
- Part No.:
- LT3752HFE#WTRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Datasheet:
-
LT3752HFE#WTRPBF.pdf
- Description:
- ACTIVE CLAMP SYNC FOR CNTRS W/ I
- Quantity:
- Payment:
- Shipping:
Inventory:1,245
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Product details
Overview
LT3752HFE#WTRPBF from Analog Devices is a high-voltage active clamp synchronous forward controller with integrated housekeeping DC/DC controller, supporting 6.5V–100V input and operating up to 150°C junction temperature. It delivers programmable volt-second clamp (DVSEC), active clamp MOSFET timing control (tAO/tOA), synchronous rectifier timing (tSO/tOS), and hiccup-mode overcurrent protection - enabling high-efficiency isolated power supplies in automotive and industrial 48V systems.
For engineers reviewing the LT3752HFE#WTRPBF datasheet, LT3752HFE#WTRPBF pinout, LT3752HFE#WTRPBF application, or LT3752HFE#WTRPBF equivalent, key selection criteria include its –40°C to 150°C automotive-grade thermal rating, dual-loop control architecture (forward + housekeeping), programmable switching frequency (100–500 kHz), active clamp topology support, and TSSOP-38 package with high-voltage pin spacing.
Technical Context
The LT3752HFE#WTRPBF implements a current-mode PWM control architecture optimized for active clamp forward converters, featuring independent forward and housekeeping oscillator loops with foldback capability. Its dual-control structure enables simultaneous regulation of primary-side main switch (OUT), active clamp switch (AOUT), and secondary-side synchronous rectifier (SOUT) with precise, programmable timing delays (tAO, tOA, tSO, tOS).
It integrates two error amplifiers (FB for main loop, HFB for housekeeping), separate current sense paths (ISENSEP/ISENSEN for forward, HISENSE for housekeeping), and dedicated regulators: INTVCC linear regulator (7.0 V nominal for LT3752 variant) and internal housekeeping DC/DC controller. The device supports micropower start-up, soft-start/stop, and AEC-Q100 qualification for automotive use.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6.5 V to 100 V - supports wide-range industrial and automotive battery inputs without external pre-regulation. |
| Operating Junction Temp | –40°C to +150°C - qualified for under-hood automotive and high-ambient industrial environments. |
| Switching Frequency | 100 kHz to 500 kHz - programmable via RT resistor; line regulation ≤0.1%/V ensures stable operation across input range. |
| DVSEC Clamp Accuracy | ±4% duty cycle error at UVLO_VSEC = 1.25 V - enables precise volt-second limiting for transformer reset and duty >50% operation. |
| Gate Driver Rise/Fall Time | 19–23 ns (OUT/AOUT/SOUT) - fast edge rates support high-frequency, low-loss switching with SiC/GaN-compatible drive strength. |
| INTVCC Regulator | 7.0 V ±0.2 V, 50 mA current limit - powers internal circuitry and gate drivers; dropout <0.8 V at 10 mA reduces conduction loss. |
| FB Reference Voltage | 1.250 V ±2.5 mV - high-precision feedback reference enables tight output voltage regulation (<±1% typical system accuracy). |
Pinout & Package
LT3752HFE#WTRPBF is housed in a 38-lead plastic TSSOP (FE package) with missing pins for enhanced high-voltage creepage and clearance. Exposed pad (Pin 39) is connected to PGND/GND and must be soldered to PCB for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Accepts 6.5–100 V; powers forward controller and INTVCC regulator; includes UVLO/OVLO detection. |
| OUT | Main power switch driver | High-current N-channel gate driver (11.9 V high level); controls primary-side MOSFET in forward topology. |
| AOUT | Active clamp switch driver | Programmable timing relative to OUT (tAO/tOA); supports external PMOS (LT3752) or NMOS (LT3752-1) clamp switches. |
| SOUT | Synchronous rectifier driver | Controls secondary-side SR MOSFET; timing adjustable vs OUT (tSO/tOS) to minimize body diode conduction loss. |
| ISENSEP / ISENSEN | Main loop current sensing | Differential inputs for primary-side peak current mode control; 220 mV threshold with 6.1 V/V gain. |
| HISENSE | Housekeeping current sensing | Peak current sense input for auxiliary DC/DC controller; 79 mV threshold with 9.1 V/V gain. |
| FB | Main output voltage feedback | 1.250 V precision reference input; connects to optocoupler or resistive divider for isolated regulation. |
| HFB | Housekeeping output feedback | 1.000 V reference input for auxiliary supply regulation; enables PGOOD signaling and OVLO/UVLO monitoring. |
| RT | Oscillator timing | Resistor sets forward controller frequency (100–500 kHz); also programs DVSEC clamp slope. |
| SS1 / SS2 | Soft-start/soft-stop control | SS1 controls frequency/DVSEC ramp-up; SS2 controls COMP pin soft-start; both support controlled shutdown sequencing. |
| OC | Overcurrent fault input | External fault signal input; triggers hiccup-mode shutdown when >96 mV applied. |
| GND / PGND | Signal and power ground | Separate analog ground (Pin 20) and power ground (Pins 19, 39) reduce noise coupling in high-dI/dt paths. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Housekeeping DC/DC Controller | Enables self-powered auxiliary supply generation (e.g., 5 V/3.3 V) without external IC, reducing BOM count and improving efficiency. |
| Programmable Volt-Second Clamp (DVSEC) | Prevents transformer saturation by limiting ON-time × VIN product; supports >50% duty cycles and high transformer utilization. |
| Independent Timing Control for AOUT/SOUT | Four programmable delays (tAO, tOA, tSO, tOS) allow precise optimization of active clamp and synchronous rectification timing to minimize losses. |
| AEC-Q100 Qualified (Grade H) | Validated for automotive applications including engine control units and ADAS power supplies; guaranteed operation from –40°C to +150°C. |
| Hiccup-Mode Overcurrent Protection | Auto-retry shutdown on overcurrent events prevents thermal runaway while maintaining system recoverability after fault clearance. |
| Micropower Start-Up (LT3752-1 variant) | Start-up current as low as 170 µA enables direct connection to high-impedance HV sources (e.g., 48 V battery via resistor divider). |
Applications
| Automotive Engine Control Unit (ECU) Power Supply | 48V Telecommunication Isolated DC/DC Converter |
|---|---|
|
Use Scenario: Generating isolated 5 V/3.3 V rails from vehicle 12 V/48 V battery for microcontrollers and sensors in harsh under-hood environments. IC Role / Device Role / Timing Role: Primary-side active clamp forward controller managing main switch (OUT), clamp switch (AOUT), and synchronous rectifier (SOUT) with adaptive blanking and programmable delays. Use Value: Enables >94% efficiency at 12.5 A output while meeting AEC-Q100 Grade H thermal requirements and surviving load dump transients. |
Use Scenario: High-density isolated 48 V to 12 V/5 V conversion for telecom base station power modules requiring high reliability and low EMI. IC Role / Device Role / Timing Role: Dual-loop controller regulating both main forward converter and auxiliary housekeeping supply, with synchronized switching and programmable frequency. Use Value: Reduces component count by integrating housekeeping DC/DC function, eliminates need for external bias supply, and supports 500 kHz operation for smaller magnetics. |
| Industrial PLC Power Management | Military Vehicle DC/DC Conversion |
|
Use Scenario: Isolated 24 V input to 5 V/12 V outputs powering I/O modules and communication interfaces in factory automation systems. IC Role / Device Role / Timing Role: Active clamp forward controller with programmable UVLO/OVLO thresholds, soft-start/stop, and hiccup-mode OCP for robust field operation. Use Value: Ensures reliable startup across wide input range (18–72 V), maintains regulation during brownouts, and provides fault recovery without manual reset. |
Use Scenario: Ruggedized 28 V aircraft or 24 V military vehicle power system delivering isolated 5 V/15 V rails to avionics and mission-critical subsystems. IC Role / Device Role / Timing Role: High-temperature rated controller (–40°C to +150°C) managing transformer reset via active clamp and minimizing voltage stress on primary switch. Use Value: Reduces primary MOSFET voltage stress by >30% versus conventional forward topologies, extending component lifetime in thermally constrained enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar active clamp forward controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3752IFE#WTRPBF | Same functionality and pinout; rated for –40°C to +125°C (vs. +150°C for H-grade). | Not qualified for under-hood automotive or high-ambient industrial use where junction >125°C occurs. | Select LT3752HFE#WTRPBF when ambient temperature or power dissipation requires full 150°C operation. |
| LT3752EFE#WTRPBF | Commercial-grade version; same electrical specs but only guaranteed from 0°C to +125°C junction. | Not suitable for automotive or extended-temperature industrial deployments; lacks AEC-Q100 validation. | Use LT3752HFE#WTRPBF for production automotive designs requiring full qualification and long-term reliability data. |
Compared with LT3752IFE#WTRPBF and LT3752EFE#WTRPBF, the LT3752HFE#WTRPBF provides verified operation up to +150°C junction temperature, AEC-Q100 Grade H compliance, and extended thermal margin for high-power density designs - making it the only choice for under-hood automotive and high-ambient industrial forward converters.
Availability
LT3752HFE#WTRPBF is available at Aetrix Electronics and suitable for automotive engine control units, 48V telecommunication power supplies, and industrial PLC power management systems requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for LT3752HFE#WTRPBF 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 digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3752 product line delivers high-voltage active clamp forward controllers with integrated housekeeping regulation, designed specifically for efficient, compact, and robust isolated DC/DC conversion in demanding automotive and industrial applications.
FAQ
What is the maximum operating junction temperature for LT3752HFE#WTRPBF?
The LT3752HFE#WTRPBF is specified for continuous operation from –40°C to +150°C junction temperature. This Grade H rating is validated per AEC-Q100 and enables reliable use in under-hood automotive environments and high-ambient industrial settings where thermal management is constrained. Derating curves and thermal resistance (θJA = 25°C/W) are provided in the datasheet for layout-dependent thermal design.
Does LT3752HFE#WTRPBF support both active clamp topologies - LO-side and HI-side?
The LT3752HFE#WTRPBF supports LO-side active clamp topology (external PMOS clamp switch), as defined for the LT3752 family. The LT3752-1 variant supports HI-side (NMOS) clamp configuration. Pin compatibility and functional operation are identical between LT3752 and LT3752-1, but clamp switch polarity and associated timing parameters differ - always verify topology match using the correct datasheet section (LO-side for LT3752HFE#WTRPBF).
How is the volt-second clamp (DVSEC) programmed on LT3752HFE#WTRPBF?
The DVSEC clamp on LT3752HFE#WTRPBF is programmed using the UVLO_VSEC pin voltage and RT resistor value. With RT = 24.9 kΩ, DVSEC duty cycle is 72.5% at UVLO_VSEC = 1.25 V, 36.5% at 2.50 V, and 18.6% at 5.00 V. The relationship is linear and documented in the Electrical Characteristics table; no external op-amp or compensation is required for open-loop DVSEC control.
Can LT3752HFE#WTRPBF operate without an optocoupler?
Yes - LT3752HFE#WTRPBF supports optocoupler-less regulation via DVSEC open-loop control. By setting UVLO_VSEC to a fixed voltage derived from output sensing (e.g., via resistor divider), the device regulates output voltage directly through volt-second balancing without feedback isolation components. This simplifies design and improves reliability in cost-sensitive or space-constrained applications.
What are the key differences between LT3752HFE#WTRPBF and LT3752IFE#WTRPBF?
The LT3752HFE#WTRPBF and LT3752IFE#WTRPBF share identical electrical specifications, pinout, and functionality. The sole difference is thermal qualification: LT3752HFE#WTRPBF is guaranteed from –40°C to +150°C and AEC-Q100 qualified, while LT3752IFE#WTRPBF is rated for –40°C to +125°C and not AEC-Q100 validated. For automotive under-hood use, LT3752HFE#WTRPBF is mandatory.
LT3752HFE#WTRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Forward Converter
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 6.5V ~ 100V
- Frequency - Switching:
- 100kHz ~ 500kHz
- Duty Cycle (Max):
- 95%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LT3752HFE#WTRPBF FAQ
1.How can I place an order for LT3752HFE#WTRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3752HFE#WTRPBF 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 LT3752HFE#WTRPBF reliable?
The price and inventory of LT3752HFE#WTRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3752HFE#WTRPBF is usually 5 days.
3.What payment methods are accepted for LT3752HFE#WTRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3752HFE#WTRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3752HFE#WTRPBF?
LT3752HFE#WTRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3752HFE#WTRPBF 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 LT3752HFE#WTRPBF?
For technical support, including LT3752HFE#WTRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3752HFE#WTRPBF requirements.
6.How does Aetrix verify that LT3752HFE#WTRPBF is sourced from the original manufacturer or authorized distributors?
All LT3752HFE#WTRPBF 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 LT3752HFE#WTRPBF meets industry standards.
7.What is the process for return or replacement of LT3752HFE#WTRPBF?
All LT3752HFE#WTRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3752HFE#WTRPBF, 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 LT3752HFE#WTRPBF part is unused and in its original packaging.
Return procedure for LT3752HFE#WTRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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