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Analog Devices Inc. LT3753HFE#TRPBF
- Part No.:
- LT3753HFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Datasheet:
-
LT3753HFE#TRPBF.pdf
- Description:
- IC REG CTRLR FWRD CONV 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,495
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Product details
Overview
LT3753HFE#TRPBF from Analog Devices is a current mode PWM controller optimized for active clamp synchronous forward converters, supporting 8.5V–100V input operation, programmable volt-second clamp (DVSEC), and dual gate drivers for main switch (OUT), active clamp (AOUT), and synchronous rectifier (SOUT). It enables high-efficiency isolated DC/DC conversion in 48V telecom power supplies.
For engineers reviewing the LT3753HFE#TRPBF datasheet, LT3753HFE#TRPBF pinout, LT3753HFE#TRPBF application, or LT3753HFE#TRPBF equivalent, key selection criteria include its –40°C to 150°C operating junction temperature, 38-lead TSSOP package with high-voltage pin spacing, programmable 100–500kHz switching frequency, and integrated hiccup-mode overcurrent protection.
Technical Context
The LT3753HFE#TRPBF implements a primary-side current-mode control architecture with adaptive leading-edge blanking and programmable slope compensation. Its volt-second clamp (DVSEC) is set via IVSEC and UVLO_VSEC pins, enabling open-loop VOUT regulation without optocoupler or secondary-side error amplifier.
It integrates three independent gate drivers: OUT (main N-MOSFET), AOUT (active clamp switch), and SOUT (secondary-side synchronous rectifier), each with nanosecond-level timing control (tAO, tAS, tOS, tSO) via external resistors. The IC features micropower shutdown (<40µA VIN quiescent current) and thermal shutdown at TJ > 170°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.5V to 100V - supports wide-range industrial and telecom inputs including 36–72V nominal systems. |
| Switching Frequency | 100kHz to 500kHz - programmable via RT resistor; line regulation <0.1%/V ensures stable timing across input range. |
| Operating Junction Temp | –40°C to +150°C - H-grade qualification enables use in high-ambient automotive and military applications. |
| Volt-Second Clamp (DVSEC) | Programmable up to 76.2% duty cycle at VIN(min) - prevents transformer saturation during transients and enables >50% duty cycles. |
| Gate Driver Outputs | OUT, AOUT, SOUT - each delivers 11.9V high-level drive at INTVCC = 12V with <25ns rise/fall times into 1nF load. |
| Overcurrent Protection | 96mV OC threshold with hiccup mode - provides accurate primary-side current limiting independent of duty cycle. |
| INTVCC Regulator | 10V ±0.6V linear regulator - powers all gate drivers; UVLO(+) at 7.4V, OVLO(–) at 16.0V ensures robust internal supply control. |
Pinout & Package
LT3753HFE#TRPBF uses a 38-lead plastic TSSOP package (FE38 variation) with missing pins (23, 25, 27, 29, 31, 33, 35) for enhanced high-voltage creepage and reliability. Exposed pad (Pin 39) is connected to PGND/GND and must be soldered to PCB ground plane for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (28) | Main power input | Accepts 8.5–100V; bypassed with 1µF capacitor; powers internal regulators and gate drivers. |
| OUT (24) | Main switch gate driver | Drives N-channel MOSFET gate; 11.9V high level, 0.1V low level; includes active pull-off in shutdown. |
| AOUT (32) | Active clamp switch driver | Controls external clamp MOSFET; timing relative to OUT programmed by TAO resistor (tAO delay). |
| SOUT (30) | Synchronous rectifier driver | Controls secondary-side SR MOSFET; timing relative to OUT programmed by TOS (tOS) and TAS (tAS) resistors. |
| IVSEC (8) | DVSEC clamp programming | Resistor sets maximum duty cycle clamp inversely proportional to system input voltage. |
| UVLO_VSEC (9) | Volt-second clamp reference | Resistor divider sets both DVSEC clamp point and undervoltage lockout threshold with 5µA hysteresis current. |
| OC (22) | Primary overcurrent sense | 96mV threshold comparator input; triggers hiccup-mode shutdown on primary MOSFET overcurrent. |
| PGND (19, 38, 39) | Power ground return | Multiple dedicated pins including exposed pad (39); critical for low-inductance current return and thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Active clamp topology support | Reduces primary switch voltage stress and improves efficiency vs. RCD clamp; enables >50% duty cycles. |
| Programmable volt-second clamp (DVSEC) | Prevents transformer saturation during load transients; enables optocoupler-free regulation in open-loop configurations. |
| Three independent gate drivers | OUT, AOUT, SOUT with nanosecond-level timing control (tAO, tAS, tOS, tSO) for precise non-overlap and sequencing. |
| Hiccup-mode overcurrent protection | 96mV OC threshold with automatic restart after fault clearance; avoids thermal runaway under short-circuit conditions. |
| Micropower shutdown | <40µA VIN quiescent current when UVLO_VSEC < 0.4V; enables ultra-low standby power in battery-backed systems. |
| High-temperature grade (H) | Guaranteed operation from –40°C to +150°C junction temperature; qualified for harsh-environment industrial and defense use. |
Applications
| 48V Telecom Isolated Power Supply | Industrial 36–72V DC/DC Converter |
|---|---|
|
Use Scenario: 36V–72V input isolated 5V/20A forward converter for telecom shelf power distribution. IC Role / Device Role / Timing Role: Primary-side PWM controller managing main switch, active clamp, and synchronous rectifier timing with DVSEC clamp to prevent saturation during line dips. Use Value: Enables >92% efficiency and compact magnetics by supporting >50% duty cycles and eliminating RCD losses. |
Use Scenario: High-reliability 400W isolated forward converter in factory automation PLC power modules. IC Role / Device Role / Timing Role: Current-mode controller with programmable UVLO/OVLO, hiccup OCP, and thermal shutdown for fail-safe operation in unattended environments. Use Value: –40°C to +150°C rating ensures continuous operation in sealed enclosures with ambient temperatures up to 85°C. |
| Automotive 48V Mild Hybrid System | Military Vehicle Power Distribution |
|
Use Scenario: 24V–60V input forward converter powering 12V auxiliary loads in 48V mild hybrid architectures. IC Role / Device Role / Timing Role: Active clamp controller with soft-start/stop sequencing (SS1/SS2) and synchronized clock input for EMI reduction across multiple converters. Use Value: Programmable tAO/tAS/tOS delays minimize shoot-through risk in high-current synchronous rectification stages. |
Use Scenario: Ruggedized 100V-tolerant forward converter for airborne or ground vehicle power conditioning. IC Role / Device Role / Timing Role: Primary-side controller with micropower shutdown (<40µA), extended temperature range, and high-voltage pin spacing (missing pins 23/25/27/29/31/33/35). Use Value: Enhanced creepage and guaranteed 150°C operation meet MIL-STD-810G environmental requirements. |
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 |
|---|---|---|---|
| LT3752HFE#TRPBF | HI-side active clamp topology; different pinout (no SOUT); no synchronous rectifier control. | Used in high-side clamp designs where secondary-side synchronous rectification is not required. | Select LT3752HFE#TRPBF only when using HI-side clamp configuration and secondary-side diode rectification. |
| UCC2897APWR | TI part with similar active clamp function but fixed 500kHz max frequency; no DVSEC clamp; different timing architecture. | Requires external circuitry for volt-second limiting; lacks integrated hiccup OCP and micropower shutdown. | Choose UCC2897APWR only if TI ecosystem compatibility and lower cost outweigh need for DVSEC, H-grade temp, and precision timing. |
Compared with LT3752HFE#TRPBF and UCC2897APWR, LT3753HFE#TRPBF uniquely integrates synchronous rectifier control (SOUT), programmable volt-second clamp (DVSEC), and H-grade temperature rating - making it the only option for high-efficiency, high-temperature, optocoupler-free active clamp forward designs.
Availability
LT3753HFE#TRPBF is available at Aetrix Electronics and suitable for 48V telecom power supplies, industrial 36–72V DC/DC converters, and automotive 48V mild hybrid systems requiring stable component supply, long-term lifecycle support, and high-temperature reliability.
Supply support for LT3753HFE#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 digital signal processing semiconductors, serving industrial, automotive, communications, and aerospace markets.
The LT3753 belongs to Analog Devices' Power by Linear™ active clamp controller product line, designed specifically for high-efficiency, high-voltage isolated forward converters requiring precise timing, robust protection, and extended temperature operation.
FAQ
What is the maximum operating junction temperature for LT3753HFE#TRPBF?
The LT3753HFE#TRPBF is rated for a maximum operating junction temperature of +150°C, with guaranteed performance across –40°C to +150°C. This H-grade qualification distinguishes it from E-grade (125°C) and I-grade (125°C) variants, enabling deployment in high-ambient environments such as sealed industrial enclosures or under-hood automotive locations where die temperature may exceed 125°C.
How does the DVSEC volt-second clamp function in LT3753HFE#TRPBF?
The DVSEC clamp in LT3753HFE#TRPBF is programmed via the IVSEC and UVLO_VSEC pins using external resistors. It limits the maximum duty cycle inversely proportional to system input voltage - for example, at VIN = 12V and UVLO_VSEC = 1.25V, DVSEC = 72.5%. This prevents transformer saturation during line transients and enables open-loop output regulation without secondary-side feedback components.
Can LT3753HFE#TRPBF drive synchronous rectifiers on the secondary side?
Yes, LT3753HFE#TRPBF includes a dedicated SOUT pin that drives secondary-side synchronous rectifiers. Timing of SOUT relative to OUT (tSO) and OUT relative to SOUT (tOS) is programmable via external resistors (TAS and TOS), allowing precise non-overlap control to prevent shoot-through. This eliminates the need for external timing ICs or optocoupler-based synchronization.
What package type and pin count does LT3753HFE#TRPBF use?
LT3753HFE#TRPBF uses a 38-lead plastic TSSOP package (FE38 variation) with intentional pin omissions (Pins 23, 25, 27, 29, 31, 33, 35) to increase creepage distance between high-voltage nodes. The exposed pad (Pin 39) serves as both PGND and GND and must be soldered to a large PCB copper area for thermal and electrical performance.
Does LT3753HFE#TRPBF support external clock synchronization?
Yes, LT3753HFE#TRPBF supports external clock synchronization via the SYNC pin (Pin 6). It accepts an external clock signal matching the programmed fOSC (100–500kHz) with guaranteed thresholds of 0.6V (low) and 1.8V (high). Synchronization enables EMI reduction in multi-converter systems and deterministic timing alignment across parallel power stages.
LT3753HFE#TRPBF 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):
- 8.5V ~ 100V
- Frequency - Switching:
- 100kHz ~ 500kHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LT3753HFE#TRPBF FAQ
1.How can I place an order for LT3753HFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3753HFE#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 LT3753HFE#TRPBF reliable?
The price and inventory of LT3753HFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3753HFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3753HFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3753HFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3753HFE#TRPBF?
LT3753HFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3753HFE#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 LT3753HFE#TRPBF?
For technical support, including LT3753HFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3753HFE#TRPBF requirements.
6.How does Aetrix verify that LT3753HFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3753HFE#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 LT3753HFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3753HFE#TRPBF?
All LT3753HFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3753HFE#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 LT3753HFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3753HFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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