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Analog Devices Inc. LT3753EFE#PBF
- Part No.:
- LT3753EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Datasheet:
-
LT3753EFE#PBF.pdf
- Description:
- IC REG CTRLR FWRD CONV 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:165
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Product details
Overview
LT3753EFE#PBF 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 synchronous rectification control via SOUT. It delivers high-efficiency isolated DC/DC conversion in telecom and industrial power supplies up to 400W.
For engineers reviewing the LT3753EFE#PBF datasheet, LT3753EFE#PBF pinout, LT3753EFE#PBF application, or LT3753EFE#PBF equivalent, key selection considerations include its 38-lead TSSOP package with high-voltage pin spacing, 100kHz–500kHz programmable switching frequency, active clamp timing control (tAO/tOA), and dual soft-start/stop functionality on SS1/SS2 pins.
Technical Context
The LT3753EFE#PBF implements a primary-side current-mode control architecture with integrated volt-second clamp regulation, enabling duty cycles >50% while preventing transformer saturation. Its DVSEC clamp is programmed via IVSEC and UVLO_VSEC pins using external resistors, and operates independently of opto-coupler feedback.
It features three independent gate drivers-OUT (main switch), AOUT (active clamp MOSFET), and SOUT (secondary-side synchronous rectifier)-with programmable nonoverlap delays (tAO, tAS, tOS) and adaptive blanking. Protection includes hiccup-mode overcurrent (96mV OC threshold), UVLO/OVLO with hysteresis, and thermal shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.5V to 100V - supports wide-range industrial and telecom inputs without pre-regulation |
| Switching Frequency | 100kHz to 500kHz - programmable via RT resistor; enables optimization of magnetics size vs. efficiency |
| DVSEC Clamp Accuracy | ±4% max duty cycle error at UVLO_VSEC = 1.25V - ensures reliable transformer reset under line/load transients |
| OC Threshold | 96mV ±11.5mV - precise primary-side overcurrent detection enabling fast hiccup-mode fault response |
| Gate Driver Output Level | 11.9V high / 0.1V low at INTVCC = 12V - drives standard N-channel MOSFETs directly without level-shifting |
| Operating Temp Range | –40°C to +125°C junction - qualified for extended industrial and automotive under-hood environments |
| INTVCC Regulator | 10V ±0.6V, 32mA max - powers all internal drivers; dropout <0.6V at 10mA enables low-VIN operation |
Pinout & Package
LT3753EFE#PBF is housed in a 38-lead plastic TSSOP (FE package) with missing pins (23, 25, 27, 29, 31, 33, 35) for enhanced high-voltage creepage and reliability. The exposed pad (Pin 39) is electrically connected to PGND and GND and must be soldered to a PCB ground plane for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (28) | Main supply input | Accepts 8.5V–100V; powers internal LDO (INTVCC) and bias circuits |
| OUT (24) | Main switch gate driver | Drives N-MOSFET primary switch; 11.9V output swing, 19ns rise/fall |
| AOUT (32) | Active clamp switch driver | Controls external clamp MOSFET; programmable delay tAO relative to OUT |
| SOUT (30) | Synchronous rectifier driver | Signals secondary-side SR MOSFET; delay tSO/tOS programmable for ZVS/ZCS optimization |
| IVSEC (8) | DVSEC clamp programming | Resistor sets maximum duty cycle inversely proportional to VIN - prevents saturation |
| UVLO_VSEC (9) | Volt-second clamp reference | Resistor divider sets both UVLO threshold and DVSEC scaling; 5µA hysteresis current |
| ISENSEP (21) / ISENSEN (20) | Primary current sense inputs | Kelvin-connected to source resistor; supports slope compensation via series R |
| OC (22) | Hiccup-mode overcurrent input | 96mV threshold, duty-cycle independent - triggers fault protection without latch-up |
| SS1 (7) / SS2 (17) | Soft-start/stop control | SS1 controls frequency/DVSEC ramp-up/down; SS2 controls COMP ramp for loop stability |
| PGND (19, 38, 39) | Power ground return | Exposed pad (39) is primary thermal path; must be soldered to large copper area |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Volt-Second Clamp (DVSEC) | Enables >50% duty cycles while guaranteeing transformer reset - eliminates need for auxiliary winding or opto-coupler in open-loop regulation |
| Three Independent Gate Drivers | OUT/AOUT/SOUT with nanosecond-level timing control (tAO, tAS, tOS) - allows precise dead-time tuning for ZVS in active clamp topology |
| Adaptive Leading Edge Blanking + Extended Blanking | Configurable via TBLNK resistor - suppresses false triggering during MOSFET turn-on dV/dt spikes |
| Programmable UVLO/OVLO with Hysteresis | UVLO_VSEC and OVLO pins accept resistor dividers - provides robust input voltage supervision with user-defined thresholds and hysteresis |
| Dual Soft-Start/Stop Architecture | SS1 controls frequency and DVSEC; SS2 controls COMP - enables controlled startup/shutdown of both power stage and control loop |
| Micropower Shutdown Mode | VIN quiescent current drops to 20–40µA when UVLO_VSEC < 0.4V - ideal for standby power-sensitive systems |
Applications
| 48V Telecom Isolated PSU | Industrial 24/48V Input Power |
|---|---|
|
Use Scenario: 36V–72V input, 5V/20A isolated forward converter for base station RF power amplifiers. IC Role / Device Role / Timing Role: Primary-side controller managing active clamp reset, synchronous rectification timing, and volt-second clamping to maintain regulation across wide input range. Use Value: Enables >92% efficiency at full load and stable output under rapid 50% load steps without secondary-side feedback components. |
Use Scenario: DIN-rail mounted 400W industrial power supply with 24V/48V nominal input and 12V/24V outputs. IC Role / Device Role / Timing Role: Core PWM controller implementing active clamp forward topology with programmable fault thresholds and thermal derating. Use Value: Supports extended temperature operation (–40°C to +125°C) and meets EN 62368-1 reinforced isolation requirements via high-voltage pin spacing. |
| Automotive 48V Mild Hybrid Systems | Military Vehicle DC/DC Conversion |
|
Use Scenario: 24V–60V battery-supplied DC/DC converter powering infotainment and ADAS subsystems in 48V architectures. IC Role / Device Role / Timing Role: Active clamp forward controller providing regulated 5V/3.3V rails with hiccup-mode OCP and programmable soft-stop for safe shutdown during battery disconnect. Use Value: Eliminates transformer saturation risk during cold-crank events (VIN dip to 6V) via DVSEC clamp and UVLO hysteresis. |
Use Scenario: Ruggedized 28V–110V input power module for airborne avionics requiring MIL-STD-704 compliance. IC Role / Device Role / Timing Role: High-reliability forward controller with missing-pin TSSOP package, extended temp grade (–55°C to +150°C MP variant), and radiation-tolerant design practices. Use Value: Delivers 400W output with single-chip solution, reducing BOM count and improving mean time between failures (MTBF). |
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 |
|---|---|---|---|
| LT3752-1HFE#PBF | High-side active clamp topology; different pinout and timing logic; no SOUT output | Requires high-side clamp MOSFET placement; not suitable for secondary-side synchronous rectification | Select only when high-side clamp configuration is mandated by layout or EMI constraints |
| UCC2897APWR | Fixed 50% max duty cycle; no volt-second clamp; requires opto-coupler for regulation; SOIC-16 package | Lacks DVSEC open-loop regulation capability; limited to lower-power designs (<150W) | Choose only for cost-sensitive, lower-power applications where transformer reset is managed externally |
Compared with LT3752-1HFE#PBF and UCC2897APWR, the LT3753EFE#PBF uniquely integrates programmable DVSEC clamp, SOUT-driven synchronous rectification, and 38-pin TSSOP packaging with HV spacing - making it the only option for high-efficiency, high-power (>200W), opto-free active clamp forward designs requiring secondary-side SR control.
Availability
LT3753EFE#PBF is available at Aetrix Electronics and suitable for 48V telecom isolated PSUs, industrial 24/48V input power modules, and automotive 48V mild hybrid systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3753EFE#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and aerospace markets.
The LT3753EFE#PBF belongs to Analog Devices' Power by Linear™ active clamp controller product line, designed specifically for high-efficiency, high-voltage isolated DC/DC conversion in telecom, industrial, and military applications.
FAQ
What is the maximum operating junction temperature for the LT3753EFE#PBF?
The LT3753EFE#PBF is rated for –40°C to +125°C junction temperature. This grade is verified per Analog Devices' characterization and statistical process controls. Derating curves and thermal resistance data (θJA = 25°C/W) are provided in the datasheet to support PCB thermal design for continuous 400W operation.
How does the DVSEC volt-second clamp function in the LT3753EFE#PBF?
The DVSEC clamp in the LT3753EFE#PBF uses UVLO_VSEC and IVSEC pins to program a maximum duty cycle inversely proportional to system input voltage. At UVLO_VSEC = 1.25V and RIVSEC = 51.1kΩ, it delivers 72.5% max duty cycle - preventing transformer saturation during line dips or load surges without requiring secondary feedback.
Can the LT3753EFE#PBF drive synchronous rectifiers on the secondary side?
Yes, the LT3753EFE#PBF provides dedicated SOUT output with programmable timing (tSO, tOS) to control external N-channel MOSFETs on the secondary side. This enables high-efficiency synchronous rectification in forward topologies, replacing Schottky diodes and reducing conduction losses by >30% at 20A output.
What are the key timing parameters controlled by TAO, TAS, and TOS pins on the LT3753EFE#PBF?
TAO sets delay from AOUT rise to OUT rise (tAO); TAS sets delay from SOUT fall to OUT rise (tAS); TOS sets delay from OUT fall to SOUT rise (tOS). These resistors enable precise nonoverlap control - critical for zero-voltage switching in active clamp forward converters and avoiding shoot-through in synchronous rectifiers.
Does the LT3753EFE#PBF support synchronization to an external clock?
Yes, the LT3753EFE#PBF supports external clock synchronization via the SYNC pin. It accepts TTL/CMOS-compatible signals from 100kHz to 500kHz with 1.2V–1.8V high threshold and 0.6V–1.025V low threshold. Frequency tracking accuracy is ±25% of programmed fOSC, enabling multi-phase or noise-spread clocking in dense power systems.
LT3753EFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Packaging:
- Tube
- 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LT3753EFE#PBF FAQ
1.How can I place an order for LT3753EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3753EFE#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 LT3753EFE#PBF reliable?
The price and inventory of LT3753EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3753EFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3753EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3753EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3753EFE#PBF?
LT3753EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3753EFE#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 LT3753EFE#PBF?
For technical support, including LT3753EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3753EFE#PBF requirements.
6.How does Aetrix verify that LT3753EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3753EFE#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 LT3753EFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3753EFE#PBF?
All LT3753EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3753EFE#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 LT3753EFE#PBF part is unused and in its original packaging.
Return procedure for LT3753EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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