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Analog Devices Inc. LT3753MPFE#PBF
- Part No.:
- LT3753MPFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Datasheet:
-
LT3753MPFE#PBF.pdf
- Description:
- IC REG CTRLR FWRD CONV 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:549
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Product details
Overview
LT3753MPFE#PBF from Analog Devices is a current mode PWM controller optimized for active clamp synchronous forward converters, supporting 8.5V–100V input operation. It delivers programmable volt-second clamping (DVSEC), synchronous rectification control via SOUT, and active clamp switching via AOUT - enabling >50% duty cycles, reduced primary switch voltage stress, and high-efficiency isolated DC/DC conversion in 48V telecom power supplies.
For engineers reviewing the LT3753MPFE#PBF datasheet, LT3753MPFE#PBF pinout, LT3753MPFE#PBF application, or LT3753MPFE#PBF equivalent, key selection criteria include its –55°C to 150°C extended temperature grade, 38-lead TSSOP package with high-voltage pin spacing, programmable tAO/tOS timing delays, and open-loop DVSEC regulation capability without optocoupler dependency.
Technical Context
The LT3753MPFE#PBF implements a primary-side current-mode control architecture with integrated adaptive leading-edge blanking and programmable slope compensation. Its volt-second clamp (DVSEC) is set by UVLO_VSEC and IVSEC pins, enabling precise duty cycle limiting inversely proportional to input voltage to prevent transformer saturation during transients.
It features three independent gate drivers: OUT for main N-channel MOSFET, AOUT for active clamp switch, and SOUT for secondary-side synchronous rectifier - each with nanosecond-level programmable nonoverlap delays (tAO, tAS, tOS) and 11.9V output swing at INTVCC = 12V, ensuring robust timing control in high-frequency (100–500kHz) isolated topologies.
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 48V systems. |
| Operating Temp Range | –55°C to 150°C - qualified for military, aerospace, and harsh-environment applications per MP grade. |
| Switching Frequency | 100kHz to 500kHz - programmable via RT resistor; enables compact magnetics and EMI optimization. |
| DVSEC Clamp Accuracy | ±4% duty cycle error at UVLO_VSEC = 1.25V - ensures reliable transformer reset and open-loop VOUT regulation. |
| Gate Driver Output | 11.9V high level (INTVCC = 12V) - drives logic-level MOSFETs directly without level-shifting. |
| OC Threshold | 96mV ±11.5mV - precise primary-side overcurrent detection triggering hiccup-mode protection. |
| INTVCC Regulator | 10V ±0.6V, 32mA max - powers all internal drivers; dropout <0.6V at 10mA load. |
Pinout & Package
The LT3753MPFE#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 in isolated designs. The exposed pad (Pin 39) is electrically connected to PGND/GND and must be soldered to PCB ground for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (28) | Main power input | Accepts 8.5–100V; bypassed with 1µF capacitor to GND for stability. |
| OUT (24) | Main switch driver | Drives gate of primary-side N-MOSFET; 11.9V swing, 19ns rise time. |
| AOUT (32) | Active clamp switch driver | Controls external clamp MOSFET; programmable tAO delay relative to OUT. |
| SOUT (30) | Synchronous rectifier driver | Signals secondary-side SR MOSFET; tSO/tOS delays prevent shoot-through. |
| IVSEC (8) | DVSEC clamp programming | Resistor sets maximum duty cycle inversely proportional to VIN to avoid saturation. |
| UVLO_VSEC (9) | Volt-second clamp reference | Resistor divider programs both UVLO threshold and DVSEC scaling factor. |
| PGND (19, 38, 39) | Power ground | 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 open-loop VOUT regulation without optocoupler, error amp, or secondary reference - reduces BOM and improves transient response. |
| Independent timing control (tAO, tAS, tOS) | Three dedicated pins (TAO, TAS, TOS) allow nanosecond-accurate nonoverlap tuning between OUT, AOUT, and SOUT - eliminates cross-conduction in high-efficiency active clamp topologies. |
| High-voltage TSSOP with missing pins | 38-lead FE package removes 6 pins to increase creepage distance - meets reinforced isolation requirements for 100V+ input systems. |
| Hiccup-mode overcurrent protection | 96mV OC threshold triggers automatic restart after fault clearance - protects primary MOSFET under short-circuit or overload without latch-up. |
| –55°C to 150°C operating range | MP grade qualification ensures functional reliability in extreme environments - validated across full junction temperature range, not just characterized. |
Applications
| 48V Telecom Isolated Power Supply | Industrial 36–72V Forward Converter |
|---|---|
Use Scenario: Generating isolated 5V/20A output from 36–72V telecom rectified bus with strict efficiency and thermal constraints. IC Role / Device Role / Timing Role: Primary-side controller managing active clamp reset, synchronous rectification timing, and DVSEC-based regulation - eliminating need for optocoupler feedback loop. Use Value: Achieves >92% peak efficiency and avoids transformer saturation during line/load transients via programmable volt-second clamp. | Use Scenario: High-reliability 400W isolated DC/DC converter in factory automation equipment requiring extended temperature operation. IC Role / Device Role / Timing Role: Core PWM controller implementing current-mode control, programmable soft-start/stop, and hiccup-mode OCP - enabling safe hot-swap and fault recovery. Use Value: MP-grade –55°C to 150°C rating ensures uninterrupted operation in uncontrolled ambient environments without derating. |
| Military Vehicle Power System | Stacked-Series High-Voltage Output |
Use Scenario: 28V aircraft bus-derived 12V/15A isolated supply with MIL-STD-704 compliance and EMI resilience. IC Role / Device Role / Timing Role: Active clamp forward controller with synchronized clock input (SYNC pin), programmable OVLO/UVLO hysteresis, and thermal shutdown - meeting DO-160 environmental requirements. Use Value: 100V absolute max VIN rating and robust 5µA UVLO hysteresis current enable stable start-up during bus dips and surges. | Use Scenario: Cascaded forward converters delivering 48V@40A output by series-stacking two 24V modules with shared control signals. IC Role / Device Role / Timing Role: Synchronizable controller (via SYNC pin) with inter-IC communication via UVLO_VSEC one-shot - enabling coordinated soft-start and fault propagation across modules. Use Value: Eliminates need for master-slave arbitration circuitry; allows parallel input/series output stacking without external timing ICs. |
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#PBF | HI-side active clamp topology; different pinout (no IVSEC); supports up to 150°C but lacks MP-grade extended low-temp validation. | Requires redesign of clamp circuit layout and timing network; not drop-in compatible due to missing DVSEC programming and altered TAO/TAS function. | Select only when HI-side clamp architecture is mandated and –55°C operation is unnecessary. |
| UCC2897APWR | TI's active clamp forward controller; 100V max VIN, but no integrated DVSEC clamp, no SOUT driver, and only –40°C to 125°C temp range. | Requires external circuitry for synchronous rectification and open-loop regulation; unsuitable for military or extended-temp deployments. | Consider for cost-sensitive commercial telecom designs where MP-grade reliability and integrated SOUT/DVSEC are not required. |
Compared with LT3752HFE#PBF and UCC2897APWR, the LT3753MPFE#PBF uniquely combines LO-side active clamp support, on-chip DVSEC regulation, dedicated SOUT timing, and full –55°C to 150°C qualification - making it the only option for ruggedized, optocoupler-free, high-efficiency forward converters demanding extended temperature compliance.
Availability
LT3753MPFE#PBF is available at Aetrix Electronics and suitable for 48V telecom power supplies, industrial 36–72V forward converters, military vehicle power systems, and stacked-series high-voltage outputs requiring stable component supply across extended temperature ranges.
Supply support for LT3753MPFE#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 precision instrumentation, industrial automation, communications, and defense markets.
The LT3753MPFE#PBF belongs to Analog Devices' Power by Linear™ active clamp forward controller family, engineered specifically for high-efficiency, high-reliability isolated DC/DC conversion in telecom, industrial, and aerospace applications where transformer saturation prevention and extended temperature operation are critical.
FAQ
What is the operating temperature range of the LT3753MPFE#PBF?
The LT3753MPFE#PBF is tested and guaranteed to operate from –55°C to 150°C junction temperature. This MP-grade qualification exceeds standard industrial and automotive grades, making it suitable for military, aerospace, and harsh-environment applications where extended low-temperature startup and high-temperature reliability are mandatory. Data sheet specifications are fully validated across this entire range.
How does the DVSEC volt-second clamp function in the LT3753MPFE#PBF?
The DVSEC clamp in the LT3753MPFE#PBF is programmed via the UVLO_VSEC and IVSEC pins using external resistors. It limits the maximum duty cycle inversely proportional to input voltage - preventing transformer saturation during load transients. At UVLO_VSEC = 1.25V and RT = 24.9kΩ, DVSEC is fixed at 72.5%, enabling open-loop regulation without optocoupler or secondary-side feedback components.
Can the LT3753MPFE#PBF drive synchronous rectifiers without external timing ICs?
Yes, the LT3753MPFE#PBF integrates a dedicated SOUT pin with programmable timing delays (tSO and tOS) relative to OUT and AOUT. By configuring TAS and TOS resistors, designers achieve precise nonoverlap control between primary switch turn-off and synchronous rectifier turn-on - eliminating shoot-through risk and removing need for external timing or driver ICs in the secondary-side gate drive path.
What package type and pin configuration does the LT3753MPFE#PBF use?
The LT3753MPFE#PBF uses a 38-lead plastic TSSOP (FE package) with six missing pins (23, 25, 27, 29, 31, 33, 35) to increase high-voltage creepage distance. Pin 39 is an exposed thermal pad electrically tied to PGND/GND and must be soldered to a continuous PCB ground plane for thermal management and optimal electrical performance.
Does the LT3753MPFE#PBF support synchronization to an external clock?
Yes, the LT3753MPFE#PBF includes a dedicated SYNC pin (Pin 6) that accepts an external clock signal matching its programmed switching frequency (100–500kHz). This enables precise phase alignment across multiple converters - essential for reducing EMI in multi-rail power systems and for coordinated operation in stacked-series or paralleled forward converter architectures.
LT3753MPFE#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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LT3753MPFE#PBF FAQ
1.How can I place an order for LT3753MPFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3753MPFE#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 LT3753MPFE#PBF reliable?
The price and inventory of LT3753MPFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3753MPFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3753MPFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3753MPFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3753MPFE#PBF?
LT3753MPFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3753MPFE#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 LT3753MPFE#PBF?
For technical support, including LT3753MPFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3753MPFE#PBF requirements.
6.How does Aetrix verify that LT3753MPFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3753MPFE#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 LT3753MPFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3753MPFE#PBF?
All LT3753MPFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3753MPFE#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 LT3753MPFE#PBF part is unused and in its original packaging.
Return procedure for LT3753MPFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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