My Inquiry
My Account
Analog Devices Inc. LT3753IFE#PBF
- Part No.:
- LT3753IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) 31 Leads, Exposed Pad
- Datasheet:
-
LT3753IFE#PBF.pdf
- Description:
- IC REG CTRLR FWRD CONV 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:114
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3753IFE#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 precise timing for AOUT/OUT/SOUT drivers - enabling high-efficiency isolated power supplies up to 400W in telecom and industrial systems.
For engineers reviewing the LT3753IFE#PBF datasheet, LT3753IFE#PBF pinout, LT3753IFE#PBF application, or LT3753IFE#PBF equivalent, key selection considerations include its 38-lead TSSOP package with high-voltage pin spacing, –40°C to 125°C operating junction temperature, active clamp timing programmability (tAO/tOA), and open-loop VOUT regulation capability via DVSEC clamp.
Technical Context
The LT3753IFE#PBF implements a primary-side current-mode control architecture with integrated INTVCC linear regulator (10V output), adaptive leading-edge blanking, and programmable slope compensation. Its volt-second clamp (DVSEC) is set by UVLO_VSEC and IVSEC resistor dividers, enabling duty cycle limiting inversely proportional to VIN to prevent transformer saturation.
Timing logic supports independent delay programming: tAO (AOUT rise to OUT rise), tOS (OUT fall to SOUT rise), and tSO (SOUT fall to OUT rise), all adjustable via external resistors. Protection includes hiccup-mode overcurrent (96mV OC threshold), UVLO/UVLO hysteresis, OVLO, and thermal shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.5V to 100V - enables wide-input isolated DC/DC designs including 48V telecom and industrial rails. |
| Switching Frequency | 100kHz to 500kHz - programmable via RT resistor; supports high-density magnetics and EMI optimization. |
| DVSEC Clamp Accuracy | ±4% at 72.5% max duty (UVLO_VSEC = 1.25V) - ensures reliable transformer reset and open-loop VOUT regulation. |
| OC Threshold | 96mV (typical) - precise primary-side overcurrent detection enabling robust hiccup-mode protection. |
| Gate Driver Outputs | OUT/AOUT/SOUT: 11.9V high-level, <25ns rise/fall - drives N-channel MOSFETs with minimal dead-time uncertainty. |
| Operating Temperature | –40°C to +125°C junction - qualified for industrial and extended-temperature embedded power systems. |
| Package | 38-lead plastic TSSOP with missing pins (FE38 variation) - provides >8mm creepage/clearance for high-voltage isolation compliance. |
Pinout & Package
The LT3753IFE#PBF is housed in a 38-lead plastic TSSOP (FE38 variation) with strategically omitted pins (23, 25, 27, 29, 31, 33, 35) to ensure high-voltage spacing between primary and secondary domains. The exposed pad (Pin 39) is electrically connected to PGND and GND and must be soldered to a continuous PCB ground plane for thermal management and noise immunity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (28) | Main power input | Accepts 8.5V–100V supply; bypassed with 1µF capacitor to PGND for stability. |
| INTVCC (26) | Internal LDO output | 10V regulated supply for gate drivers; requires 4.7µF ceramic bypass to PGND. |
| OUT (24) | Main switch driver | Drives N-MOSFET gate; 0V–11.9V swing, <25ns transitions, active pull-down in shutdown. |
| AOUT (32) | Active clamp switch driver | Controls external clamp MOSFET; timing relative to OUT programmed via TAO resistor. |
| SOUT (30) | Synchronous rectifier driver | Signals secondary-side SR controller; timing relative to OUT set by TOS/TAS resistors. |
| IVSEC (8) | DVSEC clamp programming | Resistor sets maximum duty cycle inversely proportional to VIN - prevents transformer saturation. |
| UVLO_VSEC (9) | Volt-second clamp reference | Resistor divider sets both DVSEC threshold and system UVLO with 5µA hysteresis current. |
| ISENSEP (21)/ISENSEN (20) | Primary current sense inputs | Kelvin-connected to source of main MOSFET; enable accurate peak-current mode control and slope compensation. |
| OC (22) | Overcurrent fault input | 96mV threshold comparator triggers hiccup mode; direct connection to sense resistor required. |
| PGND (19, 38, 39) | Power ground return | Low-impedance path for gate driver currents; Pin 39 (exposed pad) must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Volt-Second Clamp (DVSEC) | Enables open-loop VOUT regulation without optocoupler or secondary-side error amplifier by dynamically limiting duty cycle vs. VIN. |
| Independent Timing Control | Separate resistor-programmable delays (tAO, tOS, tSO) eliminate shoot-through risk in active clamp and synchronous rectifier stages. |
| Hiccup-Mode Overcurrent Protection | 96mV OC threshold with automatic restart after fault clearance - protects primary MOSFET under sustained overload. |
| Adaptive Leading-Edge Blanking | Configurable blanking duration (via TBLNK) suppresses switching noise during MOSFET turn-on without compromising response time. |
| Soft-Start/Soft-Stop Sequencing | SS1 controls frequency and DVSEC ramp-up/down; SS2 independently manages COMP pin voltage - prevents inrush and output overshoot. |
Applications
| 48V Telecom Isolated PSU | Industrial 24V/48V DC-DC Converter |
|---|---|
Use Scenario: 36V–72V input telecom rectifier supplying isolated 5V/20A output with strict efficiency and transient requirements. IC Role / Device Role / Timing Role: Primary-side active clamp forward controller managing OUT, AOUT, and SOUT timing to achieve >94% efficiency and <100ns nonoverlap. Use Value: DVSEC clamp maintains stable duty cycle across input range, eliminating need for optocoupler feedback while meeting GR-1089 Class 3 surge immunity. |
Use Scenario: Factory automation PLC power module requiring 400W isolated 24V output from unregulated 48V rail with hiccup-mode fault containment. IC Role / Device Role / Timing Role: Core PWM controller implementing programmable UVLO/OVLO thresholds and synchronized multi-phase stacking via shared SS1/UVLO_VSEC pins. Use Value: Dual soft-start (SS1/SS2) prevents inrush into large bulk capacitors; thermal shutdown and OC hiccup protect against motor stall faults. |
| Military Vehicle Power System | High-Voltage Industrial Sensor Supply |
Use Scenario: 28V–100V MIL-STD-1275E compliant converter generating isolated ±15V analog supplies for avionics signal conditioning. IC Role / Device Role / Timing Role: Active clamp controller with extended temperature rating (–40°C to 125°C) and high-voltage TSSOP package ensuring reliability under shock/vibe. Use Value: Missing-pin layout achieves >8mm creepage for 100V operation; INTVCC LDO powers gate drivers independently of VIN droop during cold-crank events. |
Use Scenario: Isolated auxiliary supply for HV IGBT gate drivers in motor drives, requiring precise 15V output from 800V DC link with galvanic separation. IC Role / Device Role / Timing Role: Forward controller using DVSEC clamp to regulate output without secondary feedback, reducing component count in high-isolation designs. Use Value: Open-loop DVSEC regulation eliminates optocoupler aging drift; programmable slope compensation accommodates wide inductor DCR tolerance. |
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 SOUT); 150°C rated; no DVSEC clamp. | Requires external synchronous rectifier control; suited for higher ambient temperature but lacks integrated SOUT timing. | Select when HI-side clamp layout is preferred and secondary-side timing is handled externally. |
| UCC2897APWR | Texas Instruments part; 100V max VIN; no integrated INTVCC LDO; requires external bias supply. | Lacks DVSEC open-loop regulation; needs optocoupler for regulation; lower integration reduces BOM count but increases design complexity. | Choose for cost-sensitive designs where TI ecosystem support and existing reference designs are prioritized. |
Compared with LT3753IFE#PBF, LT3752HFE#PBF offers higher temperature rating but sacrifices SOUT and DVSEC functionality, while UCC2897APWR requires external bias and feedback - making LT3753IFE#PBF the only option with integrated 10V INTVCC, SOUT, and programmable volt-second clamp in a single 38-lead TSSOP.
Availability
LT3753IFE#PBF is available at Aetrix Electronics and suitable for 48V telecom isolated PSUs, industrial 24V/48V DC-DC converters, and military vehicle power systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3753IFE#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 aerospace markets.
The LT3753IFE#PBF belongs to Analog Devices' Power by Linear™ active clamp controller family, designed specifically for high-efficiency, high-reliability isolated forward converters in telecom, industrial, and defense applications.
FAQ
What is the maximum duty cycle clamp (DVSEC) accuracy of the LT3753IFE#PBF?
The LT3753IFE#PBF provides ±4% DVSEC clamp accuracy at 72.5% maximum duty cycle (with UVLO_VSEC = 1.25V). This tight tolerance ensures consistent transformer reset and enables stable open-loop output regulation without secondary-side feedback components. The clamp value scales inversely with system input voltage, maintaining volt-second balance across the full 8.5V–100V input range.
How does the LT3753IFE#PBF implement synchronous rectification control?
The LT3753IFE#PBF generates precise timing signals for secondary-side synchronous rectifiers via its SOUT pin, with programmable delays (tSO and tOS) set by external resistors on TAS and TOS pins. This allows optimal alignment of SOUT transitions relative to OUT to minimize conduction losses and prevent shoot-through - critical for achieving >94% efficiency in 5V/20A telecom forward converters.
Can the LT3753IFE#PBF operate without an optocoupler?
Yes, the LT3753IFE#PBF supports true open-loop regulation via its programmable volt-second clamp (DVSEC), which directly links maximum duty cycle to system input voltage. When configured with appropriate IVSEC and UVLO_VSEC resistor values, the LT3753IFE#PBF maintains stable output voltage without optocoupler, error amplifier, or secondary-side reference - simplifying design and improving long-term reliability.
What thermal management requirements apply to the LT3753IFE#PBF?
The LT3753IFE#PBF requires soldering of its exposed pad (Pin 39) to a continuous copper ground plane to maintain junction temperature within the –40°C to +125°C specification. Thermal resistance θJA is 25°C/W; for 400W designs, a minimum 4cm² thermal pad with 4+ thermal vias is recommended. INTVCC LDO dropout must also be monitored at low VIN to avoid driver undervoltage.
Which protection features are integrated into the LT3753IFE#PBF?
The LT3753IFE#PBF integrates hiccup-mode overcurrent protection (96mV OC threshold), programmable input UVLO/OVLO with hysteresis, adaptive leading-edge blanking, thermal shutdown, and soft-stop sequencing. These features collectively protect the power stage during startup, load transients, and fault conditions - eliminating need for external supervisors in most industrial and telecom applications.
LT3753IFE#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
LT3753IFE#PBF FAQ
1.How can I place an order for LT3753IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3753IFE#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 LT3753IFE#PBF reliable?
The price and inventory of LT3753IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3753IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3753IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3753IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3753IFE#PBF?
LT3753IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3753IFE#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 LT3753IFE#PBF?
For technical support, including LT3753IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3753IFE#PBF requirements.
6.How does Aetrix verify that LT3753IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3753IFE#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 LT3753IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3753IFE#PBF?
All LT3753IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3753IFE#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 LT3753IFE#PBF part is unused and in its original packaging.
Return procedure for LT3753IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3753IFE#PBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
