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Analog Devices Inc. LT3757IDD#TRPBF
- Part No.:
- LT3757IDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3757IDD#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOPOLOGY 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:8,625
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Product details
Overview
LT3757IDD#TRPBF from Analog Devices is a wide-input current-mode DC/DC controller for boost, flyback, SEPIC, and inverting topologies, driving external N-channel MOSFETs. It operates from 2.9V to 40V input, supports ±0.8V/1.6V feedback regulation, delivers programmable 50kHz–1MHz switching, and features <1µA shutdown current - ideal for automotive battery-powered LED drivers and telecom power supplies.
For engineers reviewing the LT3757IDD#TRPBF datasheet, LT3757IDD#TRPBF pinout, LT3757IDD#TRPBF application, or LT3757IDD#TRPBF equivalent, key selection criteria include its dual-polarity feedback capability, internal 7.2V LDO gate driver supply, frequency synchronization support, soft-start programmability, and AEC-Q100 qualification for automotive use.
Technical Context
The LT3757IDD#TRPBF implements fixed-frequency current-mode control with slope compensation, enabling stable operation across wide VIN and VOUT ranges. Its error amplifier supports both positive (1.6V) and negative (–0.8V) FBX reference modes, allowing seamless reconfiguration between boost/flyback/SEPIC and inverting converter topologies without hardware changes.
It integrates an internal 7.2V low-dropout regulator (LDO) for gate drive, with UVLO (2.7V) and OVLO (17.5V) protection, plus programmable SHDN/UVLO thresholds using external resistors. Frequency foldback and soft-start limit inductor current during startup and short-circuit faults.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.9V to 40V - enables direct operation from 3.3V logic rails up to 36V automotive batteries. |
| Feedback Reference | +1.6V or –0.8V - single-pin polarity-selectable regulation for positive/negative output configurations. |
| Switching Frequency | 50kHz to 1MHz (RT-programmable) - balances efficiency vs. magnetics size; supports external SYNC clock alignment. |
| Shutdown Current | <1µA - preserves battery life in always-on automotive or portable systems. |
| SENSE Threshold | 110mV (typical) - sets peak switch current limit with high accuracy over temperature. |
| INTVCC Regulator | 7.2V ±0.2V LDO - powers gate driver and internal circuitry; bypassed with ≥4.7µF ceramic capacitor. |
| Operating Temp Range | –40°C to +125°C - qualified per AEC-Q100 Grade I for under-hood automotive applications. |
Pinout & Package
LT3757IDD#TRPBF uses a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed pad (Pin 11 = GND), optimized for high-power density and thermal performance in space-constrained designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC (Pin 1) | Error amplifier compensation node | Accepts RC network to stabilize voltage loop; clamped during soft-start and fault conditions. |
| FBX (Pin 2) | Positive/negative feedback input | Dual-reference pin: regulates to +1.6V (boost/flyback/SEPIC) or –0.8V (inverting); triggers frequency foldback near GND. |
| SS (Pin 3) | Soft-start timing control | 10µA pull-up to 2.5V rail; external capacitor sets ramp time; reset by UV/OV/thermal events. |
| RT (Pin 4) | Frequency programming input | Resistor-to-GND sets oscillator frequency; open-circuit disables operation. |
| SYNC (Pin 5) | External clock synchronization | Accepts digital clock signal; requires RT setting 20% below SYNC frequency; ignored when FBX ≈ GND. |
| SENSE (Pin 6) | Current sense input | Kelvin-connected to MOSFET source-side sense resistor; monitors peak switch current for cycle-by-cycle limiting. |
| GATE (Pin 7) | N-channel MOSFET gate driver | Drives external FET between INTVCC and GND; forced low during shutdown, thermal lockout, or INTVCC fault. |
| INTVCC (Pin 8) | Internal LDO output | 7.2V regulated supply for gate driver and logic; must be bypassed with ≥4.7µF ceramic cap; can be externally powered above 7.5V. |
| SHDN/UVLO (Pin 9) | Enable/undervoltage detection | 1.22V falling threshold with programmable hysteresis; pulls VIN IQ below 1µA when ≤0.4V. |
| VIN (Pin 10) | Main input supply | 2.9V–40V input; requires local 0.22µF+ ceramic bypass; powers internal LDO and bias circuits. |
| Exposed Pad (Pin 11) | Thermal ground / SENSE return | Must be soldered to PCB ground plane; serves as Kelvin return for SENSE path and primary thermal conduction path (θJA = 43°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Topology Flexibility | Single IC supports boost, flyback, SEPIC, and inverting converters via FBX polarity selection - eliminates need for multiple controller variants. |
| Automotive Qualification | AEC-Q100 Grade I (–40°C to +125°C) - validated for engine control units, ADAS lighting, and infotainment power rails. |
| Low-Power Operation | <1µA shutdown IQ and 2.9V minimum VIN enable long-life battery backup and cold-crank compatibility. |
| Robust Protection Suite | Integrated INTVCC UV/OV lockout, thermal shutdown, frequency foldback, and FBX overvoltage reset - reduces external protection components. |
| Thermal Performance | DFN package with exposed pad achieves 43°C/W θJA; supports >2A output currents with proper PCB copper area and airflow. |
Applications
| Automotive LED Headlamp Driver | Industrial Telecom DC-DC Module |
|---|---|
|
Use Scenario: High-brightness LED array powering in vehicle headlamps requiring constant-current regulation and PWM dimming. IC Role / Device Role / Timing Role: Flyback controller generating isolated 48V output from 12V battery; FBX senses secondary-side current via optocoupler feedback. Use Value: AEC-Q100 qualification ensures reliability under vibration and thermal cycling; 50kHz–1MHz programmability allows EMI optimization around automotive radio bands. |
Use Scenario: Compact 48V telecom power module converting –48V backplane to +12V for line-card subsystems. IC Role / Device Role / Timing Role: Inverting controller generating negative-to-positive conversion with tight load regulation and fast transient response. Use Value: Dual-polarity FBX reference simplifies feedback design; current-mode architecture maintains stability across wide input voltage swings typical in telecom environments. |
| Portable Medical Imaging Power | Industrial Sensor Signal Chain Supply |
|
Use Scenario: Battery-powered ultrasound probe requiring isolated ±15V analog supplies for transducer bias and ADC front-end. IC Role / Device Role / Timing Role: SEPIC controller delivering regulated outputs from single Li-ion cell (2.9V–4.2V); SS pin enables controlled start-up to avoid inrush into capacitive loads. Use Value: Low 2.9V start-up voltage extends usable battery range; soft-start prevents voltage droop on shared battery bus during system wake-up. |
Use Scenario: Precision industrial sensor node needing clean, isolated ±5V supplies for op-amp signal conditioning and ADC reference. IC Role / Device Role / Timing Role: Boost controller generating +12V from 3.3V MCU rail, followed by LDOs; RT pin set to 300kHz to minimize EMI coupling into sensitive analog paths. Use Value: Programmable frequency avoids interference with sensor sampling clocks; internal 7.2V LDO ensures consistent gate drive despite input rail variation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3757AIDD#TRPBF | Improved load transient response; tighter FBX regulation tolerance (±0.5% vs ±0.8%); identical pinout and package. | Better suited for dynamic load applications like servo drives or burst-mode LED dimming where output voltage recovery speed matters. | Select LT3757AIDD#TRPBF when faster transient performance is required; otherwise LT3757IDD#TRPBF remains optimal for cost-sensitive, steady-state designs. |
| LM5122MM/NOPB | Wider 3V–65V input; integrated high-side gate driver; no negative-output capability; different pinout and compensation scheme. | Preferred for high-voltage boost applications (e.g., solar MPPT, industrial 48V systems) where isolation is not needed and board space is constrained. | Choose LM5122MM/NOPB only if input exceeds 40V or integrated high-side drive is required; LT3757IDD#TRPBF retains advantage in topology flexibility and AEC-Q100 compliance. |
Compared with LT3757AIDD#TRPBF, the LT3757IDD#TRPBF offers lower cost and sufficient transient performance for most automotive lighting and telecom modules; versus LM5122MM/NOPB, it provides unique inverting/SEPIC support and automotive qualification but requires external low-side FET and separate gate drive design.
Availability
LT3757IDD#TRPBF is available at Aetrix Electronics and suitable for automotive LED drivers, industrial telecom power modules, portable medical imaging systems, and precision sensor signal chain supplies requiring stable component supply and long-term manufacturability.
Supply support for LT3757IDD#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3757 series was designed specifically for flexible, high-reliability DC/DC controller applications in harsh environments - emphasizing wide input range, topology adaptability, and automotive-grade robustness.
FAQ
What is the maximum operating junction temperature for LT3757IDD#TRPBF?
The LT3757IDD#TRPBF is rated for operation up to +125°C junction temperature and is qualified per AEC-Q100 Grade I. Its DFN package has θJA = 43°C/W when properly soldered to a 4-layer PCB with full thermal pad exposure. Exceeding TJMAX triggers thermal shutdown, and continuous operation above 125°C degrades long-term reliability. Derating is recommended above 100°C ambient.
Can LT3757IDD#TRPBF generate negative output voltages?
Yes, the LT3757IDD#TRPBF supports negative output generation in inverting converter configuration. When the FBX pin is pulled below GND via an external resistor divider, the internal –0.8V reference activates, enabling regulation of negative outputs. This is confirmed in the datasheet's block diagram and Applications Information section, with dedicated comparator A2 handling the inverted feedback path.
Does LT3757IDD#TRPBF require an external MOSFET?
Yes, the LT3757IDD#TRPBF is a controller IC - not a converter with integrated power switches. It drives an external low-side N-channel MOSFET via the GATE pin. The IC provides gate drive from its internal 7.2V LDO (INTVCC), and the SENSE pin monitors current through an external sense resistor placed in the MOSFET source path.
How is the switching frequency set on LT3757IDD#TRPBF?
The switching frequency of LT3757IDD#TRPBF is set using a single resistor (RT) from Pin 4 (RT) to GND. Values range from 10.5kΩ (1MHz) to 442kΩ (50kHz), per Table 1 in the datasheet. Leaving RT open disables operation. For synchronization, the SYNC pin accepts an external clock, but the RT resistor must be selected for a frequency 20% slower than the SYNC signal.
Is LT3757IDD#TRPBF pin-compatible with LT3757AIDD#TRPBF?
Yes, LT3757IDD#TRPBF and LT3757AIDD#TRPBF share identical pinout, package (10-lead DFN), and footprint. The LT3757A variant improves load transient response and tightens FBX regulation tolerance but maintains full electrical and mechanical compatibility - enabling drop-in replacement in existing designs where enhanced dynamic performance is desired.
LT3757IDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive and Negative
- Topology:
- Boost, Flyback, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 2.9V ~ 40V
- Frequency - Switching:
- 100kHz ~ 1MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3757IDD#TRPBF FAQ
1.How can I place an order for LT3757IDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3757IDD#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 LT3757IDD#TRPBF reliable?
The price and inventory of LT3757IDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3757IDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3757IDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3757IDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3757IDD#TRPBF?
LT3757IDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3757IDD#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 LT3757IDD#TRPBF?
For technical support, including LT3757IDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3757IDD#TRPBF requirements.
6.How does Aetrix verify that LT3757IDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3757IDD#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 LT3757IDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3757IDD#TRPBF?
All LT3757IDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3757IDD#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 LT3757IDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3757IDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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