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Analog Devices Inc. LT3435EFE#PBF
- Part No.:
- LT3435EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3435EFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:149
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Product details
Overview
LT3435EFE#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode 500kHz buck switching regulator with integrated 3A NPN power switch, 0.1Ω on-resistance, 1.25V feedback reference, and Burst Mode® operation enabling 100µA quiescent current at no load. It operates from 3.3V to 60V input and delivers regulated output in automotive 14V/42V systems, industrial power supplies, and battery-powered equipment.
For engineers reviewing the LT3435EFE#PBF datasheet, LT3435EFE#PBF pinout, LT3435EFE#PBF application, or LT3435EFE#PBF equivalent, key selection considerations include its 60V absolute maximum input rating, programmable Power Good flag with PGFB/CT timing control, soft-start via CSS pin, synchronous capability up to 700kHz, and thermal performance enabled by the exposed-pad 16-pin TSSOP package.
Technical Context
The LT3435EFE#PBF implements constant-frequency current-mode control using an internal 500kHz oscillator, peak-current sensing, and error amplifier output (VC pin) that directly sets the switch current trip point. Its architecture enables fast transient response and stable loop compensation across wide duty cycles.
It integrates a high-voltage NPN switch with BOOST-driven saturation, achieving low conduction loss (0.1Ω typical RCE(SAT)) and load-dump tolerance to 60V. Burst Mode® operation reduces quiescent current to 100µA at light loads by cycling the control circuitry, while shutdown draws <1µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports direct connection to 42V automotive batteries and industrial rails without pre-regulation. |
| Switch Current Limit | 3A peak - sustains full 3A output under worst-case duty cycle conditions per patented design. |
| Quiescent Current (Burst Mode) | 100µA - enables >1-year battery life in always-on 12V/24V IoT sensors and telematics modules. |
| Switching Frequency | 425–575kHz (typ. 500kHz) - allows compact magnetics; externally synchronizable up to 700kHz for EMI reduction. |
| Feedback Reference | 1.25V ±2.5% - enables precise output regulation with standard resistor dividers; FB pin bias current ≤200nA minimizes divider error. |
| Power Good Threshold | Programmable via PGFB divider - sets output voltage monitoring threshold (e.g., 90% of VREF) with adjustable delay via CT capacitor. |
| Thermal Resistance (θJA) | 45°C/W - achieved via exposed pad soldered to PCB ground plane; θJC(PAD) = 10°C/W enables high-power dissipation in confined spaces. |
Pinout & Package
LT3435EFE#PBF is housed in a thermally enhanced 16-pin TSSOP package (FE grade) with exposed pad (Pin 17), requiring soldering to PCB ground for thermal and electrical integrity. Pin 1 is NC; Pins 2 & 5 are SW (switch emitter); Pins 3 & 4 are VIN (switch collector); Pin 17 and Pin 8 are GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 2, 5) | Emitter of internal NPN switch | Drives inductor; clamped negative swing ≤ –0.8V; requires external catch diode. |
| VIN (Pins 3, 4) | Collector of internal NPN switch & primary supply input | Handles high di/dt; must be decoupled locally with low-ESR ceramic capacitor to minimize voltage spikes. |
| BOOST (Pin 6) | Boost capacitor drive node | Provides >VIN voltage to saturate NPN switch; enables 0.1Ω effective on-resistance and 60V load-dump survival. |
| GND (Pins 8, 17) | Power and signal reference / thermal pad | Exposed pad (Pin 17) must be soldered to solid ground plane to achieve θJA = 45°C/W and ensure accurate load regulation. |
| FB (Pin 12) | Feedback input to error amplifier | Sets output voltage via resistive divider; 1.25V reference; input bias ≤200nA; enables frequency foldback and soft-start control below 0.9V. |
| PGFB (Pin 13) | Power Good comparator positive input | Configures output voltage threshold for PG assertion; referenced to VREF; triggers CT timing delay when exceeded. |
| CSS (Pin 9) | Soft-start current threshold input | Controls dV/dt ramp rate via external capacitor; threshold scales with FB voltage; disabled above 0.9V. |
| SHDN (Pin 15) | Shutdown enable input | Active-high logic; 1.3V threshold; draws ≤20µA; reduces total supply current to <1µA in shutdown state. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Reduces no-load input current to 100µA while maintaining regulation - critical for long-life battery systems and always-on automotive ECUs. |
| Load Dump Protection | Withstands 60V transients on VIN without damage or latch-up - meets ISO 7637-2 Pulse 5a requirements for 42V automotive applications. |
| Programmable Power Good Flag | PGFB/CT combination allows user-defined output voltage threshold (e.g., 90% of VOUT) and delay time (via capacitor) for system sequencing and fault reporting. |
| Saturating Switch Design | 0.1Ω typical RCE(SAT) achieved via BOOST-driven NPN - delivers higher efficiency than comparable MOSFET-based regulators at 3A continuous output. |
| Thermally Enhanced TSSOP | 16-pin FE package with exposed pad achieves θJA = 45°C/W - enables 3A operation in space-constrained industrial and automotive PCB layouts without heatsinks. |
Applications
| Automotive Engine Control Unit (ECU) | Industrial 24V/48V DC-DC Converter |
|---|---|
Use Scenario: Regulating 12V battery input to 3.3V/5V for microcontroller, CAN transceiver, and sensor interfaces in harsh under-hood environments. IC Role / Device Role / Timing Role: Primary step-down regulator with load dump protection, programmable Power Good for MCU reset coordination, and Burst Mode for sleep-state current minimization. Use Value: Survives 60V load dump pulses; maintains 100µA quiescent current during vehicle sleep mode; eliminates need for external TVS or pre-regulator stages. |
Use Scenario: Converting unregulated 24V–48V factory bus to stable 5V for PLC I/O modules, motor drivers, and fieldbus gateways operating continuously at 60°C ambient. IC Role / Device Role / Timing Role: High-efficiency buck controller delivering 3A continuous output with thermal management via exposed-pad TSSOP and BIAS pin efficiency boost. Use Value: 0.1Ω switch RCE(SAT) reduces conduction loss; BIAS pin connection to VOUT improves light-load efficiency; 125°C junction rating ensures reliability in sealed enclosures. |
| Portable Medical Diagnostic Device | USB-Powered Test Instrumentation |
Use Scenario: Powering FPGA, ADCs, and analog front-ends from dual Li-ion (8.4V max) or 12V wall adapter in handheld ultrasound or ECG units requiring ultra-low standby power. IC Role / Device Role / Timing Role: Main power converter with soft-start (CSS) to limit inrush, Burst Mode for <100µA sleep current, and precise 1.25V reference for stable analog rail generation. Use Value: Enables >100-hour battery runtime in standby; controlled dV/dt prevents sensor bias disruption during startup; low FB pin current preserves accuracy of high-impedance dividers. |
Use Scenario: Deriving 3.3V/5V from USB 2.0/3.0 ports (5V±5%) for portable oscilloscopes, logic analyzers, and sensor calibrators with strict EMI and size constraints. IC Role / Device Role / Timing Role: Compact, high-frequency (500kHz) buck regulator minimizing inductor size; SYNC pin enables EMI spread-spectrum alignment with host USB frame timing. Use Value: 16-pin TSSOP fits dense USB-C form factors; 500kHz operation allows ≤2.2µH inductors; low EMI due to controlled switch edges and local input loop design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | 40V max input, 2A output, 3mm × 4mm MSOP; no BOOST pin; uses MOSFET switch; 28µA IQ in Burst Mode | Lower voltage/current rating; better suited for space-constrained 24V systems where 60V tolerance is unnecessary | Select LTC3631EMSE#PBF when board area is critical and input never exceeds 40V; avoid for 42V automotive or industrial 48V surge-prone rails. |
| MPQ4333GQ-AEC1-P | 60V input, 3.5A output, AEC-Q200 qualified, 2.5µA shutdown current; integrated MOSFET; no programmable PG flag | Automotive-grade qualification and higher peak current, but lacks PGFB/CT programmability and has fixed 1.2V reference | Select MPQ4333GQ-AEC1-P for production automotive modules requiring AEC-Q200; use LT3435EFE#PBF when programmable Power Good timing or 1.25V reference precision is required. |
Compared with LTC3631EMSE#PBF and MPQ4333GQ-AEC1-P, the LT3435EFE#PBF uniquely combines 60V input tolerance, 3A sustained current with patented peak-current maintenance, fully programmable Power Good timing, and 1.25V reference accuracy - making it optimal for industrial and automotive designs demanding both ruggedness and precise system-level control.
Availability
LT3435EFE#PBF is available at Aetrix Electronics and suitable for automotive engine control units, industrial 24V/48V power supplies, and portable medical diagnostic devices requiring stable component supply across extended temperature and lifecycle requirements.
Supply support for LT3435EFE#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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for the LT® product family, renowned for high-performance power management ICs with robust industrial and automotive qualification.
The LT3435EFE#PBF belongs to Linear's high-voltage monolithic buck regulator product line, engineered specifically for reliable operation in 14V/42V automotive, industrial 24V–60V, and battery-powered systems where input transients, thermal density, and ultra-low quiescent current are critical.
FAQ
What is the maximum input voltage rating for the LT3435EFE#PBF?
The LT3435EFE#PBF has an absolute maximum input voltage rating of 60V on the VIN pin, and it is specifically designed to withstand automotive load dump transients up to this level. Its BOOST-driven NPN switch architecture enables reliable 60V operation without external protection components, making it suitable for 42V automotive systems and industrial 48V rails.
How does Burst Mode® operation reduce quiescent current in the LT3435EFE#PBF?
Burst Mode® operation in the LT3435EFE#PBF reduces quiescent current to 100µA by cyclically disabling non-essential control circuitry during light-load conditions while maintaining output regulation. The device enters sleep mode between bursts, drawing minimal current from VIN or BIAS, then wakes to deliver energy packets - a technique validated in the LT3435EFE#PBF's Electrical Characteristics table and Typical Performance curves.
Can the LT3435EFE#PBF be synchronized to an external clock, and what is its sync range?
Yes, the LT3435EFE#PBF can be synchronized via its SYNC pin, which accepts logic-level inputs (5%–75% duty cycle) from 425kHz up to 700kHz. The sync range extends beyond its nominal 500kHz switching frequency, allowing EMI reduction through frequency alignment. Synchronization is disabled during frequency foldback (FB < 0.9V), ensuring stable operation during fault conditions.
What is the purpose of the BOOST pin on the LT3435EFE#PBF, and how is it implemented?
The BOOST pin on the LT3435EFE#PBF provides a voltage higher than VIN to fully saturate the internal NPN power switch, reducing its effective on-resistance to 0.1Ω. It is implemented using an external flying capacitor and Schottky diode (e.g., DFLS160) connected between BOOST and SW, generating a charge-pump voltage that drives the switch base - a key enabler of high efficiency at 3A output.
How is Power Good functionality configured on the LT3435EFE#PBF?
Power Good on the LT3435EFE#PBF is configured using the PGFB pin (connected to a resistive divider from VOUT) and the CT pin (connected to a timing capacitor to GND). When PGFB exceeds 90% of VREF, current sources into CT; once CT voltage reaches 1.2V (clamped), PG goes high-impedance. The delay time is t = CCT × 1.2V / 3.6µA - a fully programmable feature unique to the LT3435EFE#PBF.
LT3435EFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 55.2V
- Current - Output:
- 3A (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3435EFE#PBF FAQ
1.How can I place an order for LT3435EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3435EFE#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 LT3435EFE#PBF reliable?
The price and inventory of LT3435EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3435EFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3435EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3435EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3435EFE#PBF?
LT3435EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3435EFE#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 LT3435EFE#PBF?
For technical support, including LT3435EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3435EFE#PBF requirements.
6.How does Aetrix verify that LT3435EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3435EFE#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 LT3435EFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3435EFE#PBF?
All LT3435EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3435EFE#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 LT3435EFE#PBF part is unused and in its original packaging.
Return procedure for LT3435EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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