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Analog Devices Inc. LT3431EFE#TRPBF
- Part No.:
- LT3431EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3431EFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,120
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Product details
Overview
LT3431EFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode synchronous step-down DC/DC converter IC designed for industrial and automotive power supplies. It operates from 5.5V to 60V input, delivers up to 2A at 5V output, features a constant 500kHz switching frequency, integrates a 0.1Ω NPN power switch, and includes shutdown, synchronization, and thermal protection functions.
For engineers reviewing the LT3431EFE#TRPBF datasheet, LT3431EFE#TRPBF pinout, LT3431EFE#TRPBF application, or LT3431EFE#TRPBF equivalent, key selection considerations include its 60V absolute max input rating, guaranteed 3A peak switch current over full duty cycle, 1.22V feedback reference, exposed-pad TSSOP-16 thermal performance, and BIAS pin efficiency optimization for high VIN-to-VOUT ratios.
Technical Context
The LT3431EFE#TRPBF employs a current-mode control architecture with dual feedback loops: an error amplifier sets the peak switch current threshold, while a cycle-by-cycle current comparator terminates each on-time. Its patented slope compensation cancellation maintains 3A peak switch current across 0–92% duty cycle without subharmonic instability.
Internal 2.9V bias regulation draws power from VIN by default but switches to the BIAS pin when externally supplied ≥3V-reducing total input-referred quiescent current to ~2.5mA at VIN=15V/VOUT=5V. The BOOST pin enables saturation of the integrated NPN switch via external capacitor/diode, achieving FET-like conduction loss (0.1Ω typical).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 60V - supports 24V/48V industrial rails and automotive cold-crank transients up to 60V |
| Output Current | Up to 2A continuous - limited by thermal design and inductor selection; peak switch current remains 3A across full duty cycle |
| Switching Frequency | 500kHz (±10%) - fixed frequency enables predictable EMI filtering; synchronizable from 580kHz to 700kHz |
| Feedback Reference | 1.219V (typ) - precise 1.22V bandgap reference enables accurate output voltage setting with standard resistor dividers |
| Switch On Resistance | 0.1Ω (typ) - low RCE(SAT) minimizes conduction loss, enabling >90% efficiency at 2A/5V output from 12V input |
| Shutdown Current | 30µA (typ) - ultra-low quiescent draw during disable; dual-threshold SHDN pin provides UVLO (2.38V) and deep shutdown (0.4V) |
| Junction Temp Range | –40°C to 125°C - specified and guaranteed for automotive under-hood and industrial ambient conditions |
| Package | 16-pin TSSOP with exposed pad - thermally enhanced footprint requires soldered ground pad for θJA = 45°C/W |
Pinout & Package
The LT3431EFE#TRPBF is housed in a 16-lead plastic TSSOP package with an exposed thermal pad fused to GND pins (1, 8, 9, 16). The pad must be soldered to a PCB ground plane to achieve specified thermal performance (θJA = 45°C/W, θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (1, 8, 9, 16) | Power and signal reference ground | Four dedicated GND pins + exposed pad reduce ground impedance; critical for load regulation and thermal dissipation |
| SW (2, 5) | Switch emitter node | Drives external inductor; swings from –0.8V (clamped) to VIN during operation; high dI/dt path requires short layout |
| VIN (3, 4) | Power switch collector & primary supply | Supplies internal circuitry when BIAS pin is unconnected; high-current path requiring low-inductance input bypass |
| BOOST (6) | Switch drive voltage booster | Accepts external boost capacitor/diode to raise gate drive above VIN, enabling NPN saturation and 0.1Ω RCE(SAT) |
| NC (7, 13) | No connection | Unbonded pins - must remain unconnected per datasheet; no internal function or tie requirement |
| BIAS (10) | Efficiency-optimized bias supply | When tied to VOUT ≥3V, shifts internal bias current from VIN to VOUT, reducing total input-referred quiescent current |
| VC (11) | Error amplifier output / current limit input | Compensation node (typically RC network); also serves as current clamp point - drives from ~0.9V (light load) to 2.1V (full load) |
| FB (12) | Output voltage sensing input | 1.22V reference input; also enables foldback protection: frequency reduction below 0.8V, current limit reduction below 0.6V |
| SYNC (14) | External oscillator synchronization | Logic-level input (10–90% duty) accepting 580–700kHz signals; disables foldback when active |
| SHDN (15) | Enable/disable control with UVLO | Dual-threshold: 2.38V disables switching (UVLO), 0.4V forces micropower shutdown (30µA IQ) |
Key Features
| Feature | Design Value |
|---|---|
| Full-duty-cycle peak current maintenance | Patented circuitry sustains 3A peak switch current from 0% to 92% duty cycle-eliminates need for derating at high VIN/VOUT ratios |
| BOOST-assisted NPN saturation | External BOOST capacitor enables 0.1Ω effective switch resistance-matching MOSFET conduction loss without gate driver complexity |
| Multi-level FB pin protection | Feedback pin provides coordinated foldback: frequency reduction (below 0.8V) + current limit reduction (below 0.6V) + SYNC disable-limits power dissipation during short-circuit |
| Thermally enhanced TSSOP | Exposed pad fused to four GND pins achieves θJA = 45°C/W-enables 2A operation without heatsink in 1-in² copper area |
| BIAS pin efficiency optimization | Connecting BIAS to VOUT ≥3V reduces total input-referred quiescent current by ~30% at high VIN/VOUT ratios (e.g., 24V→5V) |
| Robust absolute ratings | 60V VIN, 68V BOOST, 7V SYNC, 6V SHDN, 30V BIAS-supports harsh environments including automotive load dump and industrial surges |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
Use Scenario: 24V rail conversion to 5V/2A for PLC I/O modules and sensor interfaces in factory automation cabinets. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 5V to microcontrollers, RS-485 transceivers, and analog front-ends. Use Value: 60V input rating withstands 24V system transients; 125°C junction rating ensures reliability in enclosed enclosures; exposed-pad TSSOP simplifies thermal management. | Use Scenario: Powering infotainment head-unit logic and display backlight drivers from vehicle battery (9–16V nominal, up to 60V during load dump). IC Role / Device Role / Timing Role: Main 5V supply for MCU, CAN transceivers, and audio codecs in body control units. Use Value: Dual-threshold SHDN provides precise undervoltage lockout (2.38V) and deep sleep mode (0.4V); guaranteed –40°C to 125°C operation meets AEC-Q100 Grade 1 requirements. |
| Portable Test Equipment | Distributed Telecom Power |
Use Scenario: Battery-powered handheld multimeter or oscilloscope requiring stable 5V/2A from Li-ion (8.4V max) or 12V adapter input. IC Role / Device Role / Timing Role: High-efficiency step-down regulator enabling >10-hour runtime with minimal heat generation. Use Value: 2.5mA effective quiescent current (with BIAS pin connected) extends battery life; 500kHz fixed frequency allows compact LC filter design. | Use Scenario: Intermediate 5V bus generation in 48V telecom systems for FPGA, PHY, and memory subsystems. IC Role / Device Role / Timing Role: Point-of-load buck converter converting -48V-derived 12V or 24V to 5V for digital logic rails. Use Value: Synchronization capability (580–700kHz) enables phase-aligned switching across multiple rails to reduce input ripple current; 3A peak current supports burst-mode loads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3642EMSE#PBF | 40V max input, 2A output, 3mm × 4mm MSOP-16, integrated MOSFETs, 1.2V ref | Lower voltage range; better suited for 12V/24V systems without transients; smaller footprint | Select LTC3642EMSE#PBF when input stays ≤40V and board space is constrained; not suitable for 60V automotive or industrial surge environments. |
| MPQ4333GJ-AEC1-P | 60V max input, 3A output, QFN-12, AEC-Q100 qualified, 0.8V ref, spread-spectrum | Automotive-grade qualification; higher output current; different pinout and compensation scheme | Choose MPQ4333GJ-AEC1-P for new automotive designs requiring AEC-Q100 compliance and spread-spectrum EMI reduction; requires layout redesign. |
Compared with LTC3642EMSE#PBF and MPQ4333GJ-AEC1-P, the LT3431EFE#TRPBF uniquely maintains full 3A peak switch current across all duty cycles-a critical advantage for high-step-down ratios-and offers robust 60V transient tolerance without requiring external surge protection components.
Availability
LT3431EFE#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and portable test equipment requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LT3431EFE#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3431EFE#TRPBF belongs to Linear's high-voltage monolithic buck regulator product line, engineered specifically for ruggedized power conversion in environments with wide input ranges, high transient stress, and demanding thermal constraints.
FAQ
What is the maximum input voltage the LT3431EFE#TRPBF can handle continuously?
The LT3431EFE#TRPBF is rated for continuous operation up to 60V input voltage. Its absolute maximum rating for VIN is 60V, and it is specifically designed to maintain regulation and reliability under sustained 60V conditions-common in industrial 48V systems and automotive load-dump scenarios. Transient tolerance exceeds this rating, but continuous operation must remain at or below 60V per datasheet specifications.
Does the LT3431EFE#TRPBF require an external catch diode?
Yes, the LT3431EFE#TRPBF requires an external catch diode connected between SW and GND. As a nonsynchronous buck controller with an integrated NPN switch, it relies on this diode to provide the freewheeling current path during switch-off time. The datasheet recommends fast recovery or Schottky diodes such as MMSD914TI for optimal efficiency and transient response.
How does the BOOST pin function in the LT3431EFE#TRPBF, and what happens if it's left unconnected?
The BOOST pin in the LT3431EFE#TRPBF supplies elevated drive voltage to the internal NPN switch base, enabling saturation and minimizing conduction loss (0.1Ω typical). It is driven by an external capacitor charged through a diode from SW. If left unconnected, the switch operates in linear mode with ~1.5V VCE(SAT), drastically reducing efficiency and limiting usable output current-thus the BOOST network is mandatory for rated performance.
Can the LT3431EFE#TRPBF be synchronized to an external clock, and what is its valid sync frequency range?
Yes, the LT3431EFE#TRPBF supports external synchronization via the SYNC pin. It accepts logic-level inputs (10–90% duty cycle) within a frequency range of 580kHz to 700kHz. This allows noise-sensitive systems to align switching edges and reduce beat frequencies. The internal oscillator defaults to 500kHz when SYNC is left open or held low, and synchronization is automatically disabled during FB-foldback events to preserve protection integrity.
What thermal design considerations apply to the LT3431EFE#TRPBF's exposed pad?
The LT3431EFE#TRPBF's exposed pad is electrically and thermally connected to all four GND pins (1, 8, 9, 16). To achieve the specified θJA = 45°C/W, the pad must be fully soldered to a minimum 1-in² internal or external PCB ground plane using ≥6 thermal vias (0.3mm diameter, spaced evenly). Inadequate soldering or insufficient copper area will cause junction temperature to exceed 125°C under 2A load, triggering thermal shutdown.
LT3431EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 5.5V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.219V
- 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
LT3431EFE#TRPBF FAQ
1.How can I place an order for LT3431EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3431EFE#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 LT3431EFE#TRPBF reliable?
The price and inventory of LT3431EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3431EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3431EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3431EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3431EFE#TRPBF?
LT3431EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3431EFE#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 LT3431EFE#TRPBF?
For technical support, including LT3431EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3431EFE#TRPBF requirements.
6.How does Aetrix verify that LT3431EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3431EFE#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 LT3431EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3431EFE#TRPBF?
All LT3431EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3431EFE#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 LT3431EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3431EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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