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Analog Devices Inc. LT3431IFE#TRPBF
- Part No.:
- LT3431IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3431IFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,237
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Product details
Overview
LT3431IFE#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 fixed 500kHz switching frequency, integrates a 0.1Ω NPN power switch, and includes cycle-by-cycle current limiting and external synchronization capability.
For engineers reviewing the LT3431IFE#TRPBF datasheet, LT3431IFE#TRPBF pinout, LT3431IFE#TRPBF application, or LT3431IFE#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and electrical specifications, real-world application constraints (e.g., BOOST capacitor requirement, GND pad soldering), and two rigorously cross-checked alternative parts for 5–60V buck conversion with ≥3A peak switch current.
Technical Context
The LT3431IFE#TRPBF implements a constant-frequency, current-mode control architecture with dual feedback loops: an error amplifier sets the peak switch current threshold, while a dedicated current-sense comparator monitors inductor current on a cycle-by-cycle basis. Its patented slope compensation cancellation maintains 3A peak switch current across the full 0–92% duty cycle range without subharmonic oscillation.
Internal bias is derived either from VIN or externally via the BIAS pin (≥3V), enabling efficiency optimization at high input-to-output voltage ratios. The BOOST pin requires an external capacitor-diode network to generate ~VIN+5V drive voltage, ensuring NPN switch saturation and minimizing conduction loss (typ. 0.1Ω RON). Shutdown and UVLO are implemented via dual SHDN pin thresholds (0.4V full shutdown, 2.38V lockout).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 60V - supports 12V/24V/48V industrial rails and transient-tolerant automotive systems (e.g., cold-crank to 60V). |
| Output Current | Up to 2A continuous - limited by thermal design and inductor selection; peak switch current remains 3A across all duty cycles. |
| Switching Frequency | Fixed 500kHz (±10%) - enables compact magnetics; synchronizable from 580kHz to 700kHz via logic-level SYNC pin. |
| Feedback Reference | 1.219V (typ.) - sets output voltage via external resistor divider; FB pin also enables foldback protection below 0.8V. |
| Switch On Resistance | 0.1Ω (typ.) - achieved via BOOST-driven NPN saturation; reduces conduction loss and thermal stress at high load currents. |
| Junction Temperature | –40°C to +125°C - rated for extended industrial and under-hood automotive environments; exposed pad must be soldered to ground plane. |
| Shutdown Current | 30µA (typ.) - ultra-low quiescent draw during disable; SHDN pin has dual thresholds for precise UVLO and deep sleep control. |
Pinout & Package
The LT3431IFE#TRPBF is housed in a thermally enhanced 16-lead plastic TSSOP package with an exposed GND pad requiring soldering to the PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 8, 9, 16) | Power and signal reference ground | Multiple low-impedance connections; exposed pad fused to these pins - mandatory soldering to PCB ground plane for θJA = 45°C/W and stable regulation. |
| SW (Pins 2, 5) | Switch emitter node | Drives inductor; swings from –0.8V (clamped) to VIN during operation; high dI/dt path requires short layout to catch diode and input cap. |
| VIN (Pins 3, 4) | Power switch collector & primary supply | Supplies internal circuitry when BIAS pin is unconnected; high-current path subject to voltage spikes - bypass capacitor must be placed adjacent. |
| BOOST (Pin 6) | Switch driver voltage boost | Requires external capacitor charged to VIN+5V via diode; enables NPN saturation and 0.1Ω effective RON; no internal charge pump. |
| BIAS (Pin 10) | Efficiency-optimized bias supply | Connect to regulated output (≥3V) to source internal bias current from VOUT instead of VIN - improves efficiency at high VIN/VOUT ratios. |
| VC (Pin 11) | Error amplifier output / current limit control | Compensation node (0.9V–2.1V range); can be clamped to override current limit or force shutdown; drives peak current comparator. |
| FB (Pin 12) | Output voltage sensing & protection | Sets VOUT via 1.219V reference; below 0.8V triggers frequency foldback; below 0.6V reduces current limit and disables SYNC - protects during short-circuit. |
| SYNC (Pin 14) | External oscillator synchronization | Logic-compatible input (10–90% duty); accepts 580–700kHz signals; disabled automatically during FB foldback for safety. |
| SHDN (Pin 15) | Enable/disable & UVLO control | 2.38V threshold enables UVLO (e.g., start only above 12V); 0.4V threshold forces micropower shutdown (30µA IQ). |
Key Features
| Feature | Design Value |
|---|---|
| Patented duty-cycle-independent current limit | Maintains 3A peak switch current from 0% to 92% duty cycle - eliminates need for slope compensation tuning and enables stable operation at high VIN/VOUT ratios. |
| BOOST-driven saturated NPN switch | 0.1Ω typical RON achieved via external BOOST capacitor - reduces conduction loss vs. standard bipolar or MOSFET-based buck controllers. |
| Integrated dual-threshold shutdown | SHDN pin provides both accurate undervoltage lockout (2.38V) and deep micropower shutdown (0.4V) - simplifies system power sequencing and battery drain management. |
| FB pin multifunction protection | Simultaneously enables output voltage setting, frequency foldback (below 0.8V), current limit reduction (below 0.6V), and SYNC disable - single-pin fault response without external circuitry. |
| Thermally enhanced TSSOP-16 | Exposed GND pad with θJC(PAD) = 10°C/W - enables 2A continuous operation at +85°C ambient with minimal copper area, unlike standard MSOP or SOIC packages. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: 24V vehicle battery powers 5V microcontroller, CAN transceiver, and sensor interface in door module. IC Role / Device Role / Timing Role: Primary buck regulator converting 9–36V battery range to stable 5V/2A rail; handles cold-crank transients up to 60V. Use Value: Maintains regulation during engine start (low-VIN) and load dump (high-VIN); BOOST and BIAS pins optimize efficiency across full input range. |
Use Scenario: DIN-rail mounted PLC uses 48V DC input to generate isolated 5V/2A for digital I/O and communication interfaces. IC Role / Device Role / Timing Role: Non-isolated pre-regulator feeding downstream isolated DC/DC; operates continuously at 60°C ambient with forced air. Use Value: Exposed-pad TSSOP package sustains 2A output without heatsink; 500kHz switching allows small 10µH inductor and ceramic output cap. |
| Portable Medical Instrument | Telecom Remote Radio Unit |
|
Use Scenario: Battery-powered ultrasound device requires clean 5V/2A from 12V Li-ion pack with strict EMI limits. IC Role / Device Role / Timing Role: Main power stage with SYNC pin locked to system clock (600kHz) to avoid beat frequencies in sensitive analog front-end. Use Value: Synchronizable 500kHz operation enables deterministic noise placement; FB foldback prevents thermal runaway during probe short-circuit. |
Use Scenario: Outdoor 4G base station remote radio head draws 5V/2A from -48V telecom supply with wide temperature swing (-40°C to +85°C). IC Role / Device Role / Timing Role: High-input buck converter operating from -48V nominal (|VIN| = 48V) with transient tolerance to ±100V surges. Use Value: 60V absolute max rating and -40°C to +125°C junction range ensure reliability in uncontrolled outdoor enclosures; GND pad soldering prevents thermal derating. |
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 |
|---|---|---|---|
| LTC3642EFE#PBF | 40V max input, 2A integrated MOSFET, 3mm × 4mm 20-lead QFN, no BOOST pin required | Better suited for space-constrained designs with VIN ≤ 40V; lacks 60V rating and external BOOST flexibility for ultra-high-efficiency at >48V | Select LTC3642EFE#PBF when board area is critical and input stays below 40V; LT3431IFE#TRPBF remains preferred for 48V/60V industrial systems. |
| LM5164QPWPRQ1 | 65V max input, 1A integrated FET, 1.5MHz switching, automotive AEC-Q100 Grade 1 | Higher frequency enables smaller inductors but lower current; AEC-Q100 qualified but not validated for 2A continuous at 125°C junction | Choose LM5164QPWPRQ1 for automotive infotainment with <1A loads and AEC-Q100 compliance; LT3431IFE#TRPBF delivers higher current and proven 125°C operation in non-automotive-qualified contexts. |
Compared with LTC3642EFE#PBF and LM5164QPWPRQ1, the LT3431IFE#TRPBF uniquely combines 60V input rating, 3A peak switch current maintained over full duty cycle, BOOST-enabled 0.1Ω RON, and –40°C to +125°C guaranteed operation - making it the only option among the three capable of delivering 2A continuously from 48V input in extended-temperature industrial enclosures.
Availability
LT3431IFE#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and portable medical instruments requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LT3431IFE#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 LT3431IFE#TRPBF belongs to Linear's high-voltage monolithic buck regulator product line, engineered specifically for robust, high-efficiency DC/DC conversion in harsh environments where input transients, wide temperature ranges, and sustained high load currents are critical design constraints.
FAQ
What is the absolute maximum input voltage rating for the LT3431IFE#TRPBF?
The LT3431IFE#TRPBF has an absolute maximum input voltage rating of 60V applied to the VIN pins (3, 4). Exceeding this voltage risks permanent damage. Transient tolerance up to 60V is supported in normal operation, and the device is commonly used in 48V systems with load-dump protection. The BOOST pin voltage rating is higher (68V), but VIN must remain ≤60V.
Does the LT3431IFE#TRPBF require an external BOOST capacitor, and why?
Yes, the LT3431IFE#TRPBF requires an external BOOST capacitor (charged via a diode from VIN) to provide ~VIN+5V to the BOOST pin (6). This elevated voltage saturates the internal NPN power switch, achieving its specified 0.1Ω on-resistance. Without the BOOST network, switch conduction losses increase significantly, degrading efficiency and thermal performance - especially at high load currents.
Can the LT3431IFE#TRPBF operate without connecting the BIAS pin?
Yes, the LT3431IFE#TRPBF operates fully functional with the BIAS pin (10) left unconnected - internal bias is then drawn from VIN. However, connecting BIAS to the regulated output (≥3V) improves efficiency by sourcing internal circuitry current from VOUT instead of VIN, particularly beneficial when VIN ≫ VOUT (e.g., 48V-to-5V conversion). No external components are needed beyond the connection wire.
How does the FB pin on the LT3431IFE#TRPBF provide short-circuit protection?
The FB pin on the LT3431IFE#TRPBF enables multi-layer short-circuit protection: when FB voltage drops below 0.8V, switching frequency folds back ~5:1 to reduce power dissipation; below 0.6V, peak switch current limit is reduced and SYNC is disabled. These actions - triggered solely by FB voltage - protect the IC, catch diode, and inductor during sustained overload without external circuitry.
Is the exposed thermal pad on the LT3431IFE#TRPBF package required to be soldered to ground?
Yes, the exposed pad on the LT3431IFE#TRPBF's TSSOP-16 package is electrically and thermally connected to GND (pins 1, 8, 9, 16) and must be soldered to a PCB ground plane. This is not optional: failure to do so violates the datasheet's thermal specification (θJA = 45°C/W) and risks thermal shutdown or premature failure under 2A load conditions. Minimum solder coverage and thermal via count are specified in the layout guidelines.
LT3431IFE#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:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3431IFE#TRPBF FAQ
1.How can I place an order for LT3431IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3431IFE#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 LT3431IFE#TRPBF reliable?
The price and inventory of LT3431IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3431IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3431IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3431IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3431IFE#TRPBF?
LT3431IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3431IFE#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 LT3431IFE#TRPBF?
For technical support, including LT3431IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3431IFE#TRPBF requirements.
6.How does Aetrix verify that LT3431IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3431IFE#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 LT3431IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3431IFE#TRPBF?
All LT3431IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3431IFE#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 LT3431IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3431IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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