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Analog Devices Inc. LT3514IUFD#TRPBF
- Part No.:
- LT3514IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3514IUFD#TRPBF.pdf
- Description:
- IC REG BCK ADJ 2A/1A TRPL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,287
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Product details
Overview
LT3514IUFD#TRPBF from Analog Devices (formerly Linear Technology) is a triple-output synchronous buck switching regulator IC with 2A/1A/1A channel capability, wide 3.2V–36V input range, and integrated boost regulator enabling true 100% duty cycle operation. It features independent soft-start pins, output voltage tracking, programmable switching frequency (350kHz–2.2MHz), and power-good indication - deployed in automotive battery regulation, industrial control supplies, and distributed DC-DC systems.
For engineers reviewing the LT3514IUFD#TRPBF datasheet, LT3514IUFD#TRPBF pinout, LT3514IUFD#TRPBF application, or LT3514IUFD#TRPBF equivalent, key selection criteria include verified 28-pin 4mm × 5mm QFN thermal performance, confirmed 800mV feedback reference, validated catch diode current limiting per channel, and documented anti-phase switching for ripple reduction.
Technical Context
The LT3514IUFD#TRPBF integrates three independent buck regulators (CH1: 1A, CH3: 2A, CH4: 1A) and one dedicated boost regulator (CH5) driving the SKY rail at +4.85V above VIN. Its oscillator supports resistor-programmed or external SYNC operation across 350kHz–2.2MHz, with antiphase clocking between CH3/CH4 and CH5 to minimize input ripple.
Each channel employs cycle-by-cycle peak current limiting and dedicated catch diode current sensing, with thermal shutdown protection and internal compensation. The device uses bipolar power switches driven from the SKY rail, requiring external inductor and capacitor on SW5/SKY for boost functionality - no external bootstrap capacitors needed.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.2V to 36V (40V transient rating); enables direct connection to 12V/24V automotive and industrial rails without pre-regulation. |
| Output Current Capability | CH1: 1A, CH3: 2A, CH4: 1A - verified per-channel switch current limits of 1.75A (CH1/CH4) and 3.5A (CH3) ensure robust overload handling. |
| Feedback Reference Voltage | 790–810mV (±1.25% over temp); enables precise output programming using standard resistor dividers (e.g., R2 = 10.2kΩ). |
| Switching Frequency Range | 350kHz to 2.2MHz via RT resistor or SYNC signal; supports compact magnetics and EMI optimization in space-constrained designs. |
| Package Thermal Resistance | θJA = 43°C/W (28-lead 4mm × 5mm QFN); exposed pad must be soldered to PCB ground plane for safe 125°C junction operation. |
| Power Good Threshold Accuracy | ±90mV offset from FB rising threshold; ensures reliable system sequencing when all outputs reach regulation. |
| Undervoltage Lockout | Programmable EN/UVLO threshold (1.2–1.6V rising) with 110mV hysteresis; prevents erratic startup during brownout conditions. |
Pinout & Package
Tiny 28-lead (4mm × 5mm) thermally enhanced plastic QFN package with exposed GND pad (Pin 29). Requires soldering exposed pad to PCB ground plane with thermal vias for thermal reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 9,11,26,28) | Main input supply rail | Supplies internal LDOs and power switches; must be locally bypassed to GND; multiple pins reduce IR drop and improve current sharing. |
| GND (Pins 10,18,27,29) | Ground reference and thermal path | Exposed pad (Pin 29) is electrically GND and mandatory thermal interface; all GND pins must connect to low-impedance ground plane. |
| SW1/SW3/SW4 (Pins 4,5,7) | Buck switch node outputs | Drive external inductors; SW3 handles 2A load with higher current limit (3.5A typ); each requires Schottky catch diode to DA pin. |
| DA1/DA3/DA4 (Pins 3,6,8) | Catch diode anode return | Internal comparator monitors diode current to prevent inductor runaway during transients; connects directly to cathode of external Schottky diode. |
| RUN/SS1/SS3/SS4 (Pins 12,13,15) | Per-channel enable & soft-start | 1.3µA internal current source charges external capacitor; pulling below 0.1V shuts down individual channel; supports output tracking via resistor divider. |
| EN/UVLO (Pin 16) | Global enable & input UVLO | 1.44V rising threshold with 110mV hysteresis; draws <2µA when pulled below 0.7V; doubles as accurate input undervoltage lockout. |
| RT/SYNC (Pin 17) | Oscillator control | Resistor-to-GND sets frequency (e.g., 18.2kΩ = 1MHz); accepts 350kHz–2.2MHz external clock with >50ns pulse width; logic-compatible input. |
| FB1/FB3/FB4 (Pins 19,20,21) | Output voltage feedback | Regulated to 800mV ±10mV; connects to resistor divider from output; 15nA max bias current minimizes divider error. |
| PG (Pin 23) | Power good open-collector output | Asserts high-Z when all FB pins exceed 710mV; sinks 250µA at 300mV low-level; disabled during shutdown. |
| SW5 (Pin 24) | Boost regulator switch output | Drives external inductor to VIN; generates SKY rail; 320mA switch current limit protects during boost startup and overload. |
| SKY (Pin 25) | Boost output voltage rail | Fixed +4.85V above VIN; powers internal buck gate drivers; requires 1µF ceramic cap to VIN; no external loading permitted. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent buck regulation | CH1 (1A), CH3 (2A), CH4 (1A) with separate RUN/SS, FB, and DA pins - enables flexible multi-rail power sequencing and fault isolation. |
| 100% duty cycle support | Integrated boost regulator (CH5) generates SKY rail at +4.85V above VIN - allows regulation down to VOUT ≈ VIN, critical for automotive cold-crank scenarios. |
| Anti-phase switching | CH3 and CH4 clocks run 180° out-of-phase; reduces input capacitor RMS current and eases EMI filtering requirements in multi-output systems. |
| Programmable frequency & synchronization | 350kHz–2.2MHz operation via single RT resistor or external SYNC signal - supports noise-sensitive applications and clock domain alignment. |
| Robust fault protection | Cycle-by-cycle current limit per switch, catch diode current limit sensing, thermal shutdown, and soft-start current limiting - prevents damage during short-circuit or startup overload. |
| Output voltage tracking & sequencing | Individual RUN/SS pins accept resistor-divider inputs from other outputs - enables controlled ramp-up order (e.g., core before I/O) without external circuitry. |
Applications
| Automotive Battery Regulation | Industrial Control Supplies |
|---|---|
|
Use Scenario: Powering infotainment head units and ADAS ECUs from 12V battery with cold-crank tolerance (down to 3.2V) and load dump immunity (40V transient). IC Role / Device Role / Timing Role: Triple buck regulator providing 1.8V (core), 3.3V (I/O), and 5V (USB/peripherals) rails with independent sequencing and 100% duty cycle during cranking. Use Value: Eliminates need for external pre-regulators; SKY boost ensures stable 3.3V/5V output even at 4.5V battery; PG pin confirms all rails in regulation before MCU boot. |
Use Scenario: Generating isolated 3.3V, 5V, and 12V rails for PLC I/O modules operating from unregulated 24V DC industrial bus. IC Role / Device Role / Timing Role: Single-chip triple-output DC-DC solution replacing discrete buck controllers; RUN/SS pins enable staggered startup to limit inrush current. Use Value: Reduces BOM count by 3× vs. single-channel ICs; anti-phase switching cuts input cap size by ~30%; thermal QFN package sustains 125°C ambient. |
| Wall Transformer Regulation | Distributed Supply Regulation |
|
Use Scenario: Converting 9–24V AC/DC adapter output into clean, low-noise 1.8V, 3.3V, and 5V for embedded networking gear (switches, routers). IC Role / Device Role / Timing Role: High-efficiency triple buck with programmable 1MHz switching - balances size, efficiency, and EMI for compact wall-wart designs. Use Value: Achieves >85% efficiency at full load across input range; RT/SYNC pin allows EMI spread-spectrum tuning; small 4mm × 5mm footprint saves PCB area. |
Use Scenario: Local point-of-load regulation on dense server backplanes where 12V or 48V intermediate bus feeds multiple ASICs and FPGAs. IC Role / Device Role / Timing Role: Compact triple regulator delivering 2A (FPGA core), 1A (memory I/O), and 1A (peripheral) rails with tight tracking for voltage-margin testing. Use Value: Independent FB pins allow fine-tuning each rail; PG pin signals system controller when all voltages are stable; thermal design supports conduction-cooled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3504EUFD#TRPBF | Four 1A channels (no 2A channel); pin-compatible QFN but lacks CH3's 2A capability; identical 3.2V–36V input and SKY architecture. | Suitable only where balanced 1A rails suffice; cannot replace LT3514IUFD#TRPBF in 2A-core applications without redesign. | Select LT3504 if system requires four independent 1A rails and board layout already accommodates its pinout. |
| MPQ4436AGL-AEC1-P | Triple buck (3A/2A/2A), AEC-Q100 Grade 1, 3.3V–36V input; no integrated boost - requires external bootstrap or charge pump for high-side drive. | Designed for automotive under-hood use; lacks 100% duty cycle; needs external components for high-side gate drive at low VIN. | Choose MPQ4436A where AEC-Q100 qualification is mandatory and 100% duty cycle is not required; verify external gate-drive implementation. |
Compared with LT3504EUFD#TRPBF and MPQ4436AGL-AEC1-P, the LT3514IUFD#TRPBF uniquely delivers a 2A channel with integrated boost for true 100% duty cycle - eliminating external gate-drive complexity while maintaining pin compatibility with LT3504 layouts where CH2 is unused.
Availability
LT3514IUFD#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial control supplies, and distributed supply regulation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3514IUFD#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 acquired Linear Technology in 2017 and maintains its high-performance power management portfolio, emphasizing robustness, integration, and precision for demanding analog-intensive applications.
The LT3514IUFD#TRPBF belongs to Linear's monolithic switching regulator family designed for high-reliability industrial and automotive power systems where input transients, thermal stress, and multi-rail sequencing are critical design constraints.
FAQ
What is the maximum input voltage rating for the LT3514IUFD#TRPBF?
The LT3514IUFD#TRPBF has an absolute maximum input voltage rating of 40V, with continuous operation specified from 3.2V to 36V. Transient spikes up to 40V are tolerated, but startup above 36V is discouraged due to instantaneous power dissipation risks that may exceed the 125°C junction limit. The LT3514IUFD#TRPBF internal protection circuits remain active within these limits.
How does the LT3514IUFD#TRPBF achieve 100% duty cycle operation?
The LT3514IUFD#TRPBF achieves 100% duty cycle via its integrated boost regulator (CH5), which generates the SKY rail at +4.85V above VIN. This elevated voltage fully saturates the internal bipolar power switches, allowing the buck regulators to maintain regulation even when VOUT approaches VIN - essential for automotive cold-crank operation. The LT3514IUFD#TRPBF requires an external inductor on SW5 and capacitor on SKY to implement this function.
Can the LT3514IUFD#TRPBF channels be synchronized to an external clock?
Yes, the LT3514IUFD#TRPBF supports external synchronization through the RT/SYNC pin, accepting logic-compatible clock signals from 350kHz to 2.2MHz with minimum pulse width of 50ns. When an external clock is applied, the internal oscillator automatically locks to it - enabling EMI reduction, noise avoidance in sensitive systems, and deterministic timing alignment across multiple LT3514IUFD#TRPBF devices.
What is the purpose of the DA pins on the LT3514IUFD#TRPBF?
The DA (diode anode) pins on the LT3514IUFD#TRPBF provide dedicated return paths for external Schottky catch diodes. An internal comparator continuously monitors diode current through these pins and disables switching if current exceeds the programmed limit - preventing inductor current runaway during load transients or short circuits. This feature enhances reliability beyond standard cycle-by-cycle current limiting.
Does the LT3514IUFD#TRPBF require external compensation components?
No, the LT3514IUFD#TRPBF features internal compensation for all three buck regulators, eliminating the need for external Type II or Type III compensation networks. This simplifies design, reduces component count, and improves stability across operating conditions - confirmed by the "Internal Compensation" feature listed in the official datasheet. Layout best practices for feedback routing still apply to maintain accuracy.
LT3514IUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 3
- Voltage - Input (Min):
- 3.2V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 36V
- Current - Output:
- 2A, 1A
- Frequency - Switching:
- 270kHz ~ 2.1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3514IUFD#TRPBF FAQ
1.How can I place an order for LT3514IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3514IUFD#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 LT3514IUFD#TRPBF reliable?
The price and inventory of LT3514IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3514IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3514IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3514IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3514IUFD#TRPBF?
LT3514IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3514IUFD#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 LT3514IUFD#TRPBF?
For technical support, including LT3514IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3514IUFD#TRPBF requirements.
6.How does Aetrix verify that LT3514IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3514IUFD#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 LT3514IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3514IUFD#TRPBF?
All LT3514IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3514IUFD#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 LT3514IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3514IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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