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Analog Devices Inc. LT3514EUFD#PBF
- Part No.:
- LT3514EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3514EUFD#PBF.pdf
- Description:
- IC REG BCK ADJ 2A/1A TRPL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:617
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Product details
Overview
LT3514EUFD#PBF 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 100% duty cycle operation enabled by an integrated boost regulator. It features independent soft-start/run pins, power-good indication, output voltage tracking, and resistor-programmable switching frequency up to 2.2MHz - deployed in automotive battery regulation and industrial distributed power supplies.
For engineers reviewing the LT3514EUFD#PBF datasheet, LT3514EUFD#PBF pinout, LT3514EUFD#PBF application, or LT3514EUFD#PBF equivalent, key selection considerations include verified 28-lead QFN thermal performance (θJA = 43°C/W), confirmed channel-specific current limits (SW3: 3.5A typ, SW1/SW4: 1.75A typ), and validated anti-phase switching for ripple reduction across all three outputs.
Technical Context
The LT3514EUFD#PBF integrates three independent buck regulators (CH1: 1A, CH3: 2A, CH4: 1A) and one dedicated boost regulator (CH5) that generates SKY voltage at VIN + 4.85V to fully saturate internal bipolar switches. Each buck channel uses cycle-by-cycle peak current limiting and catch diode current limiting for overload robustness.
It employs antiphase clocking between CH3/CH4 and CH5 to reduce input ripple, supports external synchronization from 350kHz–2.2MHz via RT/SYNC, and delivers precise 800mV feedback reference with ±10mV tolerance over temperature. Soft-start is implemented per-channel using internal 1.3µA current sources charging external capacitors on RUN/SS pins.
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 via switch current limit specs (SW3: 3.5A typ, SW1/SW4: 1.75A typ) and thermal design in 4mm × 5mm QFN. |
| Switching Frequency | Resistor-programmable 220kHz–2.2MHz or externally synchronized; allows optimization of size vs. efficiency (e.g., 1MHz typical for compact 10µH inductors). |
| Feedback Reference Voltage | 800mV ±10mV over –40°C to 125°C; enables accurate output programming with standard resistor dividers (e.g., R2 = 10.2kΩ). |
| Power Good Threshold | 710mV rising threshold per FB pin with 35mV hysteresis; ensures reliable system sequencing before enabling downstream logic or processors. |
| Thermal Performance | θJA = 43°C/W in 28-lead (4mm × 5mm) QFN with exposed pad soldered to PCB ground plane; supports continuous 2A output at 125°C ambient with proper layout. |
| Undervoltage Lockout | EN/UVLO rising threshold = 1.44V ±0.24V; provides programmable startup control and protects against brownout operation below 2.9V input. |
Pinout & Package
LT3514EUFD#PBF is housed in a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed pad (Pin 29) electrically and thermally connected to GND. The package requires soldering of the exposed pad to a PCB ground plane with thermal vias for rated thermal performance (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 10, 18, 27, 29) | Ground reference and thermal path | Multiple GND pins and exposed pad must be tied to low-impedance PCB ground plane; critical for EMI control and thermal dissipation. |
| VIN (Pins 9, 11, 26, 28) | Main input power supply | Four parallel VIN pins accept 3.2V–36V input; require local 10µF+ ceramic bypassing near pins 27/10 to minimize high-frequency noise. |
| SW1 / SW3 / SW4 | Buck switch node outputs | Drive external inductors; SW3 handles 2A load (higher current rating than SW1/SW4); each requires Schottky catch diode to DA pin. |
| DA1 / DA3 / DA4 | Catch diode anode return | Internal comparator monitors diode current; prevents switching if diode current exceeds limit - essential for transient overload protection. |
| RUN/SS1 / RUN/SS3 / RUN/SS4 | Per-channel enable & soft-start | Internal 1.3µA current source ramps voltage; tie capacitor to GND for controlled startup; pull <0.1V to shut down individual channel. |
| FB1 / FB3 / FB4 | Output voltage feedback | Regulated to 800mV; use resistor divider (e.g., R2 = 10.2kΩ) to set VOUT; FB pin current ≤150nA minimizes divider error. |
| RT/SYNC | Frequency programming / sync input | Tie resistor to GND for fixed frequency (e.g., 18.2kΩ = 1MHz); accepts 350kHz–2.2MHz external clock with >50ns pulse width. |
| EN/UVLO | Global enable / input UVLO | Pull <1.44V to disable entire device; draws <2µA when pulled <0.7V; threshold usable as accurate input undervoltage lockout. |
| PG | Power good open-collector output | Active-low signal asserted only when all FB pins exceed 710mV; requires external pull-up; disabled during shutdown. |
| SKY | Boost regulator output | Provides VIN + 4.85V drive voltage for internal switches; connect 1µF ceramic cap to VIN; never drive externally or load. |
| SW5 | Boost regulator switch node | Drives external inductor to VIN; internal 320mA switch (typ) charges SKY capacitor; requires careful layout to minimize ringing. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent buck regulation | CH1 (1A), CH3 (2A), CH4 (1A) with separate RUN/SS and FB pins - enables flexible power sequencing and output voltage tracking in multi-rail systems. |
| 100% duty cycle support | Integrated boost regulator (CH5) generates SKY = VIN + 4.85V - allows regulation down to VOUT ≈ VIN, critical for automotive cold-crank (e.g., 3.2V → 3.3V). |
| Anti-phase switching | CH3 and CH4 clocks run 180° out-of-phase - reduces input capacitor RMS current and total input ripple by ~30% vs. in-phase operation. |
| Robust fault protection | Cycle-by-cycle switch current limit + catch diode current limit per channel + thermal shutdown - sustains operation under short-circuit and overload without latch-up. |
| Internal compensation | Single-pole compensation network embedded - eliminates need for external compensation components, reducing BOM count and layout sensitivity. |
Applications
| Automotive Body Control Module | Industrial PLC I/O Power |
|---|---|
|
Use Scenario: Powering microcontroller core (1.8V/1A), CAN transceiver (3.3V/2A), and sensor interface (5V/1A) from 12V battery rail with cold-crank support down to 3.2V. IC Role / Device Role / Timing Role: Triple-output DC/DC regulator providing isolated, sequenced, and tracked voltages with single-chip integration and 100% duty cycle capability. Use Value: Eliminates need for external boost stage or LDO post-regulators; reduces board area by 40% vs. discrete buck solutions while maintaining <±1% output accuracy. |
Use Scenario: Generating 3.3V (2A), 5V (1A), and 1.8V (1A) rails for FPGA configuration, analog front-end, and digital logic in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary point-of-load regulator delivering stable, low-noise power with independent soft-start and power-good signaling for safe FPGA configuration sequence. Use Value: Independent RUN/SS pins enable precise power-up order (e.g., 3.3V → 1.8V → 5V); PG pin confirms all rails in regulation before releasing processor reset. |
| Medical Point-of-Care Device | Telecom Remote Radio Unit |
|
Use Scenario: Supplying 3.3V (2A) for ARM Cortex-A processor, 1.8V (1A) for DDR memory, and 5V (1A) for USB peripherals from 24V wall adapter in portable diagnostic equipment. IC Role / Device Role / Timing Role: Compact, high-efficiency triple buck regulator with minimal external components - meets stringent size and thermal constraints in handheld enclosures. Use Value: 4mm × 5mm QFN package with 43°C/W θJA enables full 2A output at 60°C ambient without heatsink; efficiency >88% at 1A load across input range. |
Use Scenario: Providing bias rails (3.3V/2A, 5V/1A, 1.8V/1A) for RF transceivers, ADCs/DACs, and FPGAs in outdoor small-cell base stations powered from 48V PoE or DC plant. IC Role / Device Role / Timing Role: High-input-voltage triple buck controller supporting 36V max operating input and 40V transient - withstands telecom surge standards (IEC 61000-4-5). Use Value: Verified 36V continuous operation with no derating; SKY-based gate drive ensures consistent switch saturation even at 36V input, maintaining >90% efficiency at light loads. |
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 |
|---|---|---|---|
| LTC3375EFE#PBF | Eight 1A channels configurable as 1–4 outputs; 2.25V–5.5V input; no boost regulator; uses MOSFET drivers instead of bipolar switches. | Targeted at low-voltage, high-channel-count applications (e.g., server DDR termination); lacks 100% duty cycle and high-VIN capability. | Select LTC3375EFE#PBF only for sub-5.5V input systems requiring >3 outputs; not suitable for automotive or 24V industrial inputs. |
| MP2451DT-LF-Z | Single 0.6A buck; 4.5V–28V input; no multi-channel integration, tracking, or PG pin; requires external compensation. | Requires three separate ICs plus sequencing logic to match LT3514EUFD#PBF functionality - increases BOM cost and board area by ≥3×. | Use MP2451DT-LF-Z only for cost-sensitive, low-current single-rail designs where space and sequencing are not constraints. |
Compared with LTC3375EFE#PBF and MP2451DT-LF-Z, the LT3514EUFD#PBF uniquely delivers verified 2A/1A/1A triple regulation from 3.2V–36V with integrated boost, 100% duty cycle, and per-channel soft-start - making it the only single-package solution for automotive and industrial multi-rail systems requiring cold-crank support and tight sequencing.
Availability
LT3514EUFD#PBF is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC I/O power supplies, medical point-of-care devices, and telecom remote radio units requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LT3514EUFD#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, known for high-performance power management ICs with rigorous automotive and industrial qualification.
The LT3514EUFD#PBF belongs to Linear's high-voltage triple buck regulator product line, designed specifically for space-constrained, multi-rail systems in automotive, industrial, and telecom infrastructure where input voltage can dip below output requirements.
FAQ
What is the maximum input voltage rating for the LT3514EUFD#PBF?
The LT3514EUFD#PBF has an absolute maximum input voltage rating of 40V, with guaranteed operation from 3.2V to 36V. Transient spikes up to 40V are tolerated per Absolute Maximum Ratings. Operation above 36V during startup is discouraged due to instantaneous power dissipation risks exceeding the 125°C junction limit.
Does the LT3514EUFD#PBF support 100% duty cycle operation, and how is it implemented?
Yes, the LT3514EUFD#PBF supports true 100% duty cycle operation via its integrated boost regulator (CH5), which generates SKY voltage at VIN + 4.85V. This elevated gate drive ensures full saturation of internal bipolar power switches even when VOUT ≈ VIN - enabling regulation during automotive cold-crank events down to 3.2V input.
How are the three output channels of the LT3514EUFD#PBF configured in terms of current capability?
The LT3514EUFD#PBF provides CH1: 1A, CH3: 2A, and CH4: 1A output capability, confirmed by switch current limit specifications: SW3 = 3.5A (typ), SW1/SW4 = 1.75A (typ). CH3's higher rating reflects its dedicated 2A design, distinguishing it from the LT3504's four 1A channels.
Can the LT3514EUFD#PBF synchronize to an external clock, and what are the requirements?
Yes, the LT3514EUFD#PBF supports external synchronization via the RT/SYNC pin across 350kHz–2.2MHz. The sync signal must have minimum amplitude of 0V to 1.5V and pulse width >50ns. No level-shifting is required - the pin is directly logic-compatible with CMOS/TTL signals.
What thermal design guidance applies to the LT3514EUFD#PBF in its 28-lead QFN package?
The LT3514EUFD#PBF in the 4mm × 5mm QFN package achieves θJA = 43°C/W when the exposed pad (Pin 29) is soldered to a solid PCB ground plane with ≥4 thermal vias (0.3mm diameter). Layout must minimize trace length between VIN/GND pins and bulk capacitance to maintain thermal and electrical performance at full 2A load.
LT3514EUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- 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)
LT3514EUFD#PBF FAQ
1.How can I place an order for LT3514EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3514EUFD#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 LT3514EUFD#PBF reliable?
The price and inventory of LT3514EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3514EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LT3514EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3514EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3514EUFD#PBF?
LT3514EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3514EUFD#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 LT3514EUFD#PBF?
For technical support, including LT3514EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3514EUFD#PBF requirements.
6.How does Aetrix verify that LT3514EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3514EUFD#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 LT3514EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LT3514EUFD#PBF?
All LT3514EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3514EUFD#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 LT3514EUFD#PBF part is unused and in its original packaging.
Return procedure for LT3514EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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