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Analog Devices Inc. LT3514IFE#PBF
- Part No.:
- LT3514IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3514IFE#PBF.pdf
- Description:
- IC REG BCK ADJ 2A/TRPL 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:116
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Product details
Overview
LT3514IFE#PBF from Analog Devices (formerly Linear Technology) is a triple-output synchronous buck switching regulator IC with 2A/1A/1A output capability, wide 3.2V–36V input range, and integrated boost regulator enabling true 100% duty cycle operation. It features independent soft-start/run pins per channel, programmable switching frequency (350kHz–2.2MHz), and power-good indication - used in automotive battery regulation and industrial distributed power supplies.
For engineers reviewing the LT3514IFE#PBF datasheet, LT3514IFE#PBF pinout, LT3514IFE#PBF application, or LT3514IFE#PBF equivalent, key selection considerations include its 24-lead TSSOP package with exposed pad, –40°C to 125°C operating junction temperature, channel-specific current limits (SW3: 3.5A typ, SW1/SW4: 1.75A typ), and SKY pin voltage regulation at 4.85V above VIN.
Technical Context
The LT3514IFE#PBF integrates three independent buck regulators (CH1: 1A, CH3: 2A, CH4: 1A) sharing a single on-chip boost regulator (CH5) that drives the SKY rail 4.85V above VIN to fully saturate internal bipolar switches. Each channel uses peak-current-mode control with cycle-by-cycle current limiting and catch-diode current sensing for overload robustness.
It supports anti-phase switching between CH3/CH4 and CH1 to reduce input ripple, offers resistor-programmed constant-frequency operation via RT/SYNC, and implements output voltage tracking via RUN/SS pin resistor dividers. Thermal shutdown activates at ~175°C junction temperature, and internal compensation eliminates external compensation components.
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 - supports mixed-voltage system rails (e.g., 1.8V core, 3.3V I/O, 5V peripheral) from single input. |
| Switching Frequency Range | 350kHz to 2.2MHz (programmable via RT resistor or external SYNC signal); allows optimization of size vs. efficiency in space-constrained designs. |
| Feedback Reference Voltage | 800mV ±10mV over temperature; enables precise output programming with standard resistor dividers (e.g., 10.2kΩ R2). |
| Current Limit (SW3) | 3.5A typical (min 3A); supports high-current 3.3V rail for FPGAs or processors without external current-sense amplifiers. |
| Current Limit (SW1/SW4) | 1.75A typical (min 1.45A); sufficient for 1.8V/5V logic rails with margin for transient loads. |
| SKY Voltage Regulation | 4.85V above VIN (±0.15V); ensures full saturation of internal bipolar power switches across full input range for low conduction loss. |
Pinout & Package
LT3514IFE#PBF is housed in a 24-lead plastic TSSOP package with exposed thermal pad (Pin 25 = GND), optimized for thermal performance in industrial and automotive environments. Pin count and layout match LT3504EFE/IFE variants, enabling partial board reuse where CH2 omission is acceptable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 1, 11, 12) | Main input supply connection | Supplies current to internal regulators and power switches; must be locally bypassed and tied together - not split across domains. |
| SW1, SW3, SW4 (Pins 4, 5, 6, 8) | Power switch outputs | Drive external inductors and Schottky diodes; SW3 handles 2A load, SW1/SW4 handle 1A each - routing must support respective current densities. |
| DA1, DA3, DA4 (Pins 3, 7, 9) | Catch diode anode return | Enables internal diode current limiting; connects directly to cathode of external Schottky diode - critical for transient overload protection. |
| FB1, FB3, FB4 (Pins 18, 19, 20) | Output voltage feedback inputs | Each regulated to 800mV; sets output via resistor divider - R2 = 10.2kΩ recommended to minimize bias error. |
| RUN/SS1, RUN/SS3, RUN/SS4 (Pins 13, 14, 15) | Channel enable & soft-start control | Internal 1.3µA current source ramps voltage; capacitor to GND sets startup time; pulling below 0.1V shuts down individual channel. |
| EN/UVLO (Pin 16) | Global enable & input undervoltage lockout | 1.44V rising threshold (110mV hysteresis); disables entire IC below 2.9V VIN - prevents brownout operation in automotive systems. |
| RT/SYNC (Pin 17) | Oscillator programming & synchronization | Accepts resistor-to-GND (e.g., 18.2kΩ = 1MHz) or external clock (350kHz–2.2MHz, >50ns pulse width) - enables multi-rail timing coordination. |
| PG (Pin 21) | Power-good open-collector output | Asserts high when all FB pins exceed 710mV; requires external pull-up; disabled during shutdown - used for system power sequencing. |
| SW5 (Pin 23) | Boost regulator switch output | Drives external inductor to generate SKY voltage; peak current limited to 320mA - must use low-DCR inductor (e.g., 8.2µH @ 1MHz). |
| SKY (Pin 24) | Boost regulator output (drive rail) | 4.85V above VIN; powers internal switch drivers - requires 1µF ceramic capacitor to VIN; no external loading permitted. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent buck regulation | Enables single-chip generation of three isolated DC rails (e.g., 1.8V/3.3V/5V) with independent sequencing and fault management. |
| 100% duty cycle operation | Supported by integrated boost regulator driving SKY rail - allows regulation down to VOUT ≈ VIN, critical for automotive cold-crank scenarios. |
| Anti-phase switching (CH3/CH4 vs CH1) | Reduces input capacitor RMS current and EMI by interleaving switch node transitions - lowers required bulk capacitance by ~30%. |
| Programmable undervoltage lockout | EN/UVLO threshold set by external resistor divider - enables custom start-up voltage (e.g., 6V for 12V battery systems) without additional circuitry. |
| Independent RUN/SS pins per channel | Allows flexible power sequencing (e.g., core before I/O) and individual channel disable for dynamic power management in embedded systems. |
| Internal compensation | Eliminates need for external compensation network - reduces BOM count and layout sensitivity while maintaining stability across load/line variations. |
Applications
| Automotive Battery Regulation | Industrial Control Supplies |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to stable 1.8V, 3.3V, and 5V rails for ADAS ECUs under cold-crank (4.5V) and load-dump (40V) conditions. IC Role / Device Role / Timing Role: Triple buck controller providing sequenced, current-limited, and thermally protected DC-DC conversion with 100% duty cycle support for low-VIN operation. Use Value: Eliminates need for external pre-regulators or discrete UVLO circuits; SKY rail ensures switch saturation even at 4.5V input, maintaining regulation during cranking. |
Use Scenario: Powering PLC I/O modules, sensors, and microcontrollers from unregulated 24V industrial bus with strict ripple and sequencing requirements. IC Role / Device Role / Timing Role: Single-package solution delivering three isolated, tracked, and monitored power rails with programmable startup delay and PG confirmation. Use Value: Reduces board area by 40% vs. three discrete buck ICs; anti-phase switching cuts input ripple by 50%, easing EMI filter design. |
| Wall Transformer Regulation | Distributed Supply Regulation |
Use Scenario: Converting 9–24V AC/DC wall adapter output to clean 3.3V and 5V for IoT gateways, where standby current and thermal performance are critical. IC Role / Device Role / Timing Role: High-efficiency triple regulator with <2µA shutdown current and thermal shutdown - manages heat in enclosed enclosures. Use Value: Quiescent current of 4–10µA in active mode extends battery backup runtime; exposed-pad TSSOP enables >33°C/W thermal resistance for passive cooling. |
Use Scenario: Generating local 1.2V, 2.5V, and 3.3V rails on dense PCBs for FPGA-based edge computing nodes with tight space constraints. IC Role / Device Role / Timing Role: Compact triple-buck IC with 24-pin TSSOP footprint supporting high-density layout and minimal external components (no compensation caps). Use Value: 4.7mm × 7.8mm TSSOP package saves >65% area vs. QFN alternatives; internal compensation removes 3–6 external parts per channel. |
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 |
|---|---|---|---|
| LT3504EFE#PBF | Four 1A channels (CH1–CH4); no CH3 2A capability; identical pinout and package but adds CH2. | Preferred where balanced 1A rails are needed (e.g., quad-core SoC supplies); not suitable when 2A 3.3V rail is mandatory. | Select LT3504EFE#PBF only if fourth 1A rail is required and CH3 2A capability is unnecessary - otherwise LT3514IFE#PBF provides better current density. |
| MP2451DT-LF-Z | Single-channel 0.6A buck; requires three separate ICs plus external sequencing logic; no integrated boost or SKY rail. | Suitable for cost-sensitive, low-current applications (<600mA/rail); lacks 100% duty cycle and automotive-grade temp range. | Choose MP2451DT-LF-Z only for non-automotive, low-power designs where board area and BOM count are secondary to unit cost. |
Compared with LT3504EFE#PBF, LT3514IFE#PBF trades one 1A channel for higher 2A capability on CH3 - optimizing for asymmetric rail needs - while MP2451DT-LF-Z requires three times the IC count, external sequencing, and cannot support 100% duty cycle or automotive temperature range.
Availability
LT3514IFE#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial control supplies, and distributed supply regulation requiring stable component supply, extended temperature operation (–40°C to 125°C), and long-term industrial lifecycle support.
Supply support for LT3514IFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, automotive, and industrial markets.
The LT3514IFE#PBF belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for robust, compact DC-DC conversion in harsh environments where input transients, thermal stress, and sequencing complexity demand integrated protection and control.
FAQ
What is the maximum input voltage rating for LT3514IFE#PBF?
The absolute maximum input voltage for LT3514IFE#PBF is 40V, with continuous operation rated from 3.2V to 36V. Transient tolerance up to 40V is specified, but startup above 36V is discouraged due to instantaneous power dissipation risks. The LT3514IFE#PBF uses internal clamping and thermal shutdown to protect against overvoltage events, ensuring reliability in automotive and industrial applications where load dump or surge conditions occur.
Does LT3514IFE#PBF support 100% duty cycle operation, and how is it implemented?
Yes, LT3514IFE#PBF supports true 100% duty cycle operation via its integrated boost regulator (CH5), which generates the SKY rail at 4.85V above VIN. This elevated drive voltage ensures full saturation of internal bipolar power switches even when VIN approaches VOUT - critical for automotive cold-crank (e.g., 4.5V input regulating 3.3V). The SKY pin requires a 1µF capacitor to VIN and must not be externally loaded, as confirmed in the LT3514IFE#PBF datasheet Section 9.
What are the current limit specifications for each switch in LT3514IFE#PBF?
LT3514IFE#PBF specifies distinct current limits per switch: SW3 (CH3) has a typical limit of 3.5A (min 3A), while SW1 and SW4 (CH1/CH4) have a typical limit of 1.75A (min 1.45A). These values are validated across temperature and process corners. The LT3514IFE#PBF also includes independent catch diode current limiting (2.0A min for SW3, 1.15A min for SW1/SW4) to prevent inductor current runaway during transients - a key differentiator from basic current-mode controllers.
Can LT3514IFE#PBF be synchronized to an external clock, and what are the requirements?
Yes, LT3514IFE#PBF supports external synchronization via the RT/SYNC pin, accepting clock signals from 350kHz to 2.2MHz with minimum pulse width >50ns and amplitude ≥1.5Vpp. The pin is logic-compatible and does not require level-shifting. When synchronizing, the LT3514IFE#PBF automatically disables its internal oscillator - enabling deterministic timing across multiple rails or noise-sensitive systems. No external components are needed beyond the sync source driver.
What is the purpose of the DA pins on LT3514IFE#PBF, and how should they be connected?
The DA1, DA3, and DA4 pins on LT3514IFE#PBF return the anode of the external Schottky catch diode and enable internal catch diode current limiting - a critical protection feature during output short-circuit or heavy transient conditions. Each DA pin must be connected directly to its corresponding diode anode (not to GND or elsewhere). This connection allows the LT3514IFE#PBF to sense diode conduction and disable switching before inductor current becomes destructive, enhancing system robustness without external current-sense resistors.
LT3514IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-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:
- 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:
- 24-TSSOP
LT3514IFE#PBF FAQ
1.How can I place an order for LT3514IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3514IFE#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 LT3514IFE#PBF reliable?
The price and inventory of LT3514IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3514IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3514IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3514IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3514IFE#PBF?
LT3514IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3514IFE#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 LT3514IFE#PBF?
For technical support, including LT3514IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3514IFE#PBF requirements.
6.How does Aetrix verify that LT3514IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3514IFE#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 LT3514IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3514IFE#PBF?
All LT3514IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3514IFE#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 LT3514IFE#PBF part is unused and in its original packaging.
Return procedure for LT3514IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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