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Analog Devices Inc. LT8471IUFD#PBF
- Part No.:
- LT8471IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT8471IUFD#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:610
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Product details
Overview
LT8471IUFD#PBF from Analog Devices (formerly Linear Technology) is a dual-channel PWM DC/DC converter IC with two integrated 2A, 50V NPN power switches and one 500mA Skyhook boost switch. It supports independent buck, boost, SEPIC, ZETA, flyback, and inverting topologies per channel, enabling simultaneous positive and negative outputs (e.g., +5V/–5V) from a single 6V–32V input. Designed for local power supply generation in signal chain and industrial embedded systems.
For engineers reviewing the LT8471IUFD#PBF datasheet, LT8471IUFD#PBF pinout, LT8471IUFD#PBF application, or LT8471IUFD#PBF equivalent, key selection considerations include dual-channel topology flexibility, anti-phase switching for reduced input ripple, programmable UVLO/OVLO via OV/UV pin, soft-start control per channel, and compatibility with 28-lead 4mm × 5mm QFN thermal layout requirements.
Technical Context
The LT8471IUFD#PBF implements constant-frequency current-mode control for both primary channels, with channel 2 clock phase shifted ~180° relative to channel 1 to minimize input ripple. Each channel features independent error amplifiers, peak-current sensing, and VC1/VC2 voltage clamping for current limiting.
The integrated Skyhook channel operates as a fixed-frequency voltage-mode boost regulator, delivering regulated output at 4.25V (typ) above C2 - essential for driving high-side NPN switches in buck/ZETA/inverting configurations. Its 500mA switch includes overcurrent protection and loop compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.6V to 50V - supports wide industrial input rails including 6V–32V dual-rail designs |
| Primary Switch Rating | 2A, 50V NPN - enables high-current buck/boost conversion up to 50V differential across C1/E1 or C2/E2 |
| Skyhook Switch Rating | 500mA, 50V NPN - provides boosted gate drive for high-side topologies without external charge pump |
| Switching Frequency Range | 100kHz to 2MHz - adjustable via RT resistor or external SYNC clock; foldback reduces min duty cycle during startup |
| Feedback Reference Voltage | +789mV / –788mV - precise dual-polarity reference enables accurate regulation of both positive and negative outputs |
| Power Good Threshold Accuracy | ±7.5% of target VOUT - open-drain PG1/PG2 assert low when output deviates beyond this window |
| Operating Junction Temp | –40°C to +125°C - rated for extended industrial temperature operation (I-grade) |
Pinout & Package
LT8471IUFD#PBF is housed in a 28-lead (4mm × 5mm) plastic QFN package with exposed thermal pad (Pin 29 = GND). The package provides low θJA = 44°C/W and θJC = 8°C/W for efficient heat dissipation in high-power density layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| C1, C2 (Pins 1, 20) | Primary Channel Collector Outputs | Switch node connections for internal 2A NPN transistors; require minimized trace area to reduce EMI |
| E1, E2 (Pins 2, 19) | Primary Channel Emitter Returns | Emitter terminals for primary switches; must be routed with low-inductance paths to GND |
| C3 (Pin 13) | Skyhook Collector Output | Output node of 500mA Skyhook boost switch; tie to GND if Skyhook disabled |
| SHOUT (Pin 14) | Skyhook Regulated Output | Boosted voltage (4.25V above C2) used to drive high-side NPN bases; requires local bypassing |
| VIN1, VIN2 (Pins 3, 18) | Channel Power Inputs | VIN1 powers Channel 1 + Skyhook + bias circuits; VIN2 powers Channel 2 only; both require ≥2.6V |
| FB1, FB2 (Pins 5, 16) | Output Voltage Feedback Inputs | Accept resistor dividers to set +789mV or –788mV regulated output; bias current <200nA |
| PG1, PG2 (Pins 4, 17) | Open-Drain Power Good Outputs | Assert low when respective VOUT falls >7.5% below target; require external pull-up resistors |
| OV/UV (Pin 6) | Programmable UVLO/OVLO Input | Enables device when voltage ≥1.215V; configurable threshold for input rail monitoring |
| RT (Pin 7) | Oscillator Timing Resistor | Resistor to GND sets free-running frequency (100kHz–2MHz); formula: fOSC = 85.5/(RT+1) MHz |
| SS1, SS2 (Pins 8, 15) | Soft-Start Control Inputs | Capacitors here control ramp rate of duty cycle and current limit during startup (100nF–1μF typical) |
| SYNC (Pin 9) | External Clock Synchronization Input | Accepts 100kHz–2MHz digital clock; high-level ≥1.3V, low-level ≤0.4V; duty cycle 35–65% |
| GND (Pins 10–12, 21–29) | Ground Terminals | Multiple dedicated GND pins plus exposed thermal pad (Pin 29) - all must connect to PCB ground plane |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent multitopology control | Each 2A channel configurable as buck, boost, SEPIC, ZETA, flyback or inverting - eliminates need for multiple controllers in complex power trees |
| Integrated Skyhook boost regulator | 500mA on-chip boost stage generates +4.25V above C2 to enable high-side NPN switching without external components |
| Anti-phase channel synchronization | ~180° phase shift between Channel 1 and Channel 2 clocks reduces input capacitor RMS current and EMI |
| Programmable UVLO/OVLO | Single OV/UV pin supports user-defined undervoltage lockout and overvoltage protection using external resistor divider |
| Per-channel soft-start control | Independent SS1/SS2 pins allow staggered or matched startup sequencing for multi-output systems |
| Thermal shutdown with auto-recovery | Triggers at ~164°C; initiates full soft-start cycle after junction cools to ~162.5°C - protects IC and external magnetics |
Applications
| Dual Rail Signal Chain Power | Buck/Inverting Local Supply |
|---|---|
Use Scenario: Powering precision ADC/DAC, op-amp, and sensor front-ends requiring clean ±5V or ±12V rails from a single 12V or 24V system bus. IC Role / Device Role / Timing Role: LT8471IUFD#PBF acts as dual-output DC/DC controller generating tightly regulated complementary voltages with synchronized switching to suppress common-mode noise. Use Value: Eliminates need for discrete isolated supplies or transformer-based solutions while maintaining <±1% output accuracy and <10mVpp ripple. |
Use Scenario: Generating –5V at 0.65A alongside +5V at 1.5A for mixed-signal FPGA I/O banks and core logic from a 6V–32V automotive or industrial input. IC Role / Device Role / Timing Role: LT8471IUFD#PBF configures Channel 1 as buck and Channel 2 as inverting converter, sharing input filtering and leveraging anti-phase operation. Use Value: Achieves >85% efficiency across load range with single IC, reducing BOM count and PCB area vs. dual-controller approach. |
| High-Side Buck for Wide-Input Systems | SEPIC/ZETA for Battery-Powered Devices |
Use Scenario: Implementing 24V-to-5V buck conversion in railway or factory automation where input may reach 50V transiently and high-side switch configuration is required. IC Role / Device Role / Timing Role: LT8471IUFD#PBF uses Skyhook to generate boosted gate drive for high-side NPN, enabling safe operation up to 60V C–E differential. Use Value: Supports 50V absolute max input rating while maintaining stable regulation - avoids derating or external HV gate drivers. |
Use Scenario: Providing regulated 3.3V output from Li-ion (2.7V–4.2V) or lead-acid (6V–15V) battery sources where input may fall below or rise above output voltage. IC Role / Device Role / Timing Role: LT8471IUFD#PBF configures one channel as SEPIC or ZETA to maintain regulation across full battery discharge curve without topology change. Use Value: Delivers continuous 2A output with <100µs transient response and no mode-switching artifacts - critical for real-time control systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3892EUF#PBF | Two independent 6A synchronous buck controllers; no integrated switches or Skyhook; supports up to 60V VIN | Requires external MOSFETs and gate drivers; better suited for high-current (>2A), high-efficiency synchronous buck-only designs | Select when higher output current, synchronous rectification, or wider VIN range is prioritized over integration and topology flexibility |
| MAX20406ATGB/VY+ | Single 3.5A buck controller with integrated FETs; no second channel or Skyhook; supports 3.0V–20V VIN | Limited to buck-only operation; lacks dual-output capability and negative rail generation | Select for cost-sensitive, space-constrained single-rail applications where dual topology support is unnecessary |
Compared with LTC3892EUF#PBF and MAX20406ATGB/VY+, the LT8471IUFD#PBF uniquely integrates dual 2A switches, Skyhook boost, and full multitopology support in one QFN package - making it optimal for compact, flexible local power where mixed positive/negative or buck/invert outputs are required without external FETs.
Availability
LT8471IUFD#PBF is available at Aetrix Electronics and suitable for industrial automation, test equipment, and medical imaging systems requiring stable component supply, long-term lifecycle assurance, and qualified sourcing for production programs.
Supply support for LT8471IUFD#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 product support, documentation, and manufacturing continuity for the LT® series. Linear's legacy expertise in precision analog and power management remains integral to ADI's high-performance power portfolio.
The LT8471IUFD#PBF belongs to Linear's multitopology DC/DC controller family, designed specifically for space-constrained, high-flexibility local power generation in signal chain, instrumentation, and industrial embedded systems where dual independent outputs and topology adaptability are critical.
FAQ
What topologies can each channel of the LT8471IUFD#PBF support?
Each primary channel of the LT8471IUFD#PBF supports buck, boost, SEPIC, ZETA, flyback, and inverting DC/DC configurations independently. The Skyhook channel is a fixed-voltage boost stage used to generate gate drive for high-side NPN switches in buck/ZETA/inverting modes. No external controller logic is needed to reconfigure topology - only passive component changes on the PCB.
Does the LT8471IUFD#PBF require external MOSFETs or diodes?
No - the LT8471IUFD#PBF integrates two 2A, 50V NPN power switches (for primary channels) and one 500mA NPN Skyhook switch, plus an on-chip Schottky diode for the Skyhook path. External components required are inductors, output capacitors, feedback resistors, soft-start capacitors, and optional input/output filtering - no external active switches or rectifiers are needed for basic operation.
How does the Skyhook channel function in the LT8471IUFD#PBF?
The Skyhook channel in the LT8471IUFD#PBF is an integrated 500mA boost regulator that delivers a regulated voltage 4.25V (typ) above the C2 pin. It supplies boosted base drive to high-side NPN switches in buck, ZETA, or single-inductor inverting topologies. When not needed, C3 is tied to GND to disable Skyhook and reduce quiescent current from VIN1.
What is the purpose of the OV/UV pin on the LT8471IUFD#PBF?
The OV/UV pin on the LT8471IUFD#PBF serves dual functions: applying ≥1.215V enables the device, while grounding it forces shutdown. With an external resistor divider from VIN to GND, it provides programmable undervoltage lockout (UVLO) and overvoltage lockout (OVLO) thresholds - critical for protecting downstream circuitry in industrial and automotive environments.
Can the LT8471IUFD#PBF generate both positive and negative outputs simultaneously?
Yes - the LT8471IUFD#PBF can generate simultaneous positive and negative outputs (e.g., +5V and –5V) from a single input rail. Channel 1 can be configured as a buck converter for the positive rail, while Channel 2 operates as an inverting converter for the negative rail. Its dual feedback references (+789mV and –788mV) and independent soft-start ensure stable, coordinated regulation of both polarities.
LT8471IUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Flyback, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 50V
- Voltage - Output (Min/Fixed):
- 2.6V
- Voltage - Output (Max):
- 50V (Switch)
- Current - Output:
- 1.35A (Switch), 2.1A (Switch)
- Frequency - Switching:
- 100kHz ~ 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT8471IUFD#PBF FAQ
1.How can I place an order for LT8471IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8471IUFD#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 LT8471IUFD#PBF reliable?
The price and inventory of LT8471IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8471IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LT8471IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8471IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8471IUFD#PBF?
LT8471IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8471IUFD#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 LT8471IUFD#PBF?
For technical support, including LT8471IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8471IUFD#PBF requirements.
6.How does Aetrix verify that LT8471IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LT8471IUFD#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 LT8471IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LT8471IUFD#PBF?
All LT8471IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8471IUFD#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 LT8471IUFD#PBF part is unused and in its original packaging.
Return procedure for LT8471IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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