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Analog Devices Inc. LT8471IUFD#TRPBF
- Part No.:
- LT8471IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT8471IUFD#TRPBF.pdf
- Description:
- IC REG BUCK BOOST ADJ DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,276
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Product details
Overview
LT8471IUFD#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel, multitopology PWM DC/DC controller IC with two integrated 2A/50V NPN switches and one 500mA Skyhook boost switch. It supports independent buck, boost, SEPIC, ZETA, flyback, and inverting configurations per channel, delivers ±5V outputs from a 6–32V input, and operates across –40°C to +125°C. Used in precision signal-chain dual-rail power supplies requiring tight regulation and low noise.
For engineers reviewing the LT8471IUFD#TRPBF datasheet, LT8471IUFD#TRPBF pinout, LT8471IUFD#TRPBF application, or LT8471IUFD#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed switching frequency range (100kHz–2MHz), Skyhook voltage regulation (4.25V typical), and real-world dual-rail design constraints including anti-phase operation and thermal shutdown behavior.
Technical Context
The LT8471IUFD#TRPBF implements constant-frequency current-mode control for both primary channels, with channel 2 clock phase shifted ~180° relative to channel 1 to reduce input ripple. Each channel features independent soft-start (SS1/SS2), programmable UVLO/OVLO via OV/UV pin, and open-drain power-good outputs (PG1/PG2) with ±7.5% trip thresholds referenced to FB voltage.
Skyhook operation is voltage-mode controlled, regulating SHOUT to 4.25V above C2 when enabled; it supplies boosted base drive for high-side NPN switches in buck/ZETA/inverting topologies. The internal oscillator supports free-running (RT-set) or external synchronization (SYNC pin), with foldback frequency reduction (1/2, 1/4, or 1/8) during startup under light-load or fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.6V to 50V on VIN1/VIN2 - supports wide industrial input rails and enables high-side switch biasing via Skyhook |
| Primary Switch Rating | 2A, 50V NPN - sufficient for ≥1.5A continuous output in buck/boost with margin for peak currents |
| Skyhook Switch Rating | 500mA, 50V NPN - delivers regulated 4.25V boost above C2 to enable high-side NPN base drive |
| Switching Frequency Range | 100kHz to 2MHz - adjustable via RT resistor or external SYNC clock; enables EMI optimization and compact magnetics |
| Feedback Reference Voltage | +789mV / –788mV - precise dual-polarity reference enables accurate ±5V regulation with standard resistor dividers |
| Power Good Threshold | ±7.5% of target VOUT - ensures reliable system sequencing by asserting PG only when output is within spec |
| Operating Temperature | –40°C to +125°C - qualified for automotive under-hood and industrial embedded environments |
Pinout & Package
LT8471IUFD#TRPBF is housed in a 28-lead (4mm × 5mm) plastic QFN package with exposed thermal pad (Pin 29 = GND). All GND pins (Pins 10, 11, 12, 22, 23, 24, 25, 26, 27, 28, 29) must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| C1, C2 (Pins 1, 20) | Primary channel collector terminals | Switch node connections for buck/boost/SEPIC/flyback; require minimized trace area to suppress EMI |
| E1, E2 (Pins 2, 19) | Primary channel emitter terminals | Return paths for NPN switches; tied to ground in low-side configs or float in high-side topologies |
| FB1, FB2 (Pins 5, 16) | Output voltage feedback inputs | Accept resistor divider to set positive (+789mV ref) or negative (–788mV ref) output voltages |
| SHOUT (Pin 14) | Skyhook regulator output | Fixed 4.25V boost above C2; supplies base drive for high-side NPNs in buck/ZETA/inverting modes |
| SYNC (Pin 9) | External clock input | Accepts 100kHz–2MHz digital clock; drives internal oscillator when >1.3V high, reverts to RT mode when <0.4V |
| SS1, SS2 (Pins 8, 15) | Soft-start control inputs | Charge external capacitors to ~2.15V; ramp rate sets startup current slew and duty cycle rise time |
| OV/UV (Pin 6) | Programmable UVLO/OVLO input | Enables device at >1.215V; configurable threshold for input rail monitoring and system-level protection |
| PG1, PG2 (Pins 4, 17) | Open-drain power-good outputs | Pull low when respective VOUT falls >7.5% below target; require external pull-up resistors for logic-level signaling |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent multitopology control | Each channel configurable as buck, boost, SEPIC, ZETA, flyback, or inverting - eliminates need for multiple controllers in dual-rail systems |
| Anti-phase switching | ~180° phase shift between channels reduces input capacitor RMS current and input ripple by up to 70% |
| Integrated Skyhook boost | On-chip 500mA NPN + Schottky diode generates 4.25V above C2 - enables high-side NPN operation without external charge pump |
| Frequency foldback during startup | Reduces fSW to 1/2, 1/4, or 1/8 of nominal to extend minimum on-time and improve current control at low VOUT |
| Thermal shutdown with hysteresis | Activates at ~164°C; resets at ~162.5°C - protects internal switches and external components during overload or poor heatsinking |
Applications
| Industrial Dual-Rail Signal Chain | Automotive Infotainment Power |
|---|---|
Use Scenario: Generating ±5V rails for high-resolution ADCs, DACs, and op-amps in PLC I/O modules. IC Role / Device Role / Timing Role: Dual-channel DC/DC controller providing isolated, low-noise, tightly regulated analog supply rails with coordinated soft-start. Use Value: Eliminates cross-regulation between rails and reduces input ripple via anti-phase switching, improving SNR by >3dB in 16-bit data acquisition systems. |
Use Scenario: Powering audio codecs and display drivers in head-unit systems with 6–32V battery input. IC Role / Device Role / Timing Role: Multitopology controller delivering +5V for digital logic and –5V for analog bias, with programmable UVLO for cold-crank robustness. Use Value: Skyhook enables stable high-side buck operation down to 6V input, maintaining regulation during engine start without external boost stages. |
| Medical Sensor Front-End | Test Equipment Dual Polarity Supply |
Use Scenario: Biasing low-noise instrumentation amplifiers and transimpedance stages in portable ECG monitors. IC Role / Device Role / Timing Role: Precision dual-output controller with matched feedback references (±789mV/±788mV) and independent PG flags for safety-critical sequencing. Use Value: Tight reference matching (<0.2% offset) ensures symmetrical rail tracking, reducing common-mode error in differential sensor interfaces. |
Use Scenario: Providing programmable ±12V/±15V outputs in benchtop power supplies and automated test equipment. IC Role / Device Role / Timing Role: Flexible topology engine supporting SEPIC for wide-input-range positive rails and inverting for negative rails from single input. Use Value: Independent channel configuration allows simultaneous generation of asymmetric rails (e.g., +12V @ 1A, –5V @ 0.65A) without efficiency penalty. |
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 |
|---|---|---|---|
| LTC3892-2 | Two synchronous buck controllers (no inverting/Skyhook); supports MOSFETs up to 60V; requires external FETs and gate drivers | Optimized for high-efficiency, high-current buck-only designs; lacks native negative rail generation capability | Select when efficiency >92% and >3A per rail are required; not suitable for inverting or dual-polarity applications without added circuitry |
| MAX20406 | Single-channel 3.5A buck controller with integrated MOSFETs; no secondary channel or Skyhook; supports 2.5V–28V input | Targeted at space-constrained single-rail systems; cannot generate negative outputs or support dual independent topologies | Choose for cost-sensitive, single-output applications where footprint and BOM count are prioritized over flexibility |
Compared with LTC3892-2 and MAX20406, the LT8471IUFD#TRPBF uniquely integrates dual NPN switches, Skyhook boost, and native inverting capability in one QFN package - enabling true dual-polarity, multitopology power conversion without external switches or auxiliary regulators.
Availability
LT8471IUFD#TRPBF is available at Aetrix Electronics and suitable for industrial automation, automotive infotainment, and medical sensor front-end designs requiring stable component supply, extended temperature operation, and dual-rail power architecture flexibility.
Supply support for LT8471IUFD#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 full product support, documentation, and manufacturing continuity for the LT® series.
The LT8471 belongs to Linear's high-voltage multitopology controller family, designed specifically for local dual-rail power generation in signal-chain, test equipment, and industrial systems where flexibility, precision, and thermal robustness are critical.
FAQ
What topologies does the LT8471IUFD#TRPBF support per channel?
The LT8471IUFD#TRPBF supports buck, boost, SEPIC, ZETA, flyback, and inverting configurations independently on each primary channel. Its integrated Skyhook boost channel enables high-side NPN operation in buck/ZETA/inverting modes without external components. The LT8471IUFD#TRPBF does not support synchronous rectification or LLC resonant topologies.
How is the switching frequency set on the LT8471IUFD#TRPBF?
The LT8471IUFD#TRPBF switching frequency is set either by an external resistor from RT (Pin 7) to GND, yielding 100kHz–2MHz based on fOSC = 85.5/(RT + 1), or by driving the SYNC (Pin 9) pin with an external clock between 100kHz and 2MHz. The LT8471IUFD#TRPBF reverts to RT mode when SYNC is held below 0.4V for several cycles.
What is the purpose of the SHOUT pin on the LT8471IUFD#TRPBF?
The SHOUT (Pin 14) is the output of the integrated Skyhook boost regulator, delivering a fixed 4.25V (typical) above the C2 pin voltage. It supplies boosted base drive for high-side NPN switches in buck, ZETA, or single-inductor inverting topologies. When unused, C3 must be tied to GND to disable Skyhook and reduce quiescent current in the LT8471IUFD#TRPBF.
Does the LT8471IUFD#TRPBF provide power-good status for both channels?
Yes - the LT8471IUFD#TRPBF provides independent open-drain power-good outputs PG1 (Pin 4) and PG2 (Pin 17). Each asserts low when its respective output voltage deviates more than ±7.5% from the target set by the FB1/FB2 resistor divider. Both PG pins require external pull-up resistors and are only valid when VIN1 > 2.6V and the corresponding channel is enabled.
What package and thermal characteristics apply to the LT8471IUFD#TRPBF?
The LT8471IUFD#TRPBF uses a 28-lead 4mm × 5mm QFN package with exposed thermal pad (Pin 29 = GND). Its thermal resistance is θJA = 44°C/W and θJC = 8°C/W. The exposed pad must be soldered to a solid PCB ground plane for effective heat dissipation and electrical stability - failure to do so risks thermal shutdown or parameter drift in the LT8471IUFD#TRPBF.
LT8471IUFD#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-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#TRPBF FAQ
1.How can I place an order for LT8471IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8471IUFD#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 LT8471IUFD#TRPBF reliable?
The price and inventory of LT8471IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8471IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8471IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8471IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8471IUFD#TRPBF?
LT8471IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8471IUFD#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 LT8471IUFD#TRPBF?
For technical support, including LT8471IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8471IUFD#TRPBF requirements.
6.How does Aetrix verify that LT8471IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8471IUFD#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 LT8471IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8471IUFD#TRPBF?
All LT8471IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8471IUFD#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 LT8471IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT8471IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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