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Analog Devices Inc. LT1171HVIT#PBF
- Part No.:
- LT1171HVIT#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-220-5
- Datasheet:
-
LT1171HVIT#PBF.pdf
- Description:
- IC REG BUCK BST ADJ 2.5A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,553
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Product details
Overview
LT1171HVIT#PBF from Analog Devices (formerly Linear Technology) is a monolithic high-efficiency 2.5A switching regulator IC with integrated 75V breakdown switch, operating from 3V to 60V input and delivering up to 100W output power in buck/boost/flyback topologies. It features current-mode control, 100kHz fixed-frequency operation, 6mA quiescent current, and shutdown mode drawing only 50µA - used in industrial DC-DC conversion, battery upconverters, and isolated flyback supplies.
For engineers reviewing the LT1171HVIT#PBF datasheet, LT1171HVIT#PBF pinout, LT1171HVIT#PBF application, or LT1171HVIT#PBF equivalent, key selection criteria include its HV-grade 75V switch rating, TO-220-5 package thermal performance (θJA = 75°C/W), flyback-regulated floating output capability, and adaptive anti-saturation drive for wide load-current efficiency retention.
Technical Context
The LT1171HVIT#PBF implements current-mode switching control: the internal oscillator initiates each cycle, and the 2.5A switch turns off when sensed current reaches a level set by the error amplifier's VC pin voltage. This architecture delivers fast line transient response and simplifies loop compensation across varying input and load conditions.
It supports multiple topologies via external component configuration - including flyback with fully floating outputs - and includes dedicated circuitry for flyback blanking (1.5µs delay) and dual error amplifiers (normal mode: 1.24V reference; flyback mode: 15.0V reference). The HV variant maintains 75V switch breakdown and 60V absolute max supply voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Rating | 2.5A continuous - sets maximum deliverable output power in non-flyback topologies (e.g., 30W at 12V out from 5V in). |
| Switch Breakdown Voltage | 75V - enables safe operation with ≥60V input rails and robust isolation in flyback designs up to 55V input. |
| Input Voltage Range | 3V to 60V - supports wide-range industrial, automotive, and battery-powered systems without external pre-regulation. |
| Quiescent Supply Current | 6mA - minimizes no-load power loss in always-on applications such as remote sensors or standby power supplies. |
| Shutdown Current | 50µA typical - allows ultra-low-power sleep modes in portable or energy-harvesting systems. |
| Switching Frequency | 100kHz nominal - balances EMI, inductor size, and efficiency; externally synchronizable to 120–160kHz for noise reduction. |
| Reference Voltage | 1.244V (typ) at FB pin - defines output regulation accuracy in buck/boost; enables precise feedback divider design (e.g., 5V out = R1/R2 = 3.02). |
| Flyback Reference | 15.0V (typ) - used when FB pin is pulled low; regulates transformer-coupled outputs without direct input-output connection. |
Pinout & Package
LT1171HVIT#PBF is housed in a 5-lead plastic TO-220 package (T package) with tab connected to GND. Thermal resistance is θJA = 75°C/W, enabling operation up to 100°C ambient without heatsink in moderate-power applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Primary supply rail (3–60V); connects to input capacitor and inductor feed point. |
| VSW | Switch Output | Drains internal 2.5A/75V N-channel switch; connects to inductor (buck/boost) or transformer primary (flyback). |
| GND | Ground Reference | Power and signal ground; tab is internally tied to this pin - must be soldered to PCB copper for thermal conduction. |
| FB | Feedback Input | Senses output voltage divider; <100mV triggers flyback mode; 1.244V target for standard regulation. |
| VC | Error Amplifier Output | Controls switch current limit and duty cycle; clamping between 1V–2V adjusts peak current from 0–2.5A. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 2.5A/75V Switch | Eliminates external MOSFET and driver, reducing BOM count and layout complexity in medium-power SMPS. |
| Flyback-Regulated Mode | Enables fully floating, transformer-isolated outputs with no optocoupler required - ideal for medical or safety-isolated supplies. |
| Adaptive Anti-Saturation Drive | Maintains high efficiency across 10:1 load range by dynamically adjusting gate drive to prevent switch saturation losses. |
| External Shutdown Control | VC pin pulled below 0.15V disables switching and reduces supply current to 50µA - supports system-level power sequencing. |
| Current-Mode Control | Provides inherent cycle-by-cycle current limiting and stable operation with minimal compensation components (single-pole RC on VC). |
| Wide Input Range (3–60V) | Supports direct connection to 12V/24V/48V industrial buses and unregulated battery inputs without pre-conversion stages. |
Applications
| Industrial DC-DC Conversion | Battery-Powered Upconverter |
|---|---|
Use Scenario: Converting 24V factory bus to regulated 5V/3.3V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary switching controller in synchronous buck topology, managing power delivery and thermal stability under variable load. Use Value: Delivers 2.5A at >88% efficiency with only 6mA quiescent draw - extends uptime in fanless enclosures and reduces cooling requirements. | Use Scenario: Boosting single-cell Li-ion (3.0–4.2V) to 12V for portable instrumentation or wireless transceivers. IC Role / Device Role / Timing Role: High-efficiency boost converter core with adaptive drive, maintaining regulation across full battery discharge curve. Use Value: 2.5A switch and 100kHz frequency enable compact inductor (≤10µH) and low-profile ceramic capacitors - critical for handheld form factors. |
| Flyback Isolated Power Supply | High-Voltage Logic Supply |
Use Scenario: Generating ±15V op-amp rails and 5V logic from 24V input in test equipment requiring galvanic isolation. IC Role / Device Role / Timing Role: Flyback controller regulating secondary windings via primary-side sensing - eliminates optocoupler and TL431. Use Value: 15.0V flyback reference and 1.5µs blanking time ensure tight output regulation (<±3%) despite transformer leakage variation. | Use Scenario: Providing 5V @ 10A logic supply for FPGA or microcontroller subsystems in telecom base stations. IC Role / Device Role / Timing Role: High-current buck regulator with TO-220 thermal interface, handling pulsed loads up to 10A peak. Use Value: 75V switch rating and 2.5A continuous rating support robust operation during 48V surge events - meets IEC 61000-4-5 Level 4 immunity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EMSE#PBF | 40V max input, 10A output, requires external MOSFETs, supports synchronous rectification. | Higher current, lower input voltage range; suited for high-efficiency 12V/48V intermediate bus converters. | Select when >5A output or >90% efficiency at light load is required; not drop-in due to external FET requirement. |
| LM5088MHX/NOPB | 60V max input, 5A switch, 1MHz switching, no integrated flyback mode or 15V reference. | Higher frequency enables smaller magnetics; lacks flyback regulation - requires optocoupler for isolation. | Choose for cost-sensitive, non-isolated 60V-input applications where board space is constrained and isolation is unnecessary. |
Compared with LTC3891EMSE#PBF and LM5088MHX/NOPB, the LT1171HVIT#PBF uniquely combines HV-rated integration (75V switch + flyback reference), TO-220 thermal simplicity, and self-protected operation - making it optimal for ruggedized, medium-power isolated or wide-input industrial supplies where BOM count and reliability are prioritized over peak efficiency or miniaturization.
Availability
LT1171HVIT#PBF is available at Aetrix Electronics and suitable for industrial DC-DC conversion, battery-powered upconverters, and flyback-isolated power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT1171HVIT#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, datasheets, and application notes for legacy Linear parts including the LT117x family.
The LT117x series was designed as monolithic high-power switching regulators targeting cost-sensitive, thermally constrained industrial and instrumentation applications - emphasizing integration, ruggedness, and topology flexibility over ultra-high efficiency or digital control.
FAQ
What is the maximum input voltage rating for LT1171HVIT#PBF?
The LT1171HVIT#PBF has an absolute maximum supply voltage of 60V and a switch breakdown voltage of 75V. In flyback mode, the maximum recommended input is 55V to maintain safe margin against switch avalanche. Operation above 60V violates Absolute Maximum Ratings and risks permanent damage.
Does LT1171HVIT#PBF support flyback topology without an optocoupler?
Yes. The LT1171HVIT#PBF supports primary-side regulated flyback using its dedicated flyback error amplifier and 15.0V reference. When the FB pin is pulled below 0.54V, the IC switches to flyback mode and regulates the reflected flyback pulse amplitude - eliminating need for optocoupler or secondary-side feedback components.
What is the thermal resistance (θJA) of LT1171HVIT#PBF in its TO-220 package?
The LT1171HVIT#PBF in the T-package (5-lead plastic TO-220) has a junction-to-ambient thermal resistance of 75°C/W under standard JEDEC test conditions. With proper PCB copper area (≥1 sq. in. 2oz), actual θJA can improve to ~55°C/W, enabling 2.5A continuous operation at 70°C ambient.
How does the VC pin function in LT1171HVIT#PBF?
The VC pin on LT1171HVIT#PBF serves four functions: (1) error amplifier output for loop compensation, (2) current limit adjustment (0–2.5A via 1–2V clamp), (3) soft-start control (capacitor from VC to GND), and (4) shutdown trigger (pull <0.15V to enter 50µA mode). Its gm is 3000–4400 µmho across temperature.
Can LT1171HVIT#PBF be synchronized to an external clock?
Yes. The LT1171HVIT#PBF supports external synchronization from 120kHz to 160kHz by pulling the VC pin to ground with a narrow (<0.3µs) transistor pulse. This requires adding a sync transistor and timing capacitor (e.g., 39pF) per AN19 - enabling EMI reduction in noise-sensitive systems.
LT1171HVIT#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Cuk, Flyback, Forward Converter
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.244V
- Voltage - Output (Max):
- 75V (Switch)
- Current - Output:
- 2.5A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LT1171HVIT#PBF FAQ
1.How can I place an order for LT1171HVIT#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1171HVIT#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 LT1171HVIT#PBF reliable?
The price and inventory of LT1171HVIT#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1171HVIT#PBF is usually 5 days.
3.What payment methods are accepted for LT1171HVIT#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1171HVIT#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1171HVIT#PBF?
LT1171HVIT#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1171HVIT#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 LT1171HVIT#PBF?
For technical support, including LT1171HVIT#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1171HVIT#PBF requirements.
6.How does Aetrix verify that LT1171HVIT#PBF is sourced from the original manufacturer or authorized distributors?
All LT1171HVIT#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 LT1171HVIT#PBF meets industry standards.
7.What is the process for return or replacement of LT1171HVIT#PBF?
All LT1171HVIT#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1171HVIT#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 LT1171HVIT#PBF part is unused and in its original packaging.
Return procedure for LT1171HVIT#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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