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Analog Devices Inc. LT1171HVIQ#PBF
- Part No.:
- LT1171HVIQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1171HVIQ#PBF.pdf
- Description:
- IC REG BUCK BST ADJ 2.5A DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,301
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Product details
Overview
LT1171HVIQ#PBF from Analog Devices (formerly Linear Technology) is a monolithic high-efficiency 100kHz current-mode switching regulator with an integrated 2.5A, 75V internal power switch. It operates from 3V to 60V input, delivers up to 50W in buck/boost/flyback topologies, and features 6mA quiescent current, shutdown mode drawing only 50µA, and flyback-regulated floating outputs. It is used in industrial DC-DC conversion where wide VIN, isolation, and rugged operation are required.
For engineers reviewing the LT1171HVIQ#PBF datasheet, LT1171HVIQ#PBF pinout, LT1171HVIQ#PBF application, or LT1171HVIQ#PBF equivalent, key selection factors include its HV-grade 75V switch breakdown, –40°C to 100°C operating junction temperature, 5-pin TO-220 package thermal performance (θJA = 75°C/W), and compatibility with flyback, boost, and inverting configurations without external drive circuitry.
Technical Context
The LT1171HVIQ#PBF implements current-mode control with adaptive anti-saturation switch drive, enabling stable operation across wide load ranges while maintaining efficiency. Its error amplifier provides transconductance of 2400–4400 µmho and reference voltage accuracy of ±1.2% over temperature.
It supports dual regulation modes: normal mode (1.24V feedback threshold) and flyback mode (15.0–18.0V programmable reference), with dedicated blanking time (1.5µs) to reject transformer leakage spikes. The VC pin serves as combined compensation node, current limit adjust, soft-start input, and shutdown control interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 2.5A typical at 50% duty cycle; enables robust overload protection without external sensing |
| Switch Breakdown Voltage | 75V - supports HV input rails up to 60V with margin for transients in industrial systems |
| Reference Voltage | 1.244V ±1.2% - ensures precise output regulation across –40°C to 100°C |
| Quiescent Current | 6mA - minimizes no-load power loss in battery-backed or always-on applications |
| Shutdown Current | 50µA - enables ultra-low-power standby in energy-sensitive designs |
| Switching Frequency | 85–115kHz - balances EMI control, magnetics size, and efficiency in compact converters |
| Flyback Reference | 15.0–18.0V - allows isolated output regulation without optocoupler or secondary-side sensing |
Pinout & Package
LT1171HVIQ#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 (continuous operation), suitable for convection-cooled industrial PCBs with ≥2.8 in² copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input Supply | Accepts 3V–60V unregulated DC; powers internal 2.3V regulator and switch driver |
| VSW | Switch Output | Drives external inductor/diode; connects to drain of integrated 75V/2.5A N-channel switch |
| GND | Power & Signal Ground | Common return for input, output, and internal circuitry; tab is electrically tied to this pin |
| FB | Feedback Input | Senses output via resistor divider; selects normal (1.24V) or flyback (15–18V) regulation mode |
| VC | Error Amplifier Output / Control | Provides compensation node, current limit adjustment, soft-start ramp, and shutdown activation |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 2.5A, 75V Power Switch | Eliminates external MOSFET and gate driver, reducing BOM count and layout complexity in medium-power SMPS |
| Flyback-Regulated Floating Outputs | Enables fully isolated multiple-output supplies without optocouplers or secondary-side controllers |
| Adaptive Anti-Saturation Drive | Maintains high efficiency across 0–100% load by dynamically optimizing switch turn-off timing |
| External Synchronization (120–160kHz) | Allows noise-sensitive systems to lock switching frequency to avoid interference bands |
| Self-Protected Overload Handling | Combines current-mode limiting, thermal foldback (untested but functional), and shutdown to survive sustained shorts |
Applications
| Industrial DC-DC Conversion | Battery-Powered Upconversion |
|---|---|
Use Scenario: Converting 24V rail to isolated ±15V op-amp supply in factory automation PLC modules. IC Role / Device Role / Timing Role: Primary-side controller in flyback topology; regulates secondary outputs via primary-side sensing using FB pin. Use Value: Eliminates optocoupler and TL431, reducing component count by 3–4 parts while maintaining ±1% output accuracy. | Use Scenario: Boosting 3.7V Li-ion battery to 12V for portable test equipment display backlight. IC Role / Device Role / Timing Role: High-efficiency boost converter IC with integrated switch and current-mode control loop. Use Value: Delivers >85% efficiency at 1A load with only 6mA quiescent current, extending runtime by >12% vs discrete alternatives. |
| Isolated Sensor Interface Supply | Legacy System Voltage Translation |
Use Scenario: Generating isolated 5V supply for analog sensor front-end in high-voltage motor drive cabinets. IC Role / Device Role / Timing Role: Flyback controller regulating isolated output referenced to primary ground; uses internal 15V flyback reference. Use Value: Withstands 2.5kV isolation barrier; eliminates need for external voltage reference on secondary side. | Use Scenario: Converting legacy 5V logic supply to ±12V for analog signal conditioning in retrofitted instrumentation. IC Role / Device Role / Timing Role: Inverting buck-boost regulator delivering negative output from positive input. Use Value: Achieves –12V @ 0.5A with single inductor and diode; avoids dual-rail linear regulators wasting >3W as heat. |
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 VIN, 100kHz sync capability, requires external MOSFETs, higher BOM cost | Targeted at high-efficiency synchronous buck; not suitable for flyback or isolated designs | Choose only if synchronous rectification and <40V input are mandatory |
| LM5017MMX/NOPB | 75V switch, 100kHz fixed freq, no flyback mode, lower 1.5A switch rating, SO-8 package | Optimized for non-isolated buck; lacks FB-mode flexibility and HV thermal robustness | Select when board space is constrained and isolation is unnecessary |
Compared with LTC3891EMSE#PBF and LM5017MMX/NOPB, LT1171HVIQ#PBF uniquely integrates flyback regulation, 75V switch, and –40°C to 100°C operation in a thermally efficient TO-220 package-making it optimal for ruggedized isolated DC-DC where simplicity and reliability outweigh synchronous efficiency gains.
Availability
LT1171HVIQ#PBF is available at Aetrix Electronics and suitable for industrial automation, battery-powered instrumentation, and isolated sensor interface applications requiring stable component supply, long-term lifecycle support, and extended temperature operation.
Supply support for LT1171HVIQ#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 legacy Linear power products.
The LT1170/LT1171/LT1172 family was designed for high-reliability, wide-input industrial and automotive auxiliary power supplies where integration, ruggedness, and topology flexibility outweigh ultra-high efficiency requirements.
FAQ
What is the maximum input voltage supported by the LT1171HVIQ#PBF?
The LT1171HVIQ#PBF supports a maximum supply voltage of 60V, with an absolute maximum switch breakdown rating of 75V. This HV grade (denoted by "HV" in the part number) exceeds the standard LT1171's 40V rating, enabling use in 48V industrial buses and transient-prone environments. Operation above 60V violates Absolute Maximum Ratings and risks permanent damage to the LT1171HVIQ#PBF.
Does the LT1171HVIQ#PBF support flyback topology with primary-side regulation?
Yes, the LT1171HVIQ#PBF supports flyback topology with primary-side regulation via its dedicated flyback mode. When the FB pin is pulled below 0.45V with an external resistor, the device switches to flyback regulation using a 15.0–18.0V internal reference. This allows accurate isolated output control without optocouplers or secondary-side sensing circuits - a core capability of the LT1171HVIQ#PBF.
What thermal derating applies to the LT1171HVIQ#PBF in TO-220 package?
The LT1171HVIQ#PBF in its 5-lead plastic TO-220 package has θJA = 75°C/W under standard JEDEC conditions. At 100°C maximum junction temperature and 25°C ambient, maximum continuous power dissipation is ~1.0W. For reliable operation at full 2.5A switch current, PCB copper area ≥2.8 in² (1 oz) and airflow >200 LFM are recommended - critical thermal constraints for the LT1171HVIQ#PBF in high-power applications.
Can the LT1171HVIQ#PBF be synchronized to an external clock?
Yes, the LT1171HVIQ#PBF supports external synchronization in the 120–160kHz range by pulling the VC pin to ground with a narrow (<0.3µs) transistor pulse. This feature enables EMI reduction in noise-sensitive systems and avoids beat frequencies in multi-regulator boards. Synchronization does not affect regulation accuracy of the LT1171HVIQ#PBF but introduces a small offset shift (~3.8mV typical) that remains within specification limits.
How does the LT1171HVIQ#PBF implement current-mode control?
The LT1171HVIQ#PBF implements true current-mode control by directly comparing sensed switch current against a voltage derived from the VC pin. At each oscillator cycle, the internal switch turns on; it turns off when current reaches the VC-set threshold. This provides inherent cycle-by-cycle current limiting, fast line transient response, and simplified loop compensation - fundamental behaviors confirmed in the LT1171HVIQ#PBF's block diagram and electrical characteristics table.
LT1171HVIQ#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- 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:
- Surface Mount
- Supplier Device Package:
- DDPAK-5
LT1171HVIQ#PBF FAQ
1.How can I place an order for LT1171HVIQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1171HVIQ#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 LT1171HVIQ#PBF reliable?
The price and inventory of LT1171HVIQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1171HVIQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1171HVIQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1171HVIQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1171HVIQ#PBF?
LT1171HVIQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1171HVIQ#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 LT1171HVIQ#PBF?
For technical support, including LT1171HVIQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1171HVIQ#PBF requirements.
6.How does Aetrix verify that LT1171HVIQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1171HVIQ#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 LT1171HVIQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1171HVIQ#PBF?
All LT1171HVIQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1171HVIQ#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 LT1171HVIQ#PBF part is unused and in its original packaging.
Return procedure for LT1171HVIQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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