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Analog Devices Inc. LT1172HVCQ#PBF
- Part No.:
- LT1172HVCQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1172HVCQ#PBF.pdf
- Description:
- IC REG BCK BST ADJ 1.25A DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:663
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Product details
Overview
LT1172HVCQ#PBF from Analog Devices (formerly Linear Technology) is a monolithic high-efficiency current-mode switching regulator IC with integrated 1.25A/75V power switch, operating from 3V to 60V input and delivering up to 25W in buck/boost/flyback topologies. It features 100kHz fixed-frequency operation, 6mA quiescent current, shutdown mode drawing 50µA, and supports isolated flyback regulation via dedicated FB pin functionality - used in industrial power supplies and battery-powered DC-DC converters.
For engineers reviewing the LT1172HVCQ#PBF datasheet, LT1172HVCQ#PBF pinout, LT1172HVCQ#PBF application, or LT1172HVCQ#PBF equivalent, key selection criteria include its HV-grade 75V switch breakdown voltage, 5-pin DD package thermal performance (θJA ≈ 25–45°C/W), flyback reference voltage of 15.0–18.0V, and compatibility with external synchronization up to 160kHz.
Technical Context
The LT1172HVCQ#PBF implements current-mode control with adaptive anti-saturation drive for stable operation across wide load ranges. Its internal 100kHz oscillator synchronizes externally between 120–160kHz using sub-0.3µs VC-pin pulses, and its dual error amplifier architecture enables seamless transition between normal (1.24V feedback threshold) and flyback-regulated modes (15–18V reference).
It integrates a 75V/1.25A switch with 0.6Ω typical RDS(on), operates with supply voltages from 3V to 60V, and uses a 2.3V internal LDO to bias all circuitry - enabling stable regulation even at minimum input voltage (2.6V typical). The VC pin serves quadruple functions: compensation node, current limit adjustment, soft-start control, and shutdown activation below 0.15V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Breakdown Voltage | 75V - supports input rails up to 60V with margin for transients in industrial or automotive environments. |
| Max Switch Current | 1.25A at ≥25°C - defines maximum continuous output power in buck/boost configurations (e.g., ~12V@1A from 5V input). |
| Quiescent Current | 6mA - enables low-power standby operation without external biasing circuitry. |
| Flyback Reference Voltage | 15.0–18.0V - sets isolated output regulation point in transformer-coupled flyback designs without optocoupler feedback. |
| Switching Frequency | 88–115kHz - balances EMI suppression and inductor size; externally synchronizable to 120–160kHz for noise-sensitive systems. |
| Shutdown Supply Current | 50µA - reduces system-level standby power in battery-backed applications like portable instrumentation. |
| Reference Voltage Accuracy | ±1.2% (1.224–1.274V) - ensures tight output voltage tolerance without trimming resistors in precision supplies. |
Pinout & Package
LT1172HVCQ#PBF is housed in a 5-lead DD (Dual Drain) plastic package with exposed tab connected to GND, optimized for thermal dissipation on PCB copper areas (θJA ≈ 25–45°C/W depending on layout). Pin 1 = VIN, Pin 2 = VSW, Pin 3 = GND, Pin 4 = FB, Pin 5 = VC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 3–60V unregulated DC; powers internal LDO and switch driver; requires local 1µF ceramic bypass. |
| VSW (Pin 2) | Switch collector/drain output | Connects to primary side of inductor/transformer; handles peak currents up to 3.5A during overload. |
| GND (Pin 3) | Power and signal ground | Common return for internal circuitry and external components; tab must be soldered to large copper pour for thermal management. |
| FB (Pin 4) | Feedback input / mode select | Normal mode: senses 1.24V reference; pulled low via resistor to enable flyback mode (15–18V reference). |
| VC (Pin 5) | Error amplifier output / control node | Used for frequency compensation (capacitor to GND), current limit setting (voltage clamp), soft-start (RC ramp), and shutdown (≤0.15V). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 75V/1.25A switch | Eliminates external MOSFET and gate driver, reducing BOM count and layout complexity in medium-power DC-DC designs. |
| Flyback-regulated mode | Enables fully floating, optocoupler-free isolated outputs by regulating flyback pulse amplitude referenced to VIN. |
| Adaptive anti-saturation drive | Maintains consistent switch turn-off speed across load range, minimizing conduction loss and improving efficiency at light loads. |
| External synchronization support | Allows noise-sensitive systems (e.g., medical sensors) to lock switching frequency to external clock, avoiding beat frequencies. |
| Self-protected overload handling | Combines cycle-by-cycle current limiting and thermal foldback to survive sustained short-circuit conditions without external protection. |
Applications
| Industrial Power Supply | Battery-Powered Upconverter |
|---|---|
Use Scenario: 24V industrial rail powering 12V logic and ±15V op-amp supplies in PLC I/O modules. IC Role / Device Role / Timing Role: Primary switching controller in non-isolated buck-boost configuration, regulating multiple outputs from single input. Use Value: Single-chip solution eliminates need for discrete controllers + external switches, reducing board area by >40% vs. multi-component alternatives. | Use Scenario: Portable test equipment converting 3.7V Li-ion battery to 12V for analog front-end circuitry. IC Role / Device Role / Timing Role: Boost converter controller with programmable soft-start and low-quiescent-current shutdown. Use Value: 6mA IQ extends battery runtime; 50µA shutdown mode enables firmware-controlled deep sleep without auxiliary regulators. |
| Flyback Isolated DC-DC | LCD Contrast Voltage Generator |
Use Scenario: Medical sensor interface requiring reinforced isolation between patient-connected analog section and digital MCU domain. IC Role / Device Role / Timing Role: Flyback controller regulating secondary-side output via primary-side sensing, eliminating optocoupler and TL431. Use Value: Achieves <1% output regulation drift over temperature using internal 15–18V flyback reference, reducing component count and failure points. | Use Scenario: Handheld barcode scanner generating –15V LCD bias from 5V USB supply. IC Role / Device Role / Timing Role: Inverting charge-pump-like topology using internal switch and external diode/capacitor network. Use Value: Delivers –10V to –26V adjustable contrast voltage with <50mV ripple, leveraging VC pin clamping for precise output control. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1172CQ#PBF | Standard-voltage grade (65V switch), lower cost, same pinout and thermal profile. | Not suitable for 60V input systems with transient margin requirements. | Select when input voltage remains ≤40V and cost sensitivity outweighs HV margin. |
| LT1172HVCT#PBF | Same HV rating (75V), but in 5-lead TO-220 package with θJA = 75°C/W and higher thermal mass. | Better suited for continuous 1.25A operation in ambient >60°C due to improved heat dissipation. | Choose for high-reliability industrial applications where board space allows TO-220 mounting. |
Compared with LT1172CQ#PBF, LT1172HVCQ#PBF adds 10V switch breakdown margin critical for 60V bus systems; versus LT1172HVCT#PBF, it trades thermal robustness for compact DD-package footprint and lower assembly cost in space-constrained designs.
Availability
LT1172HVCQ#PBF is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered upconverters, isolated flyback DC-DC converters, and LCD contrast voltage generators requiring stable component supply across extended product lifecycles.
Supply support for LT1172HVCQ#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 support and manufacturing continuity for legacy Linear products including the LT117x family.
The LT117x series was designed as monolithic high-power switching regulators targeting cost-sensitive, medium-power applications where integration of switch, oscillator, and protection circuitry simplifies design and improves reliability over controller+MOSFET solutions.
FAQ
What is the maximum input voltage rating for LT1172HVCQ#PBF?
The LT1172HVCQ#PBF has an absolute maximum supply voltage of 60V and a switch breakdown voltage of 75V. This HV grade allows safe operation with 60V nominal inputs while maintaining margin against transients - confirmed in the Absolute Maximum Ratings table and validated across temperature ranges from 0°C to 100°C.
Does LT1172HVCQ#PBF support flyback topology with primary-side regulation?
Yes, LT1172HVCQ#PBF supports flyback-regulated mode via its FB pin: pulling FB low with an external resistor selects flyback operation, activating a dedicated 15.0–18.0V reference that regulates output based on flyback pulse amplitude - enabling fully floating, optocoupler-free isolated outputs as documented in the Electrical Characteristics and Operation sections.
What is the thermal resistance (θJA) of the LT1172HVCQ#PBF package?
The LT1172HVCQ#PBF uses a 5-lead DD package with θJA varying from ~25°C/W (with 2.8 sq. in. of 1 oz. copper) to ~45°C/W (with 0.20 sq. in.), as specified in the Pin Configuration section. This thermal performance enables 1.25A continuous operation without heatsink in most PCB layouts - verified in Thermal Considerations and Typical Performance Characteristics.
Can LT1172HVCQ#PBF be synchronized to an external clock?
Yes, LT1172HVCQ#PBF supports external synchronization between 120kHz and 160kHz by applying sub-0.3µs pulses to the VC pin, as detailed in the Synchronizing section. Pulse width must remain ≤0.3µs to avoid disturbing DC error amplifier characteristics, and the VC pin must be pulled within 200mV of ground for reliable locking.
What is the shutdown current consumption of LT1172HVCQ#PBF?
The LT1172HVCQ#PBF draws 50µA in shutdown mode when the VC pin voltage is reduced to ≤0.15V, as specified in the Electrical Characteristics table under "Shutdown Mode Supply Current." This ultra-low standby current is confirmed across the full 0°C to 100°C operating temperature range.
LT1172HVCQ#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:
- 1.25A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DDPAK-5
LT1172HVCQ#PBF FAQ
1.How can I place an order for LT1172HVCQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1172HVCQ#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 LT1172HVCQ#PBF reliable?
The price and inventory of LT1172HVCQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1172HVCQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1172HVCQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1172HVCQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1172HVCQ#PBF?
LT1172HVCQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1172HVCQ#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 LT1172HVCQ#PBF?
For technical support, including LT1172HVCQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1172HVCQ#PBF requirements.
6.How does Aetrix verify that LT1172HVCQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1172HVCQ#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 LT1172HVCQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1172HVCQ#PBF?
All LT1172HVCQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1172HVCQ#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 LT1172HVCQ#PBF part is unused and in its original packaging.
Return procedure for LT1172HVCQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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