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Analog Devices Inc. LT1082CQ#PBF
- Part No.:
- LT1082CQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1082CQ#PBF.pdf
- Description:
- IC REG BCK BST ADJ 1.07A DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,553
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Product details
Overview
LT1082CQ#PBF from Analog Devices (formerly Linear Technology) is a monolithic high-voltage current-mode switching regulator IC with an integrated 1A power switch, operating from 3V to 75V input and supporting up to 100V switch voltage. It delivers up to 20W output power in buck, boost, flyback, forward, or inverting topologies and features 4.5mA quiescent current, 60kHz switching frequency, and isolated flyback regulation mode-enabling telecom 5V/0.7A supply from –48V input.
For engineers reviewing the LT1082CQ#PBF datasheet, LT1082CQ#PBF pinout, LT1082CQ#PBF application, or LT1082CQ#PBF equivalent, key selection considerations include its 100°C junction temperature rating, TO-220 package thermal resistance (θJA = 40°C/W), shutdown mode (120µA), and flyback reference voltage programmability via RFB.
Technical Context
The LT1082CQ#PBF implements current-mode control: switch duty cycle is set by real-time switch current sensing rather than output voltage feedback alone, enabling fast line transient response and inherent pulse-by-pulse overcurrent protection. Its internal 1.244V bandgap reference feeds the error amplifier, while the VC pin serves dual roles-as compensation node and shutdown control input (≤0.15V triggers 120µA standby mode).
It supports isolated flyback regulation by disconnecting the main error amplifier and routing the flyback amplifier output to the comparator when FB pin current reaches 60–200µA; this eliminates optocouplers and enables fully floating outputs. A unique short-circuit protection shifts switching frequency from 60kHz to 12kHz when FB pin current exceeds 350µA and voltage drops to 0.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 75V - supports wide-range industrial and telecom inputs including negative rails like –48V. |
| Switch Breakdown Voltage | 100V - enables direct interface with high-voltage bus lines without external clamp diodes. |
| Switch Current Limit (LT1082C) | 1.07A typical at 20% duty cycle - sets maximum deliverable power and defines safe operating area under overload. |
| Quiescent Supply Current | 4.5mA - minimizes no-load power loss in battery-backed or always-on systems. |
| Shutdown Supply Current | 120µA - enables ultra-low-power standby for energy-sensitive applications. |
| Switching Frequency | 60kHz typical - balances EMI, magnetics size, and efficiency for medium-power DC/DC designs. |
| Flyback Reference Voltage | 18.6V typical at 60µA FB current - determines regulated output voltage in isolated flyback configurations. |
| Junction Temperature Range | 0°C to 100°C - defines commercial-grade thermal envelope for PCB-level thermal design. |
Pinout & Package
The LT1082CQ#PBF is housed in a 5-lead plastic TO-220 (T-package) with exposed heat sink tab. Pins are arranged front-view, left-to-right: VIN, VSW, GND, FB, VC. The tab is electrically connected to GND and provides primary thermal path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Supplies internal regulator and gate driver; must be decoupled near pin with ≥10µF low-ESR capacitor. |
| VSW | Switch collector output | Drives external inductor/diode; rated for 100V breakdown and 1A peak current. |
| GND | Power and signal reference | Common return for internal circuitry, switch emitter, and heat sink tab; requires low-impedance PCB plane. |
| FB | Feedback input / Flyback sense | Monitors output voltage via resistor divider; pulls 60–200µA to enable isolated flyback mode. |
| VC | Error amplifier output / Shutdown control | Sets current limit via voltage (1.0V–2.0V); ≤0.15V forces shutdown; used for soft-start and frequency compensation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1A high-voltage switch | Eliminates external MOSFET in ≤20W converters, reducing BOM count and layout complexity. |
| Isolated flyback regulation mode | Enables optocoupler-free, fully floating outputs with transformer-coupled feedback-critical for safety-isolated supplies. |
| Current-mode control architecture | Provides inherent cycle-by-cycle current limiting and superior line regulation without complex compensation networks. |
| Frequency shift-down short-circuit protection | Reduces switching frequency to 12kHz during sustained overloads, preventing thermal runaway in high-input-voltage telecom systems. |
| External synchronization capability | Accepts 75–90kHz sync pulses on VC pin, enabling noise-sensitive multi-regulator systems to avoid beat frequencies. |
| Low 4.5mA quiescent current | Supports >10-year battery life in maintenance-free remote sensors powered from 3.6V LiSOCl₂ cells. |
Applications
| Telecom Negative-to-Positive Converter | Industrial High-Voltage DC/DC |
|---|---|
Use Scenario: Generating stable +5V/0.7A output from –48V telecom battery backup rail with full short-circuit protection. IC Role / Device Role / Timing Role: Primary controller implementing flyback topology with internal switch, reference, and error amplifier-no optocoupler required. Use Value: Achieves 79% efficiency at –48V input using powdered iron core; frequency shift-down prevents overheating during sustained shorts. | Use Scenario: Converting 30–70V industrial bus to isolated ±15V/0.3A dual outputs for analog sensor interfaces. IC Role / Device Role / Timing Role: Regulates two floating windings via single FB pin sensing of reflected flyback pulse amplitude. Use Value: Eliminates separate isolation components; maintains <±1% load regulation across 0.15–0.6A per rail without secondary feedback. |
| High-Voltage Boost Supply | Automotive Load Dump Protection |
Use Scenario: Stepping 15V automotive input up to 90V/120mA for legacy instrumentation backlighting. IC Role / Device Role / Timing Role: Configured as boost converter with internal 1A switch and 100V VSW rating-no external HV transistor needed. Use Value: Delivers full output at 15V min input; 60kHz operation keeps inductor size below 1mH, fitting compact dash modules. | Use Scenario: Protecting 12V microcontroller subsystems during ISO 7637-2 load dump transients up to +120V. IC Role / Device Role / Timing Role: Acts as clamped pre-regulator-absorbs surge energy via controlled switch conduction and thermal shutdown. Use Value: Withstands 100V continuous and brief 120V spikes; 120µA shutdown current preserves battery during parked state. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | Higher 3MHz switching frequency, lower 3.3V–60V input range, 1.5A switch, MSOP-10 package. | Better suited for compact, high-density PCBs where small magnetics and fast transient response are critical. | Select when board space is constrained and input voltage stays below 60V; not suitable for –48V telecom or 75V industrial rails. |
| LM5017MM/NOPB | 75V max input, 600mA switch, 600kHz fixed frequency, SOIC-8 package, no flyback isolation mode. | Optimized for non-isolated buck applications requiring higher frequency and smaller passive components. | Choose for cost-sensitive buck regulators where isolation and >600mA output are unnecessary. |
Compared with LTC3631EMSE#PBF and LM5017MM/NOPB, the LT1082CQ#PBF uniquely supports true negative-input operation (e.g., –48V), offers built-in flyback isolation mode, and delivers higher output current in a thermally robust TO-220 package-making it irreplaceable for telecom and high-reliability industrial converters.
Availability
LT1082CQ#PBF is available at Aetrix Electronics and suitable for telecom power supplies, industrial DC/DC converters, and automotive load-dump protected systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT1082CQ#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 legacy Linear parts including the LT1082 series.
The LT1082 product line was designed specifically for high-voltage, high-efficiency offline and telecom DC/DC conversion-emphasizing ruggedness, integrated protection, and flexibility across multiple topologies without external switches.
FAQ
What is the maximum allowable input voltage for the LT1082CQ#PBF?
The LT1082CQ#PBF supports a maximum continuous input voltage of 75V on the VIN pin. Absolute maximum rating for switch voltage (VSW) is 100V, allowing safe operation with transient overshoots up to that level. Operation beyond 75V on VIN risks permanent damage, even if VSW remains within limits. Always verify input rail stability and transient margins before final design validation.
Does the LT1082CQ#PBF support isolated flyback regulation without an optocoupler?
Yes, the LT1082CQ#PBF supports fully isolated flyback regulation without an optocoupler. When FB pin current is set between 60µA and 200µA using an external resistor, the device automatically disables the main error amplifier and engages the flyback amplifier to regulate the reflected flyback pulse amplitude-directly controlling output voltage via transformer turns ratio.
What thermal performance can be expected from the LT1082CQ#PBF in a TO-220 package?
The LT1082CQ#PBF in the Q-package (TO-220) has θJA = 40°C/W and θJC = 8°C/W. At 0.43W total dissipation (e.g., –45V input → 5V/0.5A), junction temperature rise above ambient is ~17°C-well within its 0°C to 100°C operating range. For sustained full-load operation, mounting the tab to a 25cm² copper pour improves thermal margin significantly.
How does the LT1082CQ#PBF implement short-circuit protection?
The LT1082CQ#PBF implements short-circuit protection via automatic frequency shift-down: when FB pin voltage drops to 0.6V and FB current exceeds 350µA, the internal oscillator reduces switching frequency from 60kHz to 12kHz. This extends minimum off-time, preventing switch saturation and thermal runaway-especially critical in high-input-voltage telecom supplies.
Can the LT1082CQ#PBF be synchronized to an external clock?
Yes, the LT1082CQ#PBF supports external synchronization in the 75kHz to 90kHz range via the VC pin. A transistor pulling VC to ground for <1µs pulses synchronizes the internal oscillator. Pulse width is controlled by an RC network (e.g., 350pF + 2.2kΩ), and the external clock must drive sufficient current to pull VC within 100mV of ground for reliable locking.
LT1082CQ#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
- Output Configuration:
- Positive or Negative, Isolation Capable
- Topology:
- Buck, Boost, Flyback, Forward Converter
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 75V
- Voltage - Output (Min/Fixed):
- 1.244V
- Voltage - Output (Max):
- 100V (Switch)
- Current - Output:
- 1.07A (Switch)
- Frequency - Switching:
- 12kHz ~ 60kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DDPAK-5
LT1082CQ#PBF FAQ
1.How can I place an order for LT1082CQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1082CQ#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 LT1082CQ#PBF reliable?
The price and inventory of LT1082CQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1082CQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1082CQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1082CQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1082CQ#PBF?
LT1082CQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1082CQ#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 LT1082CQ#PBF?
For technical support, including LT1082CQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1082CQ#PBF requirements.
6.How does Aetrix verify that LT1082CQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1082CQ#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 LT1082CQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1082CQ#PBF?
All LT1082CQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1082CQ#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 LT1082CQ#PBF part is unused and in its original packaging.
Return procedure for LT1082CQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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