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Analog Devices Inc. LT1082IQ#TRPBF
- Part No.:
- LT1082IQ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1082IQ#TRPBF.pdf
- Description:
- IC REG BCK BST ADJ 850MA DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,234
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Product details
Overview
LT1082IQ#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic high-voltage current-mode switching regulator IC with an integrated 1A power switch, 100V switch breakdown voltage, 60kHz switching frequency, and 4.5mA quiescent current. It supports buck, boost, flyback, forward, and inverting topologies and delivers up to 20W output power without external switches - used in telecom −48V-to-5V converters and isolated industrial supplies.
For engineers reviewing the LT1082IQ#TRPBF datasheet, LT1082IQ#TRPBF pinout, LT1082IQ#TRPBF application, or LT1082IQ#TRPBF equivalent, key selection criteria include input voltage range (3V–75V), flyback regulation capability without optocouplers, shutdown mode (120µA), thermal performance in TO-220 package, and compatibility with LT1072-based designs.
Technical Context
The LT1082IQ#TRPBF implements current-mode control: switch duty cycle is set by sensed switch current rather than output voltage feedback, enabling fast line transient response and simplified loop compensation. Its internal oscillator runs at 60kHz (shiftable to 12kHz under short-circuit via FB pin current ≥350µA).
It features dual error amplifiers - one for standard regulation (1.244V reference), another for isolated flyback mode (18.6V typical flyback reference) - and a VC pin supporting soft-start, current limit adjustment, and shutdown (≤0.15V). The TO-220 package (IQ suffix) has θJA = 75°C/W and TJMAX = 125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 75V - enables direct operation from telecom −48V rails or wide industrial inputs without pre-regulation. |
| Switch Breakdown Voltage | 100V - supports flyback designs with high reflected voltages and robust overvoltage tolerance. |
| Switch Current Limit | 1.07A (typical, 20% duty cycle) - sets maximum deliverable power and overload protection threshold. |
| Quiescent Current | 4.5mA - minimizes no-load power loss in battery-backed or standby-sensitive systems. |
| Shutdown Supply Current | 120µA - enables ultra-low-power standby in energy-conscious applications. |
| Flyback Reference Voltage | 18.6V (typical, IFB = 60µA) - defines regulated amplitude of transformer-coupled flyback pulse for isolated output control. |
| Reference Voltage Accuracy | ±1.6% (1.224V to 1.264V) - ensures tight output voltage regulation across temperature and line conditions. |
Pinout & Package
LT1082IQ#TRPBF is housed in a 5-lead plastic TO-220 package (T package), with leads 1–5 assigned as VIN, VSW, GND, FB, and VC respectively. The metal tab is electrically connected to GND and serves as primary thermal path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power Input | Supplies internal regulator and logic; accepts 3V–75V DC input; must be bypassed with low-ESR capacitor. |
| VSW (Pin 2) | Switch Output | Drives external inductor/transformer; rated for 100V breakdown and 1A peak current; connects to primary winding. |
| GND (Pin 3) | Ground Reference | Common return for internal circuitry, switch emitter, and thermal tab; requires low-impedance PCB connection. |
| FB (Pin 4) | Feedback Input | Senses output voltage (1.244V reference) or flyback pulse amplitude (18.6V mode); pulls down to 0.6V to trigger frequency shift-down. |
| VC (Pin 5) | Error Amplifier Output / Control | Provides transconductance output for loop compensation; clamped externally to adjust current limit or initiate shutdown (<0.15V). |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode switching architecture | Enables immediate line transient response and inherent pulse-by-pulse overcurrent protection without additional sensing components. |
| Isolated flyback regulation mode | Allows fully floating outputs regulated via transformer-coupled flyback pulse - eliminates need for optocouplers or auxiliary windings. |
| Frequency shift-down under short-circuit | Reduces switching frequency from 60kHz to 12kHz when FB pin sinks ≥350µA - maintains regulation at ultra-low duty cycles where blanking time limits minimum on-time. |
| Externally synchronizable | Accepts external sync pulses (75–90kHz) via VC pin pull-down - enables noise-sensitive multi-regulator systems to avoid beat frequencies. |
| Thermal-limited safe operation in TO-220 | Rated for 125°C junction temperature with θJA = 75°C/W - supports 20W output without heatsink in moderate ambient conditions. |
Applications
| Negative-to-Positive Telecom Supply | Isolated Dual-Rail Converter |
|---|---|
Use Scenario: Generating +5V at 0.7A from a −48V telecom battery bus in central office equipment. IC Role / Device Role / Timing Role: Primary controller in negative-input flyback topology; regulates output using isolated flyback pulse sensing on FB pin. Use Value: Eliminates optocoupler and secondary-side reference, reducing BOM count and improving long-term reliability while meeting -48V input ruggedness requirements. | Use Scenario: Providing ±15V at 0.3A each from a 30–70V industrial input in programmable logic controllers. IC Role / Device Role / Timing Role: Core controller in center-tapped flyback configuration; uses single transformer with independent secondary regulation via FB pin feedback. Use Value: Achieves fully isolated, tightly regulated dual outputs with <0.5% cross-regulation drift - critical for analog I/O modules requiring symmetric supply rejection. |
| High-Voltage Boost Converter | Industrial Inverting Regulator |
Use Scenario: Deriving 90V at 120mA from a 15V rail for sensor biasing or HV gate drivers in factory automation. IC Role / Device Role / Timing Role: Boost controller with 100V VSW rating; operates at fixed 60kHz with external diode and inductor. Use Value: Delivers stable 90V output with <3% line regulation across 15V–24V input variation - avoids need for cascaded converters or discrete HV stages. | Use Scenario: Generating −12V at 500mA from a 24V vehicle battery for automotive infotainment audio subsystems. IC Role / Device Role / Timing Role: Inverting topology controller; uses VSW as switching node and GND as output reference; FB senses negative output directly. Use Value: Provides clean, low-noise negative rail with 4.5mA quiescent current - extends battery runtime during sleep modes while maintaining <10mV ripple. |
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 |
|---|---|---|---|
| LT1072HV | Lower switch voltage (75V vs 100V), higher switch current (1.25A vs 1.07A), 40kHz frequency, 6mA quiescent current. | Not suitable for >75V reflected voltages or −70V telecom inputs; less efficient at light loads due to higher IQ. | Select LT1072HV only if input voltage stays ≤60V and higher peak current is required; verify flyback clamp margin. |
| LTC3891 | 40V max input, 2-phase synchronous controller, 150kHz–900kHz adjustable frequency, 50µA IQ, supports MOSFET drivers. | Cannot replace LT1082IQ#TRPBF in >40V or isolated flyback applications; lacks integrated switch and flyback mode. | Choose LTC3891 for high-efficiency, low-IQ, multi-phase step-down where input ≤40V and isolation is not required. |
Compared with LT1072HV and LTC3891, LT1082IQ#TRPBF uniquely combines 100V switch rating, integrated 1A switch, and optocoupler-free isolated flyback capability - making it irreplaceable in −48V telecom and high-isolation industrial converters where voltage headroom and simplicity are critical.
Availability
LT1082IQ#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, isolated industrial converters, high-voltage boost circuits, and automotive inverting regulators requiring stable component supply and long lifecycle support.
Supply support for LT1082IQ#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 legacy Linear parts including the LT1082 family.
The LT1082 product line was designed specifically for high-reliability, high-voltage DC/DC conversion in telecom infrastructure and industrial systems - emphasizing rugged input tolerance, isolation flexibility, and thermal robustness in through-hole packages.
FAQ
What is the maximum input voltage rating for LT1082IQ#TRPBF?
The LT1082IQ#TRPBF has an absolute maximum supply voltage of 75V and a switch breakdown voltage of 100V. This allows reliable operation with inputs up to 75V DC and safe handling of reflected flyback spikes up to 100V - critical for −48V telecom systems where input can dip to −70V and reflected voltages exceed 80V. Operation beyond 75V on VIN violates Absolute Maximum Ratings and risks permanent damage.
Does LT1082IQ#TRPBF support isolated flyback regulation without an optocoupler?
Yes, LT1082IQ#TRPBF includes dedicated isolated flyback regulation mode. When the FB pin is biased with 60–200µA current, the IC disconnects the main error amplifier and uses its internal flyback amplifier (18.6V reference) to regulate the amplitude of the transformer-coupled flyback pulse. This eliminates optocouplers and auxiliary windings while maintaining ±1.5% output regulation across load and line - confirmed in LT1082IQ#TRPBF datasheet Figure 9 and Application Note AN19.
What is the thermal resistance and maximum junction temperature for LT1082IQ#TRPBF?
LT1082IQ#TRPBF in the TO-220 package (IQ) has θJA = 75°C/W and θJC = 8°C/W, with a maximum junction temperature (TJMAX) of 125°C. At 20W output power and 45V input, typical die temperature rise is ~39°C above ambient in standard PCB layout - allowing full-load operation up to +61°C ambient. Exceeding 125°C junction triggers thermal shutdown, but this is not a guaranteed spec; derating per AN19 is recommended.
Can LT1082IQ#TRPBF be synchronized to an external clock?
Yes, LT1082IQ#TRPBF supports external synchronization between 75kHz and 90kHz by pulling the VC pin to ground with a narrow (<1µs) transistor pulse. This is implemented using a sync transistor (e.g., 2N2222) and RC network (C2 = 350pF, R2 = 2.2kΩ per Figure 1082 OP01). Synchronization avoids beat frequencies in multi-rail systems but does not alter internal 60kHz oscillator - it resets the timing cycle on each external edge.
How does the LT1082IQ#TRPBF respond during output short-circuit conditions?
Under output short-circuit, the FB pin is pulled to ~0.6V and sinks ≥350µA, causing LT1082IQ#TRPBF to shift switching frequency from 60kHz to 12kHz. This "frequency shift-down" preserves regulation at ultra-low duty cycles where internal blanking time prevents further reduction of minimum on-time. The feature is explicitly documented in the LT1082IQ#TRPBF datasheet (page 3, "Short-Circuit Frequency Shift-Down") and validated in telecom −48V-to-5V short-circuit testing.
LT1082IQ#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tape & Reel (TR)
- 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:
- 850mA (Switch)
- Frequency - Switching:
- 12kHz ~ 60kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DDPAK-5
LT1082IQ#TRPBF FAQ
1.How can I place an order for LT1082IQ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1082IQ#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 LT1082IQ#TRPBF reliable?
The price and inventory of LT1082IQ#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1082IQ#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1082IQ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1082IQ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1082IQ#TRPBF?
LT1082IQ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1082IQ#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 LT1082IQ#TRPBF?
For technical support, including LT1082IQ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1082IQ#TRPBF requirements.
6.How does Aetrix verify that LT1082IQ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1082IQ#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 LT1082IQ#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1082IQ#TRPBF?
All LT1082IQ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1082IQ#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 LT1082IQ#TRPBF part is unused and in its original packaging.
Return procedure for LT1082IQ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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