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Analog Devices Inc. LT1082IQ#PBF
- Part No.:
- LT1082IQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1082IQ#PBF.pdf
- Description:
- IC REG BCK BST ADJ 850MA DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:168
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Product details
Overview
LT1082IQ#PBF from Analog Devices (formerly Linear Technology) is a monolithic high-voltage current-mode switching regulator IC with an integrated 1A, 100V switch, 60kHz oscillator, and flyback regulation mode. It operates from 3V to 75V input, delivers up to 20W output power without external switches, and supports buck, boost, flyback, forward, and inverting topologies. It is used in telecom –48V-to-5V converters and isolated 15V/–15V dual-output supplies.
For engineers reviewing the LT1082IQ#PBF datasheet, LT1082IQ#PBF pinout, LT1082IQ#PBF application, or LT1082IQ#PBF equivalent, key selection criteria include its 100V switch breakdown voltage, 4.5mA quiescent current, shutdown mode (120µA), internal flyback reference (18.6V typ), and TO-220 package thermal performance (θJA = 75°C/W).
Technical Context
The LT1082IQ#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 error amplifier is a transconductance type (gm = 3000–6000 µmho) with externally accessible VC pin for compensation, soft-start, and current limit adjustment.
It features dual regulation modes: standard voltage-mode feedback via FB pin (1.244V reference) and isolated flyback mode activated when FB pin draws 60–200µA, enabling optocoupler-free floating outputs. A unique short-circuit protection shifts switching frequency from 60kHz to 12kHz when FB sinks ≥350µA.
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 use with 75V input in flyback/buck-boost without external clamp diodes. |
| Switch Current Limit | 1.07A (typ, 20% duty) - sets maximum deliverable power and defines safe operating area under overload. |
| Quiescent Current | 4.5mA (typ) - minimizes no-load power loss in battery-backed or standby systems. |
| Shutdown Supply Current | 120µA (typ) - enables ultra-low-power standby in always-on telecom or IoT power supplies. |
| Flyback Reference Voltage | 18.6V (typ, IFB = 60µA) - determines regulated flyback pulse amplitude for isolated output control. |
| Switching Frequency | 60kHz (typ), 12kHz (short-circuit mode) - balances EMI, transformer size, and short-circuit robustness. |
Pinout & Package
LT1082IQ#PBF is supplied in a 5-lead TO-220 (T) package with leads bent for through-hole mounting. The package includes an exposed tab electrically connected to VIN for thermal conduction and mechanical mounting. Thermal resistance is θJA = 75°C/W and θJC = 8°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Supplies internal regulator and switch driver; connects to exposed tab for thermal path. |
| VSW | Switch collector output | High-side switch node; connects to primary winding of transformer or inductor. |
| GND | Analog and power ground reference | Return path for internal circuitry and FB/VC bias currents; must be low-impedance. |
| FB | Feedback input / Flyback sense | Senses output voltage in standard mode (1.244V ref); sinks 60–200µA to enable isolated flyback regulation. |
| VC | Error amplifier output / Control interface | Provides compensation node, soft-start ramp, current limit clamp, and shutdown activation (≤0.15V). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1A, 100V switch | Eliminates external MOSFET and gate driver in ≤20W designs, reducing BOM count and layout complexity. |
| Current-mode control architecture | Enables stable operation across wide input/output ratios and simplifies loop compensation with minimal external components. |
| Isolated flyback regulation mode | Allows fully floating outputs without optocouplers or auxiliary windings-ideal for dual-rail telecom supplies. |
| Frequency shift-down short-circuit protection | Reduces switching losses during sustained overload by lowering frequency to 12kHz, improving reliability in fault conditions. |
| External synchronization capability | Supports 75–90kHz sync input via VC pin, enabling noise-sensitive applications to avoid EMI bands. |
Applications
| Negative-to-Positive Telecom Supply | Isolated Dual-Rail Converter |
|---|---|
Use Scenario: Generating +5V at 0.7A from a –48V telecom battery bus with strict efficiency and reliability requirements. IC Role / Device Role / Timing Role: Primary controller implementing flyback topology with internal switch, regulating output via isolated feedback without optocoupler. Use Value: Achieves >75% efficiency at full load while meeting Telcordia GR-63-CORE shock/vibration and long-life requirements. | Use Scenario: Providing ±15V at 0.3A each for analog signal conditioning in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Regulates two independent floating outputs using single transformer secondary with center tap and synchronous rectification. Use Value: Eliminates need for separate regulators or optocouplers, reducing cost and board space by 40% vs discrete solutions. |
| High-Voltage Boost Converter | Industrial Input Range Power Supply |
Use Scenario: Stepping 15V input up to 90V at 120mA for sensor biasing or HV op-amp rails in factory automation. IC Role / Device Role / Timing Role: Operates in boost configuration with internal switch and 60kHz fixed-frequency PWM control. Use Value: Delivers stable 90V output across 10–20V input variation with <±1% line regulation due to current-mode architecture. | Use Scenario: Powering embedded controllers from unregulated 24–72V DC industrial buses with brownout immunity. IC Role / Device Role / Timing Role: Functions as buck-boost regulator supporting both step-up and step-down operation depending on input level. Use Value: Maintains regulated output during wide input transients (e.g., 24V → 72V motor drive surges) without reconfiguration. |
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 |
|---|---|---|---|
| LTC3891EMSE#PBF | Higher switching frequency (100kHz–850kHz), lower IQ (45µA), requires external MOSFETs, supports 4–60V input. | Targeted at higher-efficiency, smaller-inductor designs; lacks integrated switch and flyback mode. | Select when footprint, efficiency, or programmability outweigh integration and isolation needs. |
| LM5017MM/NOPB | 75V max input, 100mA max switch current, requires external FET, fixed 600kHz frequency, no flyback mode. | Designed for compact, high-frequency flyback with external switch; not suitable for ≥1A loads or isolated regulation without optocoupler. | Choose for space-constrained, medium-power flyback where external FET thermal management is acceptable. |
Compared with LTC3891EMSE#PBF and LM5017MM/NOPB, LT1082IQ#PBF offers unique value in self-contained 1A, 100V flyback designs requiring optocoupler-free isolation and robust short-circuit handling-without sacrificing thermal performance in TO-220 packaging.
Availability
LT1082IQ#PBF is available at Aetrix Electronics and suitable for telecom power conversion, industrial HV DC-DC, isolated dual-rail supplies, and negative-input voltage regulation requiring stable component supply and long-term lifecycle support.
Supply support for LT1082IQ#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 LT1082IQ#PBF belongs to Linear's high-voltage monolithic switching regulator family, designed specifically for rugged, high-reliability power conversion in telecom infrastructure, industrial controls, and test equipment where wide input range and integrated isolation capability are critical.
FAQ
What is the maximum input voltage rating for the LT1082IQ#PBF?
The LT1082IQ#PBF has an absolute maximum supply voltage rating of 75V and a switch breakdown voltage of 100V. This allows it to safely operate with input voltages up to 75V while sustaining transient spikes up to 100V on the VSW node-critical for telecom –48V systems with line surges. Operation beyond 75V on VIN violates Absolute Maximum Ratings and risks permanent damage.
Does the LT1082IQ#PBF support isolated flyback regulation without an optocoupler?
Yes, the LT1082IQ#PBF supports optocoupler-free isolated flyback regulation. When the FB pin sinks 60–200µA, the device enters flyback mode and regulates the amplitude of the reflected flyback pulse relative to VIN. This enables fully floating outputs-such as ±15V-using only a single transformer, eliminating optocouplers and auxiliary windings required by most other controllers.
What is the purpose of the VC pin on the LT1082IQ#PBF?
The VC pin on the LT1082IQ#PBF serves four key functions: (1) compensation node for loop stability, (2) current limit adjustment via external clamping, (3) soft-start control using capacitor coupling, and (4) shutdown activation when pulled below 0.15V. Its voltage (0.9–2.0V during normal operation) directly modulates switch current limit, making it central to both dynamic performance and protection behavior of the LT1082IQ#PBF.
How does the LT1082IQ#PBF handle short-circuit conditions?
Under short-circuit, the LT1082IQ#PBF detects FB pin sinking ≥350µA and automatically shifts switching frequency from 60kHz to 12kHz. This reduces average switch power dissipation and prevents thermal runaway. The feature is intrinsic to the IC's design and requires no external circuitry-enabling robust protection in telecom 5V supplies fed from –70V inputs without additional fault-handling components.
What thermal considerations apply to the LT1082IQ#PBF in TO-220 package?
The LT1082IQ#PBF in TO-220 (T) package has θJA = 75°C/W and θJC = 8°C/W. With proper heatsinking on the VIN-connected tab, it sustains full 1A load at 75V input without exceeding 125°C junction temperature. Without a heatsink, ambient must be limited to ~60°C at full load. PCB copper area (≥2 in²) and thermal vias under the tab significantly improve performance-verified in typical telecom 5V/0.7A designs.
LT1082IQ#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:
- 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#PBF FAQ
1.How can I place an order for LT1082IQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1082IQ#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 LT1082IQ#PBF reliable?
The price and inventory of LT1082IQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1082IQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1082IQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1082IQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1082IQ#PBF?
LT1082IQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1082IQ#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 LT1082IQ#PBF?
For technical support, including LT1082IQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1082IQ#PBF requirements.
6.How does Aetrix verify that LT1082IQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1082IQ#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 LT1082IQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1082IQ#PBF?
All LT1082IQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1082IQ#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 LT1082IQ#PBF part is unused and in its original packaging.
Return procedure for LT1082IQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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