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Analog Devices Inc. LT1082CT#PBF
- Part No.:
- LT1082CT#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-220-5
- Datasheet:
-
LT1082CT#PBF.pdf
- Description:
- IC REG BCK BST ADJ 1.07A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:329
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Product details
Overview
LT1082CT#PBF 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, 4.5mA quiescent current, and flyback regulation capability. It operates across 3V–75V input, supports buck/boost/flyback/forward/inverting topologies, and is used in telecom −48V-to-5V isolated supplies delivering up to 0.7A.
For engineers reviewing the LT1082CT#PBF datasheet, LT1082CT#PBF pinout, LT1082CT#PBF application, or LT1082CT#PBF equivalent, key selection considerations include its 100V switch rating, internal current-limit protection, isolated flyback mode without optocouplers, shutdown current of 120µA, and TO-220 thermal performance at 75°C/W junction-to-ambient.
Technical Context
The LT1082CT#PBF 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 oscillator runs at 60kHz (typical), shifting to 12kHz under high FB pin current (≥350µA) for short-circuit protection.
It features dual error amplifiers - one for standard regulation (1.244V reference), another for isolated flyback mode (18.6V typical flyback reference) - with externally programmable thresholds via RFB. The VC pin serves as error amplifier output, current limit adjust, soft-start node, and shutdown control (≤150mV triggers 120µA standby).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 75V - enables direct operation from telecom −48V rails or industrial 24V/48V systems without pre-regulation. |
| Switch Breakdown Voltage | 100V - supports flyback designs with ≥70V reflected voltages and withstands voltage spikes in high-VIN boost/flyback. |
| Switch Current Limit | 1.07A (typ, 20% duty) - sets maximum deliverable power (~20W no-external-FET) and defines overload trip point. |
| Quiescent Current | 4.5mA (typ) - minimizes no-load power loss in battery-backed or always-on telecom systems. |
| Flyback Reference Voltage | 18.6V (typ, IFB = 60µA) - allows precise floating output regulation using transformer turns ratio, eliminating optocoupler need. |
| Shutdown Supply Current | 120µA (typ) - enables ultra-low-power standby in remote or energy-sensitive applications. |
| Operating Frequency | 60kHz (typ) - balances EMI, magnetics size, and efficiency for medium-power DC/DC conversion. |
Pinout & Package
LT1082CT#PBF 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 TO-220 case serves as thermal path and electrical ground; emitter connections are internally tied to GND (unlike MiniDIP variants).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 3V–75V supply; powers internal LDO (2.3V) and oscillator; must be bypassed with low-ESR capacitor. |
| VSW (Pin 2) | Switch collector output | Drives external inductor/transformer; rated for 100V breakdown; connects to primary winding in flyback/boost. |
| GND (Pin 3) | Power and signal reference | Common return for internal circuitry, switch emitter, and heat sink; requires low-inductance PCB layout. |
| FB (Pin 4) | Feedback input / mode select | Senses output voltage (1.244V threshold) or flyback pulse (18.6V threshold); pulls down to 0.6V to enter flyback mode. |
| VC (Pin 5) | Error amplifier output / control | Outputs gm-amplifier current; clamped externally to set current limit; pulled ≤150mV to enter 120µA shutdown mode. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1A, 100V switch | Eliminates external MOSFET in ≤20W designs, reducing BOM count and layout complexity for telecom and industrial converters. |
| Isolated flyback regulation mode | Regulates floating outputs using transformer-coupled flyback pulse amplitude - no optocoupler, extra winding, or secondary-side sensing required. |
| Current-mode control architecture | Provides inherent cycle-by-cycle current limiting, superior line regulation, and simplified Type II/III compensation vs. voltage-mode controllers. |
| Frequency shift-down short-circuit protection | Automatically reduces switching frequency from 60kHz to 12kHz when FB pin sinks ≥350µA - maintains regulation under severe overload without latch-off. |
| External synchronization support | Accepts 75–90kHz sync pulses via VC pin, enabling noise-sensitive multi-rail systems to avoid beat frequencies and EMI peaks. |
Applications
| Negative-to-Positive Telecom Supply | Isolated Dual-Rail Flyback Converter |
|---|---|
Use Scenario: Generating regulated +5V at 0.7A from a −48V telecom battery bus with full isolation and short-circuit robustness. IC Role / Device Role / Timing Role: Primary-side controller implementing flyback topology with internal switch, current sensing, and adaptive frequency shift-down. Use Value: Achieves >75% efficiency at −48V input without optocoupler or secondary-side feedback components; survives sustained short-circuit via 12kHz low-frequency operation. |
Use Scenario: Providing isolated ±15V outputs (0.3A each) from a 30–70V industrial input, requiring minimum load stability and transformer-based safety isolation. IC Role / Device Role / Timing Role: Single-chip flyback controller managing primary-side PWM, output voltage sensing via reflected flyback pulse, and cross-regulation. Use Value: Delivers two fully floating outputs with <±5% cross-regulation using single transformer and no secondary-side regulators or optos. |
| High-Voltage Boost Converter | Industrial Inverting Regulator |
Use Scenario: Stepping up 15V industrial rail to 90V at 120mA for sensor biasing or analog front-end supplies. IC Role / Device Role / Timing Role: Boost controller with integrated 100V switch, current-mode regulation, and fixed 60kHz operation. Use Value: Enables compact, high-efficiency boost stage without external HV FET; 100V rating accommodates 90V output plus margin for ringing and transients. |
Use Scenario: Generating −12V at 250mA from a 24V factory automation bus for op-amp rails or interface logic. IC Role / Device Role / Timing Role: Inverting topology controller using LT1082CT#PBF's internal switch and current-mode feedback loop. Use Value: Simplifies negative rail generation with no external PNP pass transistor or charge pump; achieves stable regulation with minimal external parts. |
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 |
|---|---|---|---|
| LTC3703-5 | Higher 150V switch rating, 200kHz max frequency, external MOSFET drive only - no integrated switch. | Requires external high-voltage FET and gate driver; better suited for >30W or higher-frequency designs where efficiency and thermal management dominate. | Select LTC3703-5 when >20W output or tighter EMI control is needed; LT1082CT#PBF remains optimal for ≤20W, lower-BOM, TO-220-mount designs. |
| LM5020MM | Fixed 60kHz frequency, 100V switch, but only 0.5A current limit and no flyback regulation mode. | Lacks isolated flyback capability and has half the switch current rating - unsuitable for telecom 5V/0.7A or multi-output isolation. | Choose LM5020MM for simpler, lower-current boost/buck applications where flyback isolation is unnecessary; LT1082CT#PBF is preferred when isolation or 1A capability is required. |
Compared with LTC3703-5 and LM5020MM, the LT1082CT#PBF uniquely combines integrated 1A/100V switching, flyback regulation without optocouplers, and frequency-shift short-circuit protection - making it the most self-contained solution for isolated telecom and industrial DC/DC below 20W.
Availability
LT1082CT#PBF is available at Aetrix Electronics and suitable for telecom power supplies, isolated industrial converters, and high-voltage boost applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LT1082CT#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 supply chain support for legacy Linear products including the LT1082 series.
The LT1082 product line was designed specifically for high-input-voltage, isolated, and ruggedized DC/DC conversion in telecom infrastructure, industrial controls, and test equipment - emphasizing integration, fault resilience, and ease of transformer-coupled design.
FAQ
What is the maximum input voltage supported by the LT1082CT#PBF?
The LT1082CT#PBF supports a maximum continuous input voltage of 75V, as specified in its Absolute Maximum Ratings. This allows direct operation from telecom −48V battery systems (with appropriate polarity handling) and industrial 48V/60V rails. Exceeding 75V risks permanent damage to the internal switch and control circuitry.
Does the LT1082CT#PBF support isolated flyback regulation without an optocoupler?
Yes, the LT1082CT#PBF supports isolated flyback regulation without an optocoupler via its dedicated flyback mode. When the FB pin is pulled below 0.6V and draws 60–200µA, the IC switches to flyback regulation using the amplitude of the reflected flyback pulse - enabling fully floating outputs referenced only to the primary-side transformer winding.
What is the purpose of the VC pin on the LT1082CT#PBF?
The VC pin on the LT1082CT#PBF serves four critical functions: (1) error amplifier output for loop compensation, (2) current limit adjustment via external clamp voltage, (3) soft-start initiation using a capacitor, and (4) shutdown control - pulling VC ≤150mV reduces supply current to 120µA while disabling switching.
How does the LT1082CT#PBF protect against output short circuits?
The LT1082CT#PBF protects against output short circuits using frequency shift-down: when FB pin current exceeds ~350µA (e.g., during sustained short), the switching frequency drops from 60kHz to 12kHz. This preserves regulation under overload by extending minimum off-time, avoiding uncontrolled current runaway while maintaining thermal manageability.
What package type is used for the LT1082CT#PBF and what are its thermal characteristics?
The LT1082CT#PBF uses a 5-lead plastic TO-220 (T) package with θJA = 75°C/W and θJC = 8°C/W. Its metal tab is electrically connected to GND and serves as the primary thermal path - mounting to a heatsink significantly improves power handling, especially above 10W dissipation or in ambient temperatures >60°C.
LT1082CT#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-220-5
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-5
LT1082CT#PBF FAQ
1.How can I place an order for LT1082CT#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1082CT#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 LT1082CT#PBF reliable?
The price and inventory of LT1082CT#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1082CT#PBF is usually 5 days.
3.What payment methods are accepted for LT1082CT#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1082CT#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1082CT#PBF?
LT1082CT#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1082CT#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 LT1082CT#PBF?
For technical support, including LT1082CT#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1082CT#PBF requirements.
6.How does Aetrix verify that LT1082CT#PBF is sourced from the original manufacturer or authorized distributors?
All LT1082CT#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 LT1082CT#PBF meets industry standards.
7.What is the process for return or replacement of LT1082CT#PBF?
All LT1082CT#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1082CT#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 LT1082CT#PBF part is unused and in its original packaging.
Return procedure for LT1082CT#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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