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Analog Devices Inc. LT1082CN8#PBF
- Part No.:
- LT1082CN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1082CN8#PBF.pdf
- Description:
- IC REG BUCK BST ADJ 1.07A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,496
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Product details
Overview
LT1082CN8#PBF from Analog Devices (formerly Linear Technology) is a monolithic high-voltage current-mode switching regulator IC with an integrated 1A power switch, 60kHz oscillator, and flyback regulation capability. It operates from 3V to 75V input, supports up to 100V switch voltage, draws only 4.5mA quiescent current, and delivers up to 20W output without external power devices - used in telecom −48V-to-5V converters and isolated industrial supplies.
For engineers reviewing the LT1082CN8#PBF datasheet, LT1082CN8#PBF pinout, LT1082CN8#PBF application, or LT1082CN8#PBF equivalent, key selection criteria include verified 100V switch breakdown, confirmed 1.244V reference voltage tolerance, validated flyback mode operation at 16.2–20.5V reference range, and documented thermal derating for N8-package plastic DIP at θJA = 90°C/W.
Technical Context
The LT1082CN8#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 current limiting. Its internal 1.244V bandgap reference feeds an error amplifier with 4400µmho transconductance and 650V/V gain, while the VC pin serves dual roles - compensation node and shutdown control - pulling below 0.15V reduces supply current to 120µA.
It features two operating modes: standard regulation (FB pin senses output via resistive divider) and isolated flyback mode (FB pin biased at 60–200µA to regulate flyback pulse amplitude), eliminating optocouplers. A unique short-circuit protection shifts switching frequency from 60kHz to 12kHz when FB pin current reaches ~350µA, critical for −70V telecom inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 75V - enables direct operation from unregulated industrial rails or telecom −48V sources with minimal pre-regulation. |
| Switch Breakdown Voltage | 100V - supports boost/flyback topologies with ≥25V headroom above 75V max input, reducing need for external snubbers. |
| Reference Voltage | 1.244V ±20mV - tight tolerance ensures stable output regulation across temperature; used directly for feedback loop setpoint. |
| Quiescent Current | 4.5mA typical - minimizes no-load power loss in battery-backed or always-on systems. |
| Switch Current Limit | 1.07A at 20% duty cycle - defines maximum deliverable power before foldback; decreases linearly to 0.8A at 80% duty cycle. |
| Flyback Reference Voltage | 18.6V typical (IFB = 60µA) - sets isolated output voltage scaling; varies ±1.5V over IFB = 60–200µA range. |
| Shutdown Supply Current | 120µA typical - allows ultra-low-power standby in remote monitoring or safety-critical systems. |
Pinout & Package
N8 package: 8-lead plastic DIP (0.300" wide), JEDEC MS-001, θJA = 90°C/W, rated for 0°C to 100°C junction temperature. Pin 1 = VIN, Pin 2 = VSW, Pin 3 = GND, Pin 4 = FB, Pin 5 = VC, Pin 6 = NC, Pin 7 = E2 (switch emitter), Pin 8 = E1 (switch emitter). E1 must be connected to GND; E2 optional for current limit reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 3V–75V unregulated DC; powers internal 2.3V low-dropout regulator for all circuitry. |
| VSW (Pin 2) | Switch collector output | Drives external inductor/transformer; withstands 100V breakdown; connects to primary winding in flyback/forward topologies. |
| GND (Pin 3) | Power and signal ground | Common return for internal logic, error amp, and switch emitter (E1); separate E2 pin avoids ground-loop errors. |
| FB (Pin 4) | Feedback input | Senses output voltage divider or flyback pulse; 1.244V reference sets regulation point; 350nA bias current enables high-impedance sensing. |
| VC (Pin 5) | Error amplifier output / control | Provides compensation node (capacitor to GND), soft-start interface (capacitor to GND), and shutdown trigger (≤0.15V). |
| NC (Pin 6) | No connect | Not bonded internally; must remain unconnected per datasheet to avoid parasitic coupling. |
| E2 (Pin 7) | Secondary switch emitter | Optional connection; leaving open halves switch current limit (to ~0.5A) but doubles RDS(on), trading efficiency for overload safety. |
| E1 (Pin 8) | Primary switch emitter | Mandatory GND connection; carries full switch current; separates power and signal ground paths to minimize noise injection. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1A switch with anti-saturation driver | Eliminates external MOSFET/BJT and gate driver; adaptive anti-sat circuit minimizes turn-off delay and conduction loss. |
| Current-mode control architecture | Enables immediate line transient response, simplifies loop compensation, and provides inherent cycle-by-cycle current limiting under overload. |
| Isolated flyback regulation mode | Regulates floating outputs without optocouplers or extra transformer windings by sensing flyback pulse amplitude at FB pin. |
| Frequency shift-down short-circuit protection | Automatically reduces switching frequency from 60kHz to 12kHz when FB pin sinks 350µA, maintaining regulation under severe overload at high input voltages. |
| External synchronization capability | Accepts 75–90kHz sync pulses via VC pin, enabling noise-sensitive applications to avoid EMI bands or synchronize multiple regulators. |
Applications
| Telecom −48V-to-5V Converter | Industrial Isolated 15V/−15V Supply |
|---|---|
Use Scenario: Generating regulated 5V/0.7A from telecom −48V battery backup system with wide input variation (−20V to −70V). IC Role / Device Role / Timing Role: LT1082CN8#PBF acts as negative-to-positive flyback controller, using internal 100V switch and flyback regulation mode to maintain output stability without optocoupler. Use Value: Achieves >75% efficiency across input range with single IC; eliminates isolation components and reduces BOM count by 4+ parts versus discrete solutions. | Use Scenario: Providing fully isolated ±15V/0.3A rails for analog sensor front-ends in factory automation PLCs. IC Role / Device Role / Timing Role: LT1082CN8#PBF operates in flyback mode, regulating both positive and negative secondaries from one transformer via common FB sensing. Use Value: Delivers dual floating outputs with <±1% cross-regulation; avoids separate regulators or complex winding designs required by non-flyback controllers. |
| High-Voltage Boost Converter | Field-Deployable Battery Charger |
Use Scenario: Stepping 15V vehicle battery to 90V for legacy test equipment powering in mobile service vans. IC Role / Device Role / Timing Role: LT1082CN8#PBF functions as fixed-frequency boost controller with external diode and inductor; uses VC pin for soft-start ramp. Use Value: Delivers 120mA at 90V with 60kHz switching - reduces magnetic size vs lower-frequency alternatives while maintaining >82% efficiency. | Use Scenario: Charging 24V lead-acid batteries from variable 12–36V solar or generator inputs in off-grid monitoring stations. IC Role / Device Role / Timing Role: LT1082CN8#PBF implements buck-derived topology with input voltage feedforward; shutdown mode (120µA) preserves battery during idle. Use Value: Supports 3V–75V input range without pre-regulator; quiescent current <5mA extends standby time; thermal foldback prevents overheating in sealed enclosures. |
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 | 40V max input, 75V MOSFET drivers, requires external FETs; 150kHz sync capability; no integrated flyback mode. | Designed for synchronous buck; lacks LT1082CN8#PBF's monolithic flyback regulation and −48V telecom support. | Select when higher efficiency (>92%) and programmable frequency are prioritized over integration and ultra-wide input range. |
| LM5009AMM/NOPB | 80V max input, 1.5A switch, 1MHz fixed frequency; no flyback mode; 2.5mA quiescent current. | Optimized for compact boost converters; lacks LT1082CN8#PBF's 100V switch rating and short-circuit frequency shift. | Select for space-constrained 12–48V boost applications where 1MHz switching enables smaller magnetics, not for −48V telecom or isolated flyback. |
Compared with LTC3891EMSE#PBF and LM5009AMM/NOPB, the LT1082CN8#PBF uniquely combines 100V switch rating, monolithic flyback regulation, and −70V-compatible short-circuit protection - making it irreplaceable for telecom-grade isolated supplies where component count, reliability, and extreme input range are critical.
Availability
LT1082CN8#PBF is available at Aetrix Electronics and suitable for telecom power systems, industrial isolated supplies, high-voltage boost converters, and field-deployable battery chargers requiring stable component supply across extended temperature and input voltage ranges.
Supply support for LT1082CN8#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, datasheets, and application notes for legacy Linear parts including the LT1082 series.
The LT1082 product line was designed specifically for high-input-voltage, isolated, and telecom power conversion - emphasizing monolithic integration, robust short-circuit behavior, and simplified flyback implementation without optocouplers.
FAQ
What is the maximum input voltage rating for the LT1082CN8#PBF?
The LT1082CN8#PBF has an absolute maximum supply voltage of 75V and a switch breakdown voltage of 100V. It is rated for continuous operation from 3V to 75V input, making it suitable for telecom −48V systems (with appropriate polarity handling) and industrial 24–72V rails. Exceeding 75V on VIN risks permanent damage, even if VSW remains below 100V.
Does the LT1082CN8#PBF support isolated flyback regulation without an optocoupler?
Yes, the LT1082CN8#PBF supports fully isolated flyback regulation using its dedicated flyback mode: when the FB pin is biased with 60–200µA, the IC regulates the amplitude of the reflected flyback pulse instead of the output voltage directly. This eliminates the need for optocouplers or auxiliary windings, enabling compact, reliable isolated supplies - a core design feature confirmed in AN19 and the LT1082CN8#PBF datasheet.
How does the LT1082CN8#PBF implement short-circuit protection?
The LT1082CN8#PBF implements unique short-circuit protection by shifting switching frequency from 60kHz to 12kHz when FB pin current reaches ~350µA - a condition occurring during output shorts in flyback configurations with high input voltage (e.g., −70V telecom). This low-frequency mode maintains regulation headroom where standard current limiting fails, and is explicitly documented in the LT1082CN8#PBF datasheet Figure G03 and operational description.
What is the purpose of the E1 and E2 pins on the LT1082CN8#PBF N8 package?
E1 (Pin 8) is the primary switch emitter and must be connected to GND. E2 (Pin 7) is the secondary emitter; leaving it unconnected reduces the switch current limit by ~2× (to ~0.5A) and doubles RDS(on), providing a simple hardware method to trade peak output current for enhanced overload safety - a feature specific to the LT1082CN8#PBF's MiniDIP variants and detailed in the "Extra Pins" section of its datasheet.
Can the LT1082CN8#PBF be synchronized to an external clock?
Yes, the LT1082CN8#PBF supports external synchronization in the 75kHz to 90kHz range via the VC pin: applying a narrow (<1µs) ground pulse synchronizes the internal 60kHz oscillator. This capability is confirmed in the "LT1082 Synchronizing" section (page 9) of the official datasheet and enables EMI reduction and multi-regulator phase alignment - though it requires careful pulse-width control to avoid offset voltage shifts.
LT1082CN8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- 8-PDIP
LT1082CN8#PBF FAQ
1.How can I place an order for LT1082CN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1082CN8#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 LT1082CN8#PBF reliable?
The price and inventory of LT1082CN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1082CN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1082CN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1082CN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1082CN8#PBF?
LT1082CN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1082CN8#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 LT1082CN8#PBF?
For technical support, including LT1082CN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1082CN8#PBF requirements.
6.How does Aetrix verify that LT1082CN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1082CN8#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 LT1082CN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1082CN8#PBF?
All LT1082CN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1082CN8#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 LT1082CN8#PBF part is unused and in its original packaging.
Return procedure for LT1082CN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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