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Analog Devices Inc. LT1249IN8#PBF
- Part No.:
- LT1249IN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- PFC (Power Factor Correction)
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1249IN8#PBF.pdf
- Description:
- IC PFC CTR AVER CURR 100KHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,746
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Product details
Overview
LT1249IN8#PBF from Analog Devices (formerly Linear Technology) is an active power factor correction (PFC) controller IC designed for universal offline AC/DC preregulators. It implements fixed-frequency (100 kHz) current-mode PFC using line current averaging, delivers 1.5 A peak gate drive, supports synchronization up to 160 kHz, and operates across –40°C to +125°C. It targets high-efficiency, low-distortion preregulators in industrial and telecom power supplies up to 1500 W.
For engineers reviewing the LT1249IN8#PBF datasheet, LT1249IN8#PBF pinout, LT1249IN8#PBF application, or LT1249IN8#PBF equivalent, key selection criteria include its 100 kHz internal oscillator, 1.5 A gate driver capability, –40°C to +125°C operating range, undervoltage lockout thresholds (16.5 V turn-on / 10.5 V turn-off), and multiplier-based voltage-current feedforward architecture for low line current distortion.
Technical Context
The LT1249IN8#PBF employs a voltage-controlled current-mode architecture with a dedicated multiplier stage that squares the error amplifier output (VAOUT) to reduce AC gain at light load-maintaining stability and minimizing line current THD. Its current amplifier features 320 µmho transconductance and is compensated to provide >300 gain at 120 Hz while limiting gain to <15 at 100 kHz to prevent subharmonic oscillation.
Protection is integrated at the functional level: instantaneous overvoltage shutdown triggers when VAOUT sink current exceeds 44 µA; line current limiting is enforced via RMOUT voltage clamping at 1.1 V; and MOUT pin voltage is restricted to –6 V during operation to avoid gate driver malfunction. The device rejects line switching noise via internal 32 kΩ series impedance at IAC and supports external synchronization through CAOUT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 100 kHz typical; sets fixed PWM timing for stable current-loop control without slope compensation. |
| Gate Driver Peak Current | 1.5 A; directly drives high-Ciss MOSFET gates without external buffer, reducing component count. |
| Operating Temperature Range | –40°C to +125°C; qualified for industrial and telecom environments with no derating up to TJ = 125°C. |
| VCC UVLO Thresholds | Turn-on at 16.5 V, turn-off at 10.5 V; ensures clean startup and brownout recovery in wide-input AC systems. |
| Multiplier Gain Constant | 0.035 V⁻²; enables square-law feedforward to suppress light-load distortion and improve system stability. |
| Current Amplifier Transconductance | 320 µmho typical; provides precise line current regulation with minimal offset-induced input power error. |
| Reference Voltage | 7.5 V ±1.2% over temperature; serves as stable bias for voltage error amplifier and sense circuitry. |
Pinout & Package
LT1249IN8#PBF is housed in an 8-lead PDIP (N8) package with 0.300-inch width, rated for θJA = 100°C/W and suitable for through-hole mounting in high-reliability industrial designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Power and signal reference ground | Common return path for all internal amplifiers, oscillator, and gate driver; must be low-impedance. |
| CAOUT (Pin 2) | Current amplifier output | Drives PWM modulator; goes low to force zero duty cycle; clamped at 8 V for protection. |
| MOUT (Pin 3) | Multiplier current output | Sinks current through RMOUT to generate current-loop reference; voltage limited to –1.1 V max. |
| IAC (Pin 4) | AC line voltage sensing input | High-impedance current input biased at 2 V; includes 32 kΩ series resistor for noise filtering. |
| VAOUT (Pin 5) | Voltage error amplifier output | Clamped at 12 V; controls multiplier gain; drops below 1.5 V to disable multiplier output. |
| VSENSE (Pin 6) | Voltage feedback input | Inverting input of 100 dB gain error amplifier; referenced to 7.5 V internal bandgap. |
| VCC (Pin 7) | Supply voltage input | Accepts 11.5–25 V; powers all circuitry; draws only 250 µA during start-up. |
| GTDR (Pin 8) | Gate driver output | 1.5 A totem-pole output; clamped at 15 V; requires ≥5 Ω series gate resistor to suppress overshoot. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 100 kHz PWM frequency | Eliminates need for external timing components and slope compensation in current-mode PFC design. |
| 1.5 A peak gate driver | Directly switches high-power MOSFETs (e.g., IRF840) without external drivers, reducing BOM and layout complexity. |
| Line current averaging architecture | Achieves lower THD than peak-current or ZCS methods, especially in discontinuous conduction mode (DCM). |
| Integrated overvoltage protection | Shuts down within one cycle when output overvoltage causes VAOUT sink current to exceed 44 µA. |
| Synchronization capability (127–160 kHz) | Enables noise-sensitive systems (e.g., RF equipment) to align switching with external clocks and avoid beat frequencies. |
| Low start-up supply current (250 µA) | Permits trickle-start using high-value resistors from rectified line, simplifying auxiliary supply design. |
Applications
| Industrial Motor Drive Preregulators | Telecom Rectifier Modules |
|---|---|
|
Use Scenario: 3 kW telecom rectifier with universal AC input (90–264 VAC) and 54 VDC output requiring >98% efficiency and EN 61000-3-2 Class A compliance. IC Role / Device Role / Timing Role: Primary PFC controller enforcing sinusoidal line current draw and regulating 385 VDC bus voltage via average current mode control. Use Value: Delivers <3% THD at full load and maintains PF >0.99 from 20% to 100% load due to square-law multiplier and 100 kHz fixed-frequency operation. |
Use Scenario: High-density 1U server PSU with dual-stage conversion where PFC stage feeds isolated LLC resonant converter. IC Role / Device Role / Timing Role: Standalone PFC controller managing boost inductor current and synchronizing to downstream LLC clock to minimize EMI. Use Value: Synchronization range (127–160 kHz) allows alignment with 140 kHz LLC fundamental, reducing conducted emissions by 8–10 dBµV. |
| Medical Imaging Power Supplies | Industrial PLC Power Modules |
|
Use Scenario: CT scanner power system requiring ultra-stable 400 VDC bus with immunity to line transients and zero downtime during diagnostic cycles. IC Role / Device Role / Timing Role: Core PFC controller with fast overvoltage response (<1 µs detection latency) and robust noise rejection on IAC and CAOUT pins. Use Value: Instantaneous OV protection prevents capacitor overvoltage during sudden load removal; 250 µA start-up current enables reliable cold-start from backup hold-up capacitors. |
Use Scenario: DIN-rail mounted programmable logic controller with wide ambient range (–40°C to +70°C) and long service life requirement (>10 years). IC Role / Device Role / Timing Role: Industrial-grade PFC controller operating continuously at TJ = 125°C with validated thermal performance in N8 PDIP package. Use Value: Specified –40°C to +125°C junction range and 100°C/W θJA enable convection-cooled designs without forced air, reducing system cost and failure modes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power factor controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1248CN8#PBF | 16-pin SOIC; offers adjustable oscillator frequency (50–200 kHz), programmable overvoltage threshold, and independent current limit setting. | Used where design flexibility (e.g., EMI tuning, multi-rail PFC) outweighs board space constraints and cost sensitivity. | Select LT1248CN8#PBF if variable frequency or user-defined protection thresholds are required; not pin-compatible with LT1249IN8#PBF. |
| UCC28180DR | Texas Instruments' 8-pin PFC controller with 65–300 kHz programmable frequency, built-in soft-start, and enhanced brownout protection. | Targets cost-optimized consumer and industrial SMPS where TI's ecosystem and WEBENCH support are preferred. | Choose UCC28180DR for new designs needing soft-start or wider frequency range; requires PCB redesign due to different pinout and biasing. |
Compared with LT1248CN8#PBF and UCC28180DR, the LT1249IN8#PBF offers superior integration density and lower THD in fixed-frequency, high-reliability industrial preregulators-but lacks programmability and requires external sync circuitry for frequency coordination.
Availability
LT1249IN8#PBF is available at Aetrix Electronics and suitable for industrial motor drives, telecom rectifiers, medical imaging systems, and PLC power modules requiring stable component supply, extended temperature operation, and proven PFC performance.
Supply support for LT1249IN8#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1249IN8#PBF belongs to Linear's legacy high-voltage power factor controller family, engineered specifically for universal-input, high-power preregulators demanding low THD, robust protection, and minimal external components.
FAQ
What is the maximum operating junction temperature for LT1249IN8#PBF?
The LT1249IN8#PBF is rated for continuous operation up to +125°C junction temperature. Its electrical specifications-including oscillator frequency, gate drive strength, and reference voltage accuracy-are guaranteed across the full –40°C to +125°C range, making it suitable for convection-cooled industrial enclosures without derating.
Does LT1249IN8#PBF require slope compensation in current-mode operation?
No, the LT1249IN8#PBF does not require external slope compensation. Its fixed-frequency, line current averaging architecture inherently avoids subharmonic oscillation in both continuous and discontinuous conduction modes-unlike peak-current-mode controllers-reducing external component count and design complexity.
How does the LT1249IN8#PBF implement overvoltage protection?
The LT1249IN8#PBF detects overvoltage via the voltage error amplifier: when output overvoltage forces excess current through the VSENSE divider into VAOUT, the amplifier sinks more than 44 µA, causing its output to collapse and immediately disable the multiplier. This shuts off gate drive within one switching cycle, protecting downstream components.
Can LT1249IN8#PBF synchronize to an external clock, and what is the valid frequency range?
Yes, the LT1249IN8#PBF supports external synchronization via the CAOUT pin. A Schottky-clamped transistor pulls CAOUT below 0.35 V to trigger sync, with a valid input frequency range of 127 kHz to 160 kHz. Pulse width must remain under 60 ns to avoid introducing measurable offset in the current loop.
What is the purpose of the 32 kΩ resistor inside the IAC pin of LT1249IN8#PBF?
The internal 32 kΩ resistor at the IAC pin establishes a high-impedance, noise-immune interface for AC line voltage sensing. It enables effective filtering with a small external capacitor (e.g., 1 nF) to reject high-frequency switching noise-preventing instability caused by ripple injection into the multiplier-while minimizing line current dead zone via 2 V biasing.
LT1249IN8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Mode:
- Average Current
- Frequency - Switching:
- 100kHz
- Current - Startup:
- 250 µA
- Voltage - Supply:
- 15.5V ~ 27V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LT1249IN8#PBF FAQ
1.How can I place an order for LT1249IN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1249IN8#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 LT1249IN8#PBF reliable?
The price and inventory of LT1249IN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1249IN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1249IN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1249IN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1249IN8#PBF?
LT1249IN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1249IN8#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 LT1249IN8#PBF?
For technical support, including LT1249IN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1249IN8#PBF requirements.
6.How does Aetrix verify that LT1249IN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1249IN8#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 LT1249IN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1249IN8#PBF?
All LT1249IN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1249IN8#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 LT1249IN8#PBF part is unused and in its original packaging.
Return procedure for LT1249IN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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