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STMicroelectronics L6566BTR
- Part No.:
- L6566BTR
- Manufacturer:
- STMicroelectronics
- Category:
- AC DC Converters, Offline Switches
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
L6566BTR.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,136
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Product details
Overview
L6566BTR from STMicroelectronics is a multi-mode current-mode primary-side controller IC for offline flyback and single-stage PFC converters, featuring selectable fixed-frequency or quasi-resonant operation, 700 V high-voltage start-up, adaptive UVLO, <3 mA quiescent current, and integrated 800 mA totem-pole gate driver in SO16N package - used in Hi-end AC-DC adapters, LCD TV/monitor power supplies, and digital consumer equipment.
For engineers reviewing the L6566BTR datasheet, L6566BTR pinout, L6566BTR application, or L6566BTR equivalent, key selection criteria include QR/FF mode flexibility, line feedforward-enabled constant-power regulation across mains voltage range, transformer saturation detection, programmable frequency modulation for EMI reduction, and latched/autorestart OVP/OCP configuration options.
Technical Context
The L6566BTR implements dual-mode control logic: in quasi-resonant (QR) mode, ZCD pin (11) senses transformer demagnetization to enable zero-voltage switching, while MODE/SC pin (12) selects QR when tied to VREF (10); in fixed-frequency (FF) mode, OSC pin (13) sets exact switching frequency via external resistor, with slope compensation applied via MODE/SC–CS connection. The oscillator supports frequency modulation via FMOD pin (6) for spread-spectrum EMI suppression.
Protection architecture includes two-tier OCP: pulse-by-pulse current limiting at CS pin (7) with 1.5 V saturation latch, plus hiccup-mode shutdown on sustained overload; OVP is implemented via ZCD pin (11) with 5 V threshold and strobed digital filtering; brownout protection uses AC_OK pin (16) with 0.45 V trip and 15 µA hysteresis current source; adaptive UVLO dynamically lowers VCC turn-off threshold under light load to maintain stable self-supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Modes | Selectable fixed-frequency (FF) or quasi-resonant (QR) - FF enables precise timing control; QR enables ZVS for efficiency at heavy load. |
| Start-up Voltage Range | 700 V max on HVS pin (1) - allows direct connection to rectified mains without external HV resistor network. |
| Quiescent Current | <3 mA - minimizes no-load power consumption to meet energy-saving standards like ErP Tier 2. |
| Gate Driver Output | ±800 mA peak totem-pole with active pull-down during UVLO - ensures fast MOSFET turn-off even during supply dip. |
| Oscillator Frequency Range | 20–500 kHz (FF), up to 500 kHz max (QR) - set by resistor from OSC (13) to GND; modulated via FMOD (6) for EMI reduction. |
| Line Feedforward Input | VFF pin (15): 0–3 V linear range - scales current limit inversely with input voltage to maintain constant output power across 85–265 VAC. |
| Protection Thresholds | ZCD OVP = 5 V (latched/autorestart); AC_OK brownout = 0.45 V; CS saturation = 1.5 V; DIS disable = 4.5 V - all digitally filtered or hysteresis-stabilized. |
Pinout & Package
Package: SO16N (16-pin small outline, 1.27 mm pitch, body size 10.3 × 7.5 mm, JEDEC MS-012).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HVS (1) | High-voltage start-up input | 700 V-rated pin sourcing 1 mA internal current to charge VCC capacitor - eliminates need for external HV bias resistor. |
| N.C. (2) | No internal connection | PCB clearance provision for creepage/clearance compliance in safety-critical AC-DC designs. |
| GND (3) | Signal and gate-drive return | Common ground for analog circuitry and 800 mA driver - requires dedicated low-impedance trace separate from power return paths. |
| GD (4) | Gate driver output | Totem-pole stage driving MOSFET/IGBT gate directly - active pull-down during UVLO prevents unintended turn-on. |
| VCC (5) | IC supply rail | Self-supplied after start-up; UVLO thresholds adapt dynamically (e.g., 14 V turn-on, lowered under light load). |
| FMOD (6) | Frequency modulation control | Accepts RC network or resistor to OSC (13) to spread switching frequency spectrum and reduce EMI peaks. |
| CS (7) | Current sense input | 150 ns leading-edge blanking; dual-threshold comparator (0.45 V normal OCP, 1.5 V saturation latch). |
| DIS (8) | Latched disable input | 4.5 V threshold triggers permanent shutdown until VCC drops below UVLO - used for external OTP or fault lockout. |
| COMP (9) | Control loop feedback | 2.5–5 V dynamic range; voltage below ~2 V initiates burst-mode; clamped at 1.4 V for hard shutdown. |
| VREF (10) | 5 V ±2% reference output | Supplies ≤5 mA to optocoupler or external circuitry; internally monitored - failure causes latch-off. |
| ZCD (11) | Zero-current detection / OVP | Transformer auxiliary winding interface; negative edge triggers QR turn-on; >5 V triggers OVP shutdown. |
| MODE/SC (12) | Mode selection / slope comp | Tied to VREF for QR; left open for FF; connected to CS via resistor for slope compensation in FF mode. |
| OSC (13) | Oscillator timing node | 1 V accurate voltage source; resistor to GND sets frequency - defines actual fSW (FF) or max fSW (QR). |
| SS (14) | Soft-start timing | Internal current charges external capacitor; controls duty ramp-up and delays OLP shutdown via same capacitor. |
| VFF (15) | Line voltage feedforward | 0–3 V input scaling current limit inversely with mains - maintains constant output power from 85–265 VAC. |
| AC_OK (16) | Brownout detection | 0.45 V threshold with 15 µA hysteresis - non-latched shutdown clears all latches and reduces consumption during low-line. |
Key Features
| Feature | Design Value |
|---|---|
| Multi-mode operation selection | Hardware-configurable FF or QR via MODE/SC pin tie - avoids firmware dependency and enables robust analog control. |
| Adaptive UVLO | Dynamically lowers VCC turn-off threshold under light load - compensates for transformer parasitic-induced VCC droop and prevents false shutdown. |
| Transformer saturation detection | CS pin 1.5 V secondary OCP threshold - detects core saturation or secondary diode short, triggering latched intermittent operation. |
| Programmable frequency modulation | FMOD pin enables resistor-controlled oscillator jitter - spreads EMI energy across bandwidth, easing EN55022 Class B compliance. |
| Valley skipping in QR mode | Automatically skips switching cycles at light load - maintains operation near valley point for continued ZVS and low EMI. |
| Externally controllable burst-mode | COMP pin voltage <2 V initiates controlled burst - reduces no-load consumption to <300 mW in typical 65 W adapter designs. |
Applications
| Hi-end AC-DC Adapter/Charger | LCD TV / Monitor Power Supply |
|---|---|
|
Use Scenario: 65 W universal-input adapter for laptop charging with <300 mW no-load consumption and EN61000-3-2 Class D compliance. IC Role / Device Role / Timing Role: Primary-side current-mode controller managing QR flyback topology, real-time ZCD-triggered MOSFET turn-on, and line feedforward-based constant power regulation. Use Value: Achieves >89% average efficiency across load range and passes CoC Tier 2 requirements due to adaptive UVLO, valley skipping, and <3 mA quiescent current. |
Use Scenario: 120 W main power supply for 32″ LCD TV with PFC + LLC or flyback + synchronous rectification stages. IC Role / Device Role / Timing Role: Single-stage PFC controller with FF operation and line feedforward - regulates input current shape while maintaining constant output power over 85–265 VAC. Use Value: Eliminates need for separate PFC controller IC, reducing BOM count and PCB area; meets JEITA-MITI harmonic limits without additional compensation circuitry. |
| Digital Consumer Equipment | IT Equipment Power Supply |
|
Use Scenario: Compact 45 W power supply for streaming box with low-profile heatsink and no audible noise requirement. IC Role / Device Role / Timing Role: QR flyback controller using ZCD sensing and frequency foldback - operates in silent burst-mode below 10% load and transitions smoothly to QR above 20%. Use Value: Enables fanless design by minimizing conduction and switching losses; FMOD-driven spread-spectrum reduces 100–300 kHz EMI peaks that cause coil whine. |
Use Scenario: 90 W internal power supply for network-attached storage (NAS) unit requiring high reliability and thermal margin. IC Role / Device Role / Timing Role: FF-mode flyback controller with latched OVP/OCP and DIS-pin OTP integration - provides fail-safe shutdown on overtemperature or output short. Use Value: Dual-level OCP (pulse-by-pulse + saturation latch) protects MOSFET and transformer under sustained overload, extending MTBF beyond 100,000 hours. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar primary-side SMPS controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28056DR | Fixed-frequency only; no QR capability; integrated 600 V startup; lower gate drive (±500 mA); no adaptive UVLO. | Targeted at cost-sensitive, medium-efficiency adapters where ZVS is not required; lacks valley skipping and feedforward. | Select when QR operation and wide mains-range constant power are not needed; preferred for simpler BOM and layout. |
| ICE2QS03G | QR-only operation; no FF mode; 650 V startup; built-in soft-start; no VFF or FMOD pins; lower integration (no VREF, no DIS). | Optimized for entry-level QR flyback in monitors and printers; no line feedforward or programmable EMI reduction. | Choose for basic QR designs with tight cost targets and minimal feature requirements - not suitable for PFC or wide-input constant-power apps. |
Compared with UCC28056DR and ICE2QS03G, the L6566BTR uniquely supports both FF and QR modes in one device, includes adaptive UVLO for stable light-load operation, and offers full line feedforward and frequency modulation - making it the only option among the three capable of meeting strict ErP Tier 2 and EN55022 Class B requirements in high-end adapters.
Availability
L6566BTR is available at Aetrix Electronics and suitable for Hi-end AC-DC adapters, LCD TV/monitor power supplies, and single-stage PFC applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across manufacturing lots.
Supply support for L6566BTR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, analog, microcontrollers, and automotive ICs with vertical manufacturing and broad industrial qualification.
The L6566BTR belongs to ST's high-performance SMPS controller product line, designed specifically for energy-efficient, safety-compliant offline power conversion in consumer, computing, and display applications demanding QR/FF flexibility and robust protection.
FAQ
What is the maximum allowable switching frequency in quasi-resonant mode?
The L6566BTR's maximum switching frequency in QR mode is set by the external resistor on the OSC pin (13) and is limited to 500 kHz. This value represents the upper bound - actual operating frequency varies dynamically with load and transformer demagnetization time, dropping at light loads via valley skipping to maintain ZVS and minimize EMI.
How does the adaptive UVLO function improve light-load stability?
The adaptive UVLO lowers the VCC turn-off threshold under light load conditions to counteract natural VCC voltage reduction caused by transformer leakage inductance and parasitic capacitance. This prevents premature shutdown during burst-mode operation and ensures reliable restart after line dips, improving no-load hold-up time and energy efficiency compliance.
Can the L6566BTR be used in single-stage PFC topologies?
Yes - the L6566BTR is explicitly qualified for single-stage single-switch input-current-shaping converters compliant with EN61000-3-2 and JEITA-MITI regulations. Its line voltage feedforward (VFF pin) and programmable current limit enable constant output power across universal AC input, eliminating the need for a separate PFC controller.
What is the purpose of the MODE/SC pin in fixed-frequency operation?
In FF mode, the MODE/SC pin (12) serves two roles: it provides a synchronized ramp signal (zero during GD low, rising during GD high) for slope compensation when connected to CS via a resistor, and acts as a diagnostic node for oscilloscope monitoring of PWM timing alignment - critical for stable current-mode control at high duty cycles.
L6566BTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Isolation:
- Isolated
- Internal Switch(s):
- No
- Voltage - Breakdown:
- -
- Topology:
- Flyback
- Voltage - Start Up:
- 14 V
- Voltage - Supply (Vcc/Vdd):
- 8V ~ 23V
- Duty Cycle:
- 75%
- Frequency - Switching:
- 10kHz ~ 300kHz
- Power (Watts):
- -
- Fault Protection:
- Current Limiting, Over Load
- Control Features:
- Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-SO
- Mounting Type:
- Surface Mount
L6566BTR FAQ
1.How can I place an order for L6566BTR through Aetrix?
Please submit a Request for Quotation (RFQ) for L6566BTR 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 L6566BTR reliable?
The price and inventory of L6566BTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6566BTR is usually 5 days.
3.What payment methods are accepted for L6566BTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6566BTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L6566BTR?
L6566BTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L6566BTR 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 L6566BTR?
For technical support, including L6566BTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6566BTR requirements.
6.How does Aetrix verify that L6566BTR is sourced from the original manufacturer or authorized distributors?
All L6566BTR 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 L6566BTR meets industry standards.
7.What is the process for return or replacement of L6566BTR?
All L6566BTR units undergo pre-shipment inspection (PSI). If there is an issue with L6566BTR, 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 L6566BTR part is unused and in its original packaging.
Return procedure for L6566BTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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