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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > AC DC Converters, Offline Switches

STMicroelectronics E-L6565N

Name: E-L6565N
Brand: STMicroelectronics
SKU: E-L6565N
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: E-L6565N

Manufacturer:: STMicroelectronics

Category:: AC DC Converters, Offline Switches

Package:: 8-DIP (0.300", 7.62mm)

Datasheet:: E-L6565N.pdf

Description:: IC OFFLINE SWITCH FLYBACK 8DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6565N from STMicroelectronics is a current-mode quasi-resonant (QR) zero-voltage-switching (ZVS) flyback controller IC designed for primary-side regulation in offline AC-DC converters. It features 1% precision internal 2.5 V reference, ultra-low start-up current (<70 µA), ±400 mA totem-pole gate driver, line voltage feedforward for constant power delivery, and frequency foldback for standby efficiency - deployed in TV/monitor SMPS and digital consumer adapters.

For engineers reviewing the L6565N datasheet, L6565N pinout, L6565N application, or L6565N equivalent, key selection considerations include ZCD-triggered QR timing accuracy, VFF-based adaptive overcurrent clamping, hiccup-mode OCP response under short-circuit, and UVLO-controlled gate-driver pull-down behavior during startup and fault recovery.

Technical Context

The L6565N implements transformer demagnetization sensing via its ZCD pin (1.6 V negative-edge trigger, 2.1 V arming threshold) to synchronize MOSFET turn-on at valley points, enabling true ZVS operation across universal input (88–264 VAC). Its internal error amplifier uses a 2.5 V ±1% bandgap reference with 60–80 dB open-loop gain and 1 MHz GBW to support stable primary feedback loops.

Line feedforward is applied through the VFF pin to dynamically scale the CS comparator's current-limit threshold (0–1.5 V range) inversely with input voltage, maintaining constant output power across mains variation. Frequency foldback is implemented by blanking the ZCD trigger for 3.5–18 µs (voltage-dependent on COMP pin level), forcing cycle-skipping before transitioning to burst mode at ultra-light load.

Key Specifications

Parameter	Value and Actual Design Meaning
V_REF	2.5 V ±1% @ T_j = 25°C - enables ±1% output voltage regulation in primary-feedback designs without optocoupler
I_START-UP	<70 µA - allows high-value startup resistor (e.g., 3 MΩ) to minimize no-load dissipation in Energy Star-compliant adapters
I_Q (operating)	2.3–3.5 mA - ensures sub-50 mW quiescent loss at 12 V_CC, critical for Blue Angel standby compliance
I_GD (peak)	±400 mA - directly drives 1 Ω gate impedance MOSFETs (e.g., STP7NB80FI) without external buffer in 50 W TV SMPS
V_CS-DIS	2.0 V typical - sets hiccup-mode OCP threshold; disables GD when sensed primary current exceeds limit, preventing thermal runaway
T_BLANK	3.5 µs min. (COMP-dependent) - prevents false ZCD triggering from leakage inductance ringing, enabling robust QR operation under short-circuit
V_CC-OFF	8.7–10.3 V - defines UVLO hysteresis window (4 V typical); ensures gate driver remains pulled low until sufficient V_CC is established

Pinout & Package

DIP8 (Minidip) package with 2.54 mm pitch, JEDEC MS-012 compliant; thermally rated R_{th j-amb} = 100 °C/W (SO-8) / 150 °C/W (Minidip).

Pin/Terminal	Circuit Role	Design Meaning
1 INV	Inverting input of error amplifier	Accepts primary-side auxiliary winding voltage divider or optocoupler emitter signal; sets regulation setpoint against 2.5 V reference
2 COMP	Error amplifier output	Drives compensation network (RC between pins 1–2); modulated by optocoupler in secondary feedback; controls blanking time and frequency foldback
3 VFF	Line voltage feedforward input	Resistor-divider interface to bulk DC; scales CS overcurrent threshold inversely with input voltage to maintain constant power delivery
4 CS	Current sense comparator input	Monitors primary current via sense resistor; compared to VFF-scaled threshold; >2.0 V triggers hiccup-mode OCP
5 ZCD	Zero-current detection / sync input	Detects transformer demagnetization (negative edge at 1.6 V); requires 2.1 V arming pulse; grounded = disable; blanked post-GD low
6 GND	Signal and gate-driver return	Common reference for all analog blocks and 400 mA totem-pole driver; must be low-impedance to avoid noise coupling into CS/ZCD
7 GD	Gate driver output	±400 mA totem-pole stage; includes UVLO pull-down; drives MOSFET gate directly; no external clamp needed due to internal NPN/MOSFET structure
8 V_CC	Supply input	10.3–18 V operating range; powers internal 7 V regulator and gate driver; startup via high-value resistor from bulk DC

Key Features

Feature	Design Value
Quasi-resonant ZVS control	ZCD pin enables valley-switching with <3.5 µs blanking, reducing EMI and MOSFET switching losses in 50–100 kHz flyback designs
Adaptive overcurrent protection	VFF-modulated CS threshold ensures consistent power limiting across 88–264 VAC input, eliminating overdesign at low line
Frequency foldback + burst mode	COMP-dependent blanking forces discrete cycle skipping below minimum OFF-time, then transitions to low-stress burst mode at <5% load
Primary-side regulation ready	2.5 V ±1% reference + high-gain error amplifier supports stable output regulation using only auxiliary winding feedback - no optocoupler required
Ultra-low standby consumption	<70 µA start-up + <3.5 mA quiescent current meets Blue Angel and Energy Star Level V requirements for TV/printer adapters

Applications

TV/Display SMPS

AC-DC Adapters

Use Scenario: 50 W wide-input (88–264 VAC) flyback supply for 14" LCD TV with primary-side regulation.

IC Role / Device Role / Timing Role: QR controller synchronizing MOSFET turn-on to transformer demagnetization valleys via ZCD pin; regulates output using auxiliary winding voltage at INV pin.

Use Value: Achieves >85% full-load efficiency and <300 mW no-load consumption - compliant with Energy Star v5.0 for displays.

Use Scenario: 40 W universal-input adapter for inkjet printers with variable output loading (standby to full print).

IC Role / Device Role / Timing Role: Implements line feedforward (VFF) and frequency foldback to maintain constant 40 W output across input range while reducing light-load switching frequency.

Use Value: Enables <150 mW standby power via burst-mode transition, meeting IEC 62301 Ed.2 Class B limits for office equipment.

Digital Consumer Power

Office Equipment SMPS

Use Scenario: Compact 25 W QR flyback in set-top box power supply with tight EMI constraints.

IC Role / Device Role / Timing Role: Uses ZCD-triggered valley switching and internal 1 nF soft-start capacitor to limit inrush; GD pin drives 650 V MOSFET directly.

Use Value: Reduces peak EMI by 8–10 dBµV vs. fixed-frequency PWM, easing CISPR-22 Class B certification.

Use Scenario: 30 W multi-output SMPS in fax machine with burst-mode operation during sleep mode.

IC Role / Device Role / Timing Role: Leverages hiccup-mode OCP and UVLO pull-down on GD to safely handle secondary rectifier shorts without latch-off.

Use Value: Ensures field-reliable operation under sustained overload - no thermal shutdown or component stress during repeated fault events.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quasi-resonant flyback controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ICE2QS03G	Integrated 650 V CoolMOS + QR controller in DSO-8; no external HV startup needed; higher integration but fixed topology	Eliminates external MOSFET and startup resistor; not suitable for discrete MOSFET upgrades or custom layout optimization	Select when minimizing BOM count and board area is prioritized over flexibility in MOSFET selection or gate drive tuning
UCC28600DR	TI QR controller with programmable frequency limit, better light-load efficiency via adaptive burst, but requires external V_REF for primary feedback	Superior standby performance (<75 mW) and tighter V_REF drift (±0.5%) but lacks integrated 2.5 V reference for direct primary regulation	Select for ultra-low-power applications where secondary feedback or external reference is acceptable and tighter regulation tolerance is required

Compared with ICE2QS03G and UCC28600DR, the L6565N offers unique value in discrete-MOSFET-based designs requiring primary-side regulation without optocoupler, robust hiccup-mode fault recovery, and proven compatibility with legacy TV/printer reference designs - making it ideal for cost-sensitive, high-volume industrial replacements.

Availability

L6565N is available at Aetrix Electronics and suitable for TV/monitor SMPS, AC-DC adapters, and digital consumer power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for L6565N 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, Switzerland, designing and manufacturing microcontrollers, power ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The L6565N belongs to ST's legacy AC-DC controller product line, engineered specifically for quasi-resonant flyback topologies in universal-input offline power supplies targeting energy efficiency standards like Energy Star and Blue Angel.

FAQ

What is the purpose of the VFF pin on the L6565N?

The VFF (Voltage FeedForward) pin enables line-voltage compensation by scaling the current-sense comparator's overcurrent threshold inversely with input voltage. A resistor divider from bulk DC to VFF adjusts the CS clamp level from ~1.4 V at low line to ~0.2 V at high line, ensuring constant output power across 88–264 VAC input - critical for adapter compliance with Energy Star constant-power requirements.

How does the L6565N implement zero-voltage switching?

The L6565N achieves ZVS by monitoring transformer demagnetization via the ZCD pin: a negative-going edge below 1.6 V triggers MOSFET turn-on only after an arming pulse above 2.1 V confirms valley detection. Internal blanking (≥3.5 µs post-GD low) prevents false triggering from leakage ringing, ensuring reliable valley synchronization across load and line conditions in flyback converters.

Can the L6565N operate without an optocoupler?

Yes - the L6565N supports primary-side regulation using the auxiliary winding voltage fed to the INV pin, leveraging its 2.5 V ±1% internal reference and high-gain error amplifier. This eliminates the optocoupler in cost-sensitive applications like TV SMPS, though secondary feedback via TL431 + PC817 remains supported via COMP-driven optocoupler configuration.

What happens during hiccup-mode overcurrent protection?

When the CS pin voltage exceeds 2.0 V, the gate driver is disabled and the IC enters hiccup mode: quiescent current drops to 1.4–2.1 mA, V_CC discharges via startup resistor until UVLO turn-off (~8.7 V), then the internal starter initiates a new start-up cycle. This low-duty-cycle pulsing reduces MOSFET and transformer stress during sustained faults like secondary diode shorts - verified in printer and fax machine reference designs.

E-L6565N Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Output Isolation:: Isolated

Internal Switch(s):: No

Voltage - Breakdown:: -

Topology:: Flyback

Voltage - Start Up:: 13.5 V

Voltage - Supply (Vcc/Vdd):: 10.3V ~ 18V

Duty Cycle:: -

Frequency - Switching:: -

Power (Watts):: -

Fault Protection:: Current Limiting

Control Features:: -

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Supplier Device Package:: 8-DIP

Mounting Type:: Through Hole

E-L6565N FAQ

1.How can I place an order for E-L6565N through Aetrix?

Please submit a Request for Quotation (RFQ) for E-L6565N 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 E-L6565N reliable?

The price and inventory of E-L6565N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-L6565N is usually 5 days.

3.What payment methods are accepted for E-L6565N?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-L6565N transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for E-L6565N?

E-L6565N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your E-L6565N 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 E-L6565N?

For technical support, including E-L6565N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-L6565N requirements.

6.How does Aetrix verify that E-L6565N is sourced from the original manufacturer or authorized distributors?

All E-L6565N 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 E-L6565N meets industry standards.

7.What is the process for return or replacement of E-L6565N?

All E-L6565N units undergo pre-shipment inspection (PSI). If there is an issue with E-L6565N, 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 E-L6565N part is unused and in its original packaging.

Return procedure for E-L6565N:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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