SG6859DTY

SG6859DTY Datasheet

SG6859D

Part	Datasheet
SG6859DTY	SG6859DTY (pdf)

PDF Datasheet Preview
February 2009 SG6859D Low-Cost, Green-Mode PWM Controller for Flyback Converters Green-Mode PWM Supports the Standard Low Startup Current 9 A Low Operating Current 3mA 300mA Driving Capability Leading-Edge Blanking Constant Output Power Limit Universal Input Built-in Synchronized Slope Compensation Current-Mode Operation Cycle-by-Cycle Current Limiting Under-Voltage Lockout UVLO Programmable PWM Frequency with Frequency Hopping VDD Over-Voltage Protection Auto Restart Gate Output Voltage Clamped at 17V Low Cost Few External Components Required Small SSOT-6 Package This highly integrated PWM controller provides several enhancements designed to meet the low standby-power needs of low-power SMPS. To minimize standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load conditions. This green-mode function enables the power supply to meet even the strictest power conservation requirements. The BiCMOS fabrication process enables reducing the startup current to 9 A and the operating current to 3mA. To further improve power conservation, a large startup resistance can be used. Built-in synchronized slope compensation ensures the stability of peak current mode control. Proprietary internal compensation provides a constant output power limit over a universal AC input range 90VAC to 264VAC . Pulse-by-pulse current limiting ensures safe operation during short-circuits. To protect the external power MOSFET from damage by supply over voltage, the SG6859Ds output driver is clamped at 17V. SG6859D controllers can be used to improve the performance and reduce the production cost of power supplies. The best choice for replacing linear and RCC-mode power adapters. Available in 8pin DIP and 6-pin SSOT-6 packages. General-purpose switching mode power supplies and flyback power converters, such as: Battery chargers for cellular phones, cordless phones, PDAs, digital cameras, and power tools Power adapters for ink jet printers, video game consoles, and portable audio players Open-frame SMPS for TV/DVD standby and auxiliary supplies, home appliances, and consumer electronics Replacements for linear transformers and RCC SMPS PC 5V standby power Ordering Information Part Number SG6859DTY SG6859DDY Operating Temperature Range -40 to +105 C Package SSOT-6 DIP-8 Eco Status Green Packing Method Tape & reel Tube For Fairchild’s definition of “green” Eco Status, please visit: SG6859D Low-Cost, Green-Mode PWM Controller for Flyback Converters Application Diagram SG6859D Figure Typical Application Internal Block Diagram OSC Generator Figure Functional Block Diagram 2008 Fairchild Semiconductor Corporation SG6859D Low-Cost, Green-Mode PWM Controller for Flyback Converters Marking Information XXXX ABBK=SG6859D T Die Run Code Year Code - - - Week Code Marking for SG6859DTY Green compound ZXYTT 6859D TPM F- Fairchild Logo Z- Plant Code X- 1 Digit Year Code Y- 1 Digit Week Code TT 2 Digits die Run Code T Package Type D=DIP P Y Green Package M Manufacture Flow Code Marking for SG6859DDY Green compound Figure Top Mark Pin Configurations Figure 8-Pin DIP Pin Definitions Figure 6-Pin SSOT DIP Pin # 1 2 3 4 SSOT Pin # Name Description GATE VDD NC SENSE NC FB GND The totem-pole output driver for driving the power MOSFET. Power Supply. No Connection. Current Sense. This pin senses the voltage across a resistor. When the voltage reaches the internal threshold, PWM output is disabled. This activates over-current protection. This pin provides current amplitude information for current-mode control. A resistor connected from the RI pin to ground generates a constant current source used to charge an internal capacitor and determine the switching frequency. Increasing the resistance reduces the amplitude of the current source and the switching frequency. A 95k resistor RI results in a 50 A constant current II and a 65kHz switching frequency. No Connection. Feedback. The FB pin provides the output voltage regulation signal. It provides feedback to the internal PWM comparator, so that the PWM comparator can control the duty cycle. Ground.

PDF Datasheet Preview

February 2009

SG6859D

Low-Cost, Green-Mode PWM Controller for Flyback Converters

Green-Mode PWM Supports the Standard Low Startup Current 9 A Low Operating Current 3mA 300mA Driving Capability Leading-Edge Blanking Constant Output Power Limit Universal Input Built-in Synchronized Slope Compensation Current-Mode Operation Cycle-by-Cycle Current Limiting Under-Voltage Lockout UVLO Programmable PWM Frequency with Frequency Hopping VDD Over-Voltage Protection Auto Restart Gate Output Voltage Clamped at 17V Low Cost Few External Components Required Small SSOT-6 Package

This highly integrated PWM controller provides several enhancements designed to meet the low standby-power needs of low-power SMPS. To minimize standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load conditions. This green-mode function enables the power supply to meet even the strictest power conservation requirements.

The BiCMOS fabrication process enables reducing the startup current to 9 A and the operating current to 3mA. To further improve power conservation, a large startup resistance can be used. Built-in synchronized slope compensation ensures the stability of peak current mode control. Proprietary internal compensation provides a constant output power limit over a universal AC input range 90VAC to 264VAC . Pulse-by-pulse current limiting ensures safe operation during short-circuits.

To protect the external power MOSFET from damage by supply over voltage, the SG6859Ds output driver is clamped at 17V. SG6859D controllers can be used to improve the performance and reduce the production cost of power supplies. The best choice for replacing linear and RCC-mode power adapters. Available in 8pin DIP and 6-pin SSOT-6 packages.

General-purpose switching mode power supplies and flyback power converters, such as:

Battery chargers for cellular phones, cordless phones, PDAs, digital cameras, and power tools

Power adapters for ink jet printers, video game consoles, and portable audio players

Open-frame SMPS for TV/DVD standby and auxiliary supplies, home appliances, and consumer electronics

Replacements for linear transformers and RCC SMPS

PC 5V standby power
Ordering Information

Part Number SG6859DTY SG6859DDY

Operating Temperature Range -40 to +105 C

Package SSOT-6 DIP-8

Eco Status Green

Packing Method Tape & reel Tube

For Fairchild’s definition of “green” Eco Status, please visit:

SG6859D Low-Cost, Green-Mode PWM Controller for Flyback Converters

Application Diagram

SG6859D Figure Typical Application

Internal Block Diagram

OSC Generator

Figure Functional Block Diagram
2008 Fairchild Semiconductor Corporation

SG6859D Low-Cost, Green-Mode PWM Controller for Flyback Converters

Marking Information

XXXX ABBK=SG6859D T Die Run Code

Year Code
- - - Week Code
*Marking for SG6859DTY Green compound

ZXYTT 6859D TPM

F- Fairchild Logo Z- Plant Code X- 1 Digit Year Code Y- 1 Digit Week Code TT 2 Digits die Run Code T Package Type D=DIP P Y Green Package M Manufacture Flow Code
*Marking for SG6859DDY Green compound Figure Top Mark

Pin Configurations

Figure 8-Pin DIP

Pin Definitions

Figure 6-Pin SSOT

DIP Pin #
1 2 3 4

SSOT Pin #

Name Description

GATE VDD NC SENSE

NC FB GND

The totem-pole output driver for driving the power MOSFET.

Power Supply.

No Connection.

Current Sense. This pin senses the voltage across a resistor. When the voltage reaches the internal threshold, PWM output is disabled. This activates over-current protection. This pin provides current amplitude information for current-mode control.

A resistor connected from the RI pin to ground generates a constant current source used to charge an internal capacitor and determine the switching frequency. Increasing the resistance reduces the amplitude of the current source and the switching frequency. A 95k resistor RI results in a 50 A constant current II and a 65kHz switching frequency.

No Connection.

Feedback. The FB pin provides the output voltage regulation signal. It provides feedback to the internal PWM comparator, so that the PWM comparator can control the duty cycle.

Ground.

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Datasheet ID: SG6859DTY 634737