SG6859 Ver la hoja de datos (PDF) - Fairchild Semiconductor
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SG6859 Datasheet PDF : 13 Pages
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Low Cost Green-Mode PWM Controller for Flyback Converters
MARKING DIAGRAMS
AAJMW
AAJ: SG6859
M: Mask Version
W: Week code A~Z=W1~W26
A~Z=W27~W52
: Lead Free Package
Product Specification
SG6859
PIN CONFIGURATION
GND
FB
RI
SOT-26
GATE
VDD
SENSE
SG6859TP
XXXXXXXXYWWV
T: D=DIP
P: Z =Lead Free
Null=Regular Package
XXXXXXXX: Wafer Lot
Y: Year; WW: Week
V: Assembly Location
GATE
VDD
NC
SENSE
DIP-8
GND
FB
NC
RI
ORDERING INFORMATION
Part Number
Pb-Free
SG6859TZ
SG6859DZ
Package
6-Pin SOT-26
8-Pin DIP-8
PIN DESCRIPTIONS
Name
Pin No.
DIP-8(SOT-26)
GATE 1 / (6)
VDD 2 / (5)
NC
3
SENSE 4 / (4)
RI
5 / (3)
NC
6
FB
7 / (2)
GND 8 / (1)
Type
Driver Output
Supply
Analog Input
Analog
Input/Output
Analog Input
Supply
Function
The totem-pole output driver for driving the power MOSFET.
Power supply.
NC pin.
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 also provides current amplitude information for
current-mode control.
A resistor connected from the RI pin to ground will generate a constant current
source for the SG6859. This current is used to charge an internal capacitor, to
determine the switching frequency. Increasing the resistance will reduce the
amplitude of the current source and reduce the switching frequency. A 95kΩ
resistor Ri results in a 50uA constant current Ii and a 70kHz switching frequency.
NC pin.
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.
© System General Corp.
Version 1.2.1(IAO33.0067.B2)
-2-
www.sg.com.tw • www.fairchildsemi.com
September 28, 2007
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