SG6846A Fairchild Semiconductor, SG6846A Datasheet - Page 7

• Manufacturer Part Number: SG6846A
• Description: The highly integrated SG6846A series of PWM controllers provides features to enhance the performance of flyback converters
• Manufacturer: Fairchild Semiconductor

© 2008 Fairchild Semiconductor Corporation
SG6846A • Rev. 1.1.5
Oscillator Section
Electrical Characteristics
V
DD
Symbol
f
f
OSC,MAX
OSC,MIN
f
V
V
t
t
OSC-G
f
= 15V and T
hop-1
hop-3
OSC
S
f
f
FB-N
FB-G
DV
DT
G
Normal PWM Frequency
Maximum PWM
Frequency
Minimum PWM Frequency
Jitter Period
Green-Mode Minimum Frequency
FB Pin Frequency
Reduction Threshold
FB Voltage at f
Slope for Green-Mode Modulation
Frequency Variation vs. V
Frequency Variation vs. Temperature
Deviation
NO
A
= 25°C unless otherwise noted.
Timing = 100 ms
FB V
I
(1) Normal
Operation
P
> 2/3I
>
(2)
(3)
or
FB-OLP
OSC-G
Parameter
PK
Figure 6. SG6846A OCP/SCP Logic Flow Diagram
(Continued)
Pin, FB voltage
Jitter Range
Pin, FB voltage
Jitter Range
DD
Center
Frequency
Jitter Range
Center
Frequency
Jitter Range
Center
Frequency
Jitter Range
Deviation
Timing = 1700ms
(5 )
OCP
7
R
R
R
R
R
R
R
R
R
V
T
A
DD
Test Condition
I
I
I
I
I
I
I
I
I
= 26kΩ, V
= 13kΩ, V
= 36kΩ, V
= 26kΩ, V
= 26kΩ, V
= 26kΩ
= 26kΩ, V
= 26kΩ, V
= 26kΩ
= -30 to 85°C
= 11.5V to 20V
(7) Gate Off
V
DD
(4)
< 12 V
SCP
FB
FB
FB
FB
FB
FB
FB
>V
>V
>V
NO
YES
 V
= V
= V
= V
N
N
N
N
G
N
G
V
YES
DD
SCP
±2.54
Min.
44.8
10.2
18.0
1.27
±3.7
±7.4
124
3.9
1.9
3.7
1.4
62
< = 12 V
Continued on following page…
(6 )
NO
±2.90
Typ.
±4.2
±8.4
47.0
11.5
22.5
1.45
130
4.4
2.1
4.2
1.6
1.5
65
85
Max.
±3.26
49.2
12.8
25.0
1.62
±4.7
±9.4
136
4.9
2.3
4.7
1.8
5.0
68
5
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Hz/mV
Unit
KHz
KHz
kHz
kHz
kHz
kHz
ms
%
%
V
V