sg6846bftp Fairchild Semiconductor, sg6846bftp Datasheet - Page 7

• Manufacturer Part Number: sg6846bftp
• Description: Sg6846b ? Highly Integrated Green-mode Pwm Controller
• Manufacturer: Fairchild Semiconductor

© 2008 Fairchild Semiconductor Corporation
SG6846B • Rev. 1.3.4
Oscillator Section
Electrical Characteristics
V
DD
Symbol
f
f
OSC,MAX
OSC,MIN
f
V
V
t
OSC-G
f
= 15V and T
hop-1
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
Slope for Green-Mode Modulation
FB Pin Frequency
Reduction Threshold Jitter Range
FB Voltage at f
Frequency Variation vs. V
Frequency Variation vs. Temperature
Deviation
A
= 25°C unless otherwise noted.
N O
T i m i ng = 8 m s
I
P
( 1 ) no rm a l
ope r a t i on
> 2 / 3 I
( 2 )
( 3 )
OSC-G
Parameter
PK
Figure 6. SG6846B OCP/SCP Logic Flow Diagram
?
(Continued)
Pin, FB voltage
Pin, FB voltage
DD
Center
Frequency
Jitter Range
Center
Frequency
Jitter Range
Center
Frequency
Jitter Range
Deviation
Timing = 200ms
(5 )
OCP
7
R
R
R
R
R
R
R
R
V
T
A
DD
Test Condition
I
I
I
I
I
I
I
I
= 26kΩ, V
= 13kΩ, V
= 36kΩ, V
= 26kΩ, V
= 26kΩ
= 26kΩ
= 26kΩ, V
= 26kΩ, V
= -30 to 85°C
= 11.5V to 20V
V
(7 ) Gate-off
DD
(4 )
< 12 V ?
FB
FB
FB
FB
FB
FB
SCP
>V
>V
>V
≥ V
= V
= V
NO
YES
N
N
N
N
N
G
V
±2.54
Min.
44.8
18.0
±3.7
±7.4
124
YES
DD
3.9
1.9
3.7
1.4
SCP
62
Continued on following page…
< = 12 V ?
(6 )
±2.90
Typ.
±4.2
±8.4
47.0
22.5
130
4.4
2.1
4.2
1.6
1.5
NO
65
85
Max.
±3.26
49.2
25.0
±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
ms
%
%
V
V