FSCQ-SERIES
Electrical Characteristics (Continued)
(Ta=25°C unless otherwise specified)
Parameter
Symbol
Condition
Min. Typ. Max. Unit
CONTROL SECTION
Switching Frequency
Switching Frequency Variation(1)
Feedback Source Current
Maximum Duty Cycle
Minimum Duty Cycle
F
V
= 5V, V = 18V
CC
18
0
20
22
kHz
%
OSC
FB
ΔF
-25°C ≤ Ta ≤ 85°C
±5
±10
OSC
I
V
V
V
V
V
= 0.8V, V
= 18V
CC
0.5 0.65 0.8 mA
FB
FB
FB
FB
D
= 5V, V
= 0V, V
= 18V
92
-
95
0
98
-
%
%
V
MAX
CC
CC
D
= 18V
MIN
V
14
8
15
9
16
10
22
START
FB=1V
FB=1V
UVLO Threshold Voltage
V
V
STOP
Soft Start Time (1)
T
-
18
20
ms
SS
BURST MODE SECTION
Burst Mode Enable Feedback Voltage
Burst Mode Feedback Source Current
Burst Mode Switching Time
Burst Mode Hold Time
V
-
0.25 0.40 0.55
V
BEN
I
V
V
V
= 0V
60
1.2
1.2
100 140 uA
BFB
FB
FB
FB
T
= 0.9V, Duty =50%
= 0.9V -> 0V
1.4
1.4
1.6
1.6
ms
ms
BS
T
BH
PROTECTION SECTION
Shutdown Feedback Voltage
Shutdown Delay Current
V
V
V
V
V
= 18V
7.0
4
7.5
5
8.0
6
V
μA
V
SD
CC
FB
FB
CC
I
= 5V, V
= 3V
= 18V
CC
DELAY
Over Voltage Protection
V
V
11
12
1.0
-
13
1.1
-
OVP
Over Current Latch Voltage (1)
Thermal Shutdown Temp (2)
= 18V
0.9
140
V
OCL
T
-
°C
SD
Note:
1. These parameters, although guaranteed, are tested only in EDS (wafer test) process.
2. These parameters, although guaranteed at the design, are not tested in mass production.
7
FAIRCHILD [ FAIRCHILD SEMICONDUCTOR ]
