CS3972
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
FUNCTION
16L
SO Wide
16
2
3
1,4,5,6,7,8,
10,12,15
9
11
5L
TO-220
3
1
2
8L
PDIP
1
2
3
4
Gnd
V
C
V
FB
NC
V
IN
E
1
Logic and power ground on TO-220. Logic ground only on 8L
PDIP.
Control voltage can be used for frequency compensation, cur-
rent limit threshold, frequency synchronization, and soft start.
Feedback voltage is the negative input to the error amplifier.
No connection.
Supply input voltage with a range of 3V to 60V.
Emitter One is a power ground which should always be con-
nected to logic ground since it is used as the negative input to
the current sense amp.
Collector of internal 75V NPN power switch.
Emitter Two is a power ground which can be left disconnected
to reduce the switch rating to 625mA.
5
5
6
13
14
4
7
8
V
SW
E
2
Typical Performance Characteristics
Reference Voltage vs. Temperature
1.274
1.264
Switching Frequency vs. Temperature
47
45
Driver Current vs. Switch Current
100
90
80
Reference Voltage (V)
Driver Current (mA)
-25
-0
25
50
75
100
125
150
1.254
1.244
1.234
1.224
1.214
-50
Frequency (kHz)
43
41
39
37
35
33
-50
70
60
50
40
30
20
10
-25
-0
25
50
75
100
125
150
0
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Temperature (°C)
Temperature (°C)
Switch Current (A)
Maximum Duty Cycle
97
96
Switch Saturation Voltage
1.6
T
j
=25°C
Switch Saturation Voltage (V)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.0
Duty Cycle (%)
95
93
92
91
90
-50
-25
-0
25
50
75
100
125
150
Junction Temperature (°C)
Switch Current (A)
3
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
