CS2844/3845 SERIES
Electrical Characteristics: -25≤T
A
≤85˚C
for CS2844/2845, 0≤T
A
≤70˚C
for CS3844/3845. V
CC
=15V (Note 1); R
T
=10kΩ,
C
T
=3.3nF for sawtooth mode., unless otherwise stated.
PARAMETER
TEST CONDITIONS
CS2844/CS2845
MIN TYP MAX
CS3844/CS3845
MIN TYP MAX UNITS
s
Total Standby Current
Start-Up Current
Operating Supply Current
V
CC
Zener Voltage
s
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
CS2844
TYP MAX
0.5
V
FB
=V
Sense
=0V R
T
=10kΩ, C
T
=3.3nF
I
CC
=25mA
11
34
1.0
17
0.5
11
34
1.0
17
mA
mA
V
46
48
50
0
46
48
50
0
%
%
PARAMETER
TEST CONDITIONS
MIN
CS3844
MIN TYP MAX
CS2845/CS3845
MIN TYP MAX UNITS
s
Under-Voltage Lockout Section
Start Threshold
Min. Operating
Voltage
Notes:
15
After Turn On
9
16
10
17
11
14.5
8.5
16
10
17.5
11.5
7.8
7.0
8.4
7.6
9.0
8.2
V
V
1. Adjust V
cc
above the start threshold before setting at 15V.
2.These parameters, although guaranteed, are not 100% tested in production.
3. Parameter measured at trip point of latch with V
FB
=0.
4. Gain defined as:
A=
∆V
COMP
∆V
Sense
; 0
≤
V
Sense
≤
0.8V.
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
FUNCTION
8L
PDIP/SO
1
2
3
4
5
14L
SO Narrow
1
3
5
7
9
8
16L
SO Wide
3
4
5
6
11
10
12
13
14
15
1,2,7,8,9,16
COMP
V
FB
Sense
OSC
Gnd
Pwr Gnd
V
OUT
V
CC
Pwr
V
CC
V
REF
NC
Error amp output, used to compensate error amplifier.
Error amp inverting input.
Noninverting input to Current Sense Comparator.
Oscillator timing network with Capacitor to Ground, resis-
tor to V
REF
.
Ground.
Output driver Ground.
Output drive pin.
Output driver positive supply.
Positive power supply.
Output of 5V internal reference.
No Connection.
6
10
11
7
8
12
14
2,4,6,13
3
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
