CURRENT
-
-
MODE PWM CONTROLLER
The KA3842A are fixe frequency current-mode
PWM controller. They are specially designed for OFF
-
Line and DC
-
to
-
DC converter
applications with minimal external components. These integrated circuits feature a
trimmed oscillator for precise duty cycle control, a temperature compensated reference,
high gain error amplifier, current sensing comparator, and a high current totempole
output ideally suited for driving a power MOSFET.
Protection circuity includes built under
-
voltage lockout and current limiting.
The
The KA3842A ,KA384AM can
The KA3842A have Start-Up Current 0,45 mA
FEATURES
Low Start-Up Current
Maximum Duty Cycle
U/V Lockout With Hysteresis
Operating Freguency Up To 500khz
ordering
information
Device
Package
Operating temperature
KA3842AM SO-8 0 to +70
0
C
BLOCK DIAGRAM
Absolute Maximum Ratings
Characteristic
Symbol
Value
Unit
Supply Voltage
V
CC
30
V
Output Current
I
O
1
A
Analog Inputs
V
I
-
0.3 to V
CC
V
Error Amp Output Sink Current
I
SINK (E.A)
10
mA
Power Dissipation (T
A
=25
0
C)
P
O
1
W
Wing Shing Computer Components Co., (H.K.)Ltd.
Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage:
http://www.wingshing.com
E-mail: wsccltd@hkstar.com
Linear Integrated Circuit
have UVLO thresholds of 16 V(on) and 10 V (off).
operate within 100%
duty cycle
PIN CONNECTION
SO-8
1
in applications using the same
external components as Motorola's parts,among others .The
DIP-8
SO-8
"
DIP-8
DIP-8
"
"
KA3842A
KA3842AM
KA3842AMM
KA3842AN
KA3842AMN
KA3842AM
KA3842A,KA3842AM
The KA3842A has been proven
KA3842AM
has been optimized for compatibility with Samsung's parts
Many applications can use either
KA3842A or KA3842AM
KA3842AM
Electrical characteristics (*V
CC
=15V, R
T
=10k
, C
T
=3.3nF, T
A
=0
0
C to +70
0
C, unless
otherwise specified)
Characteristics
Symbol
Test Condition
Min
Typ
Max
Unit
Reference Section
Reference Output Voltege
V
REF
T
J
= 25
C, I
REF
= 1 mA
4.9
5.0
5.1
V
Line Regulation
V
REF
12V
V
CC
25 V
6.0
20
mV
Load Regulation
V
REF
1 mA
I
REF
20mA
6.0
25
Short Circit Output Current
I
SC
T
A
= 25
C
-100
-180
mA
Oscillator Section
Oscillation Freguency
f
T
J
= 25
C
47
52
57
KHz
Frequency Change with
Voltage
f/
V
CCF
12V
V
CC
25 V
0.05
1.0
%
Oscillator Amplitude
V
(OSC)
1.6
V
p-p
Error Amplifier Section
Input Bias Current
I
BIAS
-0.1
-2
A
Input Voltage
V
I(E.A)
V
1
= 2.5V
2.42
2.5
2.58
V
Open Loop Voltage Gain
G
VO
2V
V0
4V
65
90
dB
Power Supply Rejection Ratio
PSRR
12V
V
CC
25 V
60
70
Output Sink Current
I
SINK
V
2
= 2.7V, V
1
= 1.1V
2
7
mA
Output Source Current
I
SOURCE
V
2
= 2.3V, V
1
= 5V
-0.5
-1.0
mA
High Output Voltage
V
OH
V
2
= 2.3V, R
L
= 15K
to GND
5.0
6.0
V
Low Output Voltage
V
OL
V
2
= 2.7V, R
L
= 15K
to PIN 8
0.8
1.1
Current Sense Section
Gain
G
V
(Note 1 & 2)
2.85
3.0
3.15
V/V
Maximum Input Signal
V
I(MAX)
V
1
= 5V (Note1)
0.9
1.0
1.1
V
Power Supply Rejection Ratio
PSRR
12V
V
CC
25 V (Note 1)
70
dB
Input Bias Current
I
BIAS
-3.0
-10
A
Output Section
Low Output Voltage
V
OL
I
SINK
= 20 mA
0.08
0.4
I
SINK
= 200 mA
1.4
2.2
V
High Output Voltage
V
OH
I
SINK
= 20 mA
13
13.5
I
SINK
= 200 mA
12
13.0
Rise Time
t
R
T
J
= 25
C, C
L
= 1nF (Note 3)
45
150
nS
Fall Time
t
F
T
J
= 25
C, C
L
= 1nF (Note 3)
35
150
Under
-
-
Voltage Lockout Section
Start Theshold
V
TH(ST)
14.5 16.0 17.5 V
Min. Operating Voltage
V
OPR(min)
8.5 10 11.5 V
(After Turn On)
PWM Section
Max. Duty Cycle
D
(MAX)
95 97 100
%
Min. Duty Cycle
D
(MAX)
0
Total Standby Current
Start
-
Up Current I
ST
0.17 0.3 mA
Operating Supply Current
I
CC (OPR)
V
3
= V
2
= 0V
14
17
Zener Voltage
V
Z
30
38
V
* Adjust V
CC
above the start threshold before setting at 15V
Note 1: Parameter measured at trip point of lath with V
2
=0
Note 2: Gain defined as A=
V
1
/
V
3
; 0
V
3
0.8V
Note 3: These parameters, although guaranteed, are not 100% tested in production.
2
KA3842A/KA3842AM
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