ka3842.pdf part of aoc/ntc/samsung/boka aoc f1170 ka3842.pdf, swicthing ic on power supply regulator text manual preview

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Linear Integrated Circuit
KA3842A
KA3842AM
-
CURRENT-MODE PWM CONTROLLER PIN CONNECTION
The KA3842A KA3842AM 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 KA3842A,KA3842AM have UVLO thresholds of 16 V(on) and 10 V (off).
The KA3842A ,KA384AM can
operate within 100% duty cycle The KA3842A has been proven
in applications using the same external components as Motorola's parts,among others .The KA3842AM
has been optimized for compatibility with Samsung's parts Many applications can use either
KA3842A or KA3842AM The KA3842A KA3842AM have Start-Up Current 0,45 mA
SO-8
FEATURES DIP-8
ordering
· Low Start-Up Current information
· Maximum Duty Cycle Device Package Operating temperature
· U/V Lockout With Hysteresis KA3842AM SO-8 0 to +700C
· Operating Freguency Up To 500khz KA3842AMM SO-8 "
KA3842AN DIP-8 "
BLOCK DIAGRAM KA3842AMN DIP-8 "

Absolute Maximum Ratings
Characteristic Symbol Value Unit
Supply Voltage VCC 30 V
Output Current IO ±1 A
Analog Inputs VI -0.3 to VCC V
Error Amp Output Sink Current ISINK (E.A) 10 mA
Power Dissipation (TA=250C) PO 1 W

Wing Shing Computer Components Co., (H.K.)Ltd. Tel:(852)2341 9276 Fax:(852)2797 8153 1
Homepage: http://www.wingshing.com E-mail: [email protected]
KA3842A/KA3842AM

Electrical characteristics (*VCC=15V, RT=10k, CT=3.3nF, TA=00C to +700C, unless
otherwise specified)
Characteristics Symbol Test Condition Min Typ Max Unit
Reference Section
Reference Output Voltege VREF TJ = 25°C, IREF = 1 mA 4.9 5.0 5.1 V
Line Regulation VREF 12V VCC 25 V 6.0 20 mV
Load Regulation VREF 1 mA IREF 20mA 6.0 25
Short Circit Output Current ISC TA = 25°C -100 -180 mA
Oscillator Section
Oscillation Freguency f TJ = 25°C 47 52 57 KHz
Frequency Change with f/VCCF 12V VCC 25 V 0.05 1.0 %
Voltage
Oscillator Amplitude V(OSC) 1.6 Vp-p
Error Amplifier Section
Input Bias Current IBIAS -0.1 -2 µA
Input Voltage VI(E.A) V1 = 2.5V 2.42 2.5 2.58 V
Open Loop Voltage Gain GVO 2V V0 4V 65 90 dB
Power Supply Rejection Ratio PSRR 12V VCC 25 V 60 70
Output Sink Current ISINK V2 = 2.7V, V1 = 1.1V 2 7 mA
Output Source Current ISOURCE V2 = 2.3V, V1 = 5V -0.5 -1.0 mA
High Output Voltage VOH V2 = 2.3V, RL = 15K to GND 5.0 6.0 V
Low Output Voltage VOL V2 = 2.7V, RL = 15K to PIN 8 0.8 1.1
Current Sense Section
Gain GV (Note 1 & 2) 2.85 3.0 3.15 V/V
Maximum Input Signal VI(MAX) V1 = 5V (Note1) 0.9 1.0 1.1 V
Power Supply Rejection Ratio PSRR 12V VCC 25 V (Note 1) 70 dB
Input Bias Current IBIAS -3.0 -10 µA
Output Section
Low Output Voltage VOL ISINK = 20 mA 0.08 0.4
ISINK = 200 mA 1.4 2.2 V
High Output Voltage VOH ISINK = 20 mA 13 13.5
ISINK = 200 mA 12 13.0
Rise Time tR TJ = 25°C, CL = 1nF (Note 3) 45 150 nS
Fall Time tF TJ = 25°C, CL = 1nF (Note 3) 35 150
-
Under-Voltage Lockout Section
Start Theshold VTH(ST) 14.5 16.0 17.5 V

Min. Operating Voltage VOPR(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 IST 0.17 0.3 mA

Operating Supply Current ICC (OPR) V3 = V2 = 0V 14 17
Zener Voltage VZ 30 38 V

* Adjust VCC above the start threshold before setting at 15V
Note 1: Parameter measured at trip point of lath with V2=0
Note 2: Gain defined as A=V1/V3 ; 0 V3 0.8V
Note 3: These parameters, although guaranteed, are not 100% tested in production.

2
KA3842A/KA3842AM

Pad Location

Chip size: 2.38 x 1.63 mm

Pad Coordinates µm Pad Coordinates µm
N X Y N X Y
1 90 110 5 1680 1450
2 1050 110 6 1310 1410
3 1310 110
4 2000 150 7 815 1410
8 460 1390

3
KA3842A/KA3842AM

mm inch
DIM. OUTLINE AND
MIN. TYP. MAX. MIN. TYP. MAX.
MECHANICAL DATA
A 1.75 0.069
a1 0.1 0.25 0.004 0.010
a2 1.65 0.065
a3 0.65 0.85 0.026 0.033
b 0.35 0.48 0.014 0.019
b1 0.19 0.25 0.007 0.010
C 0.25 0.5 0.010 0.020
c1 45° (typ.)
D (1) 4.8 5.0 0.189 0.197
E 5.8 6.2 0.228 0.244
e 1.27 0.050
e3 3.81 0.150 KA3842AM
F (1) 3.8 4.0 0.15 0.157
KA3842AMM
L 0.4 1.27 0.016 0.050
M 0.6 0.024 SO8
S 8 ° (max.)

(1) D and F do not include mold flash or protrusions. Mold flash or
potrusions shall not exceed 0.15mm (.006inch).

4
KA3842A/KA3842AM

NOTES:
1. DIMENSION L TO CENTER OF LEAD WHEN
FORMED PARALLEL.
8 5 2. PACKAGE CONTOUR OPTIONAL (ROUND OR
SQUARE CORNERS).
3. DIMENSIONING AND TOLERANCING PER ANSI
B Y14.5M, 1982.

1 4 MILLIMETERS INCHES
DIM MIN MAX MIN MAX
A 9.40 10.16 0.370 0.400
B 6.10 6.60 0.240 0.260
F C 3.94 4.45 0.155 0.175
D 0.38 0.51 0.015 0.020
NOTE 2 A F 1.02 1.78 0.040 0.070
L G 2.54 BSC 0.100 BSC
H 0.76 1.27 0.030 0.050
J 0.20 0.30 0.008 0.012
K 2.92 3.43 0.115 0.135
C L 7.62 BSC 0.300 BSC
M 10_ 10_
J N 0.76 1.01 0.030 0.040
T
SEATING N
PLANE
M
D K
H G
0.13 (0.005) M T A M B M

KA3842AN
KA3842AMN

o
Attention: M=10

5