ET- KA384x
Electrical Characteristics
(Con.)
(TA=25 °C, VCC=15V, RT=10KΩ, CT=3.3nF, TA=0oC to +70oC, unless otherwise specified .)
Symbol
Parameter
Test Condition
Min. Typ. Max. Unit
PWM Section
KA3842 / KA3843
95
47
-
97
48
-
100
50
0
D(Max.)
Max. Duty Cycle
%
KA3844 / KA3845
D(Min.)
Min. Duty Cycle
Total Standby Current
KA3843 / KA3845
KA3842 / KA3844
Vpin3=Vpin2=0V
ICC=25mA
-
-
0.13
0.2
13
0.3
0.3
17
-
IST
Start-Up Current
mA
V
ICC(OPR)
VZ
Operating Supply Current
Zener Voltage
-
30
38
* Adjust VCC above the start threshold before setting it to 15V.
Notes:
Note 1: Parameter measured at trip point of latch with Vpin2=0.
Note 2: Gain defined as A=△Vpin1/△Vpin3; 0≤Vpin3≤0.8V
Note 3: These parameters, although guaranteed, are not 100% tested in production.
Pin Function
Pin
Function
Description
1
COMP
This pin is the Error Amplifier output and is made for loop compensation.
This is the inverting input of the Error Amplifier. It is normally connected to the switching power
supply output through a resistor divider.
2
3
VFB
A voltage proportional to inductor current is connected to this input. The PWM uses this
information to terminate the output switch conduction.
ISENSE
The oscillator frequency and maximum output duty cycle are programmed by connecting resistor
RT to VREF and capacitor CT to ground.
4
5
6
RT/CT
GND
OUT
This pin is the combined control circuitry and power ground.
This output directly drivers the gate of a power MOSFET. Peak currents up to 1A are soured and
sink by this pin.
7
8
VCC
This pin is the positive supply of the integrated circuit.
VREF
This is the reference output. It provides charging current for capacitor CT through resistor RT.
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Copyright @ Estek Electronics Co., Ltd
4
Version 0.2
27 July 2011
ESTEK [ Estek Electronics Co. Ltd ]
