KA3842B/KA3843B/KA3844B/KA3845B
Electrical Characteristics (Continued)
(V =15V, R =10KΩ, C =3.3nF, T = 0°C to +70°C unless otherwise specified)
CC
T
T
A
Parameter
Symbol
Conditions
Min.
Typ. Max. Unit
PWM SECTION
D
KA3842B/KA3843B
95
47
-
97
48
-
100
50
0
%
%
%
(max)
D
Max. Duty Cycle
KA3844B/KA3845B
Min. Duty Cycle
D
-
(MIN)
TOTAL STANDBY CURRENT
Start-Up Current
I
-
-
-
0.45
14
1
17
-
mA
mA
V
ST
Operating Supply Current
Zener Voltage
I
V =V =ON
CC(OPR)
3
2
V
I
= 25mA
30
38
Z
CC
Adjust V above the start threshould before setting at 15V
CC
Note:
1. Parameter measured at trip point of latch
2. Gain defined as:
∆V1
A = ----------
,0 ≤ V3 ≤ 0.8V
∆V3
3.These parameters, although guaranteed, are not 100 tested in production.
Figure 1. Open Loop Test Circuit
High peak currents associated with capacitive loads necessitate careful grounding techniques Timing and bypass capacitors
should be connected close to pin 5 in a single point ground. The transistor and 5KΩ potentiometer are used to sample the
oscillator waveform and apply an adjustable ramp to pin 3.
4
FAIRCHILD [ FAIRCHILD SEMICONDUCTOR ]
