Datasheet

Notes : 2. These parameters, although guaranteed, are not 100% tested in production.
3. Parameter measured at trip point of latch with V
PIN2
=0.
4. Gain defined as :
∆ V
PIN1
A= ;0≤V
PIN3
≤ 0.8 V
∆ V
PIN3
5. Adjust V
i
above the start threshold before setting at 15 V.
6. Output frequency equals oscillator frequency for the UC3842 and UC3843.
Outputfrequency is one half oscillator frequency for the UC3844 and UC3845.
ELECTRICAL CHARACTERISTICS (continued)
Symbol Parameter Test Conditions
UC284X UC384X
Unit
Min. Typ. Max. Min. Typ. Max.
UNDER-VOLTAGE LOCKOUT SECTION
Start Threshold X842/4 15 16 17 14.5 16 17.5 V
X843/5 7.8 8.4 9.0 7.8 8.4 9 V
Min Operating Voltage
After Turn-on
X842/4 9 10 11 8.5 10 11.5 V
X843/5 7.0 7.6 8.2 7.0 7.6 8.2 V
PWM SECTION
Maximum Duty Cycle X842/3 93 97 100 93 97 100 %
X844/5 46 48 50 47 48 50 %
Minimum Duty Cycle 0 0 %
TOTAL STANDBY CURRENT
I
st
Start-up Current 0.5 1 0.5 1 mA
I
i
Operating Supply Current V
PIN2
=V
PIN3
=0V 1120 1120mA
V
iz
Zener Voltage I
i
= 25mA 34 34 V
UC2842/3/4/5-UC3842/3/4/5
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