UC3842/UC3843/UC3844/UC3845

4

Note:

1. Parameter measured at trip point of latch

2. Gain defined as:

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 5k

Ω potentiometer are used to sample the

oscillator waveform and apply an adjustable ramp to pin 3.

Parameter

Symbol

Conditions

Min.

Typ.

Max.

Unit

PWM SECTION

Max. Duty Cycle

UC3842/UC3843

95

97

100

%

UC3844/UC3845

47

48

50

%

Min. Duty Cycle

-

--

0

%

TOTAL STANDBY CURRENT

Start-Up Current

-

-0.45

1

mA

Operating Supply Current

-

14

17

mA

Zener Voltage

30

38

-

V

A

∆V

pin1

∆V

pin3

------------------

=

UC3842

,0