Current Limit Sense Voltage

vs Supply Voltage

Supply Current

00871140

00871141

Supply Current

Collector Current with

Emitter Output Below Ground

00871142

00871143

Test Circuit*

Parameter tests can be made using the test circuit shown.

Select the desired V

adjustable power supplies. A digital volt meter with an input

resistance greater than 100 M

Ω should be used to measure

the following:

Input Reference Voltage to Ground; S1 in either position.

Level Shift Accuracy (%) = (T

=1mA

Input Current (mA) = (1V − T

Ω:S1atI

0 mA.

Oscillator parameters can be measured at T

quency counter or an oscilloscope.

The Current Limit Sense Voltage is measured by connecting

an adjustable 0-to-1V floating power supply in series with the

current limit terminal and referring it to either the ground or

the V

point T

until the LM2578A’s duty cycle just reaches 0%. This voltage

is the Current Limit Sense Voltage.

The Supply Current should be measured with the duty cycle

at 0% and S1 in the I

*LM2578A specifications are measured using automated

test equipment. This circuit is provided for the customer’s

convenience when checking parameters. Due to possible

variations in testing conditions, the measured values from

these testing procedures may not match those of the factory.

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