Copyright

© ANPEC Electronics Corp.

Rev. A.3 - May., 2005

APW34063

www.anpec.com.tw

4

Note :

2.T

3.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient

temperature as possible.

4.If the output switch is driven into hard saturation (non-Darlington configuration) at low switch currents (

≤300mA) and high driver

currents (

≥30mA), it may take up to 2.0µs for it to come out of saturation. This condition will shorten the off time at frequencies≥30kHz,

and is magnified at high temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot

saturate. If a non-Darlington configuration is used, the following output drive condition is recommended :

Forced

β of output switch :

≥

10

* The 100

Ω resistor in the emitter of the driver device requires about 7.0mA before the output switch conducts.

Q

S

R

Oscillator

Comp.

1.25V

Reference

Regulator

100

Q1

Q2

IN5819

8

7

6

5

1

2

3

4

180

12V

0.22

170

L

100

1500pF

R2

47k

R1

2.2k

330

28V/175mA

100

optional

Filter

1.0

Step-Up Converter

Typical Application Circuits