MC34152, MC33152, NCV33152

http://onsemi.com

8

LAYOUT CONSIDERATIONS

High frequency printed circuit layout techniques are

imperative to prevent excessive output ringing and

overshoot. Do not attempt to construct the driver circuit

on wire−wrap or plug−in prototype boards. When

driving large capacitive loads, the printed circuit board

must contain a low inductance ground plane to minimize

the voltage spikes induced by the high ground ripple

currents. All high current loops should be kept as short as

possible using heavy copper runs to provide a low

impedance high frequency path. For optimum drive

performance, it is recommended that the initial circuit

design contains dual power supply bypass capacitors

ground as the layout will permit. Suggested capacitors are

a low inductance 0.1

mF ceramic in parallel with a 4.7 mF

tantalum. Additional bypass capacitors may be required

depending upon Drive Output loading and circuit layout.

Proper printed circuit board layout is extremely

critical and cannot be over emphasized.

Figure 18. Enhanced System Performance with

Common Switching Regulators

Figure 19. MOSFET Parasitic Oscillations

The MC34152 greatly enhances the drive capabilities of common switching

regulators and CMOS/TTL logic devices.

caused by the MOSFET input capacitance and any series wiring inductance in the

the output pin from being driven below ground.

-

+

1N5819

TL494

or

TL594

47

0.1

6

5.7V

2

4

3

7

5

Figure 20. Direct Transformer Drive

Figure 21. Isolated MOSFET Drive

Output Schottky diodes are recommended when driving inductive loads at high

frequencies. The diodes reduce the driver's power dissipation by preventing the

3

5

7

4 X

1N5819

Isolation

Boundary

1N

5819

3