ZXLD1370

ZXLD1370

Document number: DS32165 Rev. 2 - 2

27 of 33

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May 2010

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The ZXLD1370 is inherently protected against open-circuit load when used in Buck configuration. However care has to be

taken with open-circuit load conditions in Buck-Boost or Boost configurations. This is because in these configurations there

is no internal open-circuit protection mechanism for the external MOSFET. In this case an Over-Voltage-Protection (OVP)

network should be provided externally to the MOSFET to avoid damage due to open circuit conditions. This is shown in

Figure 33 below, highlighted in the dotted blue box.

Fig 37: OVP circuit

Take care of the max voltage drop on the Q2 MOSFET gate.

PCB Layout considerations

PCB layout is a fundamental activity to get the most of the device in all configurations. In the following section it is possible

to find some important insight to design with the ZXLD1370 both in Buck and Buck-Boost/Boost configurations.

Figure 38: Circuit Layout

Here are some considerations useful for the PCB layout:

In order to avoid ringing due to stray inductances, the inductor L1, the anode of D1 and the drain of Q1 should be

placed as close together as possible.

SHP pin

decoupling

Inductor, Switch

and

Freewheeling

diode