L6731D

Device description

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5.3

Bypassing the LDO to avoid the voltage drop with low Vcc

maximum LDO output current is about 100 mA and so the output voltage drop is 100 mV, to

avoid this the LDO can be bypassed.

5.4

Internal and external references

It is possible to set the internal/external reference and the switching frequency by setting the

proper voltage at the DDR-IN pin. The maximum value of the external reference is 2.5 V

(typ.):

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●

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Providing an external reference from 0V to 450mV the output voltage will be regulated but

some restrictions must be considered:

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OV threshold saturates to a minimum value of 300 mV (OV is tracking the

reference; tracking small references will result in a narrow threshold reducing

noise immunity)

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The under-voltage-protection doesn't work;

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The PGOOD signal remains low;

To set the resistor divider it must be considered that a 100 k pull-down resistor is integrated

into the device (see Figure 5.). Finally it must be taken into account that the voltage at the

DDR-IN pin is captured by the device at the start-up when V

Figure 4.

Bypassing the LDO