L9908 datasheet(53/152 Pages) STMICROELECTRONICS

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Figure 28. VPRE monitor boot masking

Note:

The total external capacitance applied to VPRE should be selected in order to allow a VPRE boot time always

lower than VPRE boot time masking. This means that the maximum total capacitance shall be:

CVPRE_tot≤CP1iout_min

CP1vout_maxTvpre_boot_mask_min=7.192μF

(5)

Table 49. VPRE Monitor electrical characteristics

Symbol

Parameter

Min

Typ Max Unit

Notes

VPRE_uv_th

VPRE under-voltage threshold

6.4

6.7

Comparator output Low to High

VPRE_uv_hys

VPRE under-voltage hysteresis

100

200

mV -

T_vpre_uv_flt

VPRE under-voltage detection filter time

μs

Digital filter

VPRE_ov_th

VPRE over-voltage threshold

14.5 15.5 16.5

Comparator output Low to High

VPRE_ov_hys

VPRE over-voltage hysteresis

100

250

mV -

T_vpre_ov_flt

VPRE over-voltage detection filter time

μs

Digital filter

T_vpre_boot_mask VPRE boot masking time

1.7

2.3

Note:

All parameters are guaranteed, and tested, in the voltage ranges reported above in Table 5 unless otherwise

specified. Where not specified the parametrical operating range equals the functional operating range.

L9908

Functional description

DS13546 - Rev 5

page 53/152

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