Symbol

Parameter

Test condition

Min Typ Max Unit

PIN

CP_UV_flt

Charge pump undervoltage

filter time

Guaranteed by SCAN

7

10

12

μs

-

Fs

CP switching frequency

-

-

385

-

kHz

-

Cfly

C1 and C2 flying capacitor

-

80

100 120

nF

-

CPTANK

Tank output capacitor

-

176 220 264

nF

CPTANK

CP_UV_TIMEOUT

Charge pump undervoltage

timeout

Guaranteed by SCAN

1.8

-

2.2

s

-

CPRegulation_OVmode

Charge pump regulation in

OV condition

Put OV pin higher than 1.26 V and

measure CP regulation

8.5

-

10.5

V

CPTANK

4.1.8

Hot swap pre-driver and soft start

An internal pre-driver, supplied by charge pump, can drive HGATE at a voltage that typically is clamped

ΔVHG1_12V above battery line, completely turning ON hot swap MOSFET.

Figure 9. Hot swap pre-driver simplified structure

The pre-driver is floating with respect to the substrate and directly referred to the external FET gate-source

terminals, allowing a better driving also during fast transient commutations, and can sustain, without being

damaged, deep negative pulses.

A capacitor (maximum value 100 nF) is connected on HGATE pin, allowing the control of soft start timing during

hot swap switching ON. This turn-on transient is, in fact, controlled by the charge at constant current IHG_PU (gate

pull-up current) of this capacitor. The more soft start timing is increased, the more the inrush current during the

power-up is reduced. On the other hand, the switching OFF is realized with a strong pull-down current.

When ENOUT is de-asserted, hot swap VDS comparator is ignored. When the full on condition (OUT > VB -

VFULL_ON, ENOUT asserted) is reached, the VDS comparator is enabled after MASK_VDS_rising_flt masking

time. Indeed, when ENOUT is de-asserted again, the VDS comparator is ignored after MASK_VDS_falling_flt

masking time. The behavior of VDS diagnostics is shown in Figure 10.

STPM801

Functional behavior in detail

DS13990 - Rev 2

page 17/38