V

CC

V

PORR

V

PORF

Time

POR

Time

VCC

Time

VCC_GH

VCC_GW

21

TCA9543A

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SCPS206B – MARCH 2014 – REVISED NOVEMBER 2019

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Glitches in the power supply can also affect the power-on reset performance of this device. The glitch width

(VCC_GW) and height (VCC_GH) are dependent on each other. The bypass capacitance, source impedance, and

device impedance are factors that affect power-on reset performance. Figure 21 and Table 3 provide more

information on how to measure these specifications.

Figure 21. Glitch Width and Glitch Height

VPOR is critical to the power-on reset. VPOR is the voltage level at which the reset condition is released and all the

registers and the I2C/SMBus state machine are initialized to their default states. The value of VPOR differs based

on the VCC being lowered to or from 0. Figure 22 and Table 3 provide more details on this specification.

Figure 22. VPOR