VCC

Ramp-Up

Time to Re-Ramp

Time

Ramp-Down

VCC drops below V

50 mV

PORF –

VCC_RT

VCC_FT

VCC_TRR

20

TCA9543A

SCPS206B – MARCH 2014 – REVISED NOVEMBER 2019

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(1)

All supply sequencing and ramp rate values are measured at TA = 25°C

10 Power Supply Recommendations

The operating power-supply voltage range of the TCA9543A is 1.65-V to 5.5-V applied at the VCC terminal.

When the TCA9543A is powered on for the first time or anytime the device needs to be reset by cycling the

power supply, the power-on reset requirements must be followed to ensure the I2C bus logic is initialized

properly.

10.1 Power-On Reset Requirements

In the event of a glitch or data corruption, TCA9543A can be reset to its default conditions by using the power-on

reset feature. Power-on reset requires that the device go through a power cycle to be completely reset. This

reset also happens when the device is powered on for the first time in an application.

A power-on reset is shown in Figure 20.

Figure 20. VCC is Lowered Below the POR Threshold, Then Ramped Back Up to VCC

Table 3 specifies the performance of the power-on reset feature for TCA9543A for both types of power-on reset.

Table 3. Recommended Supply Sequencing And Ramp Rates(1)

PARAMETER

MIN

TYP

MAX

UNIT

VCC_FT

Fall time

See Figure 20

1

100

ms

VCC_RT

Rise time

See Figure 20

0.1

100

ms

VCC_TRR

Time to re-ramp (when VCC drops below VPORF(min) – 50 mV or

when VCC drops to GND)

See Figure 20

40

μs

VCC_GH

Level that VCC can glitch down to, but not cause a functional

disruption when VCC_GW = 1 μs

See Figure 21

1.2

V

VCC_GW

Glitch width that will not cause a functional disruption when

VCC_GH = 0.5 × VCC

See Figure 21

10

μs

VPORF

Voltage trip point of POR on falling VCC

See Figure 22

0.8

1.25

V

VPORR

Voltage trip point of POR on rising VCC

See Figure 22

1.05

1.5

V