TDA4VM21 datasheet(198/331 Pages) TI

198 / 331 page

J7ES_WKUP_OSC_SC_06

Device

WKUP_OSC0_XO

WKUP_OSC0_XI

PCBXIXO

PCB

Signal Traces

Crystal Circuit

Components

XIXO

Figure 6-26. Shunt Capacitance

A crystal should be chosen such that the below equation is satisfied. CO in the equation is the maximum shunt

capacitance specified by the crystal manufacturer.

Cshunt ≥ CO + CPCBXIXO + CXIXO

For example, the equation would be satisfied when the crystal being used is 25 MHz with an ESR = 30 Ω,

CPCBXIXO = 0.04 pF, CXIXO = 0.01 pF, and shunt capacitance of the crystal is less than or equal to 6.95 pF.

6.9.4.1.2 WKUP_OSC0 LVCMOS Digital Clock Source

Figure 6-27 shows the recommended oscillator connections when WKUP_OSC0_XI is connected to a 1.8-V

LVCMOS square-wave digital clock source.

Note

A DC steady-state condition is not allowed on WKUP_OSC0_XI when the oscillator is powered up.

This is not allowed because WKUP_OSC0_XI is internally AC coupled to a comparator that may enter

a unknown state when DC is applied to the input. Therefore, application software should power down

WKUP_OSC0 any time WKUP_OSC0_XI is not toggling between logic states.

Device

WKUP_OSC0_XO

WKUP_OSC0_XI

J7ES_WKUP_OSC_EXT_CLK_05

PCB Ground

Figure 6-27. 1.8-V LVCMOS-Compatible Clock Input

6.9.4.1.3 Auxiliary OSC1 Internal Oscillator Clock Source

Figure 6-28 shows the recommended crystal circuit. All discrete components used to implement the oscillator

circuit should be placed as close as possible to the OSC1_XI and OSC1_XO pins.

TDA4VM-Q1, TDA4VM

SPRSP36K – SEPTEMBER 2021 – REVISED APRIL 2024

www.ti.com

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TDA4VM21 Datasheet(PDF) 198 Page - Texas Instruments