AM6548ACD datasheet(153/284 Pages) TI

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7.9.4.1.1 WKUP_OSC0 Internal Oscillator Clock Source

Figure 7-15 shows the recommended crystal circuit. It is recommended that preproduction printed-circuit board

(PCB) designs include the two optional resistors Rbias and Rd in case they are required for proper oscillator

operation when combined with production crystal circuit components. In most cases, Rbias is not required and

Rd is a 0-Ω resistor. These resistors may be removed from production PCB designs after evaluating oscillator

performance with production crystal circuit components installed on preproduction PCBs.

Device

WKUP_OSC0_XO

WKUP_OSC0_XI

Crystal

(Optional)

SPRSP08_PCB_CLK_OSC_2

Rbias

(Optional)

PCB Ground

Figure 7-15. WKUP_OSC0 Crystal Implementation

Note

The load capacitors, Cf1 and Cf2 in the load capacitance equation (1) below, should be chosen

such that the below equation is satisfied. CL in the equation is the load specified by the crystal

manufacturer. All discrete components used to implement the oscillator circuit should be placed as

close as possible to the associated oscillator WKUP_OSC0_XI, WKUP_OSC0_XO, and VSS pins.

CL=

C C

(C +C )

SPRS932_CLOCK_03

(1)

The crystal must be in the fundamental mode of operation and parallel resonant. Table 7-14 summarizes the

required electrical constraints.

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AM6548, AM6528, AM6546, AM6526

SPRSP52B – DECEMBER 2019 – REVISED JUNE 2021

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AM6548ACD 数据表(PDF) 153 Page - Texas Instruments