AMX PTM-D15 User Manual download pdf (Page 88)

MC9S12H256 Device User Guide — V01.18

The PCB must be carefully laid out to ensure proper operation of the voltage regulator as well as of the

MCU itself. The following rules must be observed:

• Every supply pair must be decoupled by a ceramic/tantalum capacitor connected as near as possible

to the corresponding pins(C1 – C9).

• Central point of the ground star should be the VSS1 pin.

• Use low ohmic low inductance connections between VSS1, VSS2, VSSA, VSSX1,2 and

VSSM1,2,3.

• VSSPLL must be directly connected to VSS1.

• Keep traces of VSSPLL, EXTAL and XTAL as short as possible and occupied board area for C10,

C11, C14 and Q1 as small as possible.

• Do not place other signals or supplies underneath area occupied by C10, C11, C14 and Q1 and the

connection area to the MCU.

• Central power input should be fed in at the VDDA/VSSA pins.

Table 21-1 Recommended Components

Component Purpose Type Value

C1 VDD1 ﬁlter cap ceramic X7R 100 .. 220nF

C2 VDDA ﬁlter cap X7R/tantalum >=100nF

C3 VDDX2 ﬁlter cap X7R/tantalum >=100nF

C4 VDDR ﬁlter cap X7R/tantalum >=100nF

C5 VDDM3 ﬁlter cap X7R/tantalum >=100nF

C6 VDDM2 ﬁlter cap X7R/tantalum >=100nF

C7 VDDM1 ﬁlter cap X7R/tantalum >=100nF

C8 VDDX1 ﬁlter cap X7R/tantalum >=100nF

C9 VDDPLL ﬁlter cap ceramic X7R 100nF .. 220nF

C10 OSC load cap

See CRG Block User Guide

C11 OSC load cap

C12 PLL loop ﬁlter cap

C13 PLL loop ﬁlter cap

C14 DC cutoff cap

R1 PLL loop ﬁlter res

Q1 Quartz/Resonator

1 ... 87 88 89 ... 130

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AMX PTM-D15 User Manual Page 88