Chapter 1 MC9S12Q Device Overview (MC9S12Q128-Family)
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MC9S12Q128
Freescale Semiconductor
Rev 1.10
1.3.5.4
VDDA, VSSA — Power Supply Pins for ATD and VREG
VDDA,VSSA are the power supply and ground input pins for the voltage regulator reference and the analog
to digital converter.
1.3.5.5
VRH, VRL — ATD Reference Voltage Input Pins
VRH and VRL are the reference voltage input pins for the analog to digital converter.
1.3.5.6
VDDPLL, VSSPLL — Power Supply Pins for PLL
Provides operating voltage and ground for the oscillator and the phased-locked loop. This allows the
supply voltage to the oscillator and PLL to be bypassed independently. This 2.5V voltage is generated by
the internal voltage regulator.
NOTE
All VSS pins must be connected together in the application. Because fast
signal transitions place high, short-duration current demands on the power
supply, use bypass capacitors with high-frequency characteristics and place
them as close to the MCU as possible. Bypass requirements depend on
MCU pin load.
Table 1-6. Power and Ground Connection Summary
Mnemonic
Nominal
Voltage (V)
Description
VDD1, VDD2
2.5
Internal power and ground generated by internal regulator. These also allow an external source
to supply the core VDD/VSS voltages and bypass the internal voltage regulator.
In the 48 and 52 LQFP packages VDD2 and VSS2 are not available.
VSS1, VSS2
0
VDDR
5.0
External power and ground, supply to internal voltage regulator.
VSSR
0
VDDX
5.0
External power and ground, supply to pin drivers.
VSSX
0
VDDA
5.0
Operating voltage and ground for the analog-to-digital converters and the reference for the
internal voltage regulator, allows the supply voltage to the A/D to be bypassed independently.
VSSA
0
VRH
5.0
Reference voltage low for the ATD converter.
In the 48 and 52 LQFP packages VRL is bonded to VSSA.
VRL
0
VDDPLL
2.5
Provides operating voltage and ground for the phased-locked loop. This allows the supply voltage
to the PLL to be bypassed independently. Internal power and ground generated by internal
regulator.
VSSPLL
0