MC68HC16Z1CFC16 Freescale Semiconductor, MC68HC16Z1CFC16 Datasheet - Page 207

• Manufacturer Part Number: MC68HC16Z1CFC16
• Description: IC MPU 1K RAM 16MHZ 132-PQFP
• Manufacturer: Freescale Semiconductor
• Series: HC16r

Specifications of MC68HC16Z1CFC16

• Core Processor: CPU16
• Core Size: 16-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, SCI, SPI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Type: ROMless
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 132-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -

8.8.6 Analog Input Pins
M68HC16 Z SERIES
USER’S MANUAL
C
V
Analog inputs should have low AC impedance at the pins. Low AC impedance can be
realized by placing a capacitor with good high frequency characteristics at the input
pin of the part. Ideally, that capacitor should be as large as possible (within the practi-
cal range of capacitors that still have good high frequency characteristics). This capac-
itor has two effects. First, it helps attenuate any noise that may exist on the input.
Second, it sources charge during the sample period when the analog signal source is
a high-impedance source.
Series resistance can be used with the capacitor on an input pin to implement a simple
RC filter. The maximum level of filtering at the input pins is application dependent and
is based on the bandpass characteristics required to accurately track the dynamic
characteristics of an input. Simple RC filtering at the pin may be limited by the source
impedance of the transducer or circuit supplying the analog signal to be measured.
Refer to
itor at the pin may be very small.
Figure 8-10
ing discussion of the interaction between the user's external circuitry and the circuitry
inside the ADC.
SRC
DAC
R
C
C
V
F
F
S
I
= SOURCE VOLTAGE
= FILTER IMPEDANCE (SOURCE IMPEDANCE INCLUDED)
= FILTER CAPACITOR
= INTERNAL CAPACITANCE (FOR A BYPASSED CHANNEL, THIS IS THE C
= DAC CAPACITOR ARRAY
= INTERNAL VOLTAGE SOURCE FOR PRECHARGE (V
V
SRC
S1
8.8.6.2 Error Resulting from
EXTERNAL CIRCUIT
is a simplified model of an input channel. Refer to this model in the follow-
Figure 8-10 Electrical Model of an A/D Input Pin
R
F
C
Freescale Semiconductor, Inc.
F
For More Information On This Product,
ANALOG-TO-DIGITAL CONVERTER
INTERNAL CIRCUIT MODEL
Go to: www.freescale.com
S2
Leakage. In some cases, the size of the capac-
C
DDA
S
/2)
AMP
DAC
CAPACITANCE)
S3
C
DAC
S4
ADC SAMPLE AMP MODEL
V
I
8-21