Analog-to-Digital Converter (ADC) Characteristics
Table 3-15 ADC Characteristics (Continued)
Characteristic
Symbol
THD
Min
55
Typ
60
Max
—
Unit
dB
dB
bit
Total Harmonic Distortion5
Signal-to-Noise plus Distortion5
Effective Number of Bits5
SINAD
ENOB
SFDR
54
56
—
8.5
60
9.5
65
—
Spurious Free Dynamic Range5
Bandwidth
—
dB
BW
—
—
100
50
—
—
KHz
mA
ADC Quiescent Current (both ADCs)
IADC
VREF Quiescent Current (both ADCs)
IVREF
—
12
16.5
mA
1. For optimum ADC performance, keep the minimum VADCIN value > 250mV. Inputs less than 250mV volts may convert to
a digital output code of 0 or cause erroneous conversions.
2. VREF must be equal to or less than VDDA - 0.3V and must be greater than 2.7V.
3. Measured in 10-90% range.
4. LSB = Least Significant Bit.
5. Guaranteed by characterization.
6. t
AIC
= 1/f
ADIC
ADC analog input
1
3
2
4
1. Parasitic capacitance due to package, pin to pin, and pin to package base coupling. (1.8pf)
2. Parasitic capacitance due to the chip bond pad, ESD protection devices and signal routing. (2.04pf)
3. Equivalent resistance for the ESD isolation resistor and the channel select mux. (500 ohms)
4. Sampling capacitor at the sample and hold circuit. Capacitor 4 is normally disconnected from the input and is only connected to it at
sampling time. (1pf)
Figure 3-26 Equivalent Analog Input Circuit
56F801 Technical Data, Rev. 17
Freescale Semiconductor
37
FREESCALE [ Freescale ]
