ADuC845/ADuC847/ADuC848
Data Sheet
Rev. C | Page 4 of 108
AVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V, DVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V, REFIN(+) = 2.5 V, REFIN(–) = AGND; AGND =
DGND = 0 V; XTAL1/XTAL2 = 32.768 kHz crystal; all specifications TMIN to TMAX, unless otherwise noted. Input buffer on for primary
ADC, unless otherwise noted. Core speed = 1.57 MHz (default CD = 3), unless otherwise noted.
Table 1.
Parameter
Min
Typ
Max
Unit
Conditions
PRIMARY ADC
Conversion Rate
5.4
105
Hz
Chop on (ADCMODE.3 = 0)
16.06
1365
Hz
Chop off (ADCMODE.3 = 1)
24
Bits
≤26.7 Hz update rate with chop enabled
24
Bits
≤80.3 Hz update rate with chop disabled
Resolution (ADuC845/ADuC847)
Resolution (ADuC848)
Output Noise (ADuC845/ADuC847)
μV (rms)
Output noise varies with selected update rates,
gain range, and chop status.
Output Noise (ADuC848)
μV (rms)
Output noise varies with selected update rates,
gain range, and chop status.
Integral Nonlinearity
±15
ppm of FSR
1 LSB16
±3
μV
Chop on
Chop off, offset error is in the order of the noise
for the programmed gain and update rate
following a calibration.
Offset Error Drift vs. Tempera
ture2±10
nV/°C
Chop on (ADCMODE.3 = 0)
±200
nV/°C
Chop off (ADCMODE.3 = 1)
ADuC845/ADuC847
±10
μV
±20 mV to ±2.56 V
ADuC848
±10
μV
±20 mV to ±640 mV
±0.5
LSB16
±1.28 V to ±2.56 V
Gain Error Drift vs. Temperatur
e4±0.5
ppm/°C
Power Supply Rejection
80
dB
AIN = 1 V, ±2.56 V, chop enabled
113
dB
AIN = 7.8 mV, ±20 mV, chop enabled
80
dB
AIN = 1 V, ±2.56 V, chop disabled2
PRIMARY ADC ANALOG INPUTS
Differential Input Voltage Rang
es 5, 6Gain = 1 to 128
Bipolar Mode (ADC0CON1.5 = 0)
±1.024 ×
VREF/GAIN
V
VREF = REFIN(+) REFIN() or
REFIN2(+) REFIN2() (or Int 1.25 VREF)
Unipolar Mode (ADC0CON1.5 = 1)
0 – 1.024 ×
VREF/GAIN
V
VREF = REFIN(+) REFIN() or
REFIN2(+) REFIN2() (or Int 1.25 VREF)
ADC Range Matching
±2
μV
AIN = 18 mV, chop enabled
Common-Mode Rejection DC
Chop enabled, chop disabled
On AIN
95
dB
AIN = 7.8 mV, range = ±20 mV
113
dB
AIN = 1 V, range = ±2.56 V
Common-Mode Rejection
50 Hz/60 Hz ± 1 Hz, 16.6 Hz and 50 Hz update
rate, chop enabled, REJ60 enabled
On AIN
95
dB
AIN = 7.8 mV, range = ±20 mV
90
dB
AIN = 1 V, range = ±2.56 V
Footnotes at end of table.