ADSP-21991
PERIPHERALS ELECTRICAL CHARACTERISTICS—ADSP-21991BST
Parameter
Min
Typ
Max
Unit
ANALOG-TO-DIGITAL CONVERTER
AC Specifications
SNR
Signal-to-Noise Ratio1
SNRD
Signal-to-Noise and Distortion1
THD
Total Harmonic Distortion1
CTLK
Channel-Channel Crosstalk1
CMRR
Common-Mode Rejection Ratio1
PSRR
Power Supply Rejection Ratio1
Accuracy
INL
DNL
No missing Codes
Zero Error1
Gain Error1
Integral Nonlinearity1
Differential Nonlinearity1
Input Voltage
VIN
CIN
Conversion Time
FCLK
tCONV
Input Voltage Span
Input Capacitance2
ADC Clock Rate
Total Conversion Time All 8 Channels
VOLTAGE REFERENCE
Internal Voltage Reference3
Output Voltage Tolerance
Output Current
Load Regulation4
Power Supply Rejection Ratio
Reference Input Resistance
POWER ON RESET
VRST
VHYST
Reset Threshold Voltage
Hysteresis Voltage
68
68
0.94
–2
–2
1.4
72
71
–78
–80
–74
0.05
±0.6
±0.5
12
1.25
0.5
2.0
10
0.98
40
100
+0.5
+0.5
8
50
–68
–66
–66
0.2
±2.0
±1.25
2.5
1.5
20
725
1.02
+2
+2
2.1
dB
dB
dB
dB
dB
%FSR
LSB
LSB
Bits
%FSR
%FSR
V
pF
MHz
ns
V
mV
µA
mV
mV
kΩ
V
mV
1 In all cases, the input frequency to the ADC system is assumed to be <100 kHz.
2 Analog Input Pins VIN0 to VIN7.
3 These specifications are for operation of the internal voltage reference so that SENSE = REFCOM, with the default 1.0 V operating mode.
4 Operation with full 0.1 mA load current. For optimal operation, it is recommended to buffer the VREF output voltage before using it in other parts of the
system.
REV. 0
–21–