MSP430F673x
MSP430F672x
SLAS731A –DECEMBER 2011–REVISED APRIL 2012
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SD24_B, Performance (continued)
fSD24 = 1 MHz, SD24OSRx = 256, SD24REFS = 1
PARAMETER
TEST CONDITIONS
VCC
3 V
3 V
3 V
MIN
TYP
-110
-110
-110
MAX UNIT
SD24GAIN: 1, fCM = 50 Hz, VCM = 930 mV
SD24GAIN: 8, fCM = 50 Hz, VCM = 120 mV
SD24GAIN: 32, fCM = 50 Hz, VCM = 30 mV
Common mode rejection
at 50 Hz(8)
CMRR,50Hz
AC PSRR,ext
dB
SD24GAIN: 1, VCC = 3 V + 50 mV × sin(2π ×
fVcc × t), fVcc = 50 Hz
-61
-77
-79
-61
-77
-79
AC power supply
rejection ratio, external
reference(9)
SD24GAIN: 8, VCC = 3 V + 50 mV × sin(2π ×
fVcc × t), fVcc = 50 Hz
dB
dB
SD24GAIN: 32, VCC = 3 V + 50 mV × sin(2π ×
fVcc × t), fVcc = 50 Hz
SD24GAIN: 1, VCC = 3 V + 50 mV × sin(2π ×
fVcc × t), fVcc = 50 Hz
AC power supply
rejection ratio, internal
reference(9)
SD24GAIN: 8, VVCC = 3 V + 50 mV × sin(2π ×
fVcc × t), fVcc = 50 Hz
AC PSRR,int
SD24GAIN: 32, VCC = 3 V + 50 mV × sin(2π ×
fVcc × t), fVcc = 50 Hz
Crosstalk source: SD24GAIN: 1, Sine-wave
with max. possible Vpp. fIN = 50 Hz, 100 Hz,
Converter under test: SD24GAIN: 1
3 V
3 V
3 V
-120
-115
-100
Crosstalk source: SD24GAIN: 1, Sine-wave
with max. possible Vpp. fIN = 50 Hz, 100 Hz,
Converter under test: SD24GAIN: 8
Crosstalk between
converters(10)
XT
dB
Crosstalk source: SD24GAIN: 1, Sine-wave
with max. possible Vpp. fIN = 50 Hz, 100 Hz,
Converter under test: SD24GAIN: 32
(8) The AC CMRR is the difference between a hypothetical signal with the amplitude and frequency of the applied common mode ripple
applied to the inputs of the ADC and the actual common mode signal spur visible in the FFT spectrum:
AC CMRR = Error Spur [dBFS] - 20log(VCM/1.2V/G) [dBFS] with a common mode signal of VCM × sin(2π × fCM × t) applied to the analog
inputs.
The AC CMRR is measured with the both inputs connected to the common mode signal i.e. no differential input signal is applied.
With the specified typical values the error spur is within the noise floor (as specified by the SINAD values).
(9) The AC PSRR is the difference between a hypothetical signal with the amplitude and frequency of the applied supply voltage ripple
applied to the inputs of the ADC and the actual supply ripple spur visible in the FFT spectrum:
AC PSRR = Error Spur [dBFS] - 20log(50 mV / 1.2 V / G) [dBFS] with a signal of 50 mV × sin(2π × fVcc × t) added to VCC
The AC PSRR is measured with the inputs grounded; that is, no analog input signal is applied.
With the specified typical values the error spur is within the noise floor (as specified by the SINAD values).
SD24GAIN: 1 → Hypothetical signal: 20log(50 mV / 1.2 V / 1) = -27.6 dBFS
.
SD24GAIN: 8 → Hypothetical signal: 20log(50 mV / 1.2 V / 8) = -9.5 dBFS
SD24GAIN: 32 → Hypothetical signal: 20log(50 mV / 1.2 V / 32) = 2.5 dBFS
(10) The crosstalk XT is specified as the tone level of the signal applied to the crosstalk source seen in the spectrum of the converter under
test. It is measured with the inputs of the converter under test being grounded.
74
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