Datasheet

MSP430F673x
MSP430F672x
SLAS731C –DECEMBER 2011–REVISED FEBRUARY 2013 www.ti.com
SD24_B, Performance (continued)
f
SD24
= 1 MHz, SD24OSRx = 256, SD24REFS = 1
PARAMETER TEST CONDITIONS V
CC
MIN TYP MAX UNIT
SD24GAIN: 1, f
CM
= 50 Hz, V
CM
= 930 mV 3 V -110
Common mode rejection
CMRR,50Hz SD24GAIN: 8, f
CM
= 50 Hz, V
CM
= 120 mV 3 V -110 dB
at 50 Hz
(8)
SD24GAIN: 32, f
CM
= 50 Hz, V
CM
= 30 mV 3 V -110
SD24GAIN: 1, V
CC
= 3 V + 50 mV × sin(2π ×
-61
f
Vcc
× t), f
Vcc
= 50 Hz
AC power supply
SD24GAIN: 8, V
CC
= 3 V + 50 mV × sin(2π ×
AC PSRR,ext rejection ratio, external -77 dB
f
Vcc
× t), f
Vcc
= 50 Hz
reference
(9)
SD24GAIN: 32, V
CC
= 3 V + 50 mV × sin(2π ×
-79
f
Vcc
× t), f
Vcc
= 50 Hz
SD24GAIN: 1, V
CC
= 3 V + 50 mV × sin(2π ×
-61
f
Vcc
× t), f
Vcc
= 50 Hz
AC power supply
SD24GAIN: 8, VV
CC
= 3 V + 50 mV × sin(2π ×
AC PSRR,int rejection ratio, internal -77 dB
f
Vcc
× t), f
Vcc
= 50 Hz
reference
(9)
SD24GAIN: 32, V
CC
= 3 V + 50 mV × sin(2π ×
-79
f
Vcc
× t), f
Vcc
= 50 Hz
Crosstalk source: SD24GAIN: 1, Sine-wave
with max. possible Vpp. f
IN
= 50 Hz, 100 Hz, 3 V -120
Converter under test: SD24GAIN: 1
Crosstalk source: SD24GAIN: 1, Sine-wave
Crosstalk between
XT with max. possible Vpp. f
IN
= 50 Hz, 100 Hz, 3 V -115 dB
converters
(10)
Converter under test: SD24GAIN: 8
Crosstalk source: SD24GAIN: 1, Sine-wave
with max. possible Vpp. f
IN
= 50 Hz, 100 Hz, 3 V -100
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(V
CM
/1.2V/G) [dBFS] with a common mode signal of V
CM
× sin(2π × f
CM
× 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 × f
Vcc
× t) added to V
CC
.
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.
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