AD7190BRUZ-REEL Analog Devices Inc, AD7190BRUZ-REEL Datasheet - Page 28

• Manufacturer Part Number: AD7190BRUZ-REEL
• Description: 2ch UltraLow Noise 24Bit SD ADC IC.
• Manufacturer: Analog Devices Inc

Specifications of AD7190BRUZ-REEL

• Design Resources: Precision Weigh Scale Design Using AD7190 with Internal PGA (CN0102)
• Number Of Bits: 24
• Sampling Rate (per Second): 4.8k
• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP (0.173", 4.40mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD7190
50 Hz/60 Hz Rejection
Normal mode rejection is one of the main functions of the
digital filter. With chop disabled, 50 Hz rejection is obtained
when the output data rate is set to 50 Hz, whereas 60 Hz
rejection is achieved when the output data rate is set to 60 Hz.
Simultaneous 50 Hz/60 Hz rejection is obtained when the
output data rate is set to 10 Hz. Simultaneous 50 Hz/60 Hz
rejection can also be achieved using the REJ60 bit in the mode
register. When the output data rate is programmed to 50 Hz and
the REJ60 bit is set to 1, notches are placed at both 50 Hz and
60 Hz.
Figure 23 and Figure 24 show the frequency response of the
sinc
programmed to 50 Hz and REJ60 is set to 1.
Again, the sinc
than the sinc
achieved with the sinc
When chop is enabled, lower output data rates must be used to
achieve 50 Hz and 60 Hz rejection. With REJ60 set to 1, an output
data rate of 12.5 Hz gives simultaneous 50 Hz/60 Hz rejection
when the sinc
16.7 Hz gives simultaneous 50 Hz/ 60 Hz rejection when the sinc
4
Figure 23. Sinc
Figure 24. Sinc
and sinc
–100
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
–90
0
0
0
0
3
3
4
filter. In addition, better stop-band attenuation is
filters, respectively, when the output data rate is
4
filter is selected, whereas an output data rate of
4
3
filter provides better 50 Hz/60 Hz rejection
25
25
Filter Response (50 Hz Output Data Rate, REJ60 = 1)
Filter Response (50 Hz Output Data Rate, REJ60 = 1)
4
filter.
50
50
FREQUENCY (Hz)
FREQUENCY (Hz)
75
75
100
100
125
125
150
150
Rev. B | Page 28 of 40
3
filter is used. Figure 25 and Figure 26 show the filter response for
both output data rates when REJ60 is set to 1.
Zero Latency
Zero latency is enabled by setting the SINGLE bit in the mode
register to 1. With zero latency, the complete settling time is
allowed for each conversion. Therefore,
Zero latency means that the output data rate is constant
irrespective of the number of analog input channels enabled;
the user does not need to consider the effects of channel
changes on the output data rate. The disadvantages of zero
latency are the increased noise for a given output data rate
compared with the nonzero latency mode. For example, when
zero latency is not enabled, the AD7190 has a noise-free
resolution of 18.5 bits when the output data rate is 50 Hz and
the gain is set to 128. When zero latency is enabled, the ADC
has a resolution of 17.5 bits peak-to-peak when the output data
rate is 50 Hz. The filter response also changes. Figure 19 shows
the filter response for the sinc
is 50 Hz (zero latency disabled). Figure 27 shows the filter
response when zero latency is enabled and the output data rate
f
–100
–100
ADC
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
–90
Figure 25. Sinc
Figure 26. Sinc
0
0
= 1/t
0
0
SETTLE
25
25
4
3
Filter Response (12.5 Hz Output Data Rate,
Filter Response (16.7 Hz Output Data Rate,
Chop Enabled, REJ60 = 1)
Chop Enabled, REJ60 = 1)
50
50
FREQUENCY (Hz)
FREQUENCY (Hz)
4
filter when the output data rate
75
75
100
100
125
125
150
150