Datasheet

AFE5805
SBOS421D –MARCH 2008–REVISED MARCH 2010 www.ti.com
PROGRAMMABLE GAIN
ADDRESS
IN HEX D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 NAME
X X X X GAIN_CH4<3:0>
X X X X GAIN_CH3<3:0>
2A
X X X X GAIN_CH2<3:0>
X X X X GAIN_CH1<3:0>
X X X X GAIN_CH5<3:0>
X X X X GAIN_CH6<3:0>
2B
X X X X GAIN_CH7<3:0>
X X X X GAIN_CH8<3:0>
The AFE5805, through its registers, allows for a digital gain to be programmed for each channel. This
programmable gain can be set to achieve the full-scale output code even with a lower analog input swing. The
programmable gain not only fills the output code range of the ADC, but also enhances the SNR of the device by
using quantization information from some extra internal bits. The programmable gain for each channel can be
individually set using a set of four bits, indicated as GAIN_CHN<3:0> for Channel N. The gain setting is coded in
binary from 0dB to 12dB, as shown in Table 15.
Table 15. Gain Setting for Channel 1
GAIN_CH1<3> GAIN_CH1<2> GAIN_CH1<1> GAIN_CH1<0> CHANNEL 1 GAIN SETTING
0 0 0 0 0dB
0 0 0 1 1dB
0 0 1 0 2dB
0 0 1 1 3dB
0 1 0 0 4dB
0 1 0 1 5dB
0 1 1 0 6dB
0 1 1 1 7dB
1 0 0 0 8dB
1 0 0 1 9dB
1 0 1 0 10dB
1 0 1 1 11dB
1 1 0 0 12dB
1 1 0 1 Do not use
1 1 1 0 Do not use
1 1 1 1 Do not use
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