Data Sheet
AD5940
ADC Gain Calibration for the High Speed TIA Channel Register—ADCGAINHSTIA
Address 0x00002284, Reset: 0x00004000, Name: ADCGAINHSTIA
Table 58. Bit Descriptions for ADCGAINHSTIA Register
Bits
Bit Name
Reserved
Value
Settings
Description
Reset
0x0
Access
R
[31:15]
[14:0]
Reserved.
Gain error calibration on the high speed TIA channel.
0x4000
R/W
0x7FFF 2. Maximum positive gain adjustment.
0x4001 1.000061. Minimum positive gain adjustment.
0x4000 1.0. ADC result multiplied by 1. No gain adjustment (default).
0x3FFF 0.999939. Minimum negative gain adjustment.
0x2000 0.5. ADC result multiplied by 0.5.
0x0001 0.000061. Maximum negative gain adjustment.
0x0000 0. Illegal value; results in an ADC result of 0.
ADC Offset Calibration Auxiliary Channel (PGA Gain = 1) Register—ADCOFFSETGN1
Address 0x00002244, Reset: 0x00000000, Name: ADCOFFSETGN1
Table 59. Bit Descriptions for ADCOFFSETGN1 Register
Bits
[31:15] Reserved
[14:0] Value
Bit Name
Settings Description
Reset Access
Reserved.
0x0
0x0
R
Offset calibration gain = 1. ADC offset correction for the auxiliary channel with PGA
R/W
gain = 1, represented as a twos complement number. The calibration resolution is
0.25 LSBs of the ADCDAT LSB size. Therefore, the calibration resolution is VREF/218. If
V
REF = 1.82 V, the calibration resolution is 1.82/217 = 13.885 μV.
0x3FFF 4095.75. Maximum positive offset calibration value.
0x0001 0.25. Minimum positive offset calibration value.
0x0000 0. No offset adjustment.
0x7FFF −0.25. Minimum negative offset calibration value.
0x4000 −4096. Maximum negative offset calibration value.
ADC Gain Calibration Auxiliary Input Channel (PGA Gain = 1) Register—ADCGAINGN1
Address 0x00002240, Reset: 0x00004000, Name: ADCGAINGN1
The ADCGAINGN1 register provides gain calibration for the voltage input channels to the ADC, including the AINx channels.
Table 60. Bit Descriptions for ADCGAINGN1 Register
Bits
[31:15] Reserved
[14:0] Value
Bit Name Settings Description
Reset
Access
Reserved.
0x0
R
Gain calibration for PGA gain = 1. ADC gain correction for auxiliary input channels.
These bits are used for all channels, except the TIA and temperature sensor channels
when PGA gain = 1. This value is stored as a signed number. Bit 14 is the sign bit, and
Bits[13:0] represent the fractional part.
0x4000 R/W
0x0000
0x2000
0x4000
0x4001
0x7FFF
0x0001
0x3FFF
0. Illegal value; results in an ADC result of 0x8000.
0.5. ADC result multiplied by 0.5.
1.0. ADC result multiplied by 1. No gain adjustment (default).
1.000061. Minimum positive gain adjustment.
2. Maximum positive gain adjustment.
0.000061. Maximum negative gain adjustment.
0.999939. Minimum negative gain adjustment.
Rev. 0 | Page 61 of 130
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