Datasheet

AD7745/AD7746
Rev. 0 | Page 18 of 28
CONFIGURATION REGISTER
Address Pointer 0x0A, Default Value 0xA0
Converter update rate and mode of operation setup.
Table 17. Configuration Register Bit Map
Bit Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Mnemonic VTF1 VTF0 CAPF2 CAPF1 CAPF0 MD2 MD1 MD0
Default 0 0 0 0 0 0 0 0
Table 18.
Bit Mnemonic Description
Voltage/temperature channel digital filter setup—conversion time/update rate setup.
The conversion times in this table are valid for the CLKCTRL = 0 in the EXC SETUP register. The conversion
times are longer by a factor of two for the CLKCTRL = 1.
VTCHOP = 1
VTF1 VTF0 Conversion Time (ms) Update Rate (Hz) –3 dB Frequency (Hz)
0 0 20.1 49.8 26.4
0 1 32.1 31.2 15.9
1 0 62.1 16.1 8.0
7
6
VTF1
VTF0
1 1 122.1 8.2 4.0
Capacitive channel digital filter setup—conversion time/update rate setup.
The conversion times in this table are valid for the CLKCTRL = 0 in the EXC SETUP register.
The conversion times are longer by factor of two for the CLKCTRL = 1.
CAP CHOP = 0
CAPF2 CAPF1 CAPF0 Conversion Time (ms) Update Rate –3 dB Frequency (Hz)
0 0 0 11.0 90.9 87.2
0 0 1 11.9 83.8 79.0
0 1 0 20.0 50.0 43.6
0 1 1 38.0 26.3 21.8
1 0 0 62.0 16.1 13.1
1 0 1 77.0 13.0 10.5
1 1 0 92.0 10.9 8.9
5
4
3
CAPF2
CAPF1
CAPF0
1 1 1 109.6 9.1 8.0
Converter mode of operation setup.
MD2 MD1 MD0 Mode
0 0 0 Idle
0 0 1 Continuous conversion
0 1 0 Single conversion
0 1 1 Power-Down
1 0 0 -
1 0 1 Capacitance system offset calibration
1 1 0 Capacitance or voltage system gain calibration
2
1
0
MD2
MD1
MD0
1 1 1