Reference Manual ADuCM356
LOW-POWER POTENTIOSTAT AMPLIFIERS AND LOW-POWER TIAS
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Table 106. Recommended Switch Settings in Low-Power Potentiostat Loop (Continued)
Measurement Name
LPDACCONx Bit 5
Setting
LPDACSWx Bits[5:0]
Setting
LPTIASWx Bits[13:0]
Setting Description
inputs shorted. Gives optimal noise performance for zero bias
voltage sensors.
Amperometric Mode for 2-Lead
Sensor
0 0xXX (don’t care) 0x342C or 0b11 0100
0010 1100
Amperometric mode with SW10 closed to short counter
electrode to reference electrode internally.
Chronoamperometry (Low-Power
Pulse Test) Using Low-Power TIA
1 0x32 0x0014 or 0b00 0000
0001 0100
VBIASx output generates pulse to counter electrode.
Capacitors on low-power DACs are disconnected. Low-power
TIA measures sense electrode current response.
Chronoamperometry (Full Power
Pulse Test) Using High-Speed TIA
on Sense Electrode
1 0x31 0x0094 or 0b00 0000
1001 0100
VBIASx output generates pulse to counter electrode.
Capacitors on low-power DACs are disconnected. High-speed
TIA measures sense electrode current response.
Voltammetry (Full Power Pulse Test)
Using High-Speed TIA
1 0x31 0x0094 or 0b00 0000
1001 0100
VBIASx output generates pulse to counter electrode.
Capacitors on low-power DACs are disconnected. High-
speed TIA measures sense electrode or the DEx pin
current response. High-speed TIA resistors and switches are
configured separately.
Potentiostat Amplifier and Low-
Power TIA in Unity-Gain Mode (Test
Mode)
0 0xXX (don’t care) 0x04A4 or 0b00 0100
1010 0100
Potentiostat amplifier in unity gain mode, output to CEx pin.
Low-power TIA in unity gain mode, output to RCx_1 pin.
Useful for checking VBIASx or VZEROx DAC outputs.
Electrochemical Impedance Spectroscopy
In many electrochemical applications, there is significant value to
carrying out a diagnostic measurement. A typical diagnostic techni-
que is carrying out an impedance measurement on the sensor. For
some sensor types, the DC bias on the sensor must be maintained
when carrying out the impedance measurement. The ADuCM356
facilitates this measurement. To maintain the DC bias on the sen-
sor, set LPDACCONx, Bit 5 = 1. VZEROx is set to the input of the
high-speed TIA, and the high-speed DAC is used to generate an
AC signal. The level of the AC signal is set via the VBIASx output
of the low-power DAC. The voltage on the SE0 and SE1 pins is
maintained by VZEROx. The high-speed DAC DC buffers must also
be enabled by setting AFECON, Bit 21.
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