TABLE I:

Performance Comparison

Ref.	[1] TBioCAS 2021	[12] JSSC 2019	[17] JSSC 2020	[14] BioCAS 2022	[13] ISCAS 2020	[26] ISSCC 2023	This Work
Mode (Sensor Target)	I (Echem, Temp)	I (Echem, Temp)	R, C (Temp, RH)	I, V (Echem, pH)	I, V (Echem)	I, V (Temp, Echem, pH)	R, I, V (Temp, Echem, pH)
Active Area (mm2)	8	0.01	0.72	0.037	0.098	2.51	0.52
Processs (um)	0.18	0.25	0.18	0.18	0.18	0.18	0.18
Supply (V)	1.2	2.5	1.5 to 2	1.2	1.4	1.8	1.2
Power (μW)	493	250	15.6	2.2	40	22 (peak)	R-mode: 9.24 I-mode: 65 V-mode: 5.66
ADC Type	Relax Osc + TDC	ΔΣ ADC	VCO + TDC	Relax Osc	Incre. ADC	SAR	VCO + TDC
Communication	On-chip TC & TC	Wired	Wired	Wired and TX	Wired	Wired	Wired and TX
Amperiometric Sensing
Current Range	±6μA	±12.5nA	NA	2μA	0.1μA	±10μA	FLL only: 0.5μA With PSTAT: 200μA
R2 Error	0.995	Unknown	NA	0.999	0.998	NA	>0.9995
Input-Ref. Noise	2pA BW=Unknown	0.28PA BW=20Hz	NA	Unknown	44.6fA BW=Unknown	14pA BW=16Hz	40.6pA BW=100Hz7
Pattern Gen.	On-chip analog	Off-chip	NA	On-chip 4-bit DAC	Off-chip	On-chip DAC	On-chip 4-bit DAC
Potentiostat	On-chip	Off-chip	NA	On-chip	NA	On-chip	On-chip
Voltage Sensing
Voltage Range (V)	NA	NA	NA	0 to 1	0.32 to 1.05	0 to 1.8	0.2 to 0.6
R2 Error	NA	NA	NA	0.999	0.974	0.99999	> 0.9999
Input-Ref. Noise	NA	NA	NA	Unknown	1.7μV BW=10kHz	72.3μV BW=16Hz	31.7μV BW=100Hz8
pH Range	NA	NA	NA	4 to 10	NA	4 to 10	1.6 to 12
Temperature Sensing
Linear Range (°C)	20 to 80	25 to 65	−40 to 85	NA	NA	Unknown	0 to 759
Resolution	43mk BW=Unknown	NA	2mK BW=500Hz	NA	NA	Unknown	16.4mK BW=100Hz10
Transducer	Ring oscillator	Diode	On-chip Poly-R	NA	NA	Unknown	Off-chip thermistor

¹Estimated active readout circuit area only

²FLL readout circuit active area only. Also requires off-chip capacitors

³Includes pattern/clock generation

⁴Thermistor at nominal resistance

⁵Potentiostat idling

⁶Mid-rail input voltage

⁷With zero input current at FLL readout circuit input

⁸At minimum input voltage

^{9, 10}Based on TI TMP63 thermistor