The INA333 is a low power precision instrumentation amplifier with excellent accuracy. The gain can be set from 1 to 1000 with a single external resistor. The INA333 is designed to use industry-standard gain equations: G = 1+ (100kΩ/RG) Parameter: Low offset voltage: 25μV (max), G ≥ 100 Low drift: 0.1μV/°C, G ≥ 100 Low noise: 50nV/√Hz, G ≥ 100 High common mode rejection ratio (CMRR): 100dB (minimum), G ≥ 10 Low input bias current: 200pA (max) Low quiescent current: 50μA Input voltage: (V–) + 0.1V to (V+) – 0.1V Output voltage: (V–) + 0.05V to (V+) – 0.05V Operating temperature range: -40°C to +125°C Filtered radio frequency interference (RFI) input Power supply range: 1.8V to 5.5V (single power supply), ±0.9V to ±2.75V (dual power supply) The on-board 3.3V low-dropout LDO regulator chip directly supplies power to the INA333 amplifier. The amplifier uses a single-ended power supply mode, V- is connected to GND, and V+ is connected to the 3.3V output of the LDO. The amplifier uses a 3.3V single-ended power supply. VIN+ non-inverting input, VIN-non-inverting input. R3 on the board is not soldered. VCC regulator LDO input 5V.