●The AFE4300 is a low-cost analog front-end incorporating two separate signal chains: one chain for weight-scale (WS) measurement and the other for body composition measurement (BCM) analysis. A 16-bit, 860-SPS analog-to-digital converter (ADC) is multiplexed between both chains. The weight measurement chain includes an instrumentation amplifier (INA) with the gain set by an external resistor, followed by a 6-bit digital-to-analog converter (DAC) for offset correction, and a circuit to drive the external bridge/load cell with a fixed 1.7 V for ratiometric measurements.
●The AFE4300 can also measure body composition by applying a sinusoidal current into the body. The sinusoidal current is generated with an internal pattern generator and a 6-bit, 1-MSPS DAC. A voltage-to-current converter applies this sinusoidal current into the body, between two terminals. The voltage created across these two terminals as a result of the impedance of the body is measured back with a differential amplifier, rectified, and the amplitude is extracted and measured by the 16-bit ADC.
●The AFE4300 operates from 2 V to 3.6 V, is specified from 0°C to +70°C, and is available in a LQFP-80 package.
● Weight-Scale Front-End:
● Supports up to Four Load Cell Inputs
● On-Chip Load Cell 1.7-V Excitation Voltage for Ratiometric Measurement
● 68-nVrms Input-Referred Noise
●(0.1 Hz to 2 Hz)
● Best-Fit Linearity: 0.01% of Full-Scale
● Weight-Scale Measurement : 540 µA
● Body Composition Front-End:
● Supports Up To Three Tetra-Polar Complex Impedance Measurements
● 6-Bit, 1-MSPS Sine-Wave Generation Digital-to-Analog Converter (DAC)
● 247.5-µArms, ±20% Excitation Source
● 0.1-Ω Measurement RMS Noise in 2-Hz BW
● Body Composition Measurement : 970 µA
● Analog-to-Digital Converter (ADC):
● 16 Bits, 860 SPS
● Supply Current: 110 µA
●All trademarks are the property of their respective owners.
