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.
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|Part number||Order||Number of input channels||Resolution (Bits)||Interface||Number of LEDs||Features||Operating temperature range (C)||Package Group||Package size: mm2:W x L (PKG)||Approx. price (US$)|
||2||16||SPI||0||Biosensing||0 to 70||LQFP | 80||80LQFP: 196 mm2: 14 x 14 (LQFP | 80)||1.50 | 1ku|
||1||24||I2C||3||Optical biosensing||-20 to 70||DSBGA | 15||See datasheet (DSBGA)||2.01 | 1ku|
|AFE4405||Samples not available||2||24||
|3||Optical biosensing||-20 to 70||2.20 | 1ku|
|AFE4410||Samples not available||3||24||
|4||Optical biosensing||-20 to 70||2.33 | 1ku|
|AFE4420||Samples not available||4||24||I2C||4||Optical Biosensing||-40 to 85||3.61 | 1ku|
|AFE44I30||Samples not available||7||24||I2C||7||Optical Biosensing||-40 to 85|
|AFE44S30||Samples not available||4||24||SPI||7||Optical Biosensing||-40 to 85||5.28 | 1ku|
|AFE4900||Samples not available||3||24||
|4||Optical biosensing||-20 to 70||2.42 | 1ku|