With an external voltage regulator, the TL431 chip external voltage (2.5V) is used as the excitation source of the external pressure sensor, and the voltage is more stable.
Chip function description
CS1238 is a high-precision, low-power analog-to-digital converter chip with two differential input channels, built-in temperature sensor and
High precision oscillator.
PGA of CS1238 is optional: 1, 2, 64, 128, and the default is 128.
The ADC data output rate of CS1238 is optional: 10Hz, 40Hz, 640Hz, 1.28kHz, and the default is 10Hz;
MCU can communicate with CS1238 through 2-wire SPI interface SCLK, DRDY/DOUT
Line configuration, such as channel selection, PGA selection, output rate selection, etc.
1.1 Main functional characteristics of the chip
Built-in crystal oscillator
Integrated temperature sensor
With power down function
2-wire SPI interface, the fastest rate is 1.1MHz
ADC functional characteristics:
24-bit lossless code
PGA magnification options: 1, 2, 64, 128
Integrated 2-channel 24-bit lossless differential input, ENOB is 20.7 bits (working at 5V) 20.2 when PGA=128
Bit (working at 3.3V)
P-P noise: PGA=128, 10Hz: 150nV;
INL is less than 0.0015%
Output rate options: 10Hz, 40Hz, 640Hz, 1.28kHz
In-band short function
1.2 Chip applications
Industrial process control
Electronic scale
Chemical analysis of liquid/gas
Blood meter
Intelligent converter