We designed this CMS8H5120 series of chips with 4 OPAs, 2 DACs and the max clock frequency up to 48MHz. This series of chips are with constant current sourced pass-through the DAC and a 1-channel OPA which operates a precised current control to the H-bridge consisted of BJTs. the chip amplifies the photoelectric signal via the 1-channel OPA, and with a driving DAC, it will turn out to be an inverting amplifier which re-amplify the origin signal. This low-cost design we made is for fast and precised blood oxygen monitoring and operates with self-adjustment features catering for wide range of different users' profiles

CMS8H5120 series on pulse oximeter projects

>build-in 4-channel OPA which simplifies the external circuit

>build-in 2-channel 6-bit of DAC which precisely controls the operation current of the LED and the re-amplification of the signal.

>build-in 32K Flash、4K XRAM & 1K DataFlash

>high-speed SPI for driving different kinds of display like the OLED, TFT, LED and etc.

>measure range of the blood oxygen: 60%~100%(±1%)、40%~60%(>3%)

>measure range of the pulse: 40~200bpm(±1bpm)

>calibration under the FLUKE simulator. as when the default value of the pellucidness is 1100, its weak infusion ratio(PI) will be 0.1%