The corner frequency of the high pass filter for MAX30003 is given by
Fhp = 1/(2 x pi x Rhpf x Chpf),
where Rhpf is an internal resistance (typ value = 450kohm), and Chpf is the external capacitance connected between CAPP and CAPN.
So with a 1.47uF (1uF + 0.47uF) capacitance between CAPP and CAPN, the expected high pass filter corner frequency is 0.24Hz.
However, with specific 1uF and 0.47uF capacitors, the actual measured high pass filter corner frequency was found to be 0.5Hz.
This happens because the effective value of the capacitance between CAPP and CAPN is smaller than the nominal value because of dc and ac derating. The ac and dc voltage of the input ECG signal directly appear across CAPP and CAPN, and must be accounted for when determining the HPF corner frequency.
For example with a 1uF (nominal) cap with manufacturer part number CL03A105MQ3CSN, the ac and dc derating curves look as follows:
Note that even if there is no dc bias in the input signal, since the ac signal amplitude of an ecg signal is very small, the effective capacitance value could be smaller than the nominal capacitance by 40%.