An analog-to-digital converting device (100, 200) includes: an integrator (102, 202) arranged to generate an integrating signal according to an analog input signal and a first analog feedback signal; a low-pass filter (104, 304, 404, 504, 604, 704) arranged to generate a first filtered signal according to the integrating signal; an analog-to-digital converter (106) arranged to generate a digital output signal according to the first filtered signal; and a first digital-to-analog converter (108) arranged to generate the first analog feedback signal according to the digital output signal.