This paper presents a low-power, low-noise and high precision operational amplifier for a tracking system containing the intelligent medical device, and is an extended version of paper previously published by Nenadovic et al. in proc. of ICECS 2014. The accuracy of the tracking system strongly depends on the accurate amplitude acquisition of the received signal. Therefore, an operational amplifier with precise gain control and effective temperature compensation has been designed and fabricated. The operational amplifier provides linear and temperature independent signal amplification at frequencies between 0.2 and 20 kHz at a body temperature. The amplifier shows measured gain over temperature sensitivity as low as 32 ppm/A degrees C in temperature range from 20 to 40 A degrees C and consumes 300 mu A from a supply voltage of 2.5 V. Furthermore, the measured gain over temperature sensitivity in the range from -40 to 130 A degrees C is only 60 ppm/A degrees C. Simulated linearity for signal amplitudes up to 10 mV is 0.4 % and the input-referred noise at 1 kHz is 32 nV/aeHz. An open-loop gain of 46 dB at 1 kHz and bandwidth-gain product of 4.8 MHz is measured. The operational amplifier was designed in IHPs 250 nm SiGe BiCMOS technology and occupies an area of 0.2 mm(2).