Wireless medical devices are currently in the spotlight due to rapid growth of interest in remote diagnosis systems and long-term medical assistances. In general, such medical device contains a sensor as a front-end to detect bio-signals of a patient or health-conscious person. The output of the sensor is extremely weak for further processing and susceptible to noise. Thus, a low-noise amplifier is connected to the sensor to amplify the original signal while minimizing the effect of noise. The performance of a low-noise amplifier (LNA) determines the quality of the original signals later on. Our main goal is to design an LNA that is suitable for implantable bio-signal acquisition systems. Primarily focus is on the implantable medical system with an electrocardiogram (ECG) sensor, which records electrical activities of a person's heart. The designed LNA is inspired by a ring amplifier topology, and it provides enough voltage gain to amplify the ECG signals. Chopper stabilization is added to the structure to reduce the contamination due to flicker noise. In addition, its power consumption is minimized to enhance the lifespan of the whole system. Currently, a bio-acquisition system's overall power consumption is dominated by a low-noise amplifier. The other module in the bio-acquisition system only consumes less than 1uW each while a typical LNA consumes more than 10uW. By reducing the power consumption of the LNA, the device can maintain its performance for a longer period of time.