PS25255 EPIC Ultra High Impedance ECG Sensor Advance Information Data Sheet 291955 issue 1 FEATURES Ordering Information Ultra high input resistance, typically 20G. PS25255 Low supply current 1.4mA Custom package Dry-contact capacitive coupling. -25C to +75C Input capacitance as low as 15pF. Lower -3dB point typically 200mHz. Upper -3dB point typically 20kHz. Plessey Semiconductors Electric Potential Operates with bipolar power supply from 2.4V to Integrated Circuit (EPIC) product line targets a 5.5V. range of applications. Sensors supplied in a custom package with exposed The PS25255 is an ultra high impedance solid pins for surface mount assembly. state ECG (electrocardiograph) sensor. It can be used as a dry contact ECG sensor without APPLICATIONS the need for potentially dangerous low impedance circuits across the heart. The Contact ECG signal detection for: resolution available is as good as or better Non-critical patient monitoring than conventional wet electrodes. equipment. Emergency response diagnostics. The device uses active feedback techniques to Lifestyle sports and health products. both lower the effective input capacitance of the sensing element (Cin) and boost the input Suitable for long-term and remote resistance (Rin). These techniques are used to monitoring. realise a sensor with a frequency response suitable for both diagnostic and monitoring ECG applications. Fig. 1 PS25255 (top and bottom) Fig. 2 Internal circuit of EPIC ECG Sensor Data Sheet 291955 issue 1 Plessey Semiconductors Ltd. Design & Technology Centre, Delta 500, Delta Business Park, Great Western Way, Swindon, UK SN5 7XE Tel: +44 1793 518000 Fax: +44 1793 518030 Web: www.plesseysemi.com 1 PS25255 ELECTRICAL CHARACTERISTICS T = -25C to +75C,Vdd/Vss 2.4V to 5.5V. The electrical characteristics are guaranteed by either production amb test or by design and characterisation. They apply within the specified ambient temperature and supply voltage unless otherwise stated. Value Units Characteristics Conditions Min. Typ. Max. Supply voltage 2.4 5.5 V Bipolar supply, Gnd=0V Supply current 1.4 mA Effective input resistance 20 G Effective input capacitance 15 pF Voltage Gain (Av) 10 Coupling capacitance 250 pF Sensor to skin Set by internal DC signal rejection Lower -3dB point 0.20 Hz network coupling capacitor 250pF Upper -3dB point 20.0 kHz Noise tbd --33ddBB 00..22HHzz 2200..00kkHHzz Fig. 3 Typical Bode Plot for EPIC ECG Sensor Data Sheet 291955 Issue 1 Plessey Semiconductors Ltd. Design & Technology Centre, Delta 500, Delta Business Park, Great Western Way, Swindon, UK SN5 7XE Tel: +44 1793 518000 Fax: +44 1793 518030 Web: www.plesseysemi.com 2