PS25251 Plessey

PS25251 EPIC Ultra High Impedance ECG Sensor Advance Information Data Sheet 291766 issue 3 FEATURES Ordering Information Ultra high input resistance, typically 20G. PS25251 Dry-contact capacitive coupling. Custom package Input capacitance as low as 15pF. -25C to +75C Lower -3dB point typically 200mHz. Upper -3dB point typically 10kHz. Operates with bipolar power supply from 2.4V to Plessey Semiconductors Electric Potential 5.5V. Integrated Circuit (EPIC) product line targets a Sensors supplied in a custom package with exposed range of applications. pins for surface mount assembly. The PS25251 is an ultra high impedance solid state ECG (electrocardiograph) sensor. It can APPLICATIONS be used as a dry contact ECG sensor without the need for potentially dangerous low Contact ECG signal detection for: impedance circuits across the heart. The Non-critical patient monitoring resolution available is as good as or better equipment. than conventional wet electrodes. Emergency response diagnostics. Lifestyle sports and health products. The device uses active feedback techniques to Suitable for long-term and remote both lower the effective input capacitance of the sensing element (Cin) and boost the input monitoring. resistance (Rin). These techniques are used to realise a sensor with a frequency response suitable for both diagnostic and monitoring ECG applications. Fig. 1 PS25251 (top and bottom) Fig. 2 Internal circuit of EPIC ECG Sensor Data Sheet 291766 issue 3 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 PS25251 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 0.6 2.0 3.5 mA Effective input resistance 20 G Effective input capacitance 15 pF Primary Output Voltage Gain (Av) 47.5 50 52.5 1kHz Coupling capacitance 250 pF Sensor to skin Guard Output voltage gain 0.95 1.0 1.05 1kHz Set by internal DC signal rejection Lower -3dB point 0.20 Hz network coupling capacitor 250pF Upper -3dB point 4.0 kHz --33ddBB 00..22HHzz 1100kkHHzz Fig. 3 Typical Bode Plot for EPIC ECG Sensor Data Sheet 291766 Issue 3 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