data sheet 291839 issue 2 plessey semiconductors ltd tamerton road | roborough | plymouth | devon | pl6 7bq 1 PS25203B epic ultra high impedance electrophysiological sensor data sheet 291839 issue 2 fig. 1 PS25203B - top and bottom fig. 2 internal c ircuit of epic ecg sensor ordering information PS25203B custom package -25c to +75c plessey semiconductors electric potential integrated circuit (epic) product line targets a range of applications. the PS25203B is an ultra high impedance solid state ecg (electrocardiograph) sensor. it can be used as a dry contact ecg sensor without the need for potentially dangerous low impedance circuits across the heart. the resolution available is as good as or better than conventional wet electrodes. the device uses active feedback techniques to both lower the effective input capacitance of the sensing element (cin) and boost the input resistance (rin). these techniques are used to realise a sensor with a frequency response suitable for both diagnostic and monitoring ecg applications. features ? ultra high input resistance, typically 20g . ? dry-contact capacitive coupling. ? input capacitance as low as 15pf. ? lower -3db point typically 200mhz. ? upper -3db point typically 20khz. ? operates with bipolar power supply from 2.4v to 4.0v. ? sensors supplied in a custom package with exposed pins for surface mount assembly. applications ? contact ecg signal detection for: ? non-critical patient monitoring equipment. ? emergency response diagnostics. ? lifestyle sports and health products. ? suitable for long-term and remote monitoring.
PS25203B data sheet 291839 issue 2 plessey semiconductors ltd tamerton road | roborough | plymouth | devon | pl6 7bq 2 electrical characteristics t amb = -25c to +75c,vdd/vss 2.4v to 4.0v. the elec trical characteristics are guaranteed by either pro duction test or by design and characterisation. they apply within the specified ambient temperature and supply voltage unless otherwise stated. value characteristics min. typ. max. units conditions supply voltage 2.4 4.0 v bipolar supply, gnd=0v supply current 1.5 2.5 3.5 ma effective input resistance 20 g effective input capacitance 15 pf voltage gain (av) 10 coupling capacitance 250 pf sensor to skin lower -3db point 0.20 hz set by internal dc signal rejection network ? coupling capacitor 250pf upper -3db point 20.0 khz noise tbd 0.2hz 20.0khz -3db 0.2hz 20.0khz -3db fig. 3 typical bode plot for epic ecg sensor
PS25203B data sheet 291839 issue 2 plessey semiconductors ltd tamerton road | roborough | plymouth | devon | pl6 7bq 3 pin assignment top view output pin 1 top view vss pin 4 gnd pin 2 vdd pin 3 top view output pin 1 top view vss pin 4 gnd pin 2 vdd pin 3 fig. 4 pin assignment for the PS25203B mechanical dimensions the package diagram is shown below. it is recomme nded that a solder pad 1.6mm diameter be defined for the mounting of the sensor pins.. 3.44 0.15 0.51 0.10 side 10.50 0.08 0.75 0.75 0.75 0.75 10.50 0.08 9.0 9.0 top 1.35 0.35 1.35 0.35 10.50 0.08 bottom 7.80 0.64 7.80 0.64 1.0 10.50 0.08 1.35 0.35 1.35 0.35 3.44 0.15 0.51 0.10 side 10.50 0.08 0.75 0.75 0.75 0.75 10.50 0.08 9.0 9.0 top 1.35 0.35 1.35 0.35 10.50 0.08 bottom 7.80 0.64 7.80 0.64 1.0 10.50 0.08 1.35 0.35 1.35 0.35 fig. 5 mechanical drawing (all dimensions are nomin al and in mm)
PS25203B data sheet 291839 issue 2 plessey semiconductors ltd tamerton road | roborough | plymouth | devon | pl6 7bq 4 electrostatic discharge (esd) protection the PS25203B is manufactured using a high performan ce analog cmos process. as for all cmos components, it is essential that conventional esd p rotection protocols be applied for the handling of this device. patents this component and many of the associated applicati ons are covered by the following international patents: 602 32 911.6-08 (de) au2007228660 ca2646411 cn200780026584.8 ep1451595 (ch) ep1451595 (es) ep1451595 (fr) ep1451595 (ie) ep1451595 (it) ep1451595 (nl) ep2002273 ep2047284 ep2174416 gb1118970.1 jp2009-500908 jp4391823 tw097126903 tw1308066 us12/293872 us12/374359 us12/669615 us13/020890 us13/163988 us7885700
PS25203B data sheet 291839 issue 2 plessey semiconductors ltd tamerton road | roborough | plymouth | devon | pl6 7bq 5 application of the ecg sensor because of the large coupling capacitance to the bo dy (around 250pf) the epic sensor?s internal electr ometer can be used in differential mode to recover true surfac e potential ecg signals from the surface of the ski n. a typical ecg signal at the surface of the skin is 1mv p-p. vdiff fig. 7 differential measurement of body (skin) surf ace potential to produce ecg trace fig. 8 comparison of two vectors from a pair of epi c sensors (top) and two conventional ag/agcl electrodes (bottom)
PS25203B data sheet 291839 issue 2 plessey semiconductors ltd tamerton road | roborough | plymouth | devon | pl6 7bq 6 plessey semiconductors ltd. (plymouth) tamerton road | roborough | plymouth devon | united kingdom | pl6 7bq phone: +44 1752 693000 fax: +44 1752 693200 e-mail: info@plesseysemiconductors.com plessey semiconductors ltd.(swindon) design & technology centre | delta 500 delta business park | great western way swindon | united kingdom | sn5 7xe phone: +44 1793 518000 fax: +44 1793 518030 e-mail: info@plesseysemiconductors.com for further information about this and other produc ts, please visit: www.plesseysemiconductors.com legal notice product information provided by plessey semiconduct ors limited (?plessey?) in this document is believe d to be correct and accurate. plessey reserves the right to change/correct the specificat ions and other data or information relating to prod ucts without notice but plessey accepts no liability for errors that may appear in this docume nt, howsoever occurring, or liability arising from the use or application of any information or data provided herein. neither the supply of such in formation, nor the purchase or use of products conv eys any license or permission under patent, copyright, trademark or other intellectual property right of plessey or third parties. products sold by plessey are subject to its standar d terms and conditions of sale that are available o n request. no warranty is given that products do not infringe the intellectual property rights of third parties, and furthermore, the use o f products in certain ways or in combination with plessey, or non-plessey furnished equipments/c omponents may infringe intellectual property rights of plessey. the purpose of this document is to provide informat ion only and it may not be used, applied or reprodu ced (in whole or in part) for any purpose nor be taken as a representation relating to the pr oducts in question. no warranty or guarantee expres s or implied is made concerning the capability, performance or suitability of any produ ct, and information concerning possible application s or methods of use is provided for guidance only and not as a recommendation. the user is solely responsible for determining the performa nce and suitability of the product in any application and checking that any specification or data it seeks to rely on has not been superseded. products are intended for normal commercial applica tions. for applications requiring unusual environme ntal requirements, extended temperature range, or high reliability capability ( e.g. military or medical applications), special pro cessing/testing/conditions of sale may be available on application to plessey.
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