Medical Applications Guide (Rev. B - Mouser Electronics

Diagnostic, Patient Monitoring and TherapyECG/Portable ECG and EEG23➔3.3V High-Speed Digital IsolatorsISO721, ISO722Get samples, datasheets, evaluation modules and app reports at:www.ti.com/ISO721 or www.ti.com/sc/device/ISO722The ISO721 digital isolator is a logic input and output buffer separatedby a silicon oxide (SiO 2 ) insulation barrier that provides galvanicisolation of up to 4000V. Used in conjunction with isolated powersupplies, the IC prevents noise currents on a data bus or othercircuits from entering the local ground and interfering with ordamaging sensitive circuitry.A binary input signal is conditioned, translated to a balanced signal,then differentiated by the capacitive isolation barrier. Across theisolation barrier, a differential comparator receives the logic transitioninformation, then sets or resets a flip-flop and the output circuitaccordingly. A periodic update pulse is sent across the barrier toensure the proper DC level of the output. If this DC-refresh pulse isnot received for more than 4µs, the input is assumed to be unpoweredor not functional, and the fail-safe circuit drives the output to a logichigh state.Zerø-Drift, Low-Offset, Single-Supply Op AmpsOPA334, OPA335Get samples, datasheets, evaluation modules and app reports at:www.ti.com/sc/device/OPA334 or www.ti.com/sc/device/OPA335The OPA334 and OPA335 CMOS op amps use auto-zeroing techniquesto simultaneously provide very low offset voltage and near-zero driftover time and temperature. These high-precision amps offer high inputimpedance and rail-to-rail output swing.Key Features• Low offset voltage: 5µV (max)• Zero drift: 0.05µV/°C (max)• Quiescent current: 285µA• Packaging: SOT23-5, SOT23-6, SO-8, MSOP-10 (dual)Applications• Transducer applications• Electronic scales• Temperature measurementKey Features• 4000V isolation• Fail-safe output• Signaling rate up to 100Mbps• UL 1577, IEC 60747-5-2 (VDE 0884, Rev. 2), IEC 61010-1and CSA Approved• 25kV/µs transient immunityV EXRRRRR 1+5VOPA335V OUTR 1OSC+PWMDC ChannelIsolationBarrierV REFFilterPulse WidthDemodulationCarrierDetectOPA335 –5V supply bridge amplifier.V REFPORBIASPORINInput+FilterV REFData MUXAC Detect3-StateOutputBuffer(722 Only)ENOUTAC ChannelISO721 functional block diagram.Texas Instruments 2Q 2007Medical Applications Guide