NXP : Narrowband Receiver for Healthcare Patient Monitoring Applications


Patient Remote Monitoring Application

NXP RF-IF building block ICs are well suited for niche market handheld devices. A major niche market is in medical monitoring and data management in which the human machine interface (HMI) is critical to the patient’s wellbeing and life support. The SA606 may be used by a cardiac patient to “connect” his implanted device to the clinic or doctor’s office via a standard phone line or cellular phone. The application employs the SA606 as a narrowband receiver which is used to receive data that alerts system protocols.

Information transmitted from the implanted heart device is received using an antenna similar to a stethoscope head attached to the patient transceiver monitor. At the schedule time or when the clinic asks the patient to transmit, the monitor is simply connected to a regular phone line, the antenna is held over the implanted heart device, and the transmit button is pushed. The patient monitor sends the implanted device information and turns itself off when done. The clinical team reviews the information on a secured website and contacts the patient as needed.

The SA606 is a low voltage high performance monolithic FM IF system incorporating a mixer/oscillator, two limiting intermediate frequency amplifier blocks, quadrature detector, logarithmic Received Signal Strength Indicator (RSSI), voltage regulator and audio and RSSI op amps.

The SA606 remote monitoring receiver shown in the block diagram operates from 60kHz to 80kHz. It uses the IF limiting amplifier and RSSI portion of the RF-IF device to amplify and output the amplitude shift keyed (ASK) data to an ADC in a MCU. The MCU has a DSP which is used to resolve the pertinent information in the ASK data signal and output the patient’s data and desired system protocols.

The SA606 is featured in this and other similar system solutions utilizing other NXP products, such as MCUs, RF Discrete, and interface solution products. The SA606 is supported by several RF-IF application notes and the OM13531 – SA606DK evaluation demo board.


SA606 RF-IF Building Block IC

Wide dynamic range RSSI (>90dB)Receives both strong and weak signals well
High gain IF and limiting amplifiers (>100dB)Receiver with high performance and sensitivity
Power supply range from 2.7V to 5.5V Ideal for low voltage battery-powered applications
Available in SSOP20 and HVQFN20 package optionsAllows for miniaturization and space saving solutions
Unlicensed part 15 applications from 50kHz to 150MHz50kHz to 500kHz ASK data receivers and HF/VHF data receivers