ADX923QAQFN32 Low-Power, 2-Channel, 24-Bit Analog Front-End for Biopotential Measurements

　　The ADX92xQ devices are multichannel,simultaneous sampling,24-bit,delta-sigma(ΔΣ)analog-to-digital converters(ADCs)with a built-in programmable gain amplifier(PGA),internal reference,and an onboard oscillator.The ADX92xQ devices incorporate all features commonly required in portable,low-power medical electrocardiogram(ECG),sports,and fitness applications.With high levels of integration and exceptional performance,the ADX92xQ devices enable the creation of scalable medical instrumentation systems at significantly reduced size,power,and overall cost.The ADX92xQ devices have a flexible input multiplexer per channel that can be independently connected to the internallygenerated signals for test,temperature,and leadoff detection.Additionally,any configuration of input channels can be selected for derivation of the right leg drive(RLD)output signal.The ADX92xQ devices operate at data rates up to 8kSPS.Lead-off detection can be implemented internal to the device,using the device internal excitation current sink or source.The ADX922Q and ADX923Q versions include a fully integrated respiration impedance measurement function.Operating temperature is specified from–40°C to 125°C.

　　1.FEATURES

　　•Three low-noise(ADX923Q)PGAs and two

　　high-resolution ADCs(ADX922Q and

　　ADX923Q)

　　•Input-referred noise:8.8μVPP(150Hz BW,G=6)

　　•Input bias current:100pA(max)

　　•Data rate:125SPS to 16kSPS

　　•CMRR:117dB;THD:109dB

　　•Programmable gain:1,2,3,4,6,8,or 12

　　•Supplies:unipolar or bipolar

　　Analog:2.7V to 5.5V

　　Digital:1.65V to 3.6V

　　•Built-in right leg drive amplifier,lead-off

　　detection,test signals

　　•Integrated respiration impedance

　　measurement(ADX922Q and ADX923Q)

　　•Electrode Rotation mode(ERM)to implement

　　time-division multiplexing LEAD-I,LEAD-II,and

　　LEAD-III measurements(ADX923Q)

　　•Integrated analog PACE measurement

　　(ADX921Q,ADX922Q,ADX923Q)

　　•Flexible power mode

　　High Resolution mode

　　High Speed mode(ADX921Q,ADX922Q,

　　ADX923Q)

　　•Built-in oscillator and reference

　　•Supply monitor,internal temp sensor,OSC

　　fault detection,overrange detection

　　•Flexible power-down,standby mode

　　•SPI™-compatible serial interface,timeout reset

　　•Cyclic redundancy check(CRC)on

　　communications,checksum

　　•Support ADC data FIFO for reducing polling

　　time of the external device to save power

　　•Functional safety features to support

　　automotive application

　　•Supports systems meeting IEC 60601-2-47

　　•Operating temperature range:–40°C to 125°C

　　•AEC-Q100

　　2.APPLICATIONS

　　•Medical instrumentation(ECG)including:

　　Patient monitoring:Holter,event,stress,

　　and vital signs including ECG,AED,and

　　telemedicine

　　Personal care and fitness monitors(heart

　　rate,respiration,and ECG)

　　•High-precision,simultaneous,multichannel

　　data acquisition