Low-noise, analog-to-digital converter for biopotential measurements

Texas Instruments’ ADS1299-4, ADS1299-6 and ADS1299 devices are a family of four, six, and eight-channel, low-noise, 24-bit, simultaneous-sampling delta-sigma ADCs with a built-in PGA, internal reference, and an onboard oscillator. The devices incorporate all commonly-required features for extracranial electroencephalogram and electrocardiography applications. With its high levels of integration and exceptional performance, they enable the creation of scalable medical instrumentation systems at significantly reduced size, power and overall cost. The device has a flexible input multiplexer per channel that can be independently connected to the internally-generated signals for test, temperature, and lead-off detection. Additionally, any configuration of input channels can be selected for derivation of the patient bias output signal. Optional SRB pins are available to route a common signal to multiple inputs for a referential montage configuration. It operates at data rates from 250SPS to 16kSPS. Lead-off detection can be implemented internal to the device using an excitation current sink or source. Multiple ADS1299-4, ADS1299-6, or ADS1299 devices can be cascaded in high channel count systems in a daisy-chain configuration. They are offered in a TQFP-64 package specified from –40C to +85C.