RHD2000 Series Digital Electrophysiology Interface Chips Digital Electrophysiology Interface Chips 11 December 2012; updated 5 September 2013 ♦ Fully integrated electrophysiology amplifier array with on-chip 16-bit analog-to-digital converter (ADC) and industry-standard serial peripheral interface (SPI) ♦ ADC operation to 1.05 MSamples per second; supports sampling 32 amplifier channels at 30 kSamples/s each ♦ Low input-referred noise: 2.4 pVrms typical ♦ Standard four-wire 16-bit SPI interface with CMOS or low-voltage differential signaling (LVDS) I/O pins ♦ Upper cutoff frequency of all amplifiers set by on-chip registers; adjustable from 100 Hz to 20 kHz ♦ Lower cutoff frequency of all amplifiers set by on-chip registers; adjustable from 0.1 Hz to 500 Hz ♦ Integrated multi-frequency in situ electrode impedance measurement capability ♦ Optional on-chip DSP high-pass filters for amplifier offset removal ♦ Auxiliary ADC inputs for interfacing additional sensors. ♦ Individual amplifier power up/down for power minimization Applications ♦ Miniaturized multi-channel headstages for neural or ECoG recording ♦ Low-power wireless headstages or backpacks for electrophysiology experiments ♦ Recording spikes and/or local field potentials (LFPs) from microelectrodes ♦ “Smart Petri dish” in vitro recording systems ♦ Portable EKG or EMG monitoring systems ♦ Advanced prosthetic limb controller front-ends The Intan Technologies RHD2000-series microchips are complete low-power electrophysiology signal acquisition systems. These patent-pending devices contain arrays of low-noise amplifiers with programmable bandwidths and are suitable for a wide variety of biopotential monitoring applications. Innovative circuit architecture combines amplifiers, analog and digital filters, a multiplexed 16-bit analog-to-digital converter (ADC), and a flexible electrode impedance measurement module onto a single silicon chip. In practice, many recording electrodes are connected directly to one side of the chip, and serial digital data exits the other side on a standard SPI bus. The upper and lower bandwidths of the amplifiers may be dynamically programmed by means of internal registers on each chip. This flexibility allows the chips to be optimized for different types of signals (e.g., 0.1 - 100 Hz for EKG signals, 250 Hz - 7.5 kHz for neural action potentials). Internal capacitors reject DC offset voltages at the input electrodes, eliminating problems with built-in potentials at the electrode-tissue interface. A low-distortion, high-speed analog multiplexer (MUX) allows many amplifiers to share the on-chip ADC. The ADC can sample each channel up to 30 kSamples/s. Each chip includes three auxiliary input pins for connecting external sensors or other analog voltages which may be sampled using the ADC. Additional on-chip circuitry enables in situ electrode impedance measurements at user-programmable frequencies. By transforming weak electrode signals directly into a digital data stream, the RHD2000 replaces all analog instrumentation circuitry in electrophysiology monitoring and acquisition systems. RHD2000-series chips are packaged in standard 8mm x 8mm QFN surface mount packages, or available in bare die form. The small footprint and low power consumption of the multi-channel chips enable the miniaturization of front end electronics for miniature headstages and other wearable or portable biopotential recording systems. www.intantech.com • [email protected] intan TECHNO

Simplified Chip Diagrams RHD2000-SERIES FAMILY There are three devices in the RHD2000-series electrophysiology interface family: the RHD2216 and RHD2132, which are described in this datasheet, and the RHD2164 which is described in its own datasheet available on the Intan Technologies website. The following table lists the features of these chips: The positive and negative amplifier inputs on the RHD2216 have balanced input impedances; this will provide the best rejection of common-mode noise (most commonly, 50/60 Hz interference) if all electrodes, including reference electrodes, are roughly...

RHD2000 Series Digital Electrophysiology Interface Chips RHD2132 Simplified Diagram The RHD2132 contains an array of 32 amplifiers having unipolar inputs (in0, in1,…) and a common, shared reference line (ref_elec).

The RHD2216 contains an array of 16 amplifiers having independently accessible differential inputs (in0+, in0—, in1+, ini-,...). analog multiplexer digital controller with SPI interface amplifier bandwidth selection HEI CS SCLK —MOSI MISO temperature sensor misc. chip conliquralian bits reqister tile www.intantech.com • [email protected]

RHD2000 Series Digital Electrophysiology Interface Chips www.intantech.com • [email protected]

RHD2000 Series Digital Electrophysiology Interface Chips Electrical Characteristics Ta = 25°C, Vdd = 3.3V unless otherwise noted. www.intantech.com • [email protected]

Ta = 25°C, Vdd = 3.3V unless otherwise noted. www.intantech.com • [email protected]

RHD2000 Series Digital Electrophysiology Interface Chips Measured Performance Characteristics SAMPLING AMPLIFIERS WITH ON-CHIP ADC Figure 1. Measurement of ±5.0 mV, 100 Hz triangle wave on amplifier channel 1 with ADC running at 30 kS/s per channel, showing large-signal linearity. Amplifier channel 2, also shown, is grounded, showing low noise and lack of crosstalk. Figure 2. Measurement of ±350 µV, 100 Hz triangle wave on amplifier channel 1 with ADC running at 30 kS/s per channel, showing large-signal linearity. Amplifier channel 2, also shown, is grounded, showing low noise and lack of crosstalk....

RHD2000 Series Digital Electrophysiology Interface Chips Measured Performance Characteristics BIOPOTENTIALS MEASURED WITH RHD2000-SERIES AMPLIFIERS Figure 4. EKG signal recorded with RHD2216 using three Ag/AgCl electrodes (in0+ and in0– on chest, 5 cm apart; ground on elbow). Amplifier was configured with fL = 0.1 Hz, fH = 100 Hz, and DSP high-pass filter set to 0.6 Hz. ADC sampling rate was 2 kS/s per channel. Figure 5. EMG signal recorded with RHD2216 using three Ag/AgCl electrodes during bicep contractions (in0+ and in0– on bicep, 5 cm apart; ground on elbow). Amplifier was configured with...