Cactus Semiconductor™ has updated its microprocessor evaluation board for its application-specific standard product (ASSP) medical chip to provide new microcontroller unit (MCU) packaging for easier manufacturability, new inductors for a lower profile, and more. The EB1CSI021™ evaluation board is ideal for electronics engineers seeking to develop battery-powered neurostimulation medical applications.
The MCU for the EB1CSI021 now uses an ultra-fine pitch quad flat no-lead 28 pin UFQFPN28 package. It replaces a WLCSP package and the change improves manufacturability and simplifies reworking. The small 4x4mm MCU footprint and ultra-low power work well with the ASSP for implantable medical applications. The inductors on the board were also changed for the dual boost converter. This allows for a lower profile and smaller footprint in end designs. The inductors can offer an overall four times footprint reduction compared to the original inductors. Also, a jumper was added to separate the MCU power supply from the on-board LDO. This is to increase design and power management flexibility allowing the user to bypass the fixed LDO output voltage.
The evaluation board is provided with two Cactus Semiconductor CSI021™ medical ASSPs which can be synchronized. The ASSP is ideal for evaluating the design of many applications. They include implantable medical devices for neurostimulation / neuromodulation, MEMs and sensor applications, implantable pulse generators (IPG), and more. Cactus Semiconductor’s CSI021 features four independent 8-bit linear DAC programmable current sink / source outputs. They deliver up to a 6mA full-scale sink and 1.5mA full-scale source currents. Full-scale current ranges are programmable via an external reference resistor. An 18V supply voltage allows for 6mA output currents into 1.5k ohm loads. The CSI021 pulse timing is fully programmable via a 1MHz (up to 10MHz) 2.5V SPI. The ASSP can be programmed via the MCU using the SPI. Optionally the SPI can be externally controlled, bypassing the MCU, to program the ASSP directly. Programmable parameters include sink / source pulse widths, pulse frequencies, stimulation on / off periods, and amplitude ramp rates. For medical applications, internal timing generators in the CSI021 use the programmed parameters to create therapy profiles. This is done with only minimal intervention from a host processor. A 4:1 sink to source current ratio provides for easy stimulation charge balancing. Read more.