New Cactus Semiconductor Medical Chip Eval Board Offers Lower Profile, Better Manufacturability



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.

The evaluation board’s MCU is low-power, 8-bit, and is provided with preloaded programming firmware. An ST-Link V2 dongle is also provided to communicate with and custom program the MCU. A single battery voltage generates on-board adjustable power management circuitry. Also, test points and other options are available on all outputs for easy connection to external electrodes.

Pricing and Availability
Cactus Semiconductor’s EB1CSI021 evaluation board and CSI021 ASSP are now available for purchase via the company’s website. The evaluation board is $956.46 while the ASSP is $391. To purchase in mass quantities, parties are advised to first contact the company’s sales department. Contact information and a data sheet for both devices can be found at the company website.


About Cactus Semiconductor
Cactus Semiconductor is a fabless semiconductor company producing low power mixed-signal application-specific integrated circuits (ASICs). Through its analog IC design services, the company develops custom ASICs for a variety of applications. Cactus Semiconductor has brought to market numerous system-level analog and mixed signal ASICs for low-power battery-operated electronics. These solutions include medical integrated circuits (IC) – or medical ASIC – including ASICs for implantable medical devices. Additionally they include ICs for portable applications and power management devices where small size and low power are critical. Founded in 2002, Cactus Semiconductor is ISO 9001:2008 qualified. The company maintains its headquarters in Chandler, AZ. More information can be found at www.cactussemiconductor.com.

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