PSAS/ CapstoneLv2bRequirements

LV2b Capstone v4 Node Requirements Page

Here are our requirements for front end (microprocess and power sections) of the v4 node.

Global Requirements

  1. Minimize size (including height)
    • ~= v3 front end (the old front end was about 2.25 of double sided PCB, < 1 cm total thickness)
  2. Minimize power consumption (previously ~190mW)
  3. Minimize cost (<$150 front end)

"PIC" a New Microcontroller

See the Microcontroller Search page for requirements

Upgrade Switching Power Supply

  1. Meet old requirements:
    • 10 - 20V
    • > 70 % efficiency (old supply was 80%+ from 10mA to full load)
    • ~= existing supply size (plan area 1 with components on both sides, i.e. 2 total surface)
    • EMI compatible with onboard communication systems (e.g., crystal oscillator locked)
    • Must be able to shut down on external signal.
  2. Node protection:
    • Undervoltage lockout
    • Overvoltage protection
    • Reverse polarity protection
  3. Bus protection:
    • Current limiting (e.g., fuse)


  1. Debug connector
  2. Comm connector
    • High reliability
    • Locking
    • High density


  1. All signals routed to an edge towards the application specific circuitry
  2. Robust mechanical mounting

Secondary Goals (Things We Like)

  1. Flash over primary communication interface.