Can ClearView Mathias be used in LOW VOLTAGE targets?

Submitted by: TechTools

YES and NO.

Mathias is a 5V only emulator. It is self-powered by its internal 5V supply. In general, you can NOT plug it into a low voltage target without verifying compatability.

There are ways of dealing with low voltage targets, depending on the target.

There are 4 concerns when running a 5V ICE in a 3V target:

1. Logic levels INTO the ICE
The 3V logic levels from your target are OK for ICE *INPUTS*. The target's logic lows and highs are compatible with the ICE inputs.

2. Logic levels FROM the ICE into the target
The ICE will generate 5V OUTPUTs which may damage your target unless:
- the target is 5V tolerant or
- current limit resisters are inserted in-line with the ICE OUTPUTS or
- voltage translation circuits are used on the ICE OUTPUTs. (3V buffers with 5 tolerant inputs...for one solution)

Without proper ICE output translation, the target may pull excess current from the ICE and damage the bondouts or the target and/or cause malfunctions. Most ICs clamp inputs to their power rails. If the 5V outputs from the ICE are connected directly to 3V inputs on the target, they essentially get shorted to the target power rail. This causes high current draw from the ICE and may burn out the bondouts or the target. In less severe cases, it may cause abnormal operation, ground shifts, resets....

3. Analog references.
Any analog peripherals that use internal references will be referenced from our 5V supply rather than your target supply. You MAY be able to compensate for this by using external references or scaling your results/settings to compensate.

4. ISOLATE power rails
Since the power rails are at different potentials and the ICE can not run off of 3V, be sure to set the POWER jumper on the MEMBER MODULE to the ISOLATED position (internal power).

So it IS possible to use Mathias on a low voltage target, but your target must either be 5V tolerant OR you must take steps to make it tolerant. Further, you must be aware of the affect on any analog peripherals using internal references.