TS555 Reset levels

[TomLH]

Hi. From DS of TS555 I'm not clear about RESET acitve low level. In DS VRESET is given 0.4V(min), 1.1V(typ), 1.5V(max) for +25°C and 0.3V...2.0V for whole temp range, see attachement
Can someone help to get min/typ/max level for RESET is active and the level RESET is inactive at +5V supply and -25°C....+85°C.

Thx Tom

[Peter BENSCH · Accepted solution]

Welcome @TomLH, to the community!

Well, the TS555 was developed decades ago and the specifications found in the data sheet were set at that time. The 0.4…1.5V only applies to 25°C, at other temperatures it must be ensured that RESET can be triggered correctly, i.e. the voltage must drop to a level of ≤0.3V to trigger. 

On the other hand, it must also be taken into account that RESET may only be triggered from 2.0V.

Typically, a temperature other than 25°C will be present, so the full temperature range specification applies so that STMicroelectronics can guarantee the parameters under all circumstances.

Hope that answers your question?

Regards
/Peter