Typical application diagrams

AN3261

10/17

Doc ID 17837 Rev 1

2.6

Reliability note

Devices with timings adjusted by external components vs. environmental

considerations

several additional factors to be considered that may affect the accuracy of the timings. The

given specifications apply to the STM65xx device alone, i.e. with an ideal timing capacitor.

External tolerances, temperature dependencies and leakages are excluded.

The Smart Reset™ devices are designed to meet strict requirements for the lowest possible

current consumption and to maintain the common timing constant 10 s/µF, therefore the

constant current used to charge the external timing capacitor is very low, in the magnitude of

100 nA. Any external leakage (e.g. poor quality timing capacitors or excessive humidity,

especially if dew-point is exceeded and moisture condensation occurs on the PCB tracks)

may cause a significant leakage current which is deducted from the constant charging

current that the device provides, reducing the effective external timing capacitor charging

short as possible, properly covered with solder mask and isolated from other tracks

(ceramic or film capacitor) should be used.