STM660x advantages over alternative solutions

AN3271

10/29

Doc ID 17933 Rev 2

4

STM660x advantages over alternative solutions

4.1

Using a microprocessor

Some applications use a processor for monitoring the push-buttons. This solution however

has some disadvantages compared to the STM660x.

Disadvantages of monitoring using a microprocessor

●

If the processor is frozen, the control of the buttons is lost

●

Processor can NOT go into standby mode as it must continuously monitor the push-

buttons

●

Additional load on the processor (I/O pins are needed, the software has to monitor the

push-buttons)

●

Noise sensitivity

Advantages of monitoring with the STM660x

●

Functionality independent from the processor

●

Push-buttons monitored even if power for the system is disabled and the STM660x is in

standby mode (negligible current consumption of 0.6 µA)

●

Glitch immunity - glitches shorter than 32 ms are ignored

●

High ESD protection of the inputs

4.2

Discrete solution

Other applications try to replicate STM660x functionality by using a discrete solution.

Disadvantages of a discrete solution

●

Significant space on the PCB is needed

●

High current consumption

●

Sensitivity to accuracy of discrete components

●

Noise sensitivity

Advantages of using the STM660x

●

Compact solution, which needs a tiny fraction of PCB space compared to a discrete

solution (at least 20 discrete components are needed to reproduce only a basic

functionality of the STM660x devices which are available in a tiny TDFN12 - 2 x 3 mm

package)

●

Low current consumption of 6 µA and only 0.6 µA in standby mode

●

Push-buttons monitored even if power for the system is disabled and the STM660x is in

standby mode (negligible current consumption of 0.6 µA)

●

Glitch immunity - glitches shorter than 32 ms are ignored

●

High ESD protection of the inputs