9

9524B–AT42–04/09

AT42QT1040

Figure 4-1.

~500 ns Pulse On OUT2 Pin

4.3

Speed Selection

Speed selection is determined by a 1 M

 resistor (RFS resistor) connected between SNSK1

and either Vdd (Fast Mode) or Vss (Slow Mode).

In Fast Mode, the device sleeps for 16 ms between burst acquisitions. In Slow Mode, the device

sleeps for 64 ms between acquisitions. Hence, Slow Mode conserves more power but results in

slightly less responsiveness.

Note:

The RFS resistor should always be connected to either Vdd or Vss and not changed

during operation of the device. Changing the RFS option will affect the sensitivity of the

particular key. Always check that the sensitivity is suitable after a change. Retune Cs1 if

necessary.

Pulse on OUT2

SNS0K

OUT2

SNS0K

OUT2

~20 ms

Power-on/

Reset

Table 4-2.

RFS Resistor

RFS Connected To...

Mode

Vdd

Fast mode

Vss

Slow mode