Rainbow Electronics AT77C104B - Manual (Page 30)

30
AT77C104B
5347B–BIOM–08/04
Navigation and Click
Modes Current
Consumption
Static Current Consumption The SPI bus’ consumption is very low in click and navigation modes, the majority of the
consumption being generated by the analog part of the circuit. Therefore, the static and
dynamic consumption is almost the same.
Dynamic Current
Consumption With a 30 pF load at maximum clock frequency, the current consumption in click mode is
almost 300 µA on pins V
DD
. With a 30 pF load at maximum clock frequency, the current
consumption in navigation mode is approximately 1.5 mA.
Note: We advise use of the interrupt capabilities (IRQ signal or Interrupts register) so as to limit
the host’s overall current consumption. The host can, from time to time, check the IRQ or
Interrupt register. A strategy for very low power consumption is to use the click mode only
as a wake-up. The click mode is only 300 µA, and once a click is detected the host can
turn on the navigation mode as well.
Packaging Mechanical Data
Figure 19. AT77C104B-CB08V Top View
All dimensions in mm.
Figure 20. AT77C104B-CB08V Bottom View
All dimensions in mm.
23 ±0.3
4.6 max
1.1 min
0.74 ±0.06
1.2 max
0.56 ±0.1
4.8 ±0.4
1.75 ±0.5
4.8 max
5 ±0.3
11.98
0.2
+0.07
1.50 - 0.01
A
A
A
A
0.5 ±0.08
2.25 ±0.3
0.5 ±0.08
1.5 ±0.3
2 ±0.08
19 1