MIC2561 Datasheet, PDF (8/8 Pages) Micrel Semiconductor – PCMCIA Card Socket VCC & VPP Switching Matrix

MIC2561
Drive Enable
+5V
Switched VPP _IN
0.1µF 1N914
(Optional Schottky)
4.7kΩ
0.01µF
1N914
0.02µF
14
2
13
3
12
4
11
5
10
6
9
7
8
Micrel
2
Figure 5. Circuit for generating bias drive for the VCC switches when +12V is not readily available.
supplies generally have a quiescent current draw of a few
milliamperes, which is far more than the microamperes used
by the MIC2561. The charge pump of Figure 5 provides this
low current, using about 100µA when enabled. When V_{PP OUT}
= 12V is selected, however, the on-demand V_PP generator
must be used, as this charge pump cannot deliver the current
required for Flash memory programming. The Schottky diode
may not be necessary, depending on the configuration of the
on-demand +12V generator and whether any other loads are
on this line.
1997
2-37