MIC2593 Micrel Semiconductor, MIC2593 Datasheet - Page 25

• Manufacturer Part Number: MIC2593
• Description: Dual-Slot PCI Hot Plug Controller
• Manufacturer: Micrel Semiconductor

Gate Capacitor and Resistor Guidelines
The MIC2593 controls four external power MOSFETs, that
handle the high currents for each of the two 3.3V and 5V
outputs. A capacitor is connected in the application circuit
from each GATE pin of the MIC2593 to ground. However, an
external capacitor, C
MIC2593. Each C
respective power output (e.g., 5VOUTB). These capacitors,
which are typically in the 10nF range, cause the GATE
outputs of the MIC2593 to have very low AC impedances to
ground at any significant frequency. It is therefore necessary
to place a modest value of gate damping resistance (R
between each C
as shown in Figure 15. These resistances prevent high-
April 2004
MIC2593
GATE
GATE
GATE
and the gate of its associated MOSFET
, is not required for operation of the
controls the ramp-up rate of its
GATE
)
25
frequency MOSFET source-follower oscillations from occur-
ring. The exact value of the resistors used is not critical; 10
to 33 is usually a sufficient choice. Each R
physically located directly adjacent to the MOSFET gate lead
to which it connects.
Figure 15. C
MIC2593
GATE
GATE
and R
C
10nF
GATE
R
15
GATE
GATE
Connection
External
MOSFET
GATE
M9999-042204
should be
Micrel