pc87591l-n05 National Semiconductor Corporation, pc87591l-n05 Datasheet - Page 60

• Manufacturer Part Number: pc87591l-n05
• Description: Lpc Mobile Embedded Controller
• Manufacturer: National Semiconductor Corporation

www.national.com
3.0 Power, Reset and Clocks
by firmware until AV
AV
The PC87591L-N05 is designed to operate with a Lithium backup battery that can supply voltage up to 3.6V. The PC87591L-
N05 includes an internal current-limiting resistor on the V
V
AV
modules from noise caused by the digital modules.
The following directives are recommended for the PC87591L-N05 power and ground connections (see Figure 9 for the pow-
er supply connections):
Ground Connection
Use two ground planes, one for the digital signals (GND) and one for the analog signals (AGND). The following ground con-
nections should also be made:
Note that low-impedance ground layers improve noise isolation and reduce ground bounce problems.
Power Connection
All PC87591L-N05 supply pins must be connected to the appropriate power plane, and decoupling capacitors must be used
as recommended below.
The analog supply pin, AV
supply (3.3V). If the AV
LC or RC filter for the AV
by replacing L
Note: If VBAT pins are not used, connect the pins to GND.
Decoupling Capacitors
The following decoupling capacitors should be used to reduce power supply deeps, ground bounce and EMI (refer to
Figure 9 for the position of capacitors, e.g., C1, C2, etc.):
• The analog ground plane (AGND) should be connected at only one point to the digital ground plane (GND). This point
• The analog ground return pin of the PC87591L-N05 (AGND) should be connected to the analog ground plane.
• The decoupling capacitors of the analog supply (AV
• The ground reference of the voltage input signals to the ADC module (V
• The ground reference of the voltage output signals from the DAC module (V
• All GND pins of the PC87591L-N05 must be connected to the GND plane.
• The decoupling capacitors of the Suspend digital supply (V
• The ground reference of the voltage input signals to the ACM module (KBV
• The decoupling capacitor of the on-chip power converter (V
• The decoupling capacitors of the Host digital supply (V
• The ground return and the decoupling capacitor of the backup battery supply (V
• Suspend digital supply (V
• On-chip power converter (V
• Host digital supply (V
• Backup battery (V
• Analog supply (AV
DD
CC
CC
should be located physically near the PC87591L-N05.
as possible to the AGND pin.
AGND plane close to the PC87591L-N05.
to the AGND plane close to the PC87591L-N05.
one side of each capacitor should be connected to the ground plane.
the GND plane close to the PC87591L-N05.
of the capacitor’s sides should be connected to the ground plane.
each capacitor should be connected to the ground plane.
PC87591L-N05; one of the capacitor’s sides should be connected to the ground plane.
pin pair. Also, place one 10 47 F C
to the pin.
pair. Also, place one 10-47 F tantalum capacitor (C6) on the common net as close as possible to the chip.
close as possible to the pin.
, V
use a separate ground return, named analog ground and marked AGND. This ensures effective isolation of the analog
to be externally filtered or driven by a low-noise power supply.
CC
and V
1
(in Figure 9) with a 10 resistor (not shown in the figure).
BAT
use a common ground return, named digital ground and marked GND. The analog circuits supplied by
CC
BAT
CC
CC
is within the limits specified above. In addition, the AV
CC
): Place one 0.1 F capacitor (C7) on the V
): Place a 0.1 F capacitor (C2) and a 10-47 F tantalum capacitor (C1) on the AV
DD
pin is connected to the same power supply as the V
CC
): Place one 0.1 F capacitor (C5) on the V
pin. An example of an LC filter [L
, should be connected to a low-noise power supply that has the same voltage as the digital
CC
CORF
): Place one 0.1 F capacitor (C3) on each V
): Place one 1 F ceramic capacitor (C8) on the V
4
(Continued)
tantalum capacitor on the common net as close as possible to the chip.
CC
BAT
) pin should be connected to the analog ground plane as close
DD
60
input as required to meet UL regulations.
1
) pin should be located near the V
and (C
CORF
CC
) pin should be located near each V
) pin should be located near the PC87591L-N05; one
BAT
1
+C
DD
pin as close as possible to the pin.
2
)] is shown in Figure 9. An RC filter is obtained
-GND pin pair as close as possible to the pin
IN
CC
CC
0-9 in Figure 9) should be connected to the
CC
IN
-GND pin pair as close as possible to the
OUT
pin, it is recommended to use an external
is internally isolated from V
0-7 in Figure 9) should be connected to
0-3 in Figure 9) should be connected
BAT
CORF
) pin should be located near the
pin pair as close as possible
DD
-GND pair; one side of
CC
-GND pin pair;
CC
CC
to enable
Revision 1.2
pin as