27 Application Notes
27.1 Power Supply for 3.3V, 5V and Wide-Range Systems
The MPC82G516A consists of 5V logic device and 3V logic device; the former is directly powered from VDD pin
while the latter is powered through the internal Low Drop-Out (LDO) voltage regulator. V30 pin comes from the
LDO’s output, which should be connected to ground through a capacitor for ripple filtering in order to get a better
load regulation. Figure 27-1 shows the internal power scheme. The operating range of power supply is
determined by the connection type of VDD pin and V30 pin.
Figure 27-1. Power Scheme
Inside the Chip
VDD
3.0V
Low Drop-Out
Output
Voltage Regulator
(LDO)
V30
5V Logic Device
3V Logic Device
CPU Core,
RAM,
Flash,
Input/Output
Buffer
Peripherals,
Glue Logic
27.1.1 Power Supply for a 3.3V System
To have the MPC82G516A work in a 3.3V system with power supply varying from 2.4V to 3.6V, pin V30 should
be tied to VDD, as shown in Figure 27-2. In this condition, the internal LDO is bypassed. Thus the chip can work
down to 2.4V.
Figure 27-2. Power Supplied to a 3.3V System
Power Supply
MPC82G516A
VDD
V30
VSS
MEGAWIN
MPC82G516A Data Sheet
128
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
