M30222 Datasheet, PDF (29/237 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
Specifications in this manual are tentative and subject to change
M30222 Group
Rev. G
Voltage Down Converter
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Voltage Down Converter
The Voltage Down Converter (VDC) is a bandgap reference based voltage regulator used for generating
a low-voltage supply. The VDC block inputs the external supply VCC (up to 5.5 volts) and generates a 3.3-
volt (nominal) supply (VDD). Table 1.14 describes the specified voltage regulation. The VDC is pro-
grammable in terms of drive limit and power level. In low power mode, the VDC can source up to 20mA
and uses less than 10uA bias current. In high-power mode, the VDC can source up to 200mA. There is
a programmable option to limit the current of the VDC in high-power mode to about 80mA. The VDC
default state (from reset) is high-power mode with current limiting enabled. The current limiting is en-
abled at reset in order to avoid a large in-rush current to an external hold capacitor (required) on the
VDC pin. Once the external hold capacitor is charged, the current limiter can be disabled in software.
Figures 1.17 and 1.18 describe the programmable features of the VDC. The external hold capacitor is
required to stabilize the VDC and to minimize voltage ripple on the 3.3 volt supply during operation.
Table 1.15 describes the external hold capacitor requirements.
Table 1.14. VDC voltage regulations
Signal
Package Supply (Vcc)
Internal Supply (Vdd)
Note: Whichever is smaller
Description
Range: 2.7v to 5.5v (input to VDC)
3.3v (nominal) +/- 10% (output from VDC) OR
Vcc - 200mV @ Icc_(AVG) <15 mA (Note)
Voltage Down Converter control register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
VDCC
Address When reset
001816
XXX00X00₂
Bit symbol
Function
VDCC0
VDCC1
b1 b0
0 0 : VDC enabled
0 1 : Reserved
1 0 : Reserved
1 1 : VDC disabled
Nothing is assigned. Write "0" when writing to this bit. If read, the
value is indeterminate.
HPOWER
0 : High power
1: Low power
ILIMEN
0 : Current limit enabled
1 : Current limit disabled
Nothing is assigned. Write "0" when writing to these bits. If read, the
value is indeterminate.
RW
__
__
Figure 1.17. VDC Control/Status Register
Table 1.15. Required External Components
Component
External Hold Capacitor
Value
0.1µF +/- 20%
Material
Ceramic
1-30