HD6417705 Datasheet, PDF (670/739 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

• Power-off order
1. In the reverse order of powering-on, first turn off the 1.5 V power, then turn off the 3.3 V
power within 1 ms. It is recommended that this interval will be as short as possible.
2. Pin states are undefined while only the 1.5 V power is off. The system design must ensure
that these undefined states do not cause erroneous system operation.
3. When the power is turned off, make sure that the voltage of the 1.5 V power is lower than
that of the 3.3 V power.
Waveforms and recommended times at power on/off are shown in figure 25.1.
VccQ: 3.3 V power
VccQ (min) voltage
tpwu
Vcc: 1.5 V power
Vcc (min) voltage
Vcc/2 level voltage
tpwd
GND
tunc
States undefined
term
Normal operation term
Clock oscillation started
VccQ (min)
attain time
Vcc (min)
attain time
Oscillation settling time
Cancel the power-on reset and
go to normal operation
Operation stopped
Figure 25.1 Power On/Off Sequence
Recommended Power On/Off Times
Item
VccQ to Vcc power-on time interval
VccQ to Vcc power-off time interval
State undefined term
Symbol
tpwu
tpwd
tunc
Max. Permitted
Value
Unit
1
ms
1
ms
10
ms
The recommended times shown above do not require strict settings.
The state undefined term indicates that pins are at the power rising stage. The pin state is stabilized
at VccQ (min) attain time. However, a power-on reset (RESETP) is accepted successfully only
after VccQ (min) attain time and clock oscillation settling time. Set the state undefined term less
than 10 ms.
Rev. 2.00, 09/03, page 624 of 690