SH7211 Datasheet, PDF (1106/1228 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family

Section 27 Electrical Characteristics
27.2 Power-on/Power-off Sequence
Power-on/power-off sequence and their recommended values are shown below.
AVcc (5.0-V power supply)
AVcc Min. voltage (4.5 V)
VccQ (3.3-V power supply)
VccQ Min. voltage (3.0 V)
Vcc, PLLVcc (1.5-V power supply)
Vcc, PLLVcc Min. voltage (1.4 V)
GND
tunc
Pins status
undefined
Normal operation period
tunc
Pins status
undefined
Figure 27.1 Power-on/Power-off Sequence
Table 27.2 Recommended Time for Power-on/Power-off Sequence
Item
Symbol
Maximum Allowance Value
Unit
Undefined time
tunc
100
ms
Note:
VccQ ≥ Vcc = PLLVcc is recommended. Either VccQ, Vcc, or PLLVcc power supply can be
turned on or off first, though, an undefined period appears until Vcc rises to the Min. voltage
or after Vcc passes the Min. voltage. During these periods, pin or internal states become
undefined. Design the system so that such undefined states do not cause a system
malfunction. To avoid an increase in the current consumption during the undefined period
at power-on, it is recommended that VccQ, Vcc, and PLLVcc be turned on simultaneously.
This undefined period can be eliminated by turning on the power supplies in the order
shown in figure 27.2.
Rev. 2.00 May. 08, 2008 Page 1082 of 1200
REJ09B0344-0200