SH7619_09 Datasheet, PDF (770/860 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7619 Series

Section 25 Electrical Characteristics
25.2 Power-On and Power-Off Order
• Order of turning on 1.8-V system power (Vcc, Vcc (PLL1), and Vcc (PLL2)) and 3.3-V
system power (VccQ, Vcc1A, Vcc2A, and Vcc3A)
 First turn on the 3.3-V system power, then turn on the 1.8-V system power within 1 ms.
This time should be as short as possible. The system design must ensure that the states of
pins or undefined period of an internal state do not cause erroneous system operation.
 Until voltage is applied to all power supplies and a low level is input to the RES pin,
internal circuits remain unsettled, and so pin states are also undefined. The system design
must ensure that these undefined states do not cause erroneous system operation.
Waveforms at power-on are shown in the following figure.
GND
RES
VccQ: 3.3-V system power
VccnA: 3.3-V system power*²
VccQ (min.) power
VccnA (min.) power*²
Vcc: 1.8-V system power
t_PWU
Vcc (min.)
Vcc/2
t_UNC
Pin states undefined
Input low level in advance
Normal operation period
Other pins *¹
Pin states undefined
Power-on reset state
Notes: 1. Except power/GND and clock related pins
2. n = 1 to 3
Table 25.2 Recommended Timing at Power-On
Item
Symbol Maximum Value Unit
Time difference between turning on VccQ, VccnA (n = 1 t_PWU
1
ms
to 3), and Vcc
Time over which the internal state is undefined
t
100
ms
UNC
Note: * The values shown in table 25.2 are recommended values, so they represent guidelines
rather than strict requirements.
Rev. 6.00 Jul. 15, 2009 Page 730 of 816
REJ09B0237-0600