Renesas SH7781 - Manual (Page 1684)

Appendix
Rev.1.00 Jan. 10, 2008 Page 1654 of 1658
REJ09B0261-0100
D.2 Power-On and Power-Off Sequences for Power Supplies with Different Potentials in
DDR2-SDRAM Power Supply Backup Mode
The power-on and power-off sequences for the 1.0 V power supply (VDD10 using pins VDD,
VDD-PLL1, VDDA-PLL1, and VDD-PLL2), 1.8 V power supply (VDD18 using pin VDD-DDR),
and 3.3 V power supply (VDD33 using pins VDDQ, VDDQ-PLL1, VDDQ-PLL2, and VDDQ-
TD*) in DDR2-SDRAM power supply backup mode are as follows.
Note: * If VDDQ-TD is connected to VDDQ.
• Power-On Sequence
There is no restriction on the sequence in which the above power supplies are powered on.
Ensure that all the power supplies start within 300 ms of the start of a power supply other than
VDD-DDR.
• Power-Off Sequence
There is no restriction on the sequence in which the above power supplies are powered off.
Ensure that all the power supplies stop within 300 ms of the stop of a power supply other than
VDD-DDR.
300ms > t ≥ 0s
300ms > t ≥ 0s
0.1 × V**
V** min
0.9 × V**
0.2 [V]
V**: VDD10,VDD33
V**: VDD10, VDD18, VDD33
VDD18 = ON
VDD18 = ON
VDD10 (pins: VDD, VDD-PLL1, VDDA-PLL1, VDD-PLL2)
VDD33 (pins: VDDQ, VDDQ-PLL1, VDDQ-PLL2, VDDQ-TD*)
Note: * If VDDQ-TD is connected to VDDQ.
Figure D.2 Power-On and Power-Off Sequences for Power Supplies with Different
Potentials in DDR2-SDRAM Power Supply Backup Mode