4–6
Chapter 4: Hot Socketing and Power-On Reset in MAX V Devices
Document Revision History
For MAX V devices, the POR circuitry does not monitor the VCCINT and VCCIO voltage
levels after the device enters user mode. If there is a VCCINT voltage sag below 1.4 V
during user mode, the functionality of the device is not guaranteed and you must
power down VCCINT to 250 mV for a minimum of 10 µs before powering VCCINT and
VCCIO up again. After VCCINT rises from 250 mV back to approximately 1.55 V, the
SRAM download restarts and the device begins to operate after the tCONFIG time has
passed.
Figure 4–5 shows the voltages for POR of MAX V devices during power up into user
mode and from user mode to power down or brown out.
1
All VCCINT and VCCIO power supplies of all banks must be powered on before entering
user mode.
Figure 4–5. Power-Up Characteristics for MAX V Devices (Note 1), (2)
MAX V Device
V
CCINT
3.3 V
V
must be powered down
CCINT
to 250 mV if the V
Approximate Voltage
for SRAM Download Start
CCINT
dips below this level
1.8 V
1.55 V
1.4 V
t
minimum 10 µs
t
CONFIG
CONFIG
250 mV
User Mode
Operation
User Mode
Operation
Tri-State
Tri-State
Notes to Figure 4–5:
(1) Time scale is relative.
(2) For this figure, all the VCCIO banks are powered up simultaneously with the VCCINT profile shown. If this is not the case, tCONFIG stretches out until all
CCIO banks are powered.
V
1
After SRAM configuration, all registers in the device are cleared and released into
user function before the I/O tri-states are released. To release clears after the tri-states
are released, use the DEV_CLRnpin option. To hold the tri-states beyond the power-up
configuration time, use the DEV_OE pin option.
Document Revision History
Table 4–1 lists the revision history for this chapter.
Table 4–1. Document Revision History
Date
Version
Changes
December 2010
1.0
Initial release.
MAX V Device Handbook
December 2010 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
