SATELLINE-M3-TR3
and –TR4
Integration Guide, Version 2.1
17
5
TIME PARAMETERS FOR STARTUP AND SHUTDOWN
SEQUENCES
Parameter
Recom. Time
(*
Explanation
T
vic
Input capacitor
charge time
>50µs
When voltage is applied to VCC_IN the filter
capacitors inside the module are charged,
creating a small current surge. If the feeding
power supply is not very strong it is
recommended to wait this time before rising
ENA_MOD to minimize current surge.
T
ioen
IO module start
time
<18ms
ENA_MOD enables the LDOs feeding the
FPGA and CPU inside the module. It is
recommended to apply VCC_IO voltage
within 18ms after ENA_MOD is applied.
T
iovs
IO voltage
startup time
<1ms
It is considered good design practice to KEEP
all IO signals (except ENA_MOD) low or
floating until the internal parts of the module
have power and the IO voltage is stable.
T
ior
IO drive fall
time
< 300 µs
It is considered good design practice to set
all IO signals (except ENA_MOD) low or
floating before starting to shut down the
transceiver module. This way any latch
up/brownout problems can be avoided. IO-
pins are not internally driven after Tior.
T
ldof
LDO discharge
time
> 300 µs
To avoid any possibility of reverse biasing of
regulators inside the module, it is considered
good design practice to use ENA_MOD to
shut down the regulators before deactivating
VCC_IN.
Table. Startup and shutdown sequence parameters.
*) Recommendations:
The radio module is designed and tested for the minimum times mentioned in the table. The
recommendations are there for those who want to do the very best possible startup and
shutdown sequences.