BECKHOFF ET1200 - Manual (Page 33)

Pin Description
Slave Controller – ET1200 Hardware Description III-23
3.9 Power Supply
The ET1200 supports different power supply and I/O voltage options with 3.3V (or 5V I/O, not
recommended) and optionally single or dual power supply.
The V
CCI/O
supply voltage directly determines the I/O voltages for all inputs and outputs, i.e., with 3.3V
V
CCI/O
, the inputs are 3.3V I/O compliant and they are not 5V tolerant (V
CCI/O
has to be 5V if 5V tolerant
I/Os are required).
Two internal LDOs generate the I/O supply voltage V
CC I/O
(nom. 3.3V) and the core supply voltages
V
CC Core
/V
CC PLL
(nom. 2.5V) from the ET1200 power supply input V
CC
. V
CC
must be equal or greater
than V
CC I/O
, and V
CC PLL
is always equal to V
CC Core
. The internal LDOs cannot be switched off, they
stop operating if the external supply voltage is higher than the internal LDO output voltage, thus
external supply voltages have to be higher (at least 0.1V) than the internal LDO output voltages.
Using the internal LDOs increases power dissipation, and power consumption for 5V I/O voltage is
significantly higher than power consumption for 3.3V I/O. It is highly recommended to use 3.3V I/O
voltage and the internal LDO for V
CC Core
/V
CC PLL
.
For 3.3V I/O with external 3.3V power supply, both V
CC
and V
CCI/O
have to be connected to the
external 3.3V supply voltage, and for 5V I/O voltage, both V
CC
and V
CCI/O
have to be connected to the
external 5V supply voltage.
Voltage stabilization capacitors at all power pairs are necessary.
Table 29: Power supply options (all voltages nomal)
V
CC
V
CC I/O
V
CC Core
/V
CC PLL
Input signals Output signals Comment
3.3V External 3.3V
(= V
CC
)
Internal LDO
(2.5V) 3.3V only 3.3V only Single power
supply, low power
dissipation
3.3V External 3.3V
(= V
CC
)
External 2.5V 3.3V only 3.3V only Dual power supply,
lowest power
dissipation
5V Internal LDO
(3.3V) Internal LDO
(2.5V) 3.3V only 3.3V only Single power
supply, highest
power dissipation
5V Internal LDO
(3.3V) External 2.5V 3.3V only 3.3V only Dual power supply
Not recommended:
5V External 5V
(= V
CC
)
Internal LDO
(2.5V) 5V only 5V only Single power
supply, high power
dissipation
5V External 5V
(= V
CC
)
External 2.5V 5V only 5V only Dual power supply,
high power
dissipation
Table 30: Power supply
Pin Pin name
EP GND
14 V
CC
15 GND
6 V
CC I/O
7 GND
I/O
41 V
CC Core
(2.5V)
42 GND
Core
24 V
CC PLL
(2.5V)
23 GND
PLL