LFXP3E-4T100I Lattice, LFXP3E-4T100I Datasheet - Page 148

• Manufacturer Part Number: LFXP3E-4T100I
• Description: IC FPGA 3.1KLUTS 62I/O 100-TQFP
• Manufacturer: Lattice

Specifications of LFXP3E-4T100I

• Lead Free Status / Rohs Status: Contains lead / RoHS non-compliant

Lattice Semiconductor
5V Interface with PCI Clamp Diode
All the I/Os on the top and bottom sides of the device (Banks 0, 1, 4, and 5) have a clamp diode that is used to
clamp the voltage at the input to V
used along with an external resistor to make an input 5V tolerant.
Figure 8-3. 5V Tolerant Input Buffer
The value of this external resistor will depend on the PCI clamp diode characteristics. You can find the voltage vs.
current data across this diode in the device IBIS model.
In order to interface to 5V input, it is recommended to set the V
Below is an example for calculating the value of this external resistor when V
• Maximum voltage at input pin, V
• Bank V
• Maximum voltage drop across clamp diode, V
• The current across the clamp diode at V
Table 8-5. Power Clamp Data from IBIS Model
• Assume the maximum output voltage of the driving device is V
power clamp portion of the IBIS file for a LVCMOS3.3 input model with PCI Clamp turned on. When V
clamp diode current is I
then be calculated as follows:
CCIO
= 2.75V
D
= 27.4mA.
INMAX
CCIO
5V Input
Voltage
-1.00
-0.80
-0.60
-1.40
-1.30
-1.20
-1.10
-0.90
-0.70
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
. This is especially used for PCI I/O standards. This clamp diode can be
= 3.75V (see device data sheet for more details)
D
can be found in the power clamp data of the IBIS file. Below is the
D
= V
External
Resistor
INMAX
0.0009129
0.0001432
0.07917
I (Max.)
8-8
550.8
72.5
61.2
49.9
38.6
27.4
16.9
9.52
5.35
2.31
58.0
3.61
- V
CCIO
CCIO
EXT
V
= 3.75 - 2.75 =1V
between 2.5V to 3.3V.
= 5.25V. The value of the external resistor can
CCIO
Units
PCI Clamp
Diode
mA
mA
mA
mA
mA
mA
mA
mA
mA
µA
µA
µA
µA
µA
µA
CCIO
LatticeECP/EC and LatticeXP
is 2.75V.
sysIO Usage Guide
D
is 1V, the