EP2S90F1508I4 Altera, EP2S90F1508I4 Datasheet - Page 27

• Manufacturer Part Number: EP2S90F1508I4
• Description: IC STRATIX II FPGA 90K 1508-FBGA
• Manufacturer: Altera
• Series: Stratix® IIr

Specifications of EP2S90F1508I4

• Number Of Logic Elements/cells: 90960
• Number Of Labs/clbs: 4548
• Total Ram Bits: 4520488
• Number Of I /o: 902
• Voltage - Supply: 1.15 V ~ 1.25 V
• Mounting Type: Surface Mount
• Operating Temperature: -40°C ~ 100°C
• Package / Case: 1508-FBGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Number Of Gates: -
• Other names: 544-1923; EP2S90F1508I4

Figure 2–14. Example of a 3-bit Add Utilizing Shared Arithmetic Mode
Altera Corporation
May 2007
3-Bit Add Example
implemented in adders.
implemented in LUTs.
+
2nd stage add is
1st stage add is
1 1 0 1
1 1 0
+
Binary Add
1 1 0
1 0 1
0 1 0
0 0 1
+
C2 C1 C0
R3 R2 R1 R0
Shared Arithmetic Chain
In addition to the dedicated carry chain routing, the shared arithmetic
chain available in shared arithmetic mode allows the ALM to implement
a three-input add. This significantly reduces the resources necessary to
implement large adder trees or correlator functions.
The shared arithmetic chains can begin in either the first or fifth ALM in
an LAB. The Quartus II Compiler creates shared arithmetic chains longer
than 16 (8 ALMs in arithmetic or shared arithmetic mode) by linking
LABs together automatically. For enhanced fitting, a long shared
+
+
Equivalents
Decimal
X2 X1 X0
S2 S1 S0
2 x 6
Y2 Y1 Y0
Z2 Z1 Z0
+
13
6
5
2
1
X0
Y0
Z0
X1
Y1
Z1
X2
Y2
Z2
ALM Implementation
ALM 1
ALM 2
3-Input
3-Input
3-Input
3-Input
3-Input
3-Input
3-Input
3-Input
LUT
LUT
LUT
LUT
LUT
LUT
LUT
LUT
Stratix II Device Handbook, Volume 1
S0
C0
S1
C1
S2
C2
shared_arith_in = '0'
'0'
carry_in = '0'
Stratix II Architecture
R0
R1
R2
R3
2–19