Competitive Programmable Logic Power Comparison White Paper

Competitive
Programmable Logic
Power Comparison
White Paper
April 2008
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Power Consumption Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Power Analysis Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Power Comparison Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Devices Analyzed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Power Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Static Power Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Static Power over Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Dynamic Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Referenced Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
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Competitive Programmable Logic Power Comparison
Introduction
Today, many applications require low-power programmable logic solutions. For this reason, many
programmable logic vendors have focused on minimizing device power consumption. Of these vendors,
several claim low-power superiority. However, only one can be the true leader.
In this paper, the power consumption of six competitive programmable logic devices is compared via
published vendor datasheets, power-estimation tools, and real silicon measurements. In the end, this
paper will prove that Actel's flash-based IGLOO® FPGAs are the undisputed low-power leaders in the
industry, regardless of logic density, design configuration, or power mode.
Power Consumption Components
There are five different power components that must be considered when evaluating different FPGA
vendors. Figure 1 shows these components.
Figure 1: System Power Profile over Time
The important power components to consider include the following:
1. Power-up (inrush power)
Inrush power is the amount of power drawn by the device during power-up.
2. Configuration power
Configuration power is the amount of power required during the loading of the FPGA upon
power-up (specific to SRAM-based programmable logic devices).
3. Static (standby) power
Static power is the amount of power the device consumes when it is powered-up but not actively
performing any operation (i.e., the device is not clocked).
4. Dynamic (active) power
Dynamic power is the amount of power the device consumes when it is actively operating (i.e., the
device is clocked).
5. Sleep power (low-power mode)
Some FPGA devices offer low-power or sleep modes. In some cases, this may be different from
static power.
Competitive Programmable Logic Power Comparison
3
Power Analysis Overview
For this paper, static power and dynamic power were evaluated using devices from different programmable
logic vendors. For many battery-powered applications, the device may reside in static mode a large
percentage of the time. Handheld devices, for example, are in static mode when not being used. Static
power contributes to battery drain and determines how long the device can be powered. For this reason,
evaluating static power was our primary concern.
Dynamic power was also evaluated on devices from different vendors over multiple frequencies. To
simplify our comparison across vendors, we focused on FPGA core power, the main contributor to
programmable logic devices (PLD) power consumption. Power contributions from I/Os were not evaluated
for power comparison. In addition, this study did not analyze inrush or configuration power across vendors.
Unlike SRAM-based FPGAs, flash-based FPGAs do not suffer the additional power spikes due to inrush
power or configuration power. For more information regarding power, inrush, and configuration, refer to
Actel’s Total System Power brochure.
We gathered from the following three sources to evaluate competitive device and design power
consumption:
1. Vendor's datasheet
2. Vendor's power-estimation tools
3. Silicon measurements (taken on Actel-created power comparison board)
Power Comparison Board
Today, programmable logic vendors offer evaluation and development boards for their silicon products.
Some boards offer mechanisms to measure and evaluate power consumption. However, boards from each
vendor are designed differently with different configurations. To fairly evaluate power consumption
between different vendors using actual silicon, we developed a power comparison board. This board was
designed so that two devices could be compared against each other, side-by-side, under the same
operating conditions.
The baseboard, shown in Figure 2 on page 5, consists of two sockets with a simple interface that will allow
daughtercards (Figure 3 on page 5) to be plugged into the baseboard for power analysis. The baseboard
has different power rails that can be selected for each socket. This enables two devices with different
power rails to be compared side-by-side. In addition, the baseboard has a socket for different crystal
oscillators that can be interchanged to modify the frequency of the digital clock.
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Competitive Programmable Logic Power Comparison
Figure 2: Power Comparison Baseboard
Figure 3: Example of Daughtercards – Actel IGLOO Daughtercard and Xilinx® CoolRunner™-II Daughtercard
Competitive Programmable Logic Power Comparison
5
The daughtercards were designed specifically for the FPGA or CPLD being evaluated. Power, clock, and
I/O pins were routed from the socket to the specific power, clock, and I/O pins on the device being
evaluated. Figure 4 shows the daughtercards plugged into the baseboard.
Figure 4: Daughtercards Plugged into Baseboard
Devices Analyzed
For this paper, devices were grouped into two different logic densities: small density devices, which consist
of approximately 30 k system gates (approximately 256 macrocells or 300 equivalent logic elements) and
large density devices, which consist of approximately 600 k system gates (approximately 6,000 equivalent
logic elements). Note that identifying a logic density that is similar between vendors is challenging. As a
result, the 30 k and 600 k gate logic density devices were chosen because most programmable logic
vendors support these densities.
Table 1 lists the smaller density devices that were used in the power comparison.
Table 1: Small Density Devices (~ 30 k system gates)
Vendor
Device Family
Part Number
Actel Corporation
IGLOO FPGA
AGL030
MAX® IIZ CPLD
EPM240Z
CoolRunner-II CPLD
XC2C256
Altera® Corporation
Xilinx, Inc.
Table 2 lists the larger density devices that were used in the power comparison.
Table 2: Large Density FPGA Devices (~ 600 k system gates)
Vendor
Device Family
Part Number
Actel Corporation
IGLOO FPGA
AGL600
Altera Corporation
Cyclone® III FPGA
EP3C5
Spartan™-3AN FPGA
XC3S400AN
Xilinx, Inc.
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Competitive Programmable Logic Power Comparison
Power Analysis
Static Power Analysis
Comparing static power consumption between different programmable logic devices is straightforward,
since all vendors publish typical static or standby current numbers in their datasheets. To calculate the
static power, we multiplied the static current numbers by the supply voltage.
Static Power Analysis Using Small Densities (~ 30 k gates)
The first set of devices analyzed were the Actel IGLOO AGL030 FPGA, the Altera MAX IIZ EPM240Z CPLD,
and the Xilinx CoolRunner-II XC2C256 CPLD. Table 3 summarizes the static/standby current numbers taken
from each vendor's datasheet with the calculated static power for each device.
Table 3: Static Power Using Small Density Devices – Datasheet Values
Vendor
Device Family
Part Number
Static/Standby
Current
Supply Voltage
Static Power
Actel Corporation
IGLOO FPGA
AGL030
4 µA 1
1.2 V
4.8 µW
Altera Corporation
MAX IIZ CPLD
EPM240Z
29 µA 2
1.8 V
52.2 µW
CoolRunner-II CPLD
XC2C256
33 µA 3
1.8 V
59.4 µW
Xilinx, Inc.
Notes:
1. IDD (quiescent supply current in IGLOO Flash*Freeze mode) from the DC and Switching Characteristics section of the
IGLOO Low-Power Flash FPGAs datasheet (Advanced v0.1). IDD includes VCC, VPUMP, VCCI, VJTAG, VCCPLL, and
VMV.
2. ICCSTANDBY (VCCINT supply current—standby) from the DC and Switching Characteristics section of the MAX II Device
Family datasheet (MII51005-2.1)
3. ICCSB (standby current commercial) from the DC Electrical Characteristics section of the XC2C256 CoolRunner-II
Product Specification (DS094 v3.2)
We used the power comparison board and off-the-shelf devices from these vendors to measure and
compare the static power. Table 4 lists the static measurements taken on the small density devices. Static
power is calculated as the product of supply voltage and the static current measured on each device.
Table 4: Static Power Using Small Density Devices – Measured Values
Vendor
Device Family
Part Number
Static/Standby
Current
Supply Voltage
Static Power
Actel Corporation
IGLOO FPGA
AGL030
2.1 µA
1.2 V
2.5 µW
Actel Corporation
IGLOO FPGA
AGL030
1.7 µA*
1.2 V
2.0 µW
Altera Corporation
MAX IIZ CPLD
EPM240Z
24.5 µA
1.8 V
44.1 µW
CoolRunner-II CPLD
XC2C256
20.3 µA
1.8 V
36.5 µW
Xilinx, Inc.
Note: *In Flash*Freeze mode
Competitive Programmable Logic Power Comparison
7
Static Power Summary – Small Density Devices
The static or standby power information from each vendor's datasheet shows that Actel's IGLOO FPGA
consumes less than 5 µW, whereas the Altera MAX IIZ and Xilinx CoolRunner-II devices consume more
than 10 times that amount (52.5 µW and 59.4 µW, respectively). Also, when measuring an off-the-shelf
device from each vendor on the power comparison board, Actel confirmed the IGLOO tenfold power
advantage. The measured static power for the AGL030 device was 2.5 µW (2.0 µW in Flash*Freeze
mode), whereas the EPM240Z device consumed 44.1 µW and the XC2C256 consumed 36.5 µW. Figure 5
summarizes the results of the static power comparison for CPLD density devices.
Static Power Comparison
Small Density Devices
70.0
60.0
Power (µW)
50.0
40.0
Measured
Datasheet
30.0
20.0
10.0
0.0
Actel IGLOO
(AGL030)
Altera MAX IIZ
(EPM240Z)
Xilinx CoolRunner-II
(XC2C256)
Figure 5: Static Power Summary – Small Density Devices (measured versus datasheet)
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Competitive Programmable Logic Power Comparison
Static Power Analysis Using Large Density Devices (~ 600 k gates)
The second set of devices analyzed were the Actel IGLOO AGL600 FPGA, the Altera Cyclone III EP3C5
FPGA, and the Xilinx Spartan-3AN XC3S400AN FPGA. Static power calculation is not as straightforward
for these devices as it was for the small density devices. For the Altera Cyclone III EP3C5 and the Xilinx
Spartan-3AN XC3S400AN SRAM-based FPGAs, in addition to the static power consumed by the core,
power from other auxiliary voltage supplies must also be added to the core static power to calculate the
total static power of the device. These auxiliary power supplies are required for the SRAM-based FPGAs
during operation. Table 5 summarizes the static current numbers taken from each vendor's datasheet and
the calculated static power for each device.
Table 5: Static Power Using Large Density FPGA Devices – Datasheet Values
Vendor
Device Family
Part Number
Core Static Power
Actel Corporation
Altera Corporation
Xilinx, Inc.
IGLOO FPGA
Cyclone III FPGA
Spartan-3AN FPGA
AGL600
EP3C5
XC3S400AN
28 µA at 1.2 V 1
33.6 µW
1,700 µA at 1.2 V 2
2,040 µW
15,000 µA at 1.2 V 5 18,000 µW
Auxiliary Static Power
None
11,300 µA at 2.5 V 3
28,250 µW 12,100 µA at 3.3 V 6 39,930 µW
PLL Static Power
None
4,100 µA at 1.2 V 4
4,920 µW
Total Static Power
33.6 µW
35,210 µW
None
57,930 µW
Notes:
1. IDD (quiescent supply current) from the IGLOO DC and Switching Characteristics section of the IGLOO Low-Power
Flash FPGAs datasheet (Advanced v0.1).
2. ICCINT (VCCINT supply current—standby) from the DC and Switching Characteristics section of the Cyclone III Device
Datasheet (CIII52001-1.5). VCCINT —supply voltage for internal logic and input buffers.
3. ICCA (VCCA supply current—standby) from the DC and Switching Characteristics section of the Cyclone III Device
datasheet (CIII52001-1.5). VCCA—supply (analog) voltage for PLL regulator. All VCCA pins must powered to 2.5 V (even
when PLLs are not used).
4. ICCD_PLL (VCCD_PLL supply current—standby) from the DC and Switching Characteristics section of the Cyclone III
Device datasheet (CIII52001-1.5). VCCD_PLL—supply (digital) voltage for PLL regulator. VCCD_PLL must be connected to
VCCINT during operation.
5. ICCINTQ (quiescent VCCINT supply current) from the DC and Switching Characteristics section of the Spartan3-AN FPGA
Family datasheet (DS557-3 (v3.0)). VCCINT—internal supply voltage.
6. ICCAUXQ (quiescent VCCAUX supply current) from the DC and Switching Characteristics section of the Spartan3-AN
FPGA Family datasheet (DS557-3 (v3.0)). VCCAUX—auxiliary supply voltage.
Competitive Programmable Logic Power Comparison
9
Static Power Summary – Large Density Devices
All the supply voltages contributing to static power must be captured when comparing the different FPGA
devices. For Altera Cyclone III devices, static power from VCCINT, VCCA, and VCCD_PLL power supplies
must be added together to calculate the total static power of the device. Similarly, for Xilinx Spartan-3AN
devices, static power from VCCINTQ and VCCAUXQ power supplies must be added together to calculate total
static power. In the comparison study, the Altera EP3C5 device consumed over 1,000 times more static
power than the Actel IGLOO AGL600 device. The Xilinx XC3S400AN device consumed over 1,700 times
more standby power than the Actel IGLOO AGL600 device. Figure 6 summarizes the results of the static
power comparison for large density devices.
Static Power Comparison
Large Density Devices
Datasheet Values
70000
60000
Power (µW)
50000
40000
30000
20000
10000
0
Actel IGLOO
(AGL600)
Altera Cyclone III
(EP3C5)
Xilinx Spartan-3AN
(XC3S400AN)
Note: Actel’s IGLOO AGL600 device static power consumption is 33.6 µW.
Figure 6: Static Power Summary – Large Density Devices (datasheet)
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Competitive Programmable Logic Power Comparison
Static Power over Temperature
Table 6 captures the static current and respective calculated static power over temperature values for small
density devices, using the information from vendor datasheets and/or power estimator tools. Table 7 on
page 12 lists the calculated static power over temperature values for large density devices. Figure 7 and
Figure 8 on page 12 are graphical representations of the data from Table 6 and Table 7 on page 12,
respectively.
Table 6: Static Power Using Small Density Devices over Temperature—Source: Vendor Datasheets, Power
Estimator Tools
Temperature at 25ºC (ambient)
Device
Temperature at 70ºC (ambient)
Current (µA)
Power (µW)
Current (µA)
Power (µW)
Actel IGLOO AGL0301
4
4.8
7
8.4
Altera MAX IIZ EPM240Z2
29
52.2
150
270
Xilinx CoolRunner-II XC2C2563
33
59.4
150
270
Notes:
1. Data came from the IGLOO Power Calculator.
2. Data came from DC and Switching Characteristics section of the MAX II Device Family Datasheet (MII51005-2.1).
3. Data came from DC and Switching Characteristics section of the DC Electrical Characteristics section of the XC2C256
CoolRunner-II Product Specification (DS094 v3.2).
Static Power over Temperature
Small Density Devices
Vendor Datasheet, Vendor Power Estimator Tools
300
250
Actel IGLOO
AGL030
Power (µW)
200
Altera MAX IIZ
EPM240Z
150
Xilinx CoolRunner-II
XC2C256
100
50
0
25°C
70°C
Temperature
Figure 7: Static Power over Temperature – Small Density Devices
Competitive Programmable Logic Power Comparison
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Table 7: Static Power Using Large Density Devices—Source: Power Estimator Tools
Temperature – 25ºC
(ambient)
Temperature – 70ºC
(ambient)
Temperature – 85ºC
(ambient)
Power (µW)
Power (µW)
Power (µW)
33.6
60
101
Altera Cyclone III EP3C52
35,210
42,000
45,600
Xilinx Spartan-3AN XC3S400AN3
57,930
91,000
107,000
Device
Actel IGLOO AGL6001
Notes:
1. Data derived from the IGLOO Power Calculator.
2. Data derived from Cyclone III using Altera PowerPlay Early Power Estimator v7.2 SP1.
3. Data derived from Spartan-3 using Xilinx Xpower™ Estimator (XPE) 9.1.03.
Static Power over Temperature
Large Density Devices
Vendor Power Estimator Tools
120000
100000
80000
Power (µW)
Actel IGLOO
AGL600
Altera Cyclone-III
EP3C5
60000
Xilinx Spartan-3AN
XC3S400AN
40000
20000
0
25°C
70°C
85°C
Temperature
Figure 8: Static Power over Temperature – FPGA Density Devices
Static Power over Temperature – Summary
After analyzing the static power information from either vendor datasheets or vendor power estimator tools,
it is evident that Actel IGLOO FPGAs are orders of magnitude better than the competition.
12
•
For small density devices, Actel IGLOO FPGAs consume over 30 times lower power at 70°C
compared to Xilinx and Altera CPLDs.
•
For large density devices, Actel IGLOO FPGAs consume as much as 1,000 times lower static
power than Cyclone III and Spartan-3AN FPGAs.
Competitive Programmable Logic Power Comparison
Dynamic Power
Dynamic or active power is the amount of power consumed when the device is operating. Many vendors
offer power estimators or calculator tools that enable engineers to estimate the amount of power
consumed by the device during operation. For comparison purposes, we will use results taken from vendor
power estimation tools. For the small density devices, we will also measure the power using silicon.
Dynamic Power Comparison Designs
Dynamic power consumption is dependent on the design programmed into the programmable logic device.
To compare one programmable logic device against another, the same design was used. The design
chosen consists of an 8-bit gray-code counter that was instantiated several times to fill the device. The
gray-code counter design was chosen because it uses a ratio of combinatorial and sequential logic that is
typical of many designs. For this design, the proportion of registers to combinatorial logic is approximately
50%. Figure 9 shows a graphical representation of the 8-bit gray-code counter design.
When comparing devices against each other, the 8-bit gray-code counter was instantiated as many times
as possible into the smaller of the two devices being compared. That design was then used in both devices
to compare results.
Reset_n
Clk
8-Bit Gray
Counter
8
8-Bit Gray
Counter
8
8-Bit Gray
Counter
Bit<7>
(msb)
Bit<7>
(msb)
Cnt_out
Msb_or
8
Bit<7>
(msb)
Clk_info
D
Q
0
CLK
PRE
Figure 9: 8-Bit Gray-Code Counter Design
Actel IGLOO (AGL030) FPGA versus Altera MAX IIZ (EPM240Z) CPLD
The device closest in density to the Actel IGLOO AGL030 is the Altera MAX IIZ EPM240Z device. Since
the EPM240Z is the smaller of the two devices, the 8-bit gray-code counter was instantiated 14 times to
utilize 95% of the EPM240Z. Taking that same design (14 instantiations of the gray-code counter) and
programming it into the Actel IGLOO device, the design consumed 61% of the AGL030.
Actel IGLOO (AGL030) FPGA versus Xilinx CoolRunner-II (XC2C256) CPLD
The Actel IGLOO AGL030 device was also compared against the Xilinx CoolRunner-II XC2C256 device.
The 8-bit gray-code counter was instantiated 22 times into both the XC2C256 and AGL030 devices. The
design occupied 87% of the XC2C256 and 99% of the AGL030.
Competitive Programmable Logic Power Comparison
13
Actel IGLOO (AGL600) FPGA versus Altera Cyclone III (EP3C5) FPGA
Comparing the Actel IGLOO AGL600 device against the Altera Cyclone III EP3C5 device, the EP3C5 was
the smaller of the two devices, and the 8-bit gray-code counter was instantiated 290 times and utilized 98%
of the EP3C5. Programming the same design into the Actel IGLOO device, the design consumed 71% of
the AGL600.
Actel IGLOO (AGL600) FPGA versus Xilinx Spartan-3AN (XC3S400AN) FPGA
Comparing the Actel IGLOO AGL600 device against the Xilinx Spartan-3AN XC3S400AN device, the graycode counter design was instantiated 390 times and utilized 93% of the XC3S400AN and 98% of the
AGL600.
Table 8 summarizes the device utilization of the different designs for both small and large density devices.
Table 8: Design Information for Dynamic Power Comparison
Vendor
Device
Number of 8-Bit Gray-Code Counters
Percent Utilization
Actel Corporation
IGLOO AGL030
14, 22
61%, 99%
Altera Corporation
MAX IIZ EPM240Z
14
95%
CoolRunner-II XC2C256
22
87%
Actel Corporation
IGLOO AGL600
290, 390
71%, 98%
Altera Corporation
Cyclone III EP3C5
290
98%
Spartan-3AN XC3S400AN
390
93%
Xilinx, Inc.
Xilinx, Inc.
Dynamic Power Calculated Using Vendor Tools
Most FPGA vendors have a power calculator or estimator tools that can be used to find a preliminary
estimate of power consumed by the device. These estimator tools allow users to enter key parameters for
their design, including number of flip-flops in the design, number of combinatorial logic cells, clocks, and
toggle rates. Note that these estimator tools are pre-synthesis tools that are used primarily for power
consumption approximation. These tools are not as accurate as timing-driven estimation tools, which
provide a more precise power consumption estimation. Table 9 lists power estimator tools from different
vendors that were used for dynamic power analysis. Using each vendor's tools, we calculated the power
consumed by the design under nominal voltage and temperature conditions.
Table 9: Power Estimator Tools by Vendor
Vendor
Device Family
Power Estimator Tool
Version
Actel Corporation
IGLOO
IGLOO Power Calculator
v3d (Advanced)
Altera Corporation
MAX IIZ
PowerPlay Early Power Estimator
v7.2 SP1
Altera Corporation
Cyclone III
PowerPlay Early Power Estimator
v7.2 SP1
Xilinx, Inc.
CoolRunner-II
None
None
Xilinx, Inc.
Spartan-3AN
Xpower Estimator
9.1.03
Note: Xilinx does not offer a power estimator tool for the CoolRunner-II family of devices.
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Competitive Programmable Logic Power Comparison
Dynamic Power – Actel IGLOO versus Altera MAX IIZ
Table 10 lists the current and corresponding calculated power results taken from Actel's and Altera's power
estimator tools over frequency for the 14 instantiations of the gray-code design in the Actel IGLOO
AGL030 FPGA and the Altera MAX IIZ EPM240Z CPLD. Xilinx does not offer a power estimator tool for the
CoolRunner-II family of devices. Figure 10 shows a graphical representation of the data.
Table 10: Dynamic Power Vendor Tools – Small Density Devices
AGL030
Frequency
EPM240Z
Current (mA)
Power (mW)
Current (mA)
Power (mW)
0 MHz
0.006
0.007
0.030
0.054
10 MHz
0.525
0.630
2.250
4.050
20 MHz
1.044
1.253
4.460
8.028
30 MHz
1.563
1.876
6.680
12.024
40 MHz
2.082
2.498
8.890
16.002
50 MHz
2.601
3.121
11.100
19.980
60 MHz
3.121
3.745
13.320
23.976
70 MHz
3.641
4.370
15.540
27.972
80 MHz
4.162
4.994
17.760
31.968
Dynamic Power Consumption
Vendor Tool Data, AGL030 and EPM240Z
14 8-Bit Gray-Code Counters
35
30
25
Power (mW)
20
Actel IGLOO AGL030
Altera MAX IIZ EPM240Z
15
10
5
0
0
10
20
30
40
50
60
70
80
Frequency (MHz)
Figure 10: Dynamic Power Consumption – Vendor Estimator Tool – Small Density Devices
Competitive Programmable Logic Power Comparison
15
Dynamic Power – Actel IGLOO versus Altera Cyclone III FPGAs
Table 11 lists the dynamic power calculated using vendor tools for the Actel IGLOO AGL600 FPGA and the
Altera Cyclone III EP3C5 FPGA. For this calculation, 290 counters were used in both devices. Figure 11
shows a graphical representation of the data.
Table 11: Dynamic Power, Actel IGLOO (AGL600) versus Altera Cyclone III (EP3C5) – 290 Counters, Vendor
Estimator Tool
AGL600
EP3C5
1.2 V Current (mA)
Total Power (mW)
1.2 V Current (mA)
2.5 V VCCA
Current (mA)
Total Power (mW)
0 MHz
0.028
0.034
6.000
11.000
34.700
10 MHz
9.436
11.323
15.000
11.000
45.500
20 MHz
18.845
22.614
25.000
11.000
57.500
30 MHz
28.253
33.904
35.000
11.000
69.500
40 MHz
37.662
45.194
45.000
11.000
81.500
50 MHz
47.070
56.484
54.000
11.000
92.300
60 MHz
56.478
67.774
64.000
11.000
104.300
70 MHz
65.887
79.064
74.000
11.000
116.300
80 MHz
75.295
90.354
83.000
11.000
127.100
Frequency
Dynamic Power Consumption
Vendor Tool Data, AGL600 and EP3C5
290 8-Bit Gray-Code Counters
150
125
Power (mW)
100
Altera Cyclone III
EP3C5
75
Actel IGLOO
AGL600
50
25
0
0
10
20
30
40
50
60
70
80
Frequency (MHz)
Figure 11: Dynamic Power, Actel IGLOO and Altera Cyclone III, Vendor Estimator Tool
16
Competitive Programmable Logic Power Comparison
Dynamic Power – Actel IGLOO versus Xilinx Spartan-3AN FPGAs
Table 12 lists the dynamic power calculated using vendor tools for the Actel IGLOO AGL600 FPGA and the
Xilinx Spartan-3AN XC3S400AN FPGA, using 390 instantiations of the 8-bit gray-code counter. Figure 12
shows a graphical representation of the data.
Table 12: Dynamic Power, Actel IGLOO (AGL600) versus Xilinx Spartan-3AN (XC3S400AN) – 390 Counters,
Vendor Estimator Tool
AGL600
XC3S400AN
1.2 V Current
(mA)
Total Power (mW)
1.2 V Current
(mA)
3.3 V VCCAUX
Current (mA)
Total Power (mW)
0 MHz
0.028
0.034
15.000
12.000
57.600
10 MHz
9.726
11.671
38.000
12.000
85.200
20 MHz
19.425
23.310
61.000
12.000
112.800
30 MHz
29.123
34.948
84.000
12.000
140.400
40 MHz
38.821
46.585
106.000
12.000
166.800
50 MHz
48.519
58.223
129.000
12.000
194.400
60 MHz
58.218
69.862
152.000
12.000
222.000
70 MHz
67.916
81.499
174.000
12.000
248.400
80 MHz
77.614
93.137
197.000
12.000
276.000
Frequency
Dynamic Power Consumption
Vendor Tool Data, AGL600 and XC3S400AN
390 8-Bit Gray-Code Counters
300
275
250
225
Power (mW)
200
Xilinx Spartan-3AN
XC3S400AN
175
150
Actel IGLOO
AGL600
125
100
75
50
25
0
0
10
20
30
40
50
60
70
80
Frequency (MHz)
Figure 12: Dynamic Power, Actel IGLOO and Xilinx Spartan-3AN, Vendor Estimator Tool
Competitive Programmable Logic Power Comparison
17
Dynamic Power – Large Density Device Comparison
For the large density device comparison, we compared Actel's AGL600 FPGA against Altera's EP3C5
FPGA, and we also compared Actel's AGL600 FPGA against Xilinx's Spartan-3AN FPGA. These two
comparisons used different designs (290 counters and 390 counters, respectively) due to the different
densities of the devices we were comparing. As stated earlier, the method used for the dynamic power
comparison test was to fill the smaller of the two devices being compared and use that design for both
devices. To compare all three devices at the same time with the same design, we used the 290-counter
design across all three devices. Figure 13 shows the dynamic power consumed for all three large devices
using the 290-counter design.
Dynamic Power Consumption
Vendor Tool Data, Large Density Devices
290 8-Bit Gray-Code Counters
225
200
Power (mW)
175
Actel IGLOO
AGL600
150
Altera Cyclone III
EP3C5
Xilinx Spartan-3AN
XC3S400AN
125
100
75
50
25
0
0
10
20
30
40
50
60
70
80
Frequency (MHz)
Figure 13: Dynamic Power, Actel IGLOO (AGL600), Altera Cyclone III (EP3C5), Xilinx Spartan-3AN
(XC3S400AN) – 290 Counters, Vendor Estimator Tool
18
Competitive Programmable Logic Power Comparison
Dynamic Power Measured
Dynamic power measurements were taken on the small density devices using the power comparison
board. The designs used in the tool comparisons for dynamic data were programmed into the devices and
measured over frequency. Since there are no estimation tools available for the Xilinx CoolRunner-II
CPLDs, power measurements with taken with silicon to perform the dynamic power comparison.
Measured Dynamic Power – Small Density Devices
Table 13 shows the dynamic power consumption of the Actel IGLOO AGL030 FPGA and the Altera
MAX IIZ EPM240Z CPLD (14 counters in both devices). Figure 14 shows a graphical representation of the
data.
Table 13: Dynamic Power Measured – Small Density Devices
AGL030
Frequency
EPM240Z
Current (mA)
Power (mW)
Current (mA)
Power (mW)
0 MHz
0.002
0.003
0.025
0.044
10 MHz
0.730
0.876
1.678
3.020
20 MHz
1.460
1.752
3.230
5.814
30 MHz
2.190
2.628
4.980
8.964
40 MHz
2.770
3.324
6.620
11.916
50 MHz
3.460
4.152
8.250
14.850
60 MHz
4.160
4.992
9.880
17.784
70 MHz
4.850
5.820
11.510
20.718
80 MHz
5.520
6.624
13.120
23.616
Dynamic Power Consumption
Measured, AGL030 and EPM240Z
14 8-Bit Counter Design
25
Power (mW)
20
15
Altera MAX IIZ EPM240Z
Actel IGLOO AGL030
10
5
0
0
10
20
30
40
50
60
70
80
Frequency (MHz)
Figure 14: Dynamic Power Measured – Actel IGLOO AGL030 and Altera EPM240Z (14 counters)
Competitive Programmable Logic Power Comparison
19
Table 14 shows the dynamic power consumption of the Actel IGLOO AGL030 FPGA and the Xilinx
CoolRunner-II XC2C256 CPLD (22 counters in both devices). Figure 15 shows a graphical representation
of the data.
Table 14: Dynamic Power Measured – Actel IGLOO AGL030 and Xilinx CoolRunner-II XC2C256 (22 counters)
AGL030
Frequency
XC2C256
Current (mA)
Power (mW)
Current (mA)
Power (mW)
0 MHz
0.002
0.003
0.020
0.037
10 MHz
0.870
1.044
4.539
8.170
20 MHz
1.740
2.088
9.026
16.247
30 MHz
2.910
3.492
13.340
24.012
40 MHz
3.880
4.656
17.980
32.364
50 MHz
4.850
5.820
22.440
40.392
60 MHz
5.830
6.996
26.760
48.168
70 MHz
6.780
8.136
31.000
55.800
80 MHz
7.710
9.252
35.190
63.342
Dynamic Power Consumption
Measured, AGL030 and XC2C256
22 8-Bit Counter Design
70
60
Power (mW)
50
40
Xilinx CoolRunner-II
XC2C256
Actel IGLOO AGL030
30
20
10
0
0
10
20
30
40
50
60
70
80
Frequency (MHz)
Figure 15: Dynamic Power Measured – Actel IGLOO AGL030 and Xilinx CoolRunner-II XC2C256 (22 counters)
20
Competitive Programmable Logic Power Comparison
Measured Dynamic Power Summary– Small Density Devices
Comparing small density devices over different frequencies using the gray-code counter design makes it
clear that at any frequency, the Actel IGLOO AGL030 FPGA consumes less power than the Altera MAX IIZ
EPM240Z CPLD and the Xilinx CoolRunner-II XC2C256 CPLD. As frequency increases, Actel's IGLOO
power advantage increases.
Conclusion
This paper proves that Actel's flash-based IGLOO FPGAs are the undisputed low-power leaders in the
industry, regardless of logic density, design configuration, or power mode.
Comparing small density devices (30 k system gates) by analyzing vendor-generated data, we concluded
that Actel IGLOO FPGAS had a dominant power advantage over Xilinx CoolRunner-II and Altera MAX IIZ
CPLDs. With over 10 times lower power in static mode, static over temperature, dynamic, and total power,
the IGLOO FPGA is the clear winner in the small density space.
Analyzing the power consumption of large density FPGAs (600 k system gates) by looking at vendorgenerated data also shows a consistent power advantage for IGLOO FPGAs versus Xilinx Spartan-3AN
and Altera Cyclone III FPGAs. With 1,000 to 1,700 times better static power in typical conditions and over
a range of temperatures, and more than 100 mW difference in dynamic power, the IGLOO FPGA is the
clear winner in the large density space.
After comparing datasheets, vendor power-estimation tools, and real silicon measurements, Actel's IGLOO
FPGAs have been proven to have 10 to 1,700 times lower power than competitive programmable logic
offerings across logic densities.
Referenced Documents
Actel IGLOO Low-Power Flash FPGAs datasheet (Advanced v0.1)
http://www.actel.com/documents/IGLOO_DS.pdf
Actel’s Total System Power brochure
http://www.actel.com/documents/Power_PIB.pdf
Altera Cyclone III Device Datasheet: DC and Switching Characteristics (CIII52001-1.5)
http://www.altera.com/literature/hb/cyc3/cyc3_ciii52001.pdf
Altera MAX II Device Family DC and Switching Characteristics (MII51005-2.1)
http://www.altera.com/literature/hb/max2/max2_mii51005.pdf
Xilinx XC2C256 CoolRunner-II CPLD datasheet (DS094 v3.2)
http://www.xilinx.com/support/documentation/data_sheets/ds094.pdf
Xilinx Spartan3-AN FPGA Family datasheet (DS557-3 (v3.0)
http://www.xilinx.com/support/documentation/data_sheets/ds557.pdf
Competitive Programmable Logic Power Comparison
21
Actel is the leader in low-power and mixed-signal FPGAs and offers the most comprehensive portfolio of system and
power management solutions. Power Matters. Learn more at www.actel.com.
Actel Corporation
Actel Europe Ltd.
Actel Japan
Actel Hong Kong
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USA
Phone 650.318.4200
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