GR740-UM-DS, Nov 2017, Version 1.7
442
www.cobham.com/gaisler
GR740
.
Table 579.
Recommended AC operating conditions
Parameter
Symbol
Minimum
Nominal
Maximum
Unit
Note(s)
Externally fed PLL input clocks, PLLs enabled (in default configuration)
SYS_CLK frequency
f
sys_clk
20
50
70
MHz
1
SYS_CLK duty cycle
40
50
60
%
6
SPW_CLK frequency
f
spw_clk
20
50
55
MHz
1
SPW_CLK duty cycle
40
50
60
%
6
MEM_EXTCLK frequency
f
mem_extclk
20
50
55
MHz
1, 2
MEM_EXTCLK duty cycle
40
50
60
%
6
Externally fed PLL input clocks, PLLs bypassed
SYS_CLK frequency
f
sys_clk_bypass
0
50
100
MHz
1
SYS_CLK duty cycle
20
50
80
%
6
SPW_CLK frequency
f
spw_clk_bypass
0
50
100
MHz
1
SPW_CLK duty cycle
40
50
60
%
6
MEM_EXTCLK frequency
f
mem_extclk_bypass
0
100
100
MHz
1, 2
MEM_EXTCLK duty cycle
20
50
80
%
6
External fed clocks, non-PLL
MEM_CLK_IN frequency
0
100
100
MEM_CLK_IN duty cycle
20
50
80
%
6
PCI_CLK frequency
f
pci_clk
33
33
33
MHz
3
PCI_CLK duty cycle
20
50
80
%
6
ETH*_GTXCLK frequency
f
eth_gtxclk
125
125
125
MHz
ETH*_GTXCLK duty cycle
40
50
60
%
6
ETH*_TXCLK frequency
f
eth_txclk
25
25
25
MHz
ETH*_TXCLK duty cycle
20
50
80
%
6
ETH*_RXCLK frequency
f
eth_rxclk
25
25 or 125
125
MHz
ETH*_RXCLK duty cycle
40
50
60
%
6
GR1553_CLK frequency
f
gr1553_clk
19.999
20
20.001
MHz
GR1553_CLK duty cycle
20
50
80
%
6
GR1553_CLK jitter
5
ns
6, 7
Internally generated clocks
AMBA system clock frequency
f
soc_system
40
250
250
MHz
4, 5
Internal SPW clock frequency
10
400
400
MHz
1
Min/max values are maximum for on-chip PLL input, limits for the generated frequencies must also be satisfied.
Nominal frequency required for correct operation with PLL power-up configuration and will change if reconfigured.
2
Assuming MEM_CLKSEL has been set high so that MEM_EXTCLK is used
3
The PCI interface will not be fully compliant to the PCI specification. Interface will be characterised at a later date.
4
The minimum clock frequency for the on-chip system is determined by functional interface limitations and has not
been fully characterised. A clock frequency over 40 MHz is required for the Ethernet interfaces to function at gigabit
speeds.
5
The maximum given here is from static timing analysis in worst case PVT corner and includes margins for aging and
jitter, and it is also used as clock rate during production tests.
6
Supplied as design parameter, not tested
7
Limit on rising edge only