isppac-clk5520v-01tn100 Lattice Semiconductor Corp., isppac-clk5520v-01tn100 Datasheet - Page 32

• Manufacturer Part Number: isppac-clk5520v-01tn100
• Description: In-system Programmable Clock Generator With Universal Fan-out Buffer
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
Figure 29. Output Timing Adders for Logic Type (a) and Output Slew Rate (b)
Similarly, when one changes the slew rate of an output, the output slew rate adders (t
the resulting skew. In this case, the fastest slew setting (1) is used as the baseline against which other slews are
measured. For example, in the case of outputs configured to the same logic type (e.g. LVCMOS 1.8V), if one output
is set to the fastest slew rate (1, t
660ps of skew between the two outputs, as shown in Figure 29b.
Other Features
Profile Select
The ispClock5500 stores all internal configuration data in on-board E
figuration profiles may be stored in each device. The choice of which configuration profile is to be active is specified
thought the profile select inputs PS0 and PS1, as shown in Table 7.
Table 7. Profile Select Function
Each profile controls the following internal configuration items:
The following settings are independent of the selection of active profile and will apply regardless of which profile is
selected:
• M divider setting
• N divider setting
• V divider settings
• PLL Loop filter settings
• Output Skew settings
• Internal feedback delay compensation
• Input logic configuration
• Output bank logic configuration
LVPECL Output
(T
LVTTL Output
(T
IOS
– Logic family
– Input impedance
– Logic family
– V-Divider signal source
– Enable/SGATE control options
– Output Impedance
– Slew rate
IOS
= 0.1ns)
= 0)
(a)
IOS
0.1ns
= 0ps), and another set to slew rate 3 (t
PS1
0
0
1
1
PS0
32
0
1
0
1
LVCMOS Output
LVCMOS Output
(Slew rate=1)
(Slew rate=3)
Active Profile
2
CMOS memory. Up to four independent con-
Profile 0
Profile 1
Profile 2
Profile 3
ispClock5500 Family Data Sheet
IOS
= 660ps), then one could expect
(b)
660ps
IOS
) can be used to predict