Spartan-3E FPGA Family: DC and Switching Characteristics
DS312 (v4.1) July 19, 2013
Product Specification
144
Phase Shifter (PS)
Miscellaneous DCM Timing
Table 108: Recommended Operating Conditions for the PS in Variable Phase Mode
Symbol
Description
Speed Grade
Units
-5
-4
MinMax
Operating Frequency Ranges
PSCLK_FREQ
(FPSCLK)
Frequency for the PSCLK input
1
167
1
167
MHz
Input Pulse Requirements
PSCLK_PULSE
PSCLK pulse width as a percentage of the PSCLK period
40%
60%
40%
60%
-
Table 109: Switching Characteristics for the PS in Variable Phase Mode
Symbol
Description
Equation
Units
Phase Shifting Range
Maximum allowed number of DCM_DELAY_STEP steps
for a given CLKIN clock period, where T = CLKIN clock
period in ns. If using CLKIN_DIVIDE_BY_2 = TRUE,
double the effective clock period
.(3)CLKIN
< 60 MHz
±[INTEGER(10
(TCLKIN – 3 ns))]
steps
CLKIN
≥ 60 MHz
±[INTEGER(15
(TCLKIN – 3 ns))]
steps
FINE_SHIFT_RANGE_MIN
Minimum guaranteed delay for variable phase shifting
±[MAX_STEPS
DCM_DELAY_STEP_MIN]
ns
FINE_SHIFT_RANGE_MAX
Maximum guaranteed delay for variable phase shifting
±[MAX_STEPS
DCM_DELAY_STEP_MAX]
ns
Notes:
1.
The numbers in this table are based on the operating conditions set forth in
Table 77 and
Table 108.2.
The maximum variable phase shift range, MAX_STEPS, is only valid when the DCM is has no initial fixed phase shifting, i.e., the
PHASE_SHIFT attribute is set to 0.
3.
The DCM_DELAY_STEP values are provided at the bottom of
Table 105.Table 110: Miscellaneous DCM Timing
Symbol
Description
Min
Max
Units
Minimum duration of a RST pulse width
3
-CLKIN
cycles
Maximum duration of a RST pulse width
N/A
seconds
Maximum duration from VCCINT applied to FPGA configuration
successfully completed (DONE pin goes High) and clocks
applied to DCM DLL
N/A
minutes
Notes:
1.
This limit only applies to applications that use the DCM DLL outputs (CLK0, CLK90, CLK180, CLK270, CLK2X, CLK2X180, and CLKDV).
The DCM DFS outputs (CLKFX, CLKFX180) are unaffected.
2.
This specification is equivalent to the Virtex-4 DCM_RESET specfication.This specification does not apply for Spartan-3E FPGAs.
3.
This specification is equivalent to the Virtex-4 TCONFIG specification. This specification does not apply for Spartan-3E FPGAs.