XRK4991A Datasheet, PDF (10/13 Pages) Exar Corporation – 3.3V HIGH-SPEED (85 MHZ) PROGRAMMABLE SKEW CLOCK BUFFER

XRK4991A
PRELIMINARY
3.3V HIGH-SPEED (85 MHZ) PROGRAMMABLE SKEW CLOCK BUFFER
xr
REV. P1.0.2
5. For XRK4993-2 t_SKEW0 is measured with C_L = 0pF; for C_L = 20pF, t_SKEW0 = 0.35ns Max.
6. There are 2 classes of outputs: Nominal (multiple of t_U delay), and Divided (QC[1:0] only in Divide-by-2 or Divide-by-4
mode).
7. t_DEV is the output-to-output skew between any two devices operating under the same conditions (V_CC, ambient temperature,
air flow, etc.)
8. 8. t_LOCK is the time that is required before synchronization is achieved. This specification is valid only after V_CC is stable and
within normal operating limits. This parameter is measured from the application of a new signal or frequency at CLKIN or
FB_IN until tPD is within specified limits.
9. t_PD is measured with CLKIN input rise and fall times (from 0.8V to 2V) of 1ns.
10. Measured at 2V.
11. Measured at 0.8V.
FIGURE 4. AC TEST LOADS AND WAVEFORMS
Output
V_CC
150Ω
150Ω
20pF
2.0V
0.8V
3.0V
2.0V
Vth = 1.5V
0.8V
0V
t_ORISE
t_PWL
t_OFALL
t_PWH
LVTTL Output Waveform
<1ns
<1ns
LVTTL Input Test Waveform
10