REVISION E 6/21/16
8521 DATA SHEET
5 Low Skew, 1-to-9, Differential-to-
HSTL Fanout Buffer
TABLE 4D. LVPECL DC CHARACTERISTICS, V
DD
= 3.3V±5%, V
DDO
= 1.8V±0.2V, TA = 0°C TO 70°C
Symbol Parameter Test Conditions Minimum Typical Maximum Units
I
IH
Input High Current
PCLK V
DD
= V
IN
= 3.465V 150 µA
nPCLK V
DD
= V
IN
= 3.465V 5 µA
I
IL
Input Low Current
PCLK V
DD
= 3.465V, V
IN
= 0V -5 µA
nPCLK V
DD
= 3.465V, V
IN
= 0V -150 µA
V
PP
Peak-to-Peak Input Voltage 0.3 1 V
V
CMR
Common Mode Input Voltage;
NOTE 1, 2
1.5 V
DD
V
NOTE 1: Common mode voltage is defi ned as V
IH
.
NOTE 2: For single ended applications, the maximum input voltage for PCLK and nPCLK is V
DD
+ 0.3V.
TABLE 4E. HSTL DC CHARACTERISTICS, V
DD
= 3.3V±5%, V
DDO
= 1.8V±0.2V, TA = 0°C TO 70°C
Symbol Parameter Test Conditions Minimum Typical Maximum Units
V
OH
Output High Voltage; NOTE
1
1.0 1.4 V
V
OL
Output Low Voltage; NOTE
1
0 0.4 V
V
OX
Output Crossover Voltage 40% x (V
OH
- V
OL
) + V
OL
60% x (V
OH
- V
OL
) + V
OL
V
V
SWING
Peak-to-Peak
Output Voltage Swing
0.6 1.1 V
NOTE 1: Outputs terminated with 50Ω to ground.
TABLE 5. AC CHARACTERISTICS, V
DD
= 3.3V±5%, V
DDO
= 1.8V±0.2V, TA = 0°C TO 70°C
Symbol Parameter Test Conditions Minimum Typical Maximum Units
f
MAX
Output Frequency 500 MHz
t
PD
Propagation Delay; NOTE 1 ƒ 250MHz 1 1.8 ns
tsk(o) Output Skew; NOTE 2, 4 50 ps
tsk(pp) Part-to-Part Skew; NOTE 3, 4 250 ps
t
R
Output Rise Time 20% to 80% @ 50MHz 300 700 ps
t
F
Output Fall Time 20% to 80% @ 50MHz 300 700 ps
odc Output Duty Cycle 48 52 %
All parameters measured at 250MHz unless noted otherwise.
NOTE 1: Measured from the differential input crossing point to the differential output crossing point.
Measured from V
DD
/2 to the output differential crossing point for single ended input levels.
NOTE 2: Defi ned as skew between outputs at the same supply voltage and with equal load conditions.
Measured at the output differential cross points.
NOTE 3: Defi ned as skew between outputs on different devices operating at the same supply voltages
and with equal load conditions. Using the same type of inputs on each device, the outputs are measured
at the differential cross points.
NOTE 4: This parameter is defi ned in accordance with JEDEC Standard 65.
