sy89825u Micrel Semiconductor, sy89825u Datasheet - Page 8

• Manufacturer Part Number: sy89825u
• Description: Sy89825u 2.5/3.3v 1 22 High-performance, Low Voltage Pecl Bus Clock Driver & Translator With Internal Terminator
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
Output Considerations
Be sure to properly terminate all outputs as shown below, or
equivalent. For AC coupled applications
Notes:
1. For +2.5V systems:
Notes:
1. Power-saving alternative to Thevenin termination.
2. Place termination resistors as close to destination inputs as possible.
3. R
4. Precision, low-cost 3-Resistor networks are available from resistor manufacturers such as Thin Film Technology (www.thinfilm.com).
M9999-011907
[e-mail] or [phone]
LVPECL TERMINATION RECOMMENDATIONS
R1 = 250
R2 = 62.5
b
resistor sets the DC bias voltage equal to V
“source”
, be sure to include a pull
+3.3V
Figure 1. Parallel Termination–Thevenin Equivalent
t
. For +3.3V systems R
+3.3V
Figure 2. Three-Resistor “Y–Termination”
Z
Z
O
O
= 50
= 50
Z = 50
Z = 50
46 to 49
130
82
R1
R2
50
b
= 46 to 49 .
8
+3.3V
down resistor at the output of each driver. The emmiter follower
outputs requires a DC current path to GND. Unused outputs can be
left floating with minimal impact on skew and jitter.
R b
R1
130
R2
82
50
+3.3V
+3.3V
V t = V
CC
“destination”
—2V
Precision Edge
SY89825U
®