sy89834u Micrel Semiconductor, sy89834u Datasheet - Page 9

• Manufacturer Part Number: sy89834u
• Description: 2.5v/3.3v Two Input, 1ghz Lvttl/cmo To-lvpecl 1 4 Fanout Buffer/ Translator With 2 1 Input Mux
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
Note:
1. For +2.5V systems: R1 = 250 , R2 = 62.5
Notes:
1. Power-saving alternative to Thevenin termination.
2. Place termination resistors as close to destination inputs as possible.
3. R
Notes:
1. Unused output (/Q) must be terminated to balance the output.
2. For +2.5V systems: R1 = 250 , R2 = 62.5 , R3 = 1.25k , R4 = 1.2k .
2. Unused output pairs (Q and /Q) may be left floating.
TERMINATION RECOMMENDATIONS
For +3.3V systems: R1 = 130 , R2 = 82
b
resistor sets the DC bias voltage, equal to V
+3.3V
+3.3V
“source”
Figure 4a. Parallel Termination–Thevenin Equivalent
/Q
+3.3V
Q
t
+3.3V
. For +3.3V systems R
Figure 4c. Terminating Unused LVPECL I/O
Figure 4b. Three-Resistor “Y–Termination”
R1
130
R2
82
V
t
Z
Z
= V
O
O
= 50
= 50
CC
Z
Z = 50
Z = 50
O
—2V
= 50
R1
130
R2
82
b
50
+3.3V
50
= 50 . For +2.5V systems R
9
R1
130
R2
82
+3.3V
R b
50
R3
1k
R1
130
R2
82
R4
1.6k
V
CC
V
C1
0.01µF
(optional)
t
“destination”
= V
+3.3V
V
t
+3.3V
= V
CC
+3.3V
—1.3V
CC
b
—2V
= 19 .
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Precision Edge
M9999-080505
SY89834U
®