sy58021u Micrel Semiconductor, sy58021u Datasheet - Page 8

• Manufacturer Part Number: sy58021u
• Description: Sy58021u 4ghz, 1 4 Lvpecl Fanout Buffer/ Translator With Internal Termination
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
emitter), and small signal swing which results in low EMI.
LVPECL is ideal for driving 50Ω and 100Ω controlled
M9999-082807
[e-mail] or [phone]
Part Number
SY58020U
SY58021U
SY58022U
M-0317
LVPECL OUTPUT
Figure 4. Parallel Termination-Thevenin Equivalent
RELATED MICREL PRODUCTS AND SUPPORT DOCUMENTATION
LVPECL output have very low output impedance (open
+3.3V*
SY58021U
*Note. For +2.5V systems,
R1 = 250Ω, R2 = 62.5Ω
Z
Z
Function
6GHz, 1:4 CML Fanout Buffer/Translator
Internal I/O Termnations
4GHz, 1:4 LVPECL Fanout Buffer/Translator
with Internal Termination
5.5GHz, 1:4 Fanout Buffer/Translator
w/400mV LVPECL Outputs and Internal Terminations
16-MLF™ Manufacturing Guidelines
Exposed Pad Application Note
HBW Solutions
O
O
= 50Ω
= 50Ω
R1
130Ω
R2
82Ω
+3.3V*
Note 1. Unused output (/Q) must be terminated to balance the output.
Note 2. For +2.5V systems: R1 = 250 , R2 = 62.5 , R3 = 1.25k , R4 = 1.2k .
Note 3. Unused output pairs (Q and /Q) may be left floating.
+3.3V
R1
130Ω
R2
82Ω
/Q
Q
For +3.3V systems: R1 = 130 , R2 = 82 , R3 = 1k , R4 = 1.6k .
+3.3V
Figure 6. Terminating Unused I/O
V
R1
130Ω
R2
82Ω
T
+3.3V*
= V
V
T
CC
Z
= V
O
–2V
= 50Ω
CC
–2V
8
+3.3V
impedance transmission lines. There are several techniques
in terminating the LVPECL output, as shown in Figures 4
through 6.
R1
130Ω
R2
82Ω
“source”
Notes:
1. Power saving alternative to Thevenin termination.
2. Place termination resistors as close to destination inputs as possible.
3. Rb resistor sets the DC bias voltage, equal to VT.
+3.3V
Data Sheet Link
http://www.micrel.com/product-info/products/sy58020u.shtml
http://www.micrel.com/product-info/products/sy58021u.shtml
http://www.micrel.com/product-info/products/sy58022u.shtml
www.amkor.com/products/notes_papers/MLF_AppNote_0902.pdf
http://www.micrel.com/product-info/as/solutions.shtml
SY58021U
Figure 5. Parallel Termination (3-Resistor)
R4
1kΩ
R3
1.6kΩ
V
T
= V
Z = 50Ω
Z = 50Ω
+3.3V
CC
–1.3V
50Ω
50Ω
* For +2.5V, R b = 19Ω
* For +3.3V, R b = 46Ω to 50Ω
R
50Ω
b
*
“destination”
+3.3V
V
Precision Edge
DD
C1 (optional)
0.01µF
SY58021U
®