Texas Instruments LMK01000 Evaluation Board LMK01000EVAL/NOPB LMK01000EVAL/NOPB 데이터 시트
제품 코드
LMK01000EVAL/NOPB
0.1
P
F
0.1
P
F
50
:
Trace
5
0
:
LMK
Input
Clock Source
CLKoutX
CLKoutX*
1
2
0
:
1
2
0
:
0.1
P
F
0.1
P
F
50
:
Trace
5
0
:
Load
5
0
:
LVPECL
Driver
CLKoutX
CLKoutX*
8
2
:
50
:
Trace
1
2
0
:
Load
Vcc
8
2
:
1
2
0
:
Vcc
LVPECL
Driver
SNAS437G – FEBRUARY 2008 – REVISED OCTOBER 2009
Figure 10. Single-Ended LVPECL Operation, DC Coupling, Thevenin Equivalent
When AC coupling an LVPECL driver use a 120
Ω
emitter resistor to provide a DC path to ground and ensure a
50
Ω
termination with the proper DC bias level for the receiver. The typical DC bias voltage for LVPECL
receivers is 2 V (See Section 3.4.1). If the other driver is not used it should be terminated with either a proper AC
or DC termination. This latter example of AC coupling a single-ended LVPECL signal can be used to measure
single-ended LVPECL performance using a spectrum analyzer or phase noise analyzer. When using most RF
test equipment no DC bias point (0 V DC) is expected for safe and proper operation. The internal 50
or DC termination. This latter example of AC coupling a single-ended LVPECL signal can be used to measure
single-ended LVPECL performance using a spectrum analyzer or phase noise analyzer. When using most RF
test equipment no DC bias point (0 V DC) is expected for safe and proper operation. The internal 50
Ω
termination the test equipment correctly terminates the LVPECL driver being measured as shown in
.
When using only one LVPECL driver of a CLKoutX/CLKoutX* pair, be sure to properly terminated the unused
driver.
driver.
Figure 11. Single-Ended LVPECL Operation, AC Coupling
Conversion to LVCMOS Outputs
To drive an LVCMOS input with an LMK01000 family LVDS or LVPECL output, an LVPECL/LVDS to LVCMOS
converter such as National Semiconductor's DS90LV018A, DS90LV028A, DS90LV048A, etc. is required. For
best noise performance, LVPECL provides a higher voltage swing into input of the converter.
converter such as National Semiconductor's DS90LV018A, DS90LV028A, DS90LV048A, etc. is required. For
best noise performance, LVPECL provides a higher voltage swing into input of the converter.
OSCin INPUT
In addition to LVDS and LVPECL inputs, OSCin can also be driven with a sine wave. The OSCin input can be
driven single-ended or differentially with sine waves. These configurations are shown in
driven single-ended or differentially with sine waves. These configurations are shown in
and
.
Figure 12. Single-Ended Sine Wave Input
Copyright © 2008–2009, Texas Instruments Incorporated
19
Product Folder Links: