LMH0070SQ National Semiconductor, LMH0070SQ Datasheet - Page 17
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LMH0070SQ
Manufacturer Part Number
LMH0070SQ
Description
Manufacturer
National Semiconductor
Datasheet
1.LMH0070SQ.pdf
(26 pages)
Specifications of LMH0070SQ
Number Of Elements
1
Number Of Receivers
5
Number Of Drivers
1
Input Type
CMOS
Operating Supply Voltage (typ)
3.3V
Differential Input High Threshold Voltage
100mV
Diff. Input Low Threshold Volt
-100mV
Output Type
Serializer
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
48
Lead Free Status / Rohs Status
Supplier Unconfirmed
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LMH0070SQE/NOPB
Manufacturer:
NSC
Quantity:
2 250
SERIAL JITTER OPTIMIZATION
The SER is capable of very low jitter operation, however it is
dependent on the TXCLK provided by the host in order to op-
erate, and depending on the quality of the TXCLK provided,
the SER output jitter may not be as low as it could be.
The SER includes circuitry to filter out any TXCLK jitter at fre-
quencies above 1MHz (see
Figure
15), however, for frequen-
cies below 100 kHz, any jitter that is in the TXCLK is passed
directly through to the serialized output.
In most cases, passing the TXCLK through the FPGA will add
high frequency noise to the signal, which will be filtered out
by the SER, resulting in a clean output, however for better
jitter performance, it is best to minimize the noise that is on
the TXCLK that is provided to the SER. This can be done by
careful routing of the CLK signals, both within the FPGA and
on the board.
Very clean clocks can be derived from video reference signals
30017014
through the use of the LMH1981 Sync Separator and the
LMH1982 Clock Generator products from National Semicon-
FIGURE 15. SER Jitter Transfer Function
ductor. These products allow low jitter video frequency clocks
to be generated either independently, or phase locked to a
video reference signal.
17
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