LMH0031 Datasheet, PDF (10/31 Pages) National Semiconductor (TI) – SMPTE 292M/259M Digital Video Deserializer Descrambler with Video and Ancillary Data FIFOs

Timing Diagram
Device Operation
INTRODUCTION
The LMH0031 SMPTE 292M/259M Digital Video
Deserializer/Decoder is used in digital video signal origina-
tion and destination equipment: cameras, video tape record-
ers, telecines, editors, standards converters, video test and
other equipment. It decodes and converts serial SDTV or
HDTV component digital video signals into parallel format.
The LMH0031 decoder/deserializer processes serial digital
video (SDV) signals conforming to SMPTE 259M, SMPTE
344M (proposed) or SMPTE 292M and operates at serial
data rates of 270 Mbps, 360 Mbps, 540 Mbps, 1.483 Gbps
and 1.485 Gbps. Corresponding parallel output data rates
are 27.0 MHz, 36.0 MHz, 54.0 MHz, 74.176MHz and
74.25 MHz.
The LMH0031 accepts ECL or LVDS serial data input sig-
nals. Outputs signals are compatible with LVCMOS logic
devices.
Note: In the following explanations, these logical equiva-
lences are observed: ON ≡ Enabled ≡ Set ≡ True ≡ Logic_1
and OFF ≡ Disabled ≡ Reset ≡ False ≡ Logic_0.
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VIDEO DATA PATH
The Serial Data Inputs (SDI) accept serial video data at
SMPTE 259M standard definition, SMPTE 344M (proposed)
or SMPTE 292M high-definition data rates. These inputs
accept standard ECL or LVDS signal levels and may be used
single-ended or differentially. Inputs may be DC or AC
coupled, as required, to devices and circuits supplying the
data. Recommended operating conditions and all input DC
and AC voltage and current specifications shall be observed
when designing the input coupling circuits.
For convenience, a reference bias source, pin name R_REF,
sets the reference current available from the input bias
source, pin name R_BB. The recommended nominal value of
R_REF is 4.75kΩ, 1%. R_BB is provided so that the SDI inputs
may be supplied DC bias voltage via external resistors when
the inputs are AC-coupled. The bias source should be
loaded with a resistance to the V_SS supply. The source
current available at R_BB is 200µA. Figure 1 shows a typical
input biasing scheme using R_BB and R_REF.
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