LMH0026MHX/NOPB National Semiconductor, LMH0026MHX/NOPB Datasheet - Page 6

• Manufacturer Part Number: LMH0026MHX/NOPB
• Description: IC RECLOCKER SDI HD/SD 20-TSSOP
• Manufacturer: National Semiconductor
• Type: Reclockerr

Specifications of LMH0026MHX/NOPB

• Applications: Digital Video
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP Exposed Pad, 20-eTSSOP, 20-HTSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LMH0026MHX

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Device Description
The LMH0026 SD SDI Reclocker is used in many types of
digital video signal processing equipment. The LMH0026
supports the SMPTE 259M (C) serial digital video standard,
with a corresponding serial data rate of 270 Mbps. DVB-ASI
data at 270 Mbps may also be retimed. The LMH0026 retimes
the serial data stream to suppress accumulated jitter. It pro-
vides two low-jitter, differential, serial data outputs. The sec-
ond output may be selected to output either serial data or a
low-jitter serial data-rate clock. Controls and indicators are:
serial data-rate clock or second serial data output select, SD
indicator output, lock detect output, auto/manual data bypass,
and output mute.
Serial data inputs are CML and LVPECL compatible. Serial
data and data-rate clock outputs are differential CML and
produce LVPECL compatible levels. The output buffer design
can drive AC or DC-coupled, terminated 100Ω differential
loads. The differential output level is 800 mV
100Ω AC or DC-coupled differential loads. Logic inputs and
outputs are LVCMOS compatible.
The device package is an e-TSSOP20 with an exposed die
attach pad. The exposed die attach pad is electrically con-
nected to device ground (V
terminal for the device. This terminal must be connected to
the negative power supply or circuit ground.
Serial Data Inputs, Serial Data and
Clock Outputs
SERIAL DATA INPUT AND OUTPUTS
The differential serial data input, SDI, accepts 270 Mbps serial
digital video data. The serial data input is differential LVPECL
EE
) and is the negative electrical
FIGURE 1. Equivalent SDI input Circuit (SDI, SDI)
P-P
±10% into
6
compatible. The input is intended to be DC interfaced to de-
vices such as the LMH0074 adaptive cable equalizer. The
input is not internally terminated or biased. The input may be
AC-coupled if a suitable input bias voltage is provided.
Figure 1
The LMH0026 has two, retimed, differential, serial data out-
puts, SDO and SCO/SDO2. These outputs provide low jitter,
differential, retimed data to devices such as the LMH0001 or
LMH0002 cable driver. Output SCO/SDO2 is multiplexed and
can provide either a second serial data output or a serial data-
rate clock output.
for SDO, SDO, SCO/SDO2, and SCO/SDO2.
The SCO_EN input controls the operating mode for the SCO/
SDO2 output. When the SCO_EN input is high the SCO/
SDO2 output provides a serial data-rate clock. When
SCO_EN is low, the SCO/SDO2 output provides retimed se-
rial data.
Both differential serial data outputs, SDO and SCO/SDO2,
are muted when the OUTPUT MUTE input is a logic low level.
SCO/SDO2 also mutes when the Bypass mode is activated
when this output is operating as the serial clock output. When
muted, SDO and SDO (or SDO2 and SDO2) will assume op-
posite differential output levels. The CML serial data outputs
are differential LVPECL compatible. These outputs have in-
ternal 50Ω pull-ups and are suitable for driving AC or DC-
coupled, 100Ω center-tapped, AC grounded or 100Ω un-
center-tapped, differentially terminated networks.
shows the equivalent input circuit for SDI and SDI.
Figure 2
shows the equivalent output circuit
30001808