SD346EVK National Semiconductor, SD346EVK Datasheet - Page 13

• Manufacturer Part Number: SD346EVK
• Description: BOARD EVAL LMH0346
• Manufacturer: National Semiconductor

Specifications of SD346EVK

• Main Purpose: Video, HD/SD SDI Reclocker
• Utilized Ic / Part: LMH0346
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

DC coupled to the input of the receiving device as long as the
common mode ranges of both devices are compatible.
4
LMH0346 and LMH0302 cable driver. All that is required is a
100Ω differential termination as shown. The resistor should
be placed as close to the LMH0302 input as possible. If de-
sired, this network may be terminated with two 50Ω resisters
and a center tap capacitor to ground in place of the single
100Ω resistor.
The external loop filter capacitor (between LF1 and LF2)
should be 56 nF. This is the only supported value; the loop
filter capacitor should not be changed.
RATE0 and RATE1 have internal pulldowns to select Auto-
Rate Detect mode by default. These pins may also be used
to set the device to SD mode or HD/3G mode.
BYPASS/AUTO BYPASS has an internal pulldown to enable
Auto Bypass mode by default. This pin may be pulled high to
force the LMH0346 to bypass all data.
OUTPUT MUTE has an internal pullup to enable the outputs
by default. This pin may be pulled low to mute the outputs.
The XTAL IN/EXT CLK and XTAL OUT pins are shown with
a 27 MHz crystal and the proper loading. The crystal should
shows an example of a DC coupled interface between the
Figure
13
match the parameters described in
27MHz LVCMOS compatible clock signal may be input to
XTAL IN/EXT CLK.
The active high LOCK DETECT output provides an indication
that proper data is being received and the PLL is locked.
The SD/HD output may be used to drive the SD/HD pin of an
SDI cable driver (such as the LMH0302) in order to properly
set the cable driver’s edge rate for SMPTE compliance. It de-
faults to HD/3G (low) when the LMH0346 is not locked.
SCO_EN has an internal pulldown to set the second output
(SCO/SDO2) to output data. This pin may be pulled high to
set the second output as a serial clock.
The ground connection for the LMH0346 is through the large
exposed DAP. The DAP must be connected to ground for
proper operation of the LMH0346. This is the only ground
connection for the LMH0346MH. It is the primary ground con-
nection, required for good signal integrity, for the
LMH0346SQ.
Table
3. Alternately, a
www.national.com