LMH0001_10 Datasheet, PDF (3/4 Pages) National Semiconductor (TI) – Replacing the CLC001 Cable Driver with the LMH0001

outputs are positive supply referenced and require 75Ω
pullups to V_CC to generate the output voltage. Like the
CLC001, the LMH0001 output level is controlled by the
R_REF resistor.
OUTPUT LEVEL CONTROL (R_REF RESISTOR)
The R_REF resistor controls the output driver amplitude. The
output amplitude for both the CLC001 and LMH0001 is ad-
justable from below 800 mV_P-P to above 1.0 V_P-P. For the
CLC001, the R_REF resistor is connected to ground, and for the
LMH0001, the R_REF resistor is connected to V_CC. The output
amplitude is inversely proportional to the value of R_REF and
approximately linear. For the CLC001, R_REF is 1.91 kΩ for
800 mV_P-P output and 1.5 kΩ for 1.0 V_P-P output. For the
LMH0001, R_REF is 750Ω for 800 mV_P-P output and 590Ω for
1.0 V_P-P output.
OUTPUT RETURN LOSS
The LMH0001 output structure provides improved return loss
over the output structure used for the CLC001. This allows
the LMH0001 to exceed the SMPTE return loss specification
on the SD001SQ evaluation board with the recommended
return loss network consisting of a 5.6 nH inductor in parallel
with a 75Ω resistor. Return loss is dependent on board design
so this return loss network may need to be optimized de-
pending on the specific PCB design and BNC connector used.
LMH0001 Enhancements over the
CLC001
The LMH0001 is a solid upgrade and good replacement for
the CLC001. It is designed in a newer, more advanced pro-
cess. The LMH0001 offers much lower power and better
output return loss. The LMH0001’s smaller, space-saving
package allows for more compact designs. In addition, the
LMH0001’s pin compatibility with HD-SDI and 3G-SDI cable
drivers offers an easy upgrade path and allows future-proof
designs.
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