LMH0074_1

Manufacturer Part NumberLMH0074_1
DescriptionReplacing the CLC012 Adaptive Cable Equalizer with the LMH0074
ManufacturerNSC [National Semiconductor]
LMH0074_1 datasheet
 
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Replacing the CLC014
Adaptive Cable Equalizer
with the LMH0074
Introduction
The LMH0074 SD-SDI adaptive cable equalizer can replace
the CLC014 adaptive cable equalizer in many applications.
The LMH0074 and CLC014 are both adaptive cable equaliz-
ers designed to recover data sent over long cables, primarily
for the SMPTE 259M interface. The supported data rates and
cable lengths are similar between the two devices. The
LMH0074 and CLC014 are both rated for industrial tempera-
ture range operation (-40°C to +85°C).
The LMH0074, the newer generation SDI equalizer, has more
advanced features and is pin compatible with the LMH0044
Power Supply (V
)
CC
Package
Data Rates
ESD Rating
Input Interface
Requires 100Ω series resistor on each input
Open collector, requires external 75Ω pullups
Output Structure
AEC Capacitor Value
Carrier Detect / Mute Polarity
Other Features
How To Replace the CLC014 with
the LMH0074
Replacing the CLC014 with the LMH0074 requires a few sim-
ple steps. The device packages and pinouts are quite different
so this change requires a new PCB layout; however, the
equalizer core and features are similar. To replace the
CLC014 with the LMH0074, follow these steps:
1.
Change the power supply from 5V to 3.3V.
2.
Remove the 100Ω series resistors at the input to the
equalizer.
© 2009 National Semiconductor Corporation
National Semiconductor
Application Note 2002
Gary Melchior
September 22, 2009
HD-SDI equalizer and the LMH0344 or LMH0384 3G-SDI
equalizer. This allows a forward migration path from SD to HD
to 3G. The LMH0074 also offers a lower supply voltage
(3.3V), enabling system designers to migrate to lower-power
designs. The LMH0074 provides a 28% power savings over
the CLC014, with typical power of 209 mW in comparison with
280 mW for the CLC014.
Table 1
shows the key differences between the CLC014 and
LMH0074.
TABLE 1. CLC014 and LMH0074 Key Differences
CLC014
5.0V
14-pin SOIC
50 to 650 Mbps
±500V HBM
to 5V
100 pF
CD, MUTE
OEM
3.
Add an input return loss network consisting of a 6.8 nH
inductor in parallel with a 75Ω resistor on the active input
between the BNC and the 75Ω termination.
4.
Removed the 75Ω pullups on the output and replace with
a 100Ω differential termination located at the input of the
next stage. The outputs may also be AC coupled, but no
pullups are required.
5.
Replace the 100 pF AEC capacitor with a 1.0 µF AEC
capacitor.
Figure 1
Figure 2
301059
LMH0074
3.3V
16-pin LLP
125 to 540 Mbps
±8 kV HBM
Requires return loss network of 6.8 nH in
parallel with 75Ω on active input
CML with internal 50Ω pullups (to 3.3V)
1.0 µF
CD, MUTE
MUTE
, BYPASS
REF
shows the typical application for the CLC014, and
shows the typical application for the LMH0074.
www.national.com

LMH0074_1 Summary of contents

  • Page 1

    Replacing the CLC014 Adaptive Cable Equalizer with the LMH0074 Introduction The LMH0074 SD-SDI adaptive cable equalizer can replace the CLC014 adaptive cable equalizer in many applications. The LMH0074 and CLC014 are both adaptive cable equaliz- ers designed to recover data ...

  • Page 2

    INPUT INTERFACE For the typical input interface, the equalizer receives a single- ended signal over 75Ω coaxial cable. The CLC014 requires a 75Ω termination to ground, a 1.0 µF input coupling capaci- tor, and a 100Ω series resistor on each ...

  • Page 3

    OUTPUT INTERFACE The CLC014 outputs are open collector and require 75Ω pullups generate an output voltage. This structure has some limitations when interfacing to non-5V systems. The CLC014 outputs are essentially cut off if the DO output ...

  • Page 4

    For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo ...