LMH0044
SMPTE 292M / 259M Adaptive Cable Equalizer
General Description
The LMH0044 SMPTE 292M / 259M adaptive cable equal-
izer is a monolithic integrated circuit for equalizing data
transmitted over cable (or any media with similar dispersive
loss characteristics). The equalizer operates over a wide
range of data rates from 143 Mbps to 1.485 Gbps and
supports SMPTE 292M, SMPTE 344M and SMPTE 259M.
The LMH0044 implements DC restoration to correctly handle
pathological data conditions (DC restoration may be by-
passed for low data rate applications). The equalizer may be
driven in either a single ended or differential configuration.
Additional features include separate carrier detect and out-
put mute pins which may be tied together to mute the output
when no signal is present. A programmable mute reference
is provided to mute the output at a selectable level of signal
degradation.
Features
nSMPTE 292M, SMPTE 344M and SMPTE 259M
compliant
nSupports DVB-ASI at 270 Mbps
nHigh data rates: 143 Mbps to 1.485 Gbps
nEqualizes up to 140 meters of Belden 1694A at 1.485
Gbps or up to 350 meters of Belden 1694A at 270 Mbps
nManual bypass and output mute with a programmable
threshold
nSingle-ended or differential input
n50Ωdifferential outputs
nSingle 3.3V supply operation
n208mW typical power consumption with 3.3V supply
nReplaces the GS1574 and GS1574A
Applications
nSMPTE 292M, SMPTE 344M, and SMPTE 259M serial
digital interfaces
nSerial digital data equalization and reception
nData recovery equalization
Typical Application
20177001
PRELIMINARY
April 2006
LMH0044 SMPTE 292M / 259M Adaptive Cable Equalizer
© 2006 National Semiconductor Corporation DS201770 www.national.com
Absolute Maximum Ratings (Note 1)
Supply Voltage −0.5V to 3.6V
Input Voltage (all inputs) −0.3V to V
CC
+0.3V
Storage Temperature Range −65˚C to +150˚C
Junction Temperature +150˚C
Lead Temperature
(Soldering 4 Sec) +260˚C
Package Thermal Resistance
θ
JA
16-pin LLP
θ
JC
16-pin LLP
+115˚C/W
+105˚C/W
ESD Rating (HBM) 8kV
ESD Rating (MM) 250V
Recommended Operating
Conditions
Supply Voltage (V
CC
–V
EE
) 3.3V ±5%
Input Coupling Capacitance 1.0 µF
AEC Capacitor (Connected between
AEC+ and AEC-) 1.0 µF
Operating Free Air Temperature (T
A
) 0˚C to +85˚C
DC Electrical Characteristics
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Notes 2, 3).
Symbol Parameter Conditions Reference Min Typ Max Units
V
CMIN
Input Common Mode Voltage SDI, SDI 1.9 V
V
SDI
Input Voltage Swing At LMH0044 input, (Notes 4, 6) 720 800 950 mV
P−P
V
CMOUT
Output Common Mode Voltage SDO, SDO V
CC
–
V
SDO
/2 V
V
SDO
Output Voltage Swing 50Ωload, differential 750 mV
P-P
MUTE
REF
DC Voltage (floating) MUTE
REF
1.3 V
MUTE
REF
Range 0.7 V
CD Output Voltage Carrier not present CD 2.6 V
Carrier present 0.4 V
MUTE Input Voltage Min to mute outputs MUTE 3.0 V
Max to force outputs active 2.0 V
I
CC
Supply Current (Note 7) 63 77 mA
LMH0044
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AC Electrical Characteristics
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3).
Symbol Parameter Conditions Reference Min Typ Max Units
BR
SDI
Input Data Rate SDI, SDI 143 1485 Mbps
Maximum Equalized Cable
Length (with equalizer
pathological)
270 Mbps, Belden 1694A,
0.2UI output jitter, (Note 4) 350 m
270 Mbps, Belden 8281,
0.2UI output jitter, (Note 4) 280 m
1.485 Gbps, Belden 1694A,
0.25UI output jitter, (Note 4) 140 m
1.485 Gbps, Belden 8281,
0.25UI output jitter, (Note 4) 100 m
t
r
,t
f
Output Rise Time, Fall Time 20% – 80%, (Note 4) SDO, SDO 100 220 ps
Mismatch in Rise/Fall Time (Note 4) 2 15 ps
t
OS
Output Overshoot (Note 4) 1 5 %
R
OUT
Output Resistance single-ended, (Note 5) 50 Ω
RL
IN
Input Return Loss (Note 8) SDI, SDI 15 18-20 dB
R
IN
Input Resistance single-ended 1.3 kΩ
C
IN
Input Capacitance single-ended, (Note 5) 1 pF
Note 1: "Absolute Maximum Ratings" are those parameter values beyond which the life and operation of the device cannot be guaranteed. The stating herein of
these maximums shall not be construed to imply that the device can or should be operated at or beyond these values. The table of "Electrical Characteristics"
specifies acceptable device operating conditions.
Note 2: Current flow into device pins is defined as positive. Current flow out of device pins is defined as negative. All voltages are stated referenced to VEE = 0 Volts.
Note 3: Typical values are stated for VCC = +3.3V and TA= +25˚C.
Note 4: Specification is guaranteed by characterization.
Note 5: Specification is guaranteed by design.
Note 6: The maximum input voltage swing assumes a nonstressing, DC-balance signal; specifically, the SMPTE-recommended color bar test signal. Pathological
or other stressing signals may not be used. This specification is for 0m cable only.
Note 7: Supply current depends on the amount of cable being equalized. The current is highest for short cable and decreases as the cable length is increased. Refer
to Figures 1, 2.
Note 8: Input return loss is dependent on board design. The LMH0044 meets this specification on the SD044 evaluation board from 5MHz to 1.5GHz.
LMH0044
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Connection Diagram
20177003
16-Pin LLP
Order Number LMH0044SQ
See NS Package Number SQB16A
Pin Descriptions
Pin # Name Description
1V
EE
Negative power supply (ground).
2 SDI Serial data true input.
3 SDI Serial data complement input.
4V
EE
Negative power supply (ground).
5 AEC+ AEC loop filter external capacitor (1µF) positive connection.
6 AEC- AEC loop filter external capacitor (1µF) negative connection.
7 BYPASS Bypasses equalization and DC restoration when high. No equalization occurs in this mode.
8 MUTE
REF
Mute reference. Sets the threshold for CD and (with CD tied to MUTE) determines the
maximum cable to be equalized before muting. MUTE
REF
may be unconnected for maximum
equalization.
9V
EE
Negative power supply (ground).
10 SDO Serial data complement output.
11 SDO Serial data true output.
12 V
EE
Negative power supply (ground).
13 V
CC
Positive power supply (+3.3V).
14 MUTE Output mute. To disable the mute function and enable the output, MUTE must be tied to GND
or a low level signal. To force the outputs to a muted state, tie to V
CC
. CD may be tied to this
pin to inhibit the output when no input signal is present. MUTE has no function in BYPASS
mode.
15 CD Carrier detect. CD is high when no signal is present. CD has no function in BYPASS mode.
16 V
CC
Positive power supply (+3.3V).
LMH0044
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Block Diagram
20177002
Device Operation
BLOCK DESCRIPTION
The Equalizer Filter block is a multi-stage adaptive filter. If
Bypass is high, the equalizer filter is disabled.
The DC Restoration / Level Control block receives the
differential signals from the equalizer filter block. This block
incorporates a self-biasing DC restoration circuit to fully DC
restore the signals. If Bypass is high, this function is dis-
abled.
The signals before and after the DC Restoration / Level
Control block are used to generate the Automatic Equal-
ization Control (AEC) signal. This control signal sets the
gain and bandwidth of the equalizer filter. The loop response
in the AEC block is controlled by an external 1µF capacitor
placed across the AEC+ and AEC- pins.
The Carrier Detect / Mute block generates the carrier detect
signal and controls the mute function of the output. This
block utilizes the CD and MUTE signals along with Mute
Reference (MUTE
REF
).
The Output Driver produces SDO and SDO.
MUTE REFERENCE (MUTE
REF
)
The mute reference sets the threshold for CD and (with CD
tied to MUTE) determines the amount of cable to equalize
before automatically muting the outputs. This is set by ap-
plying a voltage inversely proportional to the length of cable
to equalize. As the applied MUTE
REF
voltage is increased,
the amount of cable that can be equalized before carrier
detect is de-asserted and the outputs are muted is de-
creased. MUTE
REF
may be left unconnected for maximum
equalization before muting.
CARRIER DETECT (CD) AND MUTE
Carrier detect CD indicates if a valid signal is present at the
LMH0044 input. If MUTE
REF
is used, the carrier detect
threshold will be altered accordingly. CD provides a high
voltage when no signal is present at the LMH0044 input. CD
is low when a valid input signal is detected.
MUTE can be used to manually mute or enable SDO and
SDO. Applying a high input to MUTE will mute the LMH0044
outputs. Applying a low input will force the outputs to be
active.
CD and MUTE may be tied together to automatically mute
the output when no input signal is present.
INPUT INTERFACING
The LMH0044 accepts either differential or single-ended
input. The input must be AC coupled. Transformer coupling
is not supported.
The LMH0044 correctly handles equalizer pathological sig-
nals for standard definition and high definition serial digital
video, as described in SMPTE RP 178 and RP 198, respec-
tively.
OUTPUT INTERFACING
The SDO and SDO outputs are internally loaded with 50Ω.
They produce a 750 mV
P-P
differential output, or a
375 mV
P-P
single-ended output.
LMH0044
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Application Information
PCB LAYOUT RECOMMENDATIONS
Please refer to the following Application Note on National’s
website: AN-1372, “CLC034 PCB Layout Techniques.”
The PCB layout techniques in the application note apply to
the LMH0044 as well.
REPLACING THE GENNUM GS1574A
The LMH0044 is footprint compatible with the Gennum
GS1574A.
SUPPLY CURRENT VS. CABLE LENGTH
The supply current (I
CC
) depends on the amount of cable
being equalized. The current is highest for short cable and
decreases as the cable length is increased. Figure 1 shows
supply current vs. Belden 1694A cable length for 1.485 Gbps
data and Figure 2 shows supply current vs. Belden 1694A
cable length for 270 Mbps data.
20177013
FIGURE 1. Supply Current vs. Belden 1694A Cable
Length, 1.485 Gbps
20177015
FIGURE 2. Supply Current vs. Belden 1694A Cable
Length, 270 Mbps
LMH0044
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Physical Dimensions inches (millimeters) unless otherwise noted
16-Pin LLP
Order Number LMH0044SQ
NS Package Number SQB16A
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
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WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR
CORPORATION. As used herein:
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which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform when
properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result
in a significant injury to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
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LMH0044 SMPTE 292M / 259M Adaptive Cable Equalizer
