LMH0024MAE скачать даташит

LMH0024MAE скачать даташит
LMH0024
3.3V SMPTE 259M / 344M Adaptive Cable Equalizer
General Description
Features
The LMH0024 SMPTE 259M / 344M adaptive cable equalizer
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 125 Mbps to 540 Mbps and supports SMPTE
259M and SMPTE 344M.
The LMH0024 implements DC restoration to correctly handle
pathological data conditions. DC restoration can be bypassed
for low data rate applications. The equalizer is flexible in allowing either single-ended or differential input drive.
Additional features include a mute pin which can be used to
manually mute the output and a cable length indicator which
determines the amount of cable being equalized.
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SMPTE 259M and SMPTE 344M compliant
Supports DVB-ASI at 270 Mbps
Data rates: 125 Mbps to 540 Mbps
Equalizes up to 350 meters of Belden 1694A at 270 Mbps
Manual bypass, cable length indicator, and output mute
Single-ended or differential input
50Ω differential outputs
Single 3.3V supply operation
Industrial temperature range: −40°C to +85°C
198 mW typical power consumption with 3.3V supply
Footprint compatible with the LMH0034 and the GS9064
Applications
■ SMPTE 259M and SMPTE 344M serial digital interfaces
■ Serial digital data equalization and reception
■ Data recovery equalization
Typical Application
20172501
© 2011 National Semiconductor Corporation
201725
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LMH0024 3.3V SMPTE 259M / 344M Adaptive Cable Equalizer
May 16, 2011
LMH0024
Absolute Maximum Ratings (Note 1)
Supply Voltage
Input Voltage (all inputs)
Storage Temperature Range
Junction Temperature
Lead Temperature
(Soldering 4 Sec)
Package Thermal Resistance
θJA 16-pin SOIC
θJC 16-pin SOIC
ESD Rating (HBM)
ESD Rating (MM)
Recommended Operating
Conditions
−0.5V to 3.6V
−0.3V to VCC+0.3V
−65°C to +150°C
+150°C
Supply Voltage (VCC – VEE)
Input Coupling Capacitance
AEC Capacitor (Connected between
AEC+ and AEC-)
Operating Free Air Temperature (TA)
+260°C
3.3V ±5%
1.0 µF
1.0 µF
−40°C to +85°C
+115°C/W
+105°C/W
8 kV
250V
DC Electrical Characteristics
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 2, Note 3).
Symbol Parameter
Conditions
VCMIN
Input Common Mode Voltage
VSDI
Input Voltage Swing
VCMOUT
Output Common Mode Voltage
VSDO
Output Voltage Swing
50Ω load, differential
CLI DC Voltage
0m cable, (Note 7)
Reference
Min
SDI, SDI
At LMH0024 input, (Note 4,
Note 6)
720
SDO, SDO
CLI
Min to mute outputs
MUTE
800
Supply Current
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(Note 8)
V
950
mVP−P
V
750
mVP-P
2.5
V
2.0
V
3.0
V
60
2
Units
VCC –
VSDO/2
Max to force outputs active
ICC
Max
1.9
Max cable, (Note 7)
MUTE Input Voltage
Typ
2.0
V
77
mA
LMH0024
AC Electrical Characteristics
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3).
Symbol Parameter
BRMIN
Minimum Input Data Rate
BRMAX
Maximum Input Data Rate
Maximum Equalized Cable
Length (with equalizer
pathological)
tr,tf
Conditions
Reference
Min
SDI, SDI
Typ
Max
125
Units
Mbps
540
Mbps
270 Mbps, Belden 1694A,
0.2UI output jitter, (Note 4)
350
m
270 Mbps, Belden 8281,
0.2UI output jitter, (Note 4)
280
m
540 Mbps, Belden 1694A,
0.2UI output jitter, (Note 4)
250
m
540 Mbps, Belden 8281,
0.2UI output jitter, (Note 4)
180
m
Output Rise Time, Fall Time
20% – 80%, (Note 4)
Mismatch in Rise/Fall Time
(Note 4)
tOS
Output Overshoot
ROUT
Output Resistance
RLIN
Input Return Loss
(Note 9)
RIN
Input Resistance
single-ended
CIN
Input Capacitance
single-ended, (Note 5)
SDO, SDO
100
220
ps
2
15
ps
(Note 4)
1
5
%
single-ended, (Note 5)
50
Ω
18-20
dB
1.3
kΩ
1
pF
SDI, SDI
15
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: Input signal must be present for valid CLI. Refer to Figure 1 for typical results.
Note 8: 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 Figure 2.
Note 9: Input return loss is dependent on board design. The LMH0024 meets this specification on the SD024 evaluation board from 5MHz to 1.5GHz.
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LMH0024
Connection Diagram
20172503
16-Pin SOIC
Order Number LMH0024MA
See NS Package Number M16A
Pin Descriptions
Pin #
Name
Description
1
CLI
Cable length indicator. Provides a voltage inversely proportional to the cable length being
equalized.
2
VCC
Positive power supply (+3.3V).
3
VEE
Negative power supply (ground).
4
SDI
Serial data true input.
5
SDI
Serial data complement input.
6
VEE
Negative power supply (ground).
7
AEC+
AEC loop filter external capacitor (1µF) positive connection.
8
AEC-
AEC loop filter external capacitor (1µF) negative connection.
9
BYPASS
Bypasses equalization and DC restoration when high. No equalization occurs in this mode.
10
NC
No connect.
11
VEE
Negative power supply (ground).
12
SDO
Serial data complement output.
13
SDO
Serial data true output.
14
VEE
Negative power supply (ground).
15
VCC
Positive power supply (+3.3V).
16
MUTE
Output mute. To force SDO and SDO to mute, tie to VCC. To disable MUTE, tie to GND. Typical
application is MUTE tied to GND to enable the outputs. MUTE must be tied either high or low; it
may not be left unconnected.
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4
LMH0024
Block Diagram
20172502
Device Operation
2.6
2.5
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 disabled.
The signals before and after the DC Restoration / Level Control block are used to generate the Automatic Equalization
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. Cable Length Indicator
(CLI) is derived from this block.
The Output Driver produces SDO and SDO. SDO and
SDO may be forced to mute by activating MUTE.
CLI (V)
2.4
2.3
2.2
2.1
2.0
1.9
1.8
0
50 100 150 200 250 300 350
BELDEN 1694A CABLE LENGTH (m)
20172504
FIGURE 1. CLI vs. Belden 1694A Cable Length
CABLE LENGTH INDICATOR (CLI)
The cable length indicator provides a voltage to indicate the
length of cable being equalized. The CLI voltage decreases
as the cable length increases. Figure 1 shows the typical CLI
voltage vs. Belden 1694A cable length. Note: CLI is only valid
when an input signal is present.
MUTE
MUTE can be used to manually mute or enable the LMH0024
outputs. MUTE must be tied to a low-level input or ground for
SDO and SDO to be active. Applying a high input to MUTE
will mute the LMH0024 outputs.
INPUT INTERFACING
The LMH0024 accepts either differential or single-ended input. The input must be AC coupled. Transformer coupling is
not supported.
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LMH0024
The LMH0024 correctly handles equalizer pathological signals for standard definition serial digital video, as described
in SMPTE RP 178.
supply current vs. Belden 1694A cable length for 270 Mbps
data.
OUTPUT INTERFACING
The SDO and SDO outputs are internally loaded with 50Ω.
They produce a 750 mVP-P differential output, or a
375 mVP-P single-ended output.
Application Information
PCB LAYOUT RECOMMENDATIONS
Please refer to the following Application Note for the CLC034
on National's website: AN-1372, “LMH0034 PCB Layout
Techniques.” The PCB layout techniques in this application
note apply to the LMH0024 as well.
REPLACING THE GENNUM GS9064
The LMH0024 is footprint compatible with the Gennum
GS9064. Pin 16 (MUTE) of the LMH0024 must be connect to
ground for correct operation.
20172515
SUPPLY CURRENT VS. CABLE LENGTH
The supply current (ICC) depends on the amount of cable being equalized. The current is highest for short cable and
decreases as the cable length is increased. Figure 2 shows
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FIGURE 2. Supply Current vs. Belden 1694A Cable
Length, 270 Mbps
6
LMH0024
Physical Dimensions inches (millimeters) unless otherwise noted
16-Pin SOIC
Order Number LMH0024MA
NS Package Number M16A
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LMH0024 3.3V SMPTE 259M / 344M Adaptive Cable Equalizer
Notes
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