LMH0034MANOPB - NATIONAL SEMICONDUCTOR

LMH0034

February 28, 2012

SMPTE 292M / 259M Adaptive Cable Equalizer

General Description

The LMH0034 SMPTE 292M / 259M adaptive cable equalizer

is a monolithic integrated circuit for equalizing data transmit-

ted over cable (or any media with similar dispersive loss

characteristics). The equalizer operates over a wide range of

data rates from 125 Mbps to 1.485 Gbps and supports

SMPTE 292M, SMPTE 344M and SMPTE 259M.

The LMH0034 implements DC restoration to correctly handle

pathological data conditions. DC restoration can be bypassed

for low data rate applications. The equalizer is flexible in al-

lowing either single-ended or differential input drive.

Additional features include a combined carrier detect and out-

put mute pin which mutes the output when no signal is

present. A programmable mute reference is used to mute the

output at a selectable level of signal degradation. A cable

length indicator is provided to determine the amount of cable

being equalized.

Features

■SMPTE 292M, SMPTE 344M and SMPTE 259M

compliant

■Supports DVB-ASI at 270 Mbps

■Data rates: 125 Mbps to 1.485 Gbps

■Equalizes up to 200 meters of Belden 1694A at 1.485

Gbps or up to 400 meters of Belden 1694A at 270 Mbps

■Manual bypass, cable length indicator, and output mute

with a programmable threshold

■Single-ended or differential input

■50Ω differential outputs

■Single 3.3V supply operation

■208 mW typical power consumption with 3.3V supply

■Replaces the GS1524 and GS1524A

Applications

■SMPTE 292M, SMPTE 344M, and SMPTE 259M serial

digital interfaces

■Serial digital data equalization and reception

■Data recovery equalization

Typical Application

20173401

LMH0034 SMPTE 292M / 259M Adaptive Cable Equalizer

Absolute Maximum Ratings (Note 1)

Supply Voltage −0.5V to 3.6V

Input Voltage (all inputs) −0.3V to VCC+0.3V

Storage Temperature Range −65°C to +150°C

Junction Temperature +150°C

Lead Temperature

(Soldering 4 Sec) +260°C

Package Thermal Resistance

θJA 16-pin SOIC

θJC 16-pin SOIC

+115°C/W

+105°C/W

ESD Rating (HBM) 8 kV

ESD Rating (MM) 250V

Recommended Operating

Conditions

Supply Voltage (VCC – VEE) 3.3V ±5%

Input Coupling Capacitance 1.0 µF

AEC Capacitor (Connected between

AEC+ and AEC-) 1.0 µF

Operating Free Air Temperature (TA) 0°C to +85°C

DC Electrical Characteristics

Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 2, Note 3).

Symbol Parameter Conditions Reference Min Typ Max Units

VCMIN Input Common Mode Voltage SDI, SDI 1.9 V

VSDI Input Voltage Swing At LMH0034 input, (Note 4,

Note 6)720 800 950 mVP−P

VCMOUT Output Common Mode Voltage SDO, SDO VCC –

VSDO/2 V

VSDO Output Voltage Swing 50Ω load, differential 750 mVP-P

CLI DC Voltage 0m cable, (Note 7) CLI 2.5 V

Max cable, (Note 7) 1.9 V

MUTEREF DC Voltage (floating) MUTEREF 1.3 V

MUTEREF Range 0.7 V

CD/MUTE Output Voltage Carrier not present CD/MUTE 2.6 V

Carrier present 0.4 V

CD/MUTE Input Voltage Min to mute outputs 3.0 V

Max to force outputs active 2.0 V

ICC Supply Current (Note 8) 63 77 mA

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LMH0034

AC Electrical Characteristics

Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3).

Symbol Parameter Conditions Reference Min Typ Max Units

BRMIN Minimum Input Data Rate SDI, SDI 125 Mbps

BRMAX Maximum Input Data Rate 1485 Mbps

Jitter for various cable lengths

(with equalizer pathological)

270 Mbps, Belden 1694A,

400 meters (Note 4)

0.2 UI

270 Mbps, Belden 8281,

280 meters (Note 4) 0.2 UI

1.485 Gbps, Belden 1694A,

140 meters (Note 4) 0.25 UI

1.485 Gbps, Belden 8281,

100 meters (Note 4) 0.25 UI

1.485 Gbps, Belden 1694A,

200 meters (Note 4) 0.3

tr,tfOutput Rise Time, Fall Time 20% – 80%, (Note 4) SDO, SDO 100 220 ps

Mismatch in Rise/Fall Time (Note 4) 2 15 ps

tOS Output Overshoot (Note 4) 1 5 %

ROUT Output Resistance single-ended, (Note 5) 50 Ω

RLIN Input Return Loss (Note 9) SDI, SDI 15 18-20 dB

RIN Input Resistance single-ended 1.3 kΩ

CIN 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: 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 Figures 2, 3.

Note 9: Input return loss is dependent on board design. The LMH0034 meets this specification on the SD034 evaluation board from 5MHz to 1.5GHz.

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LMH0034

Connection Diagram

20173403

16-Pin SOIC

Order Number LMH0034MA

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 MUTEREF Mute reference. Determines the maximum cable to be equalized before muting. May be

unconnected for maximum equalization.

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 CD/MUTE Bi-directional carrier detect and output mute. CD/MUTE is high when no signal is present. If

unconnected, MUTE is controlled automatically by carrier detect. To force MUTE on, tie to VCC. To

disable MUTE, tie to GND. CD/MUTE has no function in BYPASS mode.

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LMH0034

Block Diagram

20173402

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 dif-

ferential 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 Con-

trol 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 Carrier Detect / Mute block generates the carrier detect

signal and controls the mute function of the output. This block

utilizes the bi-directional CD/MUTE signal along with Mute

Reference (MUTEREF).

The Output Driver produces SDO and SDO.

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.

0 50 100 150 200 250 300 350 400

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

CLI (V)

BELDEN 1694A CABLE LENGTH (m)

20173404

FIGURE 1. CLI vs. Belden 1694A Cable Length

MUTE REFERENCE (MUTEREF)

The mute reference determines the amount of cable to equal-

ize before automatically muting the outputs. This is set by

applying a voltage inversely proportional to the length of cable

to equalize. As the applied MUTEREF voltage is increased, the

amount of cable that can be equalized before carrier detect is

de-asserted and the outputs are muted is decreased.

MUTEREF may be left unconnected for maximum equalization

before muting.

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LMH0034

CARRIER DETECT / MUTE (CD/MUTE)

Carrier Detect / Mute is bi-directional, serving as both a carrier

detect (output function) and mute (input function).

When used as an output, CD/MUTE determines if a valid sig-

nal is present at the LMH0034 input. If MUTEREF is used, the

carrier detect threshold will be altered accordingly.

CD/MUTE provides a high voltage when no signal is present

at the LMH0034 input, and the outputs are automatically mut-

ed. CD/MUTE is low when a valid input signal has been

detected, and the outputs are automatically enabled.

As an input, CD/MUTE can be used to override the carrier

detect and manually mute or enable the LMH0034 outputs.

Applying a high input to CD/MUTE will mute the LMH0034

outputs. Applying a low input will force the outputs to be active

regardless of the length of cable or the state of MUTEREF.

INPUT INTERFACING

The LMH0034 accepts either differential or single-ended in-

put. The input must be AC coupled. Transformer coupling is

not supported.

The LMH0034 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 mVP-P differential output, or a

375 mVP-P single-ended output.

Application Information

PCB LAYOUT RECOMMENDATIONS

Please refer to the following Application Note: AN-1372,

“LMH0034 PCB Layout Techniques.”

REPLACING THE GENNUM GS1524

The LMH0034 is form-fit-function compatible with the Gen-

num GS1524 and GS1524A.

SUPPLY CURRENT VS. CABLE LENGTH

The supply current (ICC) depends on the amount of cable be-

ing equalized. The current is highest for short cable and

decreases as the cable length is increased. Figure 2 shows

supply current vs. Belden 1694A cable length for 1.485 Gbps

data and Figure 3 shows supply current vs. Belden 1694A

cable length for 270 Mbps data.

20173413

FIGURE 2. Supply Current vs. Belden 1694A Cable

Length, 1.485 Gbps

20173415

FIGURE 3. Supply Current vs. Belden 1694A Cable

Length, 270 Mbps

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LMH0034

Physical Dimensions inches (millimeters) unless otherwise noted

16-Pin SOIC

Order Number LMH0034MA

Package Number M16A

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LMH0034

Notes

LMH0034 SMPTE 292M / 259M Adaptive Cable Equalizer

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