10 k:

SDI

SDI

VCC

10 k:

5 k:

80:

VCC

10 k:

LMH0002

www.ti.com

SNLS215E – JANUARY 2006 – REVISED APRIL 2013

APPLICATION INFORMATION

Device Operation

INPUT INTERFACING

The LMH0002 accepts either differential or single-ended input. The inputs are self-biased, allowing for simple AC

or DC coupling. DC-coupled inputs must be kept within the specified common-mode range. SDI and SDI are self-

biased at approximately 2.1V with VCC = 3.3V. Figure 3 shows the differential input stage for SDI and SDI.

Figure 3. Differential Input Stage for SDI and SDI.

OUTPUT INTERFACING

The LMH0002 uses current mode outputs. Single-ended output levels are 800 mVP-P into 75Ω AC-coupled

coaxial cable (with RREF = 750Ω). Output level is controlled by the value of the RREF resistor connected between

the RREF pin and VCC.

The RREF resistor should be placed as close as possible to the RREF pin. In addition, the copper in the plane

layers below the RREF network should be removed to minimize parasitic capacitance.

OUTPUT SLEW RATE CONTROL

The LMH0002 output rise and fall times are selectable for either SMPTE 259M or SMPTE 292M compliance via

the SD/HD pin. For slower rise and fall times, or SMPTE 259M compliance, SD/HD is set high. For faster rise

and fall times, or SMPTE 292M compliance, SD/HD is set low.

REPLACING THE GENNUM GS1528, GS1528A, and GS1578A

The LMH0002MA is form-fit-function compatible with the Gennum GS1528 and GS1528A. The LMH0002SQ is

form-fit-function compatible with the Gennum GS1578A.

Copyright © 2006–2013, Texas Instruments Incorporated

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