LMH0346 Datasheet, PDF (14/23 Pages) Texas Instruments – HD/SD SDI Reclocker with Dual Differential Outputs

LMH0346
SNLS248J – APRIL 2007 – REVISED APRIL 2013
APPLICATION INFORMATION
www.ti.com
Figure 6 shows an application circuit for the LMH0346 along with the LMH0344 3 Gbps HD/SD SDI Adaptive
Cable Equalizer and LMH0302 3 Gbps HD/SD SDI Cable Driver.
V_CC
V_CC
RATE0
RATE1
56 nF
SCO_EN
Coaxial Cable
75:
6.8 nH
LMH0344 Adaptive
Cable Equalizer
1.0 PF
SDI SDO
1.0 PF
100:
SDI SDO
75:
37.4:
1
LF1
20
SCO_EN
2
19
3 ^LF2
SD/HD
18
4 ^RATE0
V_{CCO 17}
RATE1
SDO
5
16
6 ^{SDI LMH0346 SDO} 15
SDI
7
V_{CCO 14}
8 ^VCC
SCO/SDO2
13
9 ^{BP/ AUTO-BP}
SCO/SDO2
12
OP MUTE
LOCK DET
10 _{XTAL IN/EXT CLK XTAL OUT} 11
DAP
A
B
C
Additional
Outputs
1.0 PF
27 MHz
BP/ AUTO-BP
OP MUTE
39 pF
39 pF
LOCK DET
+3.3V
A
75:
LMH0302
Cable Driver
75:
5.6 nH
SD/HD
75:
4.7 PF ^{Coaxial Cable}
B
SDI
SDO
100:
SDO
C
SDI
75:
4.7 PF ^{Coaxial Cable}
75:
R_REF
75:
+3.3V
5.6 nH
750:
Figure 6. Application Circuit
The LMH0346 inputs are LVPECL compatible. The LMH0346 has a wide input common mode range and in most
cases the input should be DC coupled. For DC coupling, the inputs must be kept within the common mode range
specified in DC ELECTRICAL CHARACTERISTICS. Figure 6 shows an example of a DC coupled interface
between the LMH0344 cable equalizer and the LMH0346. The LMH0344 output common mode voltage and
voltage swing are within the range of the input common mode voltage and voltage swing of the LMH0346. All
that is required is a 100Ω differential termination as shown. The resistor should be placed as close to the
LMH0346 input as possible. If desired, this network may be terminated with two 50Ω resisters and a center tap
capacitor to ground in place of the single 100Ω resistor.
14
Submit Documentation Feedback
Product Folder Links: LMH0346
Copyright © 2007–2013, Texas Instruments Incorporated