LMH0394_15 Datasheet, PDF (23/35 Pages) Texas Instruments – 3G HD/SD SDI Low Power Extended Reach Adaptive Cable Equalizer

www.ti.com
LMH0394
SNLS312M – AUGUST 2010 – REVISED JULY 2015
8.2 Typical Application
Figure 17 shows the application circuit for the LMH0394 in SPI mode. (Note: The application circuit shows an
external capacitor connected between the AEC+ and AEC- pins as commonly configured in legacy equalizers.
This capacitor is optional and not necessary for the LMH0394; the AEC+ and AEC- pins may be left unconnected
with no change in performance.)
(SPI) MISO
(SPI) SCK
(SPI) MOSI
V_CC
V_CC
0.1 PF
0.1 PF
Coaxial Cable
75:
5.6 nH
75:
1.0 PF
1.0 PF
V_CC
37.4:
1 _VEE
2
SDI
3
SDI
4 _{SPI_EN}
LMH0394
12
MISO
11
SDO
10
SDO
9
SS
Differential
Output
DAP
CD
MUTE_REF
(SPI) SS
1.0 PF
Figure 17. Application Circuit (SPI Mode)
8.2.1 Design Requirements
Table 2 lists the design parameters for the LMH0394.
Table 2. LMH0394 Design Parameters
DESIGN PARAMETER
Input AC coupling capacitors
Distance from Device to BNC
High-Speed SDI, and SDI trace
impedance
High-Speed SDO, and SDO
trace impedance
DC Power Supply Coupling
Capacitors
REQUIREMENT
Required. A common type of AC
coupling capacitor is 1-µF ± 10%
X7R ceramic capacitor (0402 or
0201 size). Capacitors may be
implemented on the PCB or in the
connector.
Keep this distance as short as
possible.
Design single-ended trace
impedance with 75 Ω ± 5%
Design differential trace impedance
with 100 Ω ± 5%
To minimize power supply noise, use
0.01-µF capacitors as close to the
device VDD pins as possible
Copyright © 2010–2015, Texas Instruments Incorporated
Product Folder Links: LMH0394
Submit Documentation Feedback
23