LMH0324
ZHCSIC8B –APRIL 2016–REVISED JUNE 2018
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9 Power Supply Recommendations
The LMH0324 is designed to provide flexibility in supply rails. There are two ways to power the LMH0324:
•
Single 2.5 V Supply Mode: This mode offers ease of use and pin compatibility with the LMH1219 (11.88
Gbps Ultra-HD Adaptive Cable Equalizer with Integrated Reclocker). The internal circuitry receives power
from the on-chip 1.8 V regulator. In this mode, 2.5 V is applied to VIN, VDDIO, and RSV_L. This mode
supports SPI or SMBus serial interface. See 图 24 for more details.
•
Single 1.8 V Supply Mode: This mode provides the lowest power consumption. In this mode, 1.8 V is
connected to VIN, VDD_LDO and VDDIO. RSV_L is tied to VSS. In this mode, SPI is supported, but SMBus
serial interface is not. In Single 1.8 V Supply Mode, the LMH0324 is not drop-in compatible with the
LMH1219. See 图 25 for more details.
2.5 V
1 µF
10 µF
0.1 µF
0.1 µF
0.1 µF
RSV_L
VDDIO
VIN
Internal LDO
2.5 V to 1.8 V
EP
VSS
VSS
VSS
VDD_LDO (1.8 V)
1 µF
0.1 µF
图 24. Single 2.5 V Supply Mode - Compatible with LMH1219
1.8 V
0.1 µF
10 µF
1.8 V
1 µF
0.1 µF
RSV_L
VDDIO
VIN
VDD_LDO
EP
VSS
VSS
VSS
1 µF
0.1 µF
图 25. Single 1.8 V Supply Mode - Not Compatible with LMH1219
For power supply de-coupling, 0.1-μF surface-mount ceramic capacitors are recommended to be placed close to
each supply pin to VSS. Larger bulk capacitors (for example, 10 µF and 1 µF) are recommended to be placed
close to each LMH0324 device. Good supply bypassing requires low inductance capacitors. This can be
achieved through an array of multiple small body size surface-mount bypass capacitors in order to keep low
supply impedance. Better results can be achieved through the use of a buried capacitor formed by a VDD and
VSS plane separated by 2-4 mil dielectric in a printed circuit board.
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