DS125BR800 Datasheet, PDF (48/59 Pages) Texas Instruments – Low-Power 12.5-Gbps 8-Channel Repeater With Input Equalization and Output De-Emphasis

DS125BR800
SNLS426E – AUGUST 2012 – REVISED JANUARY 2015
10 Power Supply Recommendations
www.ti.com
10.1 3.3-V or 2.5-V Supply Mode Operation
The DS125BR800 has an optional internal voltage regulator to provide the 2.5-V supply to the device. In 3.3-V
mode operation, the VIN pin = 3.3 V is used to supply power to the device. The internal regulator will provide the
2.5 V to the VDD pins of the device and a 0.1-µF cap is needed at each of the 5 VDD pins for power supply de-
coupling (total capacitance should be ≤0.5 µF), and the VDD pins should be left open. The VDD_SEL pin must
be tied to GND to enable the internal regulator. In 2.5-V mode operation, the VIN pin should be left open and 2.5-
V supply must be applied to the 5 VDD pins to power the device. The VDD_SEL pin must be left open (no
connect) to disable the internal regulator.
The DS125BR800 has an optional internal voltage regulator to provide the 2.5 V supply to the device. In 3.3-V
Mode operation, the VIN pin = 3.3 V is used to supply power to the device. The internal regulator will provide the
2.5 V to the VDD pins of the device and a 0.1-µF cap is needed at each of the 5 VDD pins for power supply
decoupling (total capacitance should be ≤0.5 µF), and the VDD pins should be left open. The VDD_SEL pin must
be tied to GND to enable the internal regulator. In 2.5-V Mode operation, the VIN pin should be left open and 2.5-
V supply must be applied to the 5 VDD pins to power the device. The VDD_SEL pin must be left open (no
connect) to disable the internal regulator.
3.3-V mode
2.5-V mode
Enable
VDD_SEL
Internal
voltage
regulator
2.5V
VIN
VDD
VDD
VDD
3.3 V
Capacitors can be
either tantalum or an
ultra-low ESR ceramic.
0.1 uF
0.1 uF
0.1 uF
Disable
VDD_SEL
open
Internal
voltage
regulator
VIN
open
VDD
0.1 uF
2.5 V
VDD
VDD
0.1 uF
Capacitors can be
either tantalum or an
ultra-low ESR ceramic.
0.1 uF
VDD
0.1 uF
VDD
0.1 uF
VDD
0.1 uF
VDD
0.1 uF
Place 0.1 uF close to VDD Pin
Total capacitance should be ~ 0.5 uF
Place capcitors close to VDD Pin
Figure 26. 3.3-V or 2.5-V Supply Connection Diagram
48
Submit Documentation Feedback
Copyright © 2012–2015, Texas Instruments Incorporated
Product Folder Links: DS125BR800