Pcb Design Requirements; Power Conditioning; Voltage Regulation; Figure 4-6: Power Supply Circuit Using Lt1963 Regulator - Xilinx RocketIO User Manual

PCB Design Requirements

PCB Design Requirements
In order to ensure reliable operation of the RocketIO transceivers, certain requirements
must be met by the designer. This section outlines these requirements governing power
filtering networks, high-speed differential signal traces, and reference clocks. Any designs
that do not adhere to these requirements will not be supported by Xilinx, Inc.

Power Conditioning

Each RocketIO transceiver has five power supply pins, all of which are sensitive to noise.
Table
requirements.
To operate properly, the RocketIO transceiver requires a certain level of noise isolation
from surrounding noise sources. For this reason, it is required that both dedicated voltage
regulators and passive high-frequency filtering be used to power the RocketIO circuitry.

Table 4-5: Transceiver Power Supplies

Voltage Regulation

The transceiver voltage regulator circuits must not be shared with any other supplies
(including FPGA supplies V
shared among transceiver power supplies of the same voltage; however, each supply pin
must still have its own separate passive filtering network.
2
V > 3VDC
IN
IN
1
SHDN
5
+
SENSE
10µF
GNDA
0.1µF
The required voltage regulator is the Linear Technology LT1963 device. This regulator
must be used in the circuit specified by the manufacturer.
UG024 (v1.5) October 16, 2002
RocketIO™ Transceiver User Guide
4-5, summarizes the power supply pins, their names, associated voltages, and power
Supply 2.5V
AVCCAUXRX
AVCCAUXTX
VTRX
VTTX
GNDA
Notes:
1. Power at max data rate. Power figures shown do not include power requirements of V
(28 mW) and V (48 mW), which power the PCS and PMA respectively.
CCAUX
2. Dependent on voltage level and whether AC or DC coupling is used. These numbers are based
on AC coupling with 2.5V V
4
OUT
3
GND
+
TAB
LT1963

Figure 4-6: Power Supply Circuit Using LT1963 Regulator

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1.8V - Power
2.625V (mW)
X 90
X 130
(2)
X 27
(2)
X 27
N/A
and V .
TTX TRX
, V , V , and V
CCINT CCO CCAUX
1µF 1µF 1µF 1µF
100µF
1-800-255-7778
(1)
Description
Analog RX supply
Analog TX supply
RX termination supply
TX termination supply
Analog ground for transmit and
receive analog supplies
). Voltage regulators may be
REF
1µF 1µF 1µF 1µF 1µF
UG024_026_050302
Figure 4-6 shows the schematic
R
CCINT
2.5V@1.5A
1µF
GNDA
89