MOTOROLA
Chapter 5. System Design Considerations
5-7
Power Supply Requirements
5.7
Power Supply Requirements
The recommended board for the MC92603 has a minimum of two solid planes of 1-ounce
copper. One plane is to be used as a ground plane and the second plane is to be used for the
1.8-V supply. It is recommended that the board has its own 1.8- and 3.3-V regulators with
less than 50-mV ripple.
5.8
Phase-Locked Loop (PLL) Power Supply Filtering
An analog power supply is required. The PLLAV
DD
signal provides power for the analog
portions of the PLL. To ensure stability of the internal clock, the power supplied to the PLL
is filtered using a circuit similar to the one shown in Figure 5-1. For maximum
effectiveness, the filter circuit is placed as close as possible to the PLLAV
DD
ball to ensure
that it filters out as much noise as possible. The ground connection should be near the
PLLAGND ball. The 0.01-
µ
F capacitor is closest to the ball, followed by the 1-
µ
F
capacitor, and finally the 1-
Ω
resistor to V
DD
on the 1.8-V power plane. The capacitors are
connected from PLLAGND to the ground plane. Ceramic chip capacitors with the highest
possible self-resonant frequency should be used. All traces should be kept short, wide, and
direct.
Figure 5-1. PLL Power Supply Filter Circuits
WSYNC0
Word synchronization enable
Device must be reset
TST_0, TST_1
Test mode identifiers
Must be low and remain low during normal
operation. Device must be reset if changed.
LBOE
Loopback output enable
Enable/disable transmit links during testing
(LBOE = high). No recovery action necessary,
STNDBY
Puts PLL in standby mode
Receiver must re-establish byte and word
synchronization
RESET
System reset bar
Device is reset
ENABLE_RED
Enable redundant mode
Device must be reset
Table 5-3. Asynchronous Configuration and Control Signals (continued)
Signal Name
Description
Effect of Changed State
VDD
1
Ω
0.01 µF
PLLAVDD
1.0 µF
GND
Summary of Contents for MC92603
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