IDT82V3380A Integrated Device Technology, IDT82V3380A Datasheet - Page 49

• Manufacturer Part Number: IDT82V3380A
• Description: Synchronous Ethernet Idt Wan Plltm Idt82v3380a
• Manufacturer: Integrated Device Technology

3.17
required to minimize supply noise modulation of the output clocks. The
common sources of power supply noise are switch power supplies and
the high switching noise from the outputs to the internal PLL. The
IDT82V3380A provides separate VDDA power pins for the internal ana-
log PLL, VDD_DIFF for the differential output driver circuit and VDDD
pins for the core logic as well as I/O driver circuits.
ing regulator, the power supply output should be filtering with sufficient
bulk capacity to minimize ripple and 0.1 uF (0402 case size, ceramic)
caps to filter out the switching transients.
VDD_AMI and VDDD are handled individually. VDDD, VDD_AMI,
VDD_DIFF and VDDA should be individually connected to the power
supply plane through vias, and bypass capacitors should be used for
each pin. Figure 16 illustrated how bypass capacitor and ferrite bead
should be connected to power pins.
Functional Description
IDT82V3380A
3.3V
To achieve optimum jitter performance, power supply filtering is
To minimize switching power supply noise generated by the switch-
For the IDT82V3380A, the decoupling for VDDA, VDD_DIFF,
SLF7028T-100M1R1
POWER SUPPLY FILTERING TECHNIQUES
10 µF
3.3V
SLF7028T-100M1R1
0.1 µF
10 µF
0.1 µF
Figure 16. IDT82V3380A Power Decoupling Scheme
0.1 µF
0.1 µF
0.1 µF
0.1 µF
0.1 µF
0.1 µF
0.1 µF
0.1 µF
0.1 µF
49
0.1 µF
impedance. This can be achieved by using one 10 uF (1210 case size,
ceramic) and at least four 0.1 uF (0402 case size, ceramic) capacitors in
parallel. The 0.1 uF (0402 case size, ceramic) capacitors must be
placed right next to the VDDA and VDD_DIFF pins as close as possible.
Note that the 10 uF capacitor must be of 1210 case size, and it must be
ceramic for lowest ESR (Effective Series Resistance) possible. The 0.1
uF should be of case size 0402, this offers the lowest ESL (Effective
Series Inductance) to achieve low impedance towards the high speed
range.
ceramic) and one 10 uF (1210 case size, ceramic) capacitors are rec-
ommended. The 0.1 uF capacitors should be placed as close to the
VDDD pins as possible.
0.1 µF
The analog power supply VDDA and VDD_DIFF should have low
For VDDD and VDD_AMI, at least ten 0.1 uF (0402 case size,
Please refer to evaluation board schematic for details.
VDD_DIFF
VDD_AMI
VDDD
VDDA
IDT82V 3380A
26
6, 19, 91
12, 13, 16, 50, 61, 85, 86
33, 39
SYNCHRONOUS ETHERNET WAN PLL™
11, 14, 15, 62, 84, 87
1, 5, 20, 92
32, 38
September 30, 2010
29
GND_DIFF
GND_AMI
DGND
AGND