si5318 ETC-unknow, si5318 Datasheet - Page 18

• Manufacturer Part Number: si5318
• Description: Sonet/sdh Precision Clock Multiplier
• Manufacturer: ETC-unknow

Si5318
The regulator’s compensation circuit is in reality a
resistor and a capacitor in series between the V
node and ground. (See Figure 5 on page 13.) Typically,
the resistor is incorporated into the capacitor’s
equivalent series resistance (ESR). The target RC time
constant for this combination is 15 to 50 µs. The
capacitor used in the Si5318 evaluation board is a
33 µF tantalum capacitor with an ESR of 0.8 Ω. This
gives an RC time constant of 26.4 µs. The Venkel part
number, TA6R3TCR336KBR, is an example of a
capacitor that meets these specs.
18
2100
V
n
42
( µ V/ √ Hz)
10 kHz
Figure 10. Power Supply Noise Tolerance Mask
500 kHz
DD25
Rev. 1.0
To get optimal performance from the Si5318 device, the
power supply noise spectrum must comply with the plot
in Figure 10. This plot shows the power supply noise
tolerance mask for the Si5318. The customer should
provide a 3.3 V supply that does not have noise density
in excess of the amount shown in the diagram.
However, the diagram cannot be used as spur criteria
for a power supply that contains single tone noise.
100 MHz
f