IDT74FCT88915TT70PY IDT, Integrated Device Technology Inc, IDT74FCT88915TT70PY Datasheet - Page 7

• Manufacturer Part Number: IDT74FCT88915TT70PY
• Description: IC PLL CLK GENERATOR 28-SSOP
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: 74FCTr
• Type: Fanout Distribution, Multiplexer , Zero Delay Bufferr

Specifications of IDT74FCT88915TT70PY

• Pll: Yes with Bypass
• Input: LVTTL
• Output: LVCMOS, LVTTL
• Number Of Circuits: 1
• Ratio - Input:output: 2:8
• Differential - Input:output: No/No
• Frequency - Max: 70MHz
• Divider/multiplier: Yes/Yes
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: *
• Frequency-max: *
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 74FCT88915TT70PY

NOTES:
1. Figure 3 shows a loop filter and analog isolation scheme which will be effective in most applications. The following guidelines should be followed to ensure stable and jitter-free
2. In addition to the bypass capacitors used in the analog filter of Figure 3, there should be a 0.1µF bypass capacitor between each of the other (digital) four V
IDT74FCT88915TT
LOW SKEW PLL-BASED CMOS CLOCK DRIVER
operation:
a. All loop filter and analog isolation components should be tied as close to the package as possible. Stray current passing through the parasitics of long traces can cause undesirable
b. The 10µF low frequency bypass capacitor and the 0.1µF high frequency bypass capacitor form a wide bandwidth filter that will minimize the 88915TT's sensitivity to voltage
c. The loop filter capacitor (0.1µF) can be a ceramic chip capacitor, the same as a standard bypass capacitor.
ground plane. This will reduce output switching noise caused by the 88915TT outputs, in addition to reducing potential for noise in the "analog" section of the chip. These bypass
capacitors should also be tied as close to the 88915TT package as possible.
voltage transients at the LF pin.
transients from the system digital V
If good bypass techniques are used on a board design near components which may cause digital V
digital V
that can occur in a high frequency, high speed digital system.
CC
supply. The purpose of the bypass filtering scheme shown in Figure 3 is to give the 88915TT additional protection from the power supply and ground plane transients
10
Low
Freq.
Bypass
μ
F
Figure 3. Recommended Loop Filter and Analog Isloation Scheme for the FCT88915TT
0.1
High
Freq.
Bypass
μ
F
CC
supply and ground planes.
BOARD V
BOARD GND
0.1
Filter Cap)
CC
μ
F (Loop
A separate Analog power supply is not necessary
and should not be used. Following these pre-
scribed guidelines is all that is necessary to use
the FCT88915TT in a norm al digital environment.
7
CC
ANALOG V
ANALOG G ND
LF
and ground noise, V
Analog loop filter/VCO
section of the FCT88915TT
CC
COMMERCIAL TEMPERATURE RANGE
CC
step deviations should not occur at the 88915TT's
CC
pins and the board