ICS83905AKLF IDT, Integrated Device Technology Inc, ICS83905AKLF Datasheet - Page 12

• Manufacturer Part Number: ICS83905AKLF
• Description: IC FANOUT BUFFER 1:6 20-VFQFPN
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: HiPerClockS™r
• Type: Fanout Buffer (Distribution)r

Specifications of ICS83905AKLF

• Number Of Circuits: 1
• Ratio - Input:output: 1:6
• Differential - Input:output: No/No
• Input: Crystal
• Output: LVCMOS, LVTTL
• Frequency - Max: 100MHz
• Voltage - Supply: 1.6 V ~ 3.465 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-VFQFN, 20-VFQFPN
• Frequency-max: 100MHz
• Number Of Outputs: 6
• Operating Supply Voltage (max): 3.465V
• Operating Temp Range: 0C to 70C
• Operating Supply Voltage (min): 1.6V
• Mounting: Surface Mount
• Pin Count: 20
• Operating Supply Voltage (typ): 1.8/2.5/3.3V
• Package Type: VFQFPN EP
• Input Frequency: 40MHz
• Duty Cycle: 53%
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 83905AKLF

ICS83905 Data Sheet
Application Information
Crystal Input Interface
Figure 2 shows an example of ICS83905 crystal interface with a
parallel resonant crystal. The frequency accuracy can be fine tuned
by adjusting the C1 and C2 values. For a parallel crystal with loading
capacitance CL = 18pF, to start with, we suggest C1 = 15pF and C2
= 15pF. These values may be slightly fine tuned further to optimize
Figure 2. Crystal Input Interface
LVCMOS to XTAL Interface
The XTAL_IN input can accept a single-ended LVCMOS signal
through an AC coupling capacitor. A general interface diagram is
shown in Figure 3. The XTAL_OUT pin can be left floating. The input
edge rate can be as slow as 10ns. For LVCMOS inputs, it is
recommended that the amplitude be reduced from full swing to half
swing in order to prevent signal interference with the power rail and
to reduce noise. This configuration requires that the output
impedance of the driver (Ro) plus the series resistance (Rs) equals
Figure 3. General Diagram for LVCMOS Driver to XTAL Input Interface
ICS83905AM REVISION B JULY 20, 2009
18pF Parallel Crystal
V
CC
Ro
X1
Rs
Zo = Ro + Rs
C2
15p
50Ω
C1
15p
R1 (optional)
V
0
CC
R1
R2
0.1µf
XTAL_IN
XTAL_OUT
XTAL_IN
XTAL_OUT
12
the frequency accuracy for different board layouts. Slightly increasing
the C1 and C2 values will slightly reduce the frequency. Slightly
decreasing the C1 and C2 values will slightly increase the frequency.
For the oscillator circuit below, R1 can be used, but is not required.
For new designs, it is recommended that R1 not be used.
the transmission line impedance. In addition, matched termination at
the crystal input will attenuate the signal in half. This can be done in
one of two ways. First, R1 and R2 in parallel should equal the
transmission line impedance. For most 50Ω applications, R1 and R2
can be 100Ω. This can also be accomplished by removing R1 and
making R2 50Ω. By overdriving the crystal oscillator, the device will
be functional, but note, the device performance is guaranteed by
using a quartz crystal.
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS/LVTTL FANOUT BUFFER
©2009 Integrated Device Technology, Inc.