SY89531LHC Micrel Inc, SY89531LHC Datasheet - Page 10

• Manufacturer Part Number: SY89531LHC
• Description: IC SYNTHESIZR LVPECL/HSTL 64TQFP
• Manufacturer: Micrel Inc
• Series: Precision Edge®r
• Type: Clock/Frequency Synthesizerr

Specifications of SY89531LHC

• Pll: Yes
• Input: Crystal
• Output: HSTL, LVPECL
• Number Of Circuits: 1
• Ratio - Input:output: 1:13
• Differential - Input:output: No/Yes
• Frequency - Max: 500MHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 1.6 V ~ 3.6 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-TQFP Exposed Pad, 64-eTQFP, 64-HTQFP, 64-VQFP
• Frequency-max: 500MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Micrel, Inc.
Crystal Input and Oscillator Interface
oscillator to minimize system implementation costs. The
oscillator is a series resonant, multivibrator type design,
and thus, a series-resonant crystal is preferred, but not
required.
with only a minor error in the desired frequency. A parallel-
resonant mode crystal used in a series resonant circuit will
exhibit a frequency of oscillation a few hundred ppm lower
than specified; a few hundred ppm translates to kHz
inaccuracies. In a general computer application this level of
inaccuracy is immaterial.
inputs, the user is advised to mount the crystal as close to
the SY89531L as possible to avoid any board level parasitics.
In addition, trace lengths should be matched. Figure 2 shows
how to interface with a crystal. Table 1 illustrates the crystal
specifications. Certain crystals may require a 10pF capacitor
across XTAL1 and XTAL2 for proper operation. This is
normally not required, but it is recommended that provisions
be made for it.
M9999-010808
[e-mail] or [phone]
Output Frequency: 14MHz-18MHz
Mode of Oscillation: Fundamental
Frequency Tolerance @25 C
Frequency Stability over 0 C to 70 C
Operating Temperature Range
Storage Temperature Range
Aging (per yr/first 3 yrs)
Load Capacitance
Equivalent Series Resistance (ESR)
Drive Level
The SY89531L features a fully integrated on-board
A parallel-resonant crystal can be used with the SY89531L
As the oscillator is somewhat sensitive to loading on its
16.666MHz
Quartz Crystal Selection:
(1) Raltron Series Resonant: AS-16.666-S-SMD-T-MI
(2) Raltron Parallel Resonant: AS-16.666-18-SMD-T-MI
XTAL
Optional
Figure 2. Crystal Interface
XTAL2
(Pin 26, SOIC)
XTAL1
(Pin 25, SOIC)
SY89531L
Table 1. Quartz Crystal Oscillator Specifications
10
External Loop Filter Considerations
allows the user to tailor the PLL’s behavior to their application
and operating environment. We recommend using ceramic
capacitors with NPO or X7R dielectric, as they have very-
low effective series resistance. For applications that require
ultra-low cycle-to-cycle jitter, use the components shown in
Figure 3. The PLL loop bandwidth is a function of feedback
divider ratio, and the external loop filter allows the user to
compensate. For instance, the PLL’s loop bandwidth can
be decreased by using a smaller resistor in the loop filter.
This results in less noise from the PLL input, but potentially
more noise from the VCO. Refer to “AC Electrical
Characteristics” for target PLL loop bandwidth. The designer
should take care to keep the loop filter components on the
same side of the board and as close as possible to the
SY89531L’s LOOP_REF and LOOP_FILTER pins. To insure
minimal noise pick up on the loop filter, it is desirable to cut
away the ground plane directly underneath the loop filter
component pads and traces. However, the benefit may not
be significant in all applications and one must be careful to
not alter the characteristic impedance of nearby traces.
Min
–20
–55
—
—
—
—
—
—
The SY89531L features an external PLL loop filter that
Figure 3. External Loop Filter Connection
18 (or series)
Typ
100
—
—
—
—
30
50
Loop
Filter
330
470pF
0.2 F
+125
Max
+70
Reference
100
—
50
—
50
5
Loop
Precision Edge
Unit
ppm
ppm
ppm
SY89531L
pF
W
C
C
®