stlc1511 STMicroelectronics, stlc1511 Datasheet - Page 16

• Manufacturer Part Number: stlc1511
• Description: Northenlite?? G.lite Bicmos Analog Front-end Circuit
• Manufacturer: STMicroelectronics

STLC1511
3.4.3 Customer Premise Equipment
In CPE mode, the STLC1511 provides the amplifier
required to power the off-chip crystal oscillator. The
crystal oscillator runs at a frequency of 35.328 MHz
(series resonant) which is further divided down to
provide the sampling clocks to both the TX and RX
converters and passed to the STLC1510 as its PLL
reference on the pin DIGREF. Note that in CPE
mode, neither the PLL or the pin FREF is used (FREF
should be connected to either Vdd or Vss) and that
the tuing for the external oscillator is generated on
the STLC1510.
Table 6. CPE PLL Specifications
16/31
Unless otherwise noted, typical specifications apply for VCC=5.0 V, temperature = 25×C, nominal process and bias
current. Maximum and minimum performance is with VCC ± 5%, -40 =< T
Output Clock Frequency
Crystal Accuracy
Crystal Frequency Tuning
Range
Oscillator Signal Level
Power Up Time
VCO Gain
Vcxo gain (crystal)
Input Impedance @OSCPB
and OSCNB
Output Impedance @OSCPE
and OSCNE
CPE Phase Noise at f
10Hz offset
20Hz offset
40Hz offset
60Hz offset
80Hz offset
100Hz offset
200Hz offset
400Hz offset
600Hz offset
800Hz offset
1000Hz offset
<1>For the CPE side a crystal oscillator will be used.
<2>50ppm accuracy is divided as ±15ppm for manufacture, ± 15ppm for 10 year drift, and ± 20ppm for temperature variation.
<3>Worst case for tuning is when CO is not locked and CPE must retime from CO. Nominally the tuning range for the CO is ±50ppm,
<4>Input and output impedance measured with 50kW from OSCPB to Vcc and OSCNB to Vcc
<5>For inband noise, phase noise at multiples of 4.3125kHz will rms add to degrade the inband SNR. Similarly, for out of band signals,
2 3
so that if the CO is free running, the CPE must tune over the CO inaccuracy and the CPE crystal inaccuracy as well.
phase noise will rms add depending on the offset between the carrier and the band of interest to reduce the SNR. For example,
noise contributions on carriers from 34 to 127 will rms add to degrade the SNR on the edge of the US band (carrier 26).
Description
4
4
1 2
s
5
-50
-125
200
1.4
min
35.328
5
1.6
typ
Note the reference design provided is based on a
Reeves Hoffman fundamental Mode AT cut crystal at
Cm@15fF max, and Co@3.5pF typ (assumes a
The following table details the CPE oscillator perfor-
mance when connected as shown in Figure 3. on
page 14. CPE mode is selected by setting b5:b0 in
register “AFE Control 5” to “001110”. See section
"Digital Interface And Memory Map" on page 20 for
more information.
35.328MHz.(Crystal accuracy@+/-50ppm (+/-15ppm
calibration tolerance, +/-15ppm 10 year aging, +/-20
ppm
HC49/43 package).)
+50
+125
500
10
1.7
-51.9
-57.9
-63.9
-67.5
-69.9
-71.9
-77.9
-83.9
-87.5
-89.9
-91.9
max
temperature
junction
MHz
ppm
ppm
mVp
msec
KHz/V
dBc/Hz
Units
=< 105×C, and worst case process.
variation,
at pin DIGREF
crystal accuracy for CPE.
Occurs at CPE. Assumes
CO is free running
see TITLE 2 3.5 on page 18
see TITLE 3 3.4.3 on page
16
see TITLE 3 3.4.3 on page
16
Phase noise at DIGREF
output (i.e. 35.328MHz) in
CPE mode.
Comments
Rs@15
max,