Cirrus Logic CS61584A - Manual (Page 50)

CS61584A
50 DS261PP5
DS261PP5
13.2 Power Supply
As shown in Figure 27, the CS61584A operates
from a 3.3 Volt or 5.0 Volt supply. Separate power
and ground pins provide internal isolation. The best
way to configure the power supplies is to connect
all of the supply pins together at the device. The
various ground pins must not be more negative than
AGND. A 4.99 k
Ω
±1% resistor must be connected
from BGREF to ground to provide an internal cur-
rent reference.
De-coupling and filtering of the power supplies is
crucial for the proper operation of the analog cir-
cuits. A capacitor should be connected between
each supply and its respective ground. For capaci-
tors smaller than 1 µF, use mylar or ceramic capac-
itors and place them as close as possible to their
respective power supply pins. Wire-wrap bread
boarding of the line interface is not recommended
because lead resistance and inductance defeat the
function of the de-coupling capacitors.
13.3 Quartz Crystal Specifications
When a reference clock signal is not available, a
quartz crystal operating at the 8X rate can be con-
nected across the REFCLK and XTALOUT pins.
The crystal must be AT-cut and fundamental mode.
The minimum specifications are shown in
Table 14. Based on these specifications, quartz
crystals suggested for use with the CS61584A are
shown in Table 15.
13.4 Crystal Oscillator Specifications
When a reference clock signal is not available, a
CMOS crystal oscillator operating at either the 1X
or 8X rate can be connected at the REFCLK pin.
The oscillator must have a minimum symmetry of
40-60% and minimum stability of ±100 ppm for T1
and E1 applications. Based on these specifications,
crystal oscillators suggested for use with the
Parameter Min Typ Max Unit
T1 parallel resonant
frequency - 12.352 - MHz
E1 parallel resonant
frequency - 16.384 - MHz
Resonant frequency
error (C
L
= 20 pF)
-50 - +50 ppm
Temperature drift
(over system limits) -100 - +100 ppm
Drive level - - 500 µW
Series resistance - - 50
Ω
Shunt capacitance - - 7 pF
Aging -5 - +5 ppm/yr
Table 14. Quartz Crystal Specifications
Manufacturer Part Number Package Type
M-tron 397-316 ATS-49
through-hole
522-372 ATSM-49
surface mount
SaRonix SRX5769
SRX5772 HC-49S
through-hole
SRX5770
SRX5773 49SMLB
surface mount
NOTE: Frequency tolerances are ±32 ppm with a -
40 to +85 °C operating temperature range.
Table 15. Suggested Quartz Crystals
Manufacturer Part Number Contact Number
Comclok CT31CH (800)333-9825
CTS CXO-65HG-5-I (815)786-8411
M-tron MH26TAD (800)762-8800
SaRonix NTH250A (800)227-8974
NOTE: Frequency tolerances are ±32 ppm with a -
40 to +85 °C operating temperature range.
All are 8-pin DIP packages and can be tristated.
Table 16. Suggested Crystal Oscillators
CS61584A
50 DS261F1