st5080d STMicroelectronics, st5080d Datasheet - Page 21

• Manufacturer Part Number: st5080d
• Description: Piafe Programmable Isdn Audio Front End
• Manufacturer: STMicroelectronics

Table 12: Examples of Usual Frequency Selection
POWER SUPPLIES
While pins of PIAFE device are well protected
against electrical misuse, it is recommended that
the standard CMOS practise of applying GND be-
fore any other connections are made should al-
ways be followed. In applications where the
printed circuit card may be plugged into a hot
socket with power and clocks already present, an
extra long ground pin on the connector should be
Tone 250 Hz
Tone 330 Hz
Tone 425 Hz
Tone 440 Hz
Tone 800 Hz
Tone 1330 Hz
DTMF 697 Hz
DTMF 770 Hz
DTMF 852 Hz
DTMF 941 Hz
DTMF 1209 Hz
DTMF 1336 Hz
DTMF 1477 Hz
DTMF 1633 Hz
SOL
LA
SI
DO
RE
MI flat
MI
FA
FA sharp
SOL
SOL sharp
LA
SI
DO
RE
MI
Description
f1 value (decimal)
102
170
109
120
155
171
189
209
100
106
113
126
134
150
169
32
42
54
56
89
99
50
56
63
67
75
80
84
89
95
Theoric value (Hz)
1174.66
523.25
587.33
622.25
659.25
1046.5
1318.5
698.5
830.6
987.8
1330
1209
1336
1477
1633
250
330
425
440
800
697
770
852
941
392
440
494
740
784
880
used.
To minimize noise sources, all ground connec-
tions to each device should meet at a common
point as close as possible to the GND pin in order
to prevent the interaction of ground return cur-
rents flowing through a common bus impedance.
A power supply decoupling capacitor of 0.1 F
should be connected from this common point to
V
CC
as close as possible to the device pins.
Typical value (Hz)
1328.1
1210.9
1335.9
1476.6
1632.8
1046.9
1171.9
1320.4
328.2
421.9
437.5
796.9
695.3
773.4
851.6
937.5
390.6
437.5
492.2
523.5
586.0
625.0
656.3
695.3
742.2
781.3
828.2
882.9
984.4
250
Error %
+.44
+.16
+.04
+.45
+.30
+.33
+.04
+.14
–.56
–.73
–.56
–.39
–.14
–.24
–.05
–.37
–.01
–.30
–.56
–.34
–.23
–.45
–.45
–.34
–.29
–.34
–.23
.00
.00
.00
ST5080A
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