L3000S Просмотр технического описания (PDF) - STMicroelectronics
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L3000S Datasheet PDF : 29 Pages
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L3000S - L3030
Table 1.
Pin 27 of L3030
Pin 11 of L3000S
+3
+ 3 Stand-by
0 Not allowed.
– 3 Not allowed.
Pin 28 of L3030 / Pin 12 of L3000S (C2)
0
–3
Conversation in Normal
Battery Direct Polarity
Conversation in Normal
Battery Reverse Polar
Conversation in Boost
Battery Direct Polarity
Conversation in Boost
Battery Reverse Polar
Ringing with Direct
Polarity
Not allowed.
states as listed in Table. 1.
Appropriate combinations of two pins define the
three modes of the ST SLIC, that are :
a) Stand-by (SBY)
b) Conversation (CVS), Normal and Reverse pola-
rity
c) Ringing (RING)
d) Boost Battery (BB), Normal and Reverse polarity
A fifth status, Power down (PD), can be set discon-
necting the bias resistor (RH) from pin 10 ofL3000S
by means of an external transistor.
The main difference between Stand-by and Power
down is that in SBY the power consumption on the
voltage battery VB– (– 48V) is reduced but the
L3000S DC feeding and monitoring circuits are still
active. In PD the power consumption on VB- is re-
duced to zero, and the L3000S is completely swit-
ched off.
The SBYstatus shouldbe used when the telephone
is in On hook and PD status onlyin emergencycon-
dition when it is mandatory to cut any possible dis-
sipation but no operation are requested.
OPERATING MODES
Stand-by (SBY) Mode
In this mode, the bias currents of both L3000S and
L3030are reducedas only someparts of the two cir-
cuits are completely active, control interface and
current sensors among them. The current supplied
to the line is limited at 7mA, and the slope of the DC
characteristic corresponds to :
R
=
2
3
x
(RFS
+
2RP)
The Line voltage in on Hook conditionisjust the bat-
teryvoltage minus the voltage drop (approx. 15V)of
the output stage amplifiers (see Fig. 1).
Figure 1 : DC Characteristics in Stand-byMode.
7/29
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