
FUNCTIONALDESCRIPTION
The STLC3055 is a device specifically developed
for WLLand ISDN-TA applications.
It is based on a SLIC core, on purpose optimised
for these applications, with the addition of a
DC/DC converter controller to fulfil the WLL and
ISDN-TA designrequirements.
The SLIC performs the standard feeding, signal-
lingand transmissionfunctions.
It can be set in three different operating modes
via the D0, D1, D2 pins of the control logic inter-
face (0 to 3.3V logic levels). The loop status is
carried out on the DET pin (active low).
The DET pinis an open drain output to allow easy
interfacingwithboth 3.3Vand 5V logic levels.
The four possibleSLIC’soperatingmodes are:
Power Down
HighImpedanceFeeding (HI-Z)
Active
Ringing
Table 1 shows how to set the differentSLIC oper-
atingmodes.
Table1. SLIC operatingmodes.
PD
D0
D1
D2
Operating Mode
0
0
0
X
Power Down
1
0
0
X
H.I. Feeding(HI-Z)
1
0
1
0
Active Normal Polarity
1
0
1
1
Active Reverse Polarity
1
1
1
0
Active TTX injection (N.P.)
1
1
1
1
Active TTX injection (R.P.)
1
1
0
0/1
Ring (D2 bit toggles @ fring)
N.
4
Name
PD
Function
Power Down input.Normally connected to CVCC (or to logic level high). Can beused to set
TIP and Ring terminals in open circuit setting PD=0 and D0=D1=0.
26
CVCC
Internal positive voltage supply filter.
35
VBAT
Regulated battery voltage self generated by the device via DC/DC converter. Must be shorted
to VBAT1.
23
GATE
Driver forexternal Power MOS transistor.
21
VF
Feedback input for DC/DC converter controller.
22
CLK
Power Switch Controller Clock (typ. 125KHz). From version marked STLC3055 A5, this pin
can also beconnected to CVCC or AGND. When the CLK pin is connected to CVCC an
internal auto-oscillation is internally generated and it is used instead of the external clock.
When the CLK pin is connected to AGND, the GATE output is disabled.
24
RSENSE
Voltage input for current sensing. RSENSE should be connected close to this pin and VPOS
pin. The PCB layout should minimize the extra resistance introduced by the copper tracks.
1
D0
Control Interface: input bit 0.
2
D1
Control Interface: input bit 1.
3
D2
Control interface: input bit 2.
8
DET
Logic interface output of the supervision detector (active low).
33
CSVR
Battery supply filter capacitor.
12
RTTX
Metering pulse cancellation buffer output. TTX filter network should be connected to this point.
If not used should be left open.
13
FTTX
Metering pulse buffer inputthis signal is sent to the line and used to perform TTX filtering.
10
CTTX1
Metering burst shaping external capacitor.
11
CTTX2
Metering burst shaping external capacitor.
9
CKTTX
Metering pulse clock input (12 KHz or16KHz square wave).
44
VBAT1
Frame connection. Must be shorted to VBAT.
5
RES
Reserved, must be connected to AGND.
6, 7,36,
38,39,
40,42
NC
Not connected.
PIN DESCRIPTION
(continued)
STLC3055
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