STLC3075
Table 5. Pin Description (continued)
N°
Pin
Function
23
CLK Power Switch Controller Clock (typ. 125KHz). This pin can also be connected 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
GATE Driver for external Power MOS transistor (P-chanell in Buck-boost configuration, N-channel in
Fly-back configuration).
25 RSENSE Voltage input for current sensing. RSENSE resistor should be connected close to this pin and
VPOS pin (Buck-boost) or GND (Fly-back). The PCB layout should minimize the extra resistance
introduced by the copper tracks.
26
VPOS Positive supply input.
27
CVCC Internal positive voltage supply filter.
28
AGND Analog Ground, must be shorted with BGND.
29
RLIM Constant current feed programming pin (via RLIM). RLIM should be connected close to this pin
and AGND pin to avoid noise injection.
30
IREF Internal bias current setting pin. RREF should be connected close to this pin and AGND pin to
avoid noise injection.
31
RTH Off-hook threshold programming pin (via RTH). RTH should be connected close to this pin and
AGND pin to avoid noise injection.
32
RD DC feedback and ring trip input. RD should be connected close to this pin and AGND pin to avoid
noise injection.
33
ILTF Transversal line current image output.
34
CSVR Battery supply filter capacitor.
35
BGND Battery Ground, must be shorted with AGND.
36
VBAT Regulated battery voltage self generated by the device via DC/DC converter.
Must be shorted to VBAT1.
37
RING 2 wire port; RING wire (Ib is the current sunk into this pin).
41
TIP 2 wire port; TIP wire (Ia is the current sourced from this pin).
43
CREV Reverse polarity transition time control. A proper capacitor connected between this pin and
AGND is setting the reverse polarity transition time. This is the same transition time used to
shape the "trapezoidal ringing" during ringing injection.
44
VBAT1 Frame connection. Must be shorted to VBAT.
3 FUNCTIONAL DESCRIPTION
The STLC3075 is a device specifically developed for WLL VoIP and ISDN-TA applications.
It is based on a SLIC core, on purpose optimised for these applications, with the addition of a DC/DC con-
verter controller to fulfil the WLL and ISDN-TA design requirements.
The SLIC performs the standard feeding, signalling and transmission functions.
It can be set in three different operating modes via the D0, D1, D2 pins of the control logic interface (0 to
3.3V logic levels). The loop status is carried out on the DET pin (active low).
The DET pin is an open drain output to allow easy interfacing with both 3.3V and 5V logic levels.
The four possible SLIC’s operating modes are:
■ Power Down
■ High Impedance Feeding (HI-Z)
■ Active
■ Ringing
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