Table 2 shows all the possible combinations be-

tween switches configurations and operating

modes.

A detailed description of each configuration can

be found in the ”OPERATING MODES” descrip-

tion section.

OPERATING MODES

Power Down (PWD)

D0

D1

D2

P1

P2

DET

DET1

DET2

0

0

X

0

0

disable

disable

disable

DC CHARACTERISTIC & SUPERVISION

When this mode is selected both 2W ports

(TIP1/RING1 and TIP2/RING2) are in high imped-

ance; all switches Sw1 to Sw6 are open (see

fig.1)

The SLIC core is switched off and the line detec-

tors are disabled therefore the off-hook condition

cannot be detected.

This mode can be selected in emergency condi-

tion when it is necessary to cut any current deliv-

ered to the line.

This mode is also forced by STLC3065 in case of

thermal overload (Tj > 140

°C).

In this case the device goes back to the previous

status as soon as the junction temperature de-

crease under the hysteresis threshold.

AC CHARACTERISTICS

Both the 2W ports (TIP1/RING1 and TIP2/RING2)

are set in high impedance, the TX output buffer is

a low impedance output, no AC transmission is

possible.

High Impedance Feeding (HI-Z)

D0

D1

D2

P1

P2

DET

DET1

DET2

0

0

X

1

1

off/hk

line 1+2

off/hk

line 1

off/hk

line 2

0

0

X

0

1

off/hk

line 2

disable

off/hk

line 1

0

0

X

1

0

off/hk

line 1

off/hk

line 1

disable

DC CHARACTERISTIC & SUPERVISION

This operating mode is normally selected when

the telephone is in on-hook in order to monitor the

line status keeping the power consumption at the

minimum.

The SLIC core of STLC3065 is in PWD mode

(see fig.1 or FUNCTIONAL DIAGRAM); the two

line series switches (Sw1; Sw2) are open. De-

pending on P1, P2 the 2W ports (TIP1/RING1

and TIP2/RING2) can be in high impedance or

connected to the built in

feeding resistors

(2x1500

Ω) via SW3T and SW5R or SW4T and

SW6R.

P1

controls

TIP1/RING1

and

P2

controls

TIP2/RING2 (see Fig.1 and Table 2).

When this mode is selected normally both P1, P2

bits should be set to one.

The output voltage in on-hook condition is equal

to the self generated battery voltage (-50V typ).

When off-hook occurs on 2W port 1 (2) the cur-

rent flowing through the RING1(2) wire activates

the DET1 (2_) detector indicating the line status

change. When DET1 or DET2 are activated also

the DET become active (low logic level).

The off-hook threshold in HI-Z mode is the same

value programmed in ACTIVE mode.

The DC characteristic in HI-Z mode is just equal

to the self generated battery with 2x(1500W+Rp)

Where:

”Open”:

the line port termination is in high impedance.

”To P.S. via Res”:

the TIP(n) wire is connected to BGND through a 1500

Ω resistor , the RING(n) wire is

connected to VBAT by a 1500

Ω resistor. The current flowing in the second resistor is used

to detect the off-hook .

”To Buffer”:

the TIP(n) wire and RING(n) wire are connected to the SLIC core line driver and the off-

hook detection is performed using the SLIC core supervision circuit that drives the DET

output.

”300

µA bias”:

the TIP(n) wire is connected to BGND through a 1500

Ω resistor , the RING(n) wire is

biased by a 300

µA current generator to negative battery (Vbat)

Note: see also Appendix C

STLC3065

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