unless otherwise specified)

Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

Line Voltage

(normal mode)

PULSE = Open

IL = 10 mA

5

6

12

V

V

V

Line Voltage

(pulse mode)

PULSE = V

–

4

5.5

9.5

V

V

V

ON/OFF-Hook

Line Current Detection

Threshold

6.5

9.5

mA

OFF/ON-Hook

Line Current Detection

Threshold

59.2

mA

OFF-Hook

Output Drive Current at Pin

HDO

IL = 10 mA

≥ 20 mA

1.5

2

mA

mA

Pulse Input Low Voltage

0.8

V

Pull-up Input Current at Pin

PULSE (pulse mode)

IL = 100 mA

Pulse = V

–

20

µA

Imput Current at Pin Pulse

(normal mode)

3

µA

°C, unless otherwise specified)

Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

AC Line Impedance

f = 1KHz

20

K

Ω

Sending/Receiving Distortion

f = 1KHz

2%

Sending/Receiving Distortion

2

%

Sending/Receiving Distortion

2(*)

%

(*) Not tested, guaranteed only by design.

APPLICATION INFORMATION

With the use of this circuit it is possible to termi-

nate an analog trunk so that all the DC current

component is flowing in the TRUNK TERMINA-

TION CIRCUIT while the AC component is de-

coupled with a low voltage capacitor and can be

used with a small and low cost audio coupler

transformer to provide the AC balancing termina-

tion and two to four wire conversion.

Therefore it is usefull both for MODEM and PABX

systems.

Figure 1 gives the typical application circuit ; it is

worth to note that the TRUNK TERMINATION

CIRCUIT, together with the LS5018 transient sup-

pressor provides a compact and low cost module

fully protected against lightning or overvoltages

frequently present on telephone lines.

The PULSE input when connected to V- allows

the device to reduce the Line Voltage and to

show a resistive impedance equal to R1 to the

line. When PULSE input is left open, this function

is disable.

L3845

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