6

FN4924.2

November 3, 2004

Design Equations

Refer to Figure 14 for programming resistor connections.

Loop Supervision Thresholds

SWITCH HOOK DETECT

The loop current threshold programming range is from 5mA

to 15mA.

RING TRIP DETECT

peak off hook current while still ringing. In addition, the ring

trip current must be set below the transient current limit

LOOP CURRENT LIMIT

The loop current limit programming range is from 15mA to

45mA.

Impedance Matching

The AC source impedance of the SLIC is programmed with

synthesize and match Resistive line terminations the

Figure 14. For complex line terminations such as the one

illustrated in Figure 1, a complex programming network is

required.

RESISTIVE IMPEDANCE SYNTHESIS

The AC source resistance of the SLIC is synthesized with a

characteristic line resistance and protection resistors as

shown in Equation 5.

COMPLEX IMPEDANCE SYNTHESIS

impedance of the line is complex as shown in Figure 1.

equations for each component are provided below where

component of the programming network.

f = 50Hz

-

76

-

dB

f = 300Hz

≤ f ≤ 3400Hz

-

55

-

dB

f = 8kHz

≤ f ≤ 16kHz

-

42

-

dB

NOTES:

2. These parameters are controlled via design and Statistical Process Control and are not directly tested. These parameters are characterized upon

initial design release and upon design changes which would affect these characteristics.

4. Tested per IEEE455-1985, with 368

Ω resistors connected to the Tip and Ring terminals.

5. These parameters are tested 100% at room temperature, and are guaranteed but not tested across the full temperature range via statistical

characterization and design.

6. The power dissipation is based on actual device measurements and will be less than worst case calculations based on data sheet supply current limits.

7. Characterized with 2 x 10us and 10 x 1000us first level lightning surge waveform (GR-1089-CORE).

Electrical Specifications

loop current limit = 25mA. All AC Parameters are specified at 600

frequency band of 300Hz to 3.4kHz. Protection resistors = 0

product offering. (Continued)

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

⁄

=

(EQ. 1)

⁄

=

(EQ. 2)

1760

-------------

=

(EQ. 3)

400

3

----------





×

()

==

(EQ. 4)

+

()

–

=

(EQ. 5)

FIGURE 1. COMPLEX PROGRAMMING NETWORK

2-WIRE TERMINATION

PROGRAMMING

133.3

–

–

()

×

=

(EQ. 6)

×

=

(EQ. 7)

ISL5586