PBL386212QNT Просмотр технического описания (PDF) - Ericsson

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PBL386212QNT

Subscriber Line Interface Circuit

Ericsson  

PBL 386 21/2

Notes

1. The overload level can be adjusted with the resistor R for

OV

higher levels e.g. min 3.1 V and is specified at the two-

Peak

wire port with the signal source at the four-wire receive

port.

2. The two-wire impedance is programmable by selection of

external component values according to:

ZTRX = ZT/|G2-4S α RSN| where:

ZTRX = impedance between the TIPX and RINGX

terminals

ZT = programming network between the VTX and RSN

terminals

G = transmit gain, nominally = 1 (or 0.5 see pin PTG)

2-4S

α RSN = receive current gain, nominally = 200 (current

defined as positive flowing into the receivesumm-

ing node, RSN, and when flowing from ring to tip).

3. Higher return loss values can be achieved by adding a

reactive component to RT, the two-wire terminating

impedance programming resistance, e.g. by dividing R

T

into two equal halves and connecting a capacitor from the

common point to ground.

4. The overload level can be adjusted with the resistor R OV

for higher levels e.g. min 3.1 VPeak and is specified at the

four-wire transmit port, VTX, with the signal source at the

two-wire port. Note that the gain from the two-wire port to

the four-wire transmit port is G2-4S = 1 (or 0.5 see pin PTG)

5. Pin PTG = Open sets transmit gain to nom. 0.0dB

Pin PTG = AGND sets transmit gain to nom. -6.02 dB

Secondary protection resistors R F and resistors RP impact

the insertion loss as explained in the text, section

Transmission. The specified insertion loss is for R = R = 0.

F

P

6. The specified insertion loss tolerance does not include

errors caused by external components.

7. The level is specified at the two-wire port.

8. The two-wire idle noise is specified with the port

terminated in 600 Ω (RL) and with the four-wire receive

port grounded (ERX = 0; see figure 6).

The four-wire idle noise at VTX is specified with the two-

wire port terminated in 600 Ω (R L). The noise

specification is referenced to a 600 Ω programmed two-

wire impedance level at VTX. The four-wire receive port is

grounded (ERX = 0).

7

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