PEB2085 SIEMENS [Siemens Semiconductor Group], PEB2085 Datasheet - Page 83

• Manufacturer Part Number: PEB2085
• Description: ISDN SubscribernAccess Controller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Figure 45
Equivalent Internal Circuits of Receiver and Transmitter Stages
The transmitter of the PEB 2086 ISAC-S is identical to that of both the PEB 2080 SBC and
PEB 2085 ISAC-S, hence, the line interface circuitry should be the same. The external
resistors (20 ... 40 ) are required in order to adjust the output voltage to the pulse mask
(nominal 750 mV according CCITT I.430, to be tested with the command "TM1") on the one
hand and in order to meet the output impedance of minimum 20
according to CCITT I.430, to be tested with the command "TM2") on the other hand.
The S-bus receiver of the PEB 2085 is designed as a threshold detector with adaptively
switched threshold levels. Pin SR1 delivers 2.5 V as an output, which is the virtual ground of
the input signal on pin SR2.
The S-bus receiver of the PEB 2086 has been changed to a symmetrical one. This results in
a simplification of the external circuitry and PCB layout to meet the I.430 receiver input
impedance specification.
Semiconductor Group
2.5
ISAC -S
V
IOM -S
R
R
50 k
2.5 V
_
+
_
+
PEB
PEB 2085
<
k 1
2086
50 k
40
40 k
k
ITS05630
ITS02357
SR1
SR2
SR1
SR2
UF1
83
2.1
2.1
2.1
2.1
V
V
V
V
ISAC -S
ISAC -S
R
R
_
<
_
<
13.4 mA
13.4 mA
Functional Description
(tansmission of a binary one
PEB
PEB
2085
2085
ITS02358
ITS02358
SX1
SX2
SX1
SX2