L3845B STMicroelectronics, L3845B Datasheet - Page 3

• Manufacturer Part Number: L3845B
• Description: IC TRUNK INTERFACE 8-MINIDIP
• Manufacturer: STMicroelectronics

Specifications of L3845B

• Applications: Monitoring, Digital Current
• Package / Case: 8-DIP (0.300", 7.62mm)
• Mounting Type: Through Hole
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Interface: -
• Other names: 497-3625

DC ELECTRICAL CHARACTERISTICS (I
unless otherwise specified)
AC ELECTRICAL CHARACTERISTICS (I
T
(*) 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.
amb
Symbol
Symbol
I
V
V
I
I
OUT
V
I
Z
I
NM
= + 25 C, unless otherwise specified)
PM
hn
PM
LP
hf
L
L
Line Voltage
(normal mode)
Line Voltage
(pulse mode)
ON/OFF-Hook
Line Current Detection
Threshold
OFF/ON-Hook
Line Current Detection
Threshold
OFF-Hook
Output Drive Current at Pin
HDO
Pulse Input Low Voltage
Pull-up Input Current at Pin
PULSE (pulse mode)
Imput Current at Pin Pulse
(normal mode)
AC Line Impedance
Sending/Receiving Distortion
Sending/Receiving Distortion
Sending/Receiving Distortion
Parameter
Parameter
L
L
PULSE = Open
IL = 10 mA
I
I
PULSE = V
I
I
I
IL = 10 mA
I
IL = 100 mA
Pulse = V
S
C
f = 1KHz
S
f = 1KHz
V
I
S
V
S
V
= 10mA to 100mA, R
= 10 mA to 100 mA, R
L
L
L
L
L
L
L
1
1
AC-L
1
AC-L
1
AC-L
1
= 20 mA
= 100 mA
= 20 mA
= 35 mA
= 80 mA
= 15 to 100mA
= Open, S
= Open, S
= Closed; S
= Open; S
= 2.2mF
20 mA
= 775mVrms
= 1.3Vrms
= 1.9Vrms
Test Condition
Test Condition
–
–
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.
2
2
2
= Open
= Open
2
= Closed
= Open
1
1
= 56 , R
= 56 , S
Min.
Min.
6.5
1.5
1.8
5
2
1
= 470K , R
= Open, T
Typ.
Typ.
2(*)
20
2
Max.
Max.
amb
0.8
5.5
9.5
9.5
9.2
12
20
3
5
6
4
3
2
= 130 K ,
= + 25 C,
L3845
Unit
Unit
mA
mA
mA
mA
K
%
%
%
V
V
V
V
V
V
V
A
A
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