PBL386151 Ericsson, PBL386151 Datasheet - Page 18

• Manufacturer Part Number: PBL386151
• Description: Subscriber Line Interface Circuit
• Manufacturer: Ericsson

PBL 386 15/1
Overvoltage Protection
PBL 386 15/1 must be protected against
overvoltages on the telephone line. The
overvoltages could be caused for instance
by lightning, ac power contact and induc-
tion. Refer to Maximum Ratings, TIPX and
RINGX terminals, for maximum continu-
ous and transient voltages.
Secondary Protection
The circuit shown in figure 15 utilizes series
resistors together with a programmable
overvoltage protector (e g Power Innova-
tions TISP PBL2), serving as a secondary
protection.
ducting buffered p-gate overvoltage pro-
tector. The protector gate references the
protection (clamping) voltage to negative
supply voltage (i.e. the battery voltage, V
As the protection voltage will track the
negative supply voltage the overvoltage
stress on the SLIC is minimized.
18
Information given in this data sheet is believed to be
accurate and reliable. However no responsibility is
assumed for the consequences of its use nor for any
infringement of patents or other rights of third
parties which may result from its use. No license is
granted by implication or otherwise under any patent
or patent rights of Ericsson Microelectronics AB.
These products are sold only according to Ericsson
Microelectronics general conditions of sale, unless
otherwise confirmed in writing.
Specifications subject to change without
notice.
1522-PBL 386 15/1 Uen Rev. R1A
© Ericsson Microelectronics AB, 2000
This product is an original Ericsson
product protected by US, European and
other patents.
Ericsson Microelectronics
SE-164 81 Kista-Stockholm, Sweden
Telephone: [phone]
The TISP PBL2 is a dual forward-con-
B
).
ground by a diode. Negative overvoltages
are initially clamped close to the SLIC neg-
ative supply rail voltage and the protector
will crowbar into a low voltage on-state
condition, by firing an internal thyristor.
ed to carry enough charge to supply a high
enough current to quickly turn on the thyris-
tor in the protector. C
close to the overvoltage protection device.
Without the capacitor even the low induc-
tance in the track to the V
the current and delay the activation of the
thyristor clamp.
purposes of being non- destructive
energy dissipators, when transients are
clamped and of being fuses, when the
line is exposed to a power cross. If a
PTC is chosen for R
important to always use the PTC´s in
series with resistors not sensitive to
temperature, as the PTC will act as a
capacitance for fast transients and
therefore will not protect the TISP.
Ordering Information
Package
28pin SSOP Tape & Reel
Positive overvoltages are clamped to
A gate decoupling capacitor, C
The fuse resistors R
F
GG
, note that it is
F
serve the dual
should be placed
B
supply will limit
Temp. Range
-40 - + 85 C
GG
, is need-
Power-up Sequence
No special power-up sequence is neces-
sary except that ground has to be present
before all other power supply voltages.
pull-up terminals.
Printed Circuit Board Layout
Care in Printed Circuit Board (PCB) layout
is essential for proper function;
input should be placed in close proximity to
that pin, such that no interference is inject-
ed into the RSN pin. Ground plane sur-
rounding the RSN pin is advisable.
nected to battery ground (BGND) on the
PCB in one point.
AGND with short leads. Pin LP and pin
PSG are sensitive to leakage currents.
be short and very close to each other.
wide leads.
The digital inputs C1 to C3 are internal
The components connecting to the RSN
Analog ground (AGND) should be con-
R
R
C
LC
SG
B
and C
Part No.
PBL 386 15/1 SHT
and C
and R
B2
LP
REF
must be connected with short
connections to VBAT2 should
should be connected to