STMICROELECTRONICS ITA25B3

ITA6V5B3 / ITA10B3
ITA18B3 / ITA25B3

Application Specific Discretes
A.S.D.TM
BIDIRECTIONAL TRANSILTM ARRAY
FOR DATALINE PROTECTION
APPLICATIONS
Differential data transmission lines protection :
- RS-232
- RS-423
- RS-422
- RS-485
FEATURES
HIGH SURGE CAPABILITY TRANSIL ARRAY
IPP = 40 A (8/20µs)
PEAK PULSE POWER : 300 W (8/20µs)
SEPARATED INPUT-OUTPUT
UP TO 9 BIDIRECTIONAL TRANSIL FUNCTIONS
LOW CLAMPING FACTOR (VCL / VBR) AT HIGH
CURRENT LEVEL
LOW LEAKAGE CURRENT
ESD PROTECTION UP TO 15kV
SO20
FUNCTIONAL DIAGRAM
DESCRIPTION
Transil diode arrays provide high overvoltage
protectionby clamping action. Their instantaneous
response to transient overvoltages makes them
particularly suited to protect voltage sensitive
devices such as MOS Technology and low voltage
supplied IC’s.
The ITA series allies high surge capability against
energetic pulses with high voltage performance
against ESD.
The separated input/output configuration of the
device ensures improved protection against very
fast transient overvoltage like ESD by elimination
of the spikes induced by parasitic inductances
created by external wiring.
COMPLIESWITHTHE FOLLOWINGSTANDARDS :
IEC 1000-4-2 : level 4
IEC 1000-4-4 : level 4
IEC 1000-4-5 : level 2
MIL STD 883C - Method 3015-6 : class 3
(human body model)
January 1998 Ed: 2
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ITA6V5B3 / ITA10B3 / ITA18B3 / ITA25B3
ABSOLUTE MAXIMUM RATINGS (Tamb = 25°C)
Symbol
Parameter
Value
Unit
PPP
Peak pulse power dissipation (8/20µs)
(see note 1)
Tj initial = Tamb
300
W
IPP
Peak pulse current (8/20µs) (see note 1)
Tj initial = Tamb
40
A
I2 t
Wire I2t value (see note 1)
0.6
A2s
- 55 to + 150
125
°C
°C
260
°C
Tstg
Tj
Storage temperature range
Maximum operating junction temperature
TL
Maximum lead temperature for soldering during 10s
Note 1 : For surges greater than the specified maximum
value, the I/O will first present a short-circuit and after an
open circuit caused by the wire melting.
%I pp
8 s
100
Pulse wave form 8/20 s
50
0
t
20 s
ELECTRICAL CHARACTERISTICS (Tamb = 25°C)
Symbol
Parameter
VRM
Stand-off voltage
VBR
Breakdown voltage
VCL
Clamping voltage
IRM
Leakage current @ VRM
IPP
Peak pulse current
αT
Voltage temperature coefficient
C
Types
Junction capacitance
IRM
@
VRM
max.
VBR
@
IR
VCL
min.
note 2
@
IPP
VCL
8/20µs
max.
note 2
@
IPP
αT
C
8/20µs
max.
max.
-4
note 2
note 3
µA
V
V
mA
V
A
V
A
10 /°C
pF
ITA6V5B3
10
5
6.5
1
9.5
10
11
25
4
1100
ITA10B3
4
8
10
1
13
10
17
25
8
800
ITA18B3
4
15
18
1
21
10
26
25
9
500
ITA25B3
4
24
25
1
31
10
36
25
12
420
Note 2 : Between I/O pin and ground.
Note 3 : Between two input Pins at 0V Bias.
Preferred types in bold.
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
ITA6V5B3 / ITA10B3 / ITA18B3 /ITA25B3
Fig. 1 : Typical peak pulse power versus
exponential pulse duration.
1E+04
Fig. 2 : Clamping voltage versus peak pulse
current (exponential waveform 8/20 µs).
P P P (W)
ITA25B3
ITA18B3
ITA6V5B3
ITA10B3
T j initial = 25 oC
1E+03
1E+02
1E+01
1E-03
t P (ms) expo
1E-02
1E-01
1E+00
1E+01
1E+02
Fig. 3 : Peak current IDC inducing open circuit of
the wire for one input/output versus pulse duration
(typical values).
1E+03
Fig. 4 : Junction capacitance versus reverse
applied voltage for one input/output (typical
values).
I DC (A)
expon ential waveform
1E+02
1E+01
t (ms)
1E+00
1E-02
1E-01
1E+00
1E+01
Fig. 5 : Relative variation of leakage current
versus junction temperature
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
ITA6V5B3 / ITA10B3 / ITA18B3 / ITA25B3
APPLICATION INFORMATION
Types
Maximum differential voltage
between two input pins at 25°C
ITA6V5B3
+ / - 3.5 V
ITA10B3
+ / - 5.0 V
ITA18B3
+ / - 9.0 V
ITA25B3
+ / - 12.5 V
This monolithic Transil Array is based on 10
unidirectionalTransils with a commoncathode and
can be configurated to offer up to 9 bidirectional
functions. This imposes a maximum differential
voltage between 2 input pins (see opposite table).
Typical application : RS232 junction.
TX
RX
RTS
CTS
DTR
DSR
CARRIER DET.
AUX
GND
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
ITA6V5B3 / ITA10B3 / ITA18B3 /ITA25B3
APPLICATION NOTICE
Design advantage of ITAxxxB3 used with 4-point structure.
The ITAxxxB3 has been designed with a 4-point structure (separated Input/output) in order to efficiently
protect against disturbances with very high di/dt rates, such as ESD.
The purpose of this 4-point structure is to eliminate the overvoltage introduced by the parasitic inductances
of the wiring (Ldi/dt).
Efficient protection depends not only on the component itself, but also on the circuit layout.The drawing
given in figure shows the layout to be used in order to take advantage of the 4-point structure of the
ITAxxxB3.
With this layout, each line to be protected passes through the protection device.
In this way, it realizes an interface between the data line and the circuit to be protected, guaranteeing an
isolation between its inputs and outputs.
The 4 - point structure layout.
ORDER CODE
ITA 25 B 3
RL
PACKAGING:
RL = Tape and reel.
= Tube.
INTEGRATED
TRANSIL ARRAY
PACKAGE : SO20 PLASTIC
VBR min
BIDIRECTIONAL
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
ITA6V5B3 / ITA10B3 / ITA18B3 / ITA25B3
MARKING
TYPE
MARKING
ITA6V5B3
ITA6V5B2
ITA10B3
ITA10B3
ITA18B3
ITA18B3
ITA25B3
ITA25B3
PACKAGE MECHANICAL DATA
SO20 (Plastic)
DIMENSIONS
REF.
Millimetres
Min.
Inches
Typ. Max. Min.
A
Typ. Max.
2.65
0.104
A1
0.10
0.20 0.004
0.008
B
0.33
0.51 0.013
0.020
C
0.23
0.32 0.009
0.013
D
12.6
13.0 0.484
0.512
E
7.40
7.60 0.291
0.299
e
H
1.27
10.0
h
L
K
0.050
10.65 0.394
0.50
0.50
0.419
0.020
1.27 0.020
0.050
8° (max)
Packaging : standard packaging is tape and reel.
Weight : 0.55g.
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information 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 SGS-THOMSON Microelectronics. Specifications mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGSTHOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems withoutexpress written approval of SGS-THOMSON Microelectronics.
 1998 SGS-THOMSON Microelectronics - Printed in Italy - All rights reserved.
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