USB6B2RL [STMICROELECTRONICS]
DATA LINES PROTECTION; 数据线保护型号: | USB6B2RL |
厂家: | ST |
描述: | DATA LINES PROTECTION |
文件: | 总9页 (文件大小:102K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
USB6Bx
®
Application Specific Discretes
A.S.D.
DATA LINES PROTECTION
APPLICATIONS
Where transient overvoltage protection in sensi-
tive equipment is required, such as:
- Universal Serial Bus ports
- RS-423 interfaces
- RS-485 interfaces
- ISDN equipment
- T1/E1 line cards
- HDSL / ASDL interfaces
SO8
FEATURES
Full diode bridge with integrated clamping protection
Breakdown voltage : VBR = 6V min.
Peak pulse power dissipation : PPP = 500W (8/20µs)
Very low capacitance, compatible with high debit
data or signal rates.
DESCRIPTION
In order to prevent fast transients from leading
to severe damages in a high speed data sys-
tem, a specific protection has been developed
by STMicroelectronics.
The USB6Bx protects the two input lines
against overvoltage. Besides, this device also
keeps the power rails in a safe limit thanks to
the integrated Transil diode.
DIL8
BENEFITS
Provides protection for each line and between
the supply voltage and GND : 25A , 8/20µs.
High ESD protection level : up to level 3 per
MIL STD 883C-Method 3015-6
Separated inputs and outputs (so-called 4-point
structure) to improve ESD susceptibility.
FUNCTIONAL DIAGRAM
Comprehensive package pin-out for immediate
implementation.
Vcc
I/01
I/02
GND
Vcc
I/01
I/02
GND
COMPLIES WITH THE FOLLOWING STANDARDS:
MIL STD 883C - Method 3015-6
class 3
C = 100 pF
R = 1500 Ω
3 positive strikes and 3 negative strikes (F = 1 Hz)
IEC-1000-4-2 level 4
15 kV (air discharge)
8 kV (contact discharge)
TM: ASD and TRANSIL are trademarks of ST Microelectronics.
August 1999 Ed : 5A
1/9
USB6Bx
TECHNICAL INFORMATION
SURGE PROTECTION
The USB6Bx is particularly optimized to perform
surge protection based on the rail to rail topology.
The clamping voltage VCL can be estimated as follow:
VCL+ =Vcc + VF for positive surges
VCL - = - VF
for negative surges
with: VF = Vt + rd.Ip
(VF forward drop voltage) / (Vt forward drop
threshold voltage)
Note: the estimations do not take into account
phenomena due to parasitic inductances.
Fig. A1 :
Lw
di
ESD
SURGE
+Vcc
Lw
Vf
dt
I/O
di
dt
surge >0
surge <0
Vcc+Vf+ Lw
di
Vcl+ =
VI/O
Lw
Vcl- = -Vf-
di
dt
dt
Lw
GND
tr=1ns
Vcl+
t
-Vf
di
di
dt
Lw
POSITIVE
SURGE
NEGATIVE
SURGE
-Lw
dt
Vcc+Vf
t
Vcl-
tr=1ns
2/9
USB6Bx
Fig. A2: ESD behavior: optimized layout and add
of a capacitance of 100nF.
HOW TO ENSURE A GOOD ESD PROTECTION
While the USB6Bx provides a high immunity to
ESD surge, an efficient protection depends on the
layout of the board. In the same way, with the rail to
rail topology, the track from the VCC pin to the
power supply and from the GND pin to GND volt-
age must be as short as possible to avoid
overvoltages due to parasitic phenomena (see Fig
A1).
Lw
ESD
SURGE
REF2=+Vcc
C=100nF
I/O
Vcc+Vf
Vcl+ =
surge >0
surge <0
VI/O
It’s often harder to connect the power supply near
to the USB6Bx unlike the ground thanks to the
ground plane that allows a short connection.
Vcl- = -Vf
REF1=GND
To ensure the same efficiency for positive surges
when the connections can’t be short enough, we
recommend to put close to the USB6Bx between
VCC and ground, a capacitance of 100nF to pre-
vent from these kinds of overvoltage disturbances
(see Fig. A2 ).
Vcl+
t
NEGATIVE
SURGE
POSITIVE
SURGE
t
Vcl-
The add of this capacitance will allow a better pro-
tection by providing during surge a constant volt-
age.
IMPORTANT:
Fig. A3 shows the improvement of the ESD pro-
tection according to the recommendations de-
scribed above.
A main precaution to take is to put the protection
device closer to the disturbance source (generally
the connection).
3/9
USB6Bx
TECHNICAL INFORMATION
Universal Serial Bus.
downstream can also be transmitted on two sepa-
rate conductors within the same cable.
The new data transmission standard, Universal
Serial Bus (USB) is being driven by market leaders
in the world of Computer and Telecommunica-
tions, including Compaq, DEC, IBM, Intel,
Microsoft, NEC and Nortel, and will become the
leading transmission protocol within the next few
years.
Protection to support USB.
Designers dealing with the USB chips are con-
cerned about electrostatic discharge sensitivity
(ESD) of their USB controller ICs.
The USB controller is more than just a driver /
receiver; it acts as a microcontroller which
manages power and direct signal traffic. This
complexity increases its cost over conven-
tional devices. Therefore, a failure of a USB
port could result in costly computer failure.
This standard mainly provides simplified
interconnectivity. Specialized ports on the back of
the present PC will largely be replaced by USB
ports. Many peripherals such as printers, key-
boards, monitors and joysticks will also host USB
ports.
In order to prevent these fast transients from
leading to severe damages in a system, a
specific protection has been developed by
STMicroelectronics. The USB6Bx protects
not only the two wires of data transmission,
but also keep the power rails in a safe limit.
The USB offers high speed communication rates
up to 12 Mbit/s. Only two wires (D+, D-) are re-
quired for data transfer. Additionally, limited
amount of power for USB devices located on the
Fig. A3: recommended configuration for USB port protection.
1
Vbus
D+
USB
IC
D-
GND
USB output
connector
The capacitance between the I/O transmission
wires provides no significant signal distortion at the
12 Mbit/s data rate, thus allowing full compatibility
with USB standard.
Available either in a compact SO8 or in a
through-hole DIL8 package, this protective ele-
ment requires minimal board space and eases the
PCB layout thanks to its direct compatibility with
the USB connector pin-out.
4/9
USB6Bx
TELECOM AND DATACOM APPLICATIONS
ISDN U interface protection.
3* SMP100
USB6Bx
LT
DC Power
Source
T1 / E1 Line Card Protection.
USB6B1
SMP75-8 or SMP100-8
RTIP
RRING
TTIP
TRING
SMP75-8 or SMP100-8
USB6B1
High Speed Line Driver / Receiver Protection.
+5V
+5V
SM6T6V8A
SM6T6V8A
INPUT
OUTPUT
DRIVER
RECEIVER
USB6B1
USB6B1
5/9
USB6Bx
ABSOLUTE MAXIMUM RATINGS (Tamb = 25°C)
Symbol
Parameter
IEC1000-4-2 contact discharge
Value
Unit
VPP
Peak pulse voltage
8
15
4
kV
IEC1000-4-2 air discharge
MIL STD883C-Method 3015-6
PPP
IPP
Peak pulse power
Peak pulse current
8/20 µs
8/20 µs
500
25
W
A
Tstg
Tj
Storage temperature range
Maximum junction temperature
- 55 to + 150
+ 150
°C
°C
TL
Lead solder temperature (10s duration)
260
°C
ELECTRICAL CHARACTERISTICS (Tamb = 25°C)
Value
Symbol
Parameter
Unit
min. typ. max.
VBR
Breakdown voltage between Vbus and
GND
IR=1mA
6
V
IRM
C
Leakage current
VRM=5.25V
10
µA
Capacitance between pins D+ and D-
VCC
not connected
15
pF
V
OSC =30mV, F=1MHz, VR=0V
Capacitance between pins D+ (or D-) and GND
VCC=5V
25
pF
VOSC =30mV, F=1MHz, VR=5V
6/9
USB6Bx
Fig 1: Peak power dissipation versus initial junc-
tion temperature.
Fig 2: Relative variation of leakage current versus
junction temperature (typical values).
IR[Tj] / IR[Tj=25°C]
Ppp[Tj initial]/Ppp[Tj initial=25°C]
10.0
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
1.0
0.1
Tj(°C)
Tj initial(°C)
0.0
0.1
-40 -20
0
20 40 60 80 100 120 140 160
-40 -20
0
20 40 60 80 100 120 140
Fig 3: Relative variation of breakdown voltage ver-
sus junction temperature (typical values).
VBR[Tj] / VBR[Tj=25°C]
1.10
1.05
1.00
0.95
Tj(°C)
0.90
-40 -20
0
20 40 60 80 100 120 140
7/9
USB6Bx
ORDER CODE
USB 6 B1 RL
PACKAGING:
RL = tape and reel.(SO8 only)
= tube
PACKAGE:
1 = SO8
2 = DIL8
VBR min
PACKAGE MECHANICAL DATA.
SO8 Plastic
DIMENSIONS
REF.
Millimetres
Inches
Min. Typ. Max. Min. Typ. Max.
A
a1
a2
a3
b
1.75
0.069
0.010
0.065
0.033
0.019
0.010
0.020
L
c1
0.1
0.25 0.004
1.65
C
a3
A
a2
0.65
0.35
0.19
0.85 0.025
0.48 0.014
0.25 0.007
b
1
a1
e
b
E
e3
b1
C
D
0.25 0.50 0.50 0.010
45° (typ)
M
c1
D
4.8
5.8
5.0 0.189
6.2 0.228
0.197
0.244
5
8
E
F
e
1.27
3.81
0.050
0.150
1
4
e3
F
3.8
0.4
4.0 0.15
1.27 0.016
0.6
0.157
0.050
0.024
L
M
S
8 (max)
8/9
USB6Bx
PACKAGE MECHANICAL DATA.
DIL8 Plastic
DIMENSIONS
Millimetres Inches
Min. Typ. Max. Min. Typ. Max.
REF.
I
a1 0.51
0.020
b1
a1
L
B
b
0.85
1.40 0.033
0.055
F
E
0.5
0.020
e
B
b1 0.38
D
0.50 0.015
10.15
0.020
0.399
b
Z
e3
D
Z
E
e
8.10 8.80 9.40 0.319 0.346 0.370
2.54
7.62
0.100
0.300
8
1
5
4
e3
F
I
7.1
5.1
0.280
0.200
L
3.3
0.130
Z
1.50
0.063
MARKING
ORDER
CODE
Types
Package
Weight
Marking
Base Qty
100 pcs (tube)
USB6B1
SO8
0.077g
USB62
USB6B1
USB6B1RL
USB6B2
2500 pcs (tape and reel)
50 pcs (tube)
USB6B2
DIL8
0.59g
USB62
- Epoxy meets UL94, V0
Information furnished is believed to be accurate and reliable. However, STMicroelectronics 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 STMicroelectronics. Specifications mentioned in this publication are subject to
change without notice. This publication supersedes and replaces all information previously supplied.
STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written ap-
proval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics
© 1999 STMicroelectronics - Printed in Italy - All rights reserved.
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9/9
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