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L054BT26
Low Capacitance Surface Mount TVS Diodes
FEATURES
•
Four ultra-low input capacitance ( 1 pF typ.)
ESD rail-to-rail protection diodes
•
ESD IEC 61000-4-2 level 4, ± 8kV contact
Discharge compliant protection
•
Low voltage clamping due to integrated
Zener diode
•
Compact SOT-23-6 package
The
L054BT26
devices are low-capacitance
transient voltage suppressors designed to
protect components which are connected to
data and transmission lines from over
voltages caused by electrostatic discharge
(ESD), electrical fast transients (EFT), and
induced lightning.
SCHEMATIC & PINNING (SOT23-6)
APPLICATION
General-purpose downstream ESD protection
high frequency analog signals and high-speed
serial data transmission for ports inside:
•
PC-/Notebook USB2.0/IEEE1394 ports
•
Cellular phone and PCS mobile handsets
•
DVI interfaces
•
Cordless telephones
•
Wireless data (WAN/LAN) systems
•
PDAs
CIRCUIT DIAGRAM
MAXIMUM RATINGS
RATING
DC input voltage range
Electrostatic Discharge, all pins (IEC 61000-4-2, Level 4, Contact)
Device Storage Temperature
SYMBOL
V
I/O
ESD
T
stg
o
MIN
0
-8
-55
MAX
+5.5
+8
+125
UNIT
Volts
KiloVolts
o
C
ELECTRICAL CHARACTERISTICS
PARAMETER
Pin capacitance to ground,
Pins 1, 3, 4, 6
Diode reverse leakage current,
Pins 1, 3, 4, 6 to ground
Zener diode capacitance to
ground, Pin 5 to 2
Zener diode breakdown voltage,
Pin 5 to 2
Forward voltage
T
C
= 25 C unless otherwise specified
SYMBOL
C
I/O
I
lkg
C
Zener
V
BR I/O
V
F
MIN
-
-
-
6
-
TYP
1.0
-
40
-
0.7
MAX
-
100
-
9
-
UNIT
pF
nA
pF
V
V
TEST CONDITIONS
Vdc = 0V; f = 1 MHz
Pin 5 = +3.0V
V = +3.0V
Vdc = 0V; f = 1 MHz
Pin 5 = +3.0V
I = 1mA
August 2007 / Rev.5
http:// www.sirectsemi.com
L054BT26
http:// www.sirectsemi.com
L054BT26
APPLICATION INFORMATION
1.0 Four High-Speed Data Lines Protection
The
L054BT26
TVS diode is designed to protect up to four data lines from transient over-voltages by
clamping them to a fixed reference. When the voltage on the protected line(s) exceeds the reference
voltage (plus diode V
F
), the steering diodes are forward biased, conducting the transient current away
from the protected circuitry. The data lines are connected to pins 1, 2, 4 and 6. The negative reference
(REF1) is connected to pin 2
(This pin should be connected directly to the ground plane on the PCB for
best results).
The path length is kept as short as possible to minimize parasitic inductance. The
positive reference (REF2) is connected to pin 5.
The typical options for connecting the positive reference are as follows:
A. DATA LINE AND POWER SUPPLY PROTECTION USING V
CC
AS REFERENCE
To protected data lines and the power line, connect pin 5 directly to the positive supply rail (VCC).
In this configuration, the data lines are referenced to the supply voltage. The internal TVS diode
prevents over-voltage on the supply rail.
http:// www.sirectsemi.com
L054BT26
APPLICATION INFORMATION
(continued)
B. DATA LINE PROTECTION WITH BIAS AND POWER SUPPLY ISOLATION RESISTOR
The
L054BT26
can be isolated from the power supply by adding a series resistor between pin 5 and
V
CC
(A resistor value of 100kΩ is recommended).
The internal TVS and steering diodes remain
biased, providing the advance of even lower capacitance.
C. DATA LINE PROTECTION USING INTERNAL TVS DIODE AS REFERENCE
In applications where no positive supply reference is available, or complete supply isolation is desired,
the internal TVS may be used as the reference. In this case, pin 5 is not used. The steering diodes
will begin to conduct when the voltage on the protected line exceeds the working voltage of the TVS
(plus one diode drop).
http:// www.sirectsemi.com
L054BT26
APPLICATION INFORMATION
(continued)
2.0 Universal Serial Bus (USB) ESD Protection
The
L054BT26
can be used to protect the USB ports on mobile phones, monitors, PCs, peripherals
and other portable systems
(please refer to schematic diagram below).
In typical applications, the
voltage bus (V
BUS
) of USB ports are connected to the power pin (pin 5) of the device. Each data line
(D+/D-) of the USB ports is connected to the ESD protection pin of the device.
When an electrostatic discharge (ESD) pulse appears on the data line, the ESD pulse current will be
conducted by the
L054BT26
away from the USB controller chip. In addition, the ESD pulse current
can also be conducted by the device away from the USB controller chip when the ESD voltage pulse
appears on the voltage bus (V
BUS
) of any of the USB ports. Therefore, the data lines (D+/D-) and
voltage bus (V
BUS
) of the two USB ports are complementally protected with the
L054BT26
device.
Typical Universal Serial Bus 2.0 Serial Application of the L054BT26
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