AOZ8844 Ultra-Low Capacitance TVS Diode General Description

AOZ8844 Ultra-Low Capacitance TVS Diode  General Description
AOZ8844
Ultra-Low Capacitance TVS Diode
General Description
Features
The AOZ8844 is a transient voltage suppressor array
designed to protect high speed data lines such as HDMI,
USB 3.0, MDDI, SATA, and Gigabit Ethernet from
damaging ESD events.
 ESD protection for high-speed data lines:
This device incorporates eight surge rated, low
capacitance steering diodes and a TVS in a single
package. During transient conditions, the steering diodes
direct the transient to either the positive side of the power
supply line or to ground.
The AOZ8844 provides a typical line-to-line capacitance
of 0.26 pF and low insertion loss up to 6 GHz providing
greater signal integrity making it ideally suited for
HDMI 1.3 or USB 3.0 applications, such as Digital TVs,
DVD players, computing, set-top boxes and MDDI
applications in mobile computing devices.
The AOZ8844 comes in a RoHS compliant and Halogen
Free 1.3 mm x 0.8 mm x 0.4 mm DFN-5 package and is
rated for -40 °C to +125 °C junction temperature range.
– IEC 61000-4-2, level 4 (ESD) immunity test
– Air discharge: ±20 kV; contact discharge: ±15 kV
– IEC61000-4-4 (EFT) 40 A (5/50 nS)
– IEC61000-4-5 (Lightning) +5 A (8/20 µS)
– Human Body Model (HBM) ±24 kV
 Array of surge rated diodes with internal TVS diode
 Small package saves board space
 Protects four I/O lines
 Low capacitance between I/O lines: 0.26 pF
 Low clamping voltage
Applications
 HDMI, USB 3.0, MDDI, SATA ports
 Monitors and flat panel displays
 Set-top box
 Video graphics cards
 Digital Video Interface (DVI)
 Notebook computers
Typical Applications
AOZ8844
AOZ8844
AOZ8802A
TX2+
TX2D+
D-
D+
D-
RX2+
RX2-
SSRX+
SSRX-
SSRX+
SSRX-
TX0+
TX0-
RX1+
RX1HDMI
Receiver
RX0+
RX0-
SSTX+
SSTX-
SSTX+
SSTX-
CLK+
CLK-
CLK+
CLK-
USB 3.0
Transceiver
USB 3.0
Connector
TX1+
TX1HDMI
Transmitter
Connector
AOZ8844
AOZ8844
Figure 1. USB 3.0 Ports
Rev. 1.0 July 2013
Connector
AOZ8844
Figure 2. HDMI Ports
www.aosmd.com
Page 1 of 8
AOZ8844
Ordering Information
Part Number
Ambient Temperature Range
Package
Environmental
AOZ8844DT
-40 °C to +85 °C
1.3 mm x 0.8 mm x 0.4 mm DFN-5
Green Product
AOS Green Products use reduced levels of Halogens, and are also RoHS compliant.
Please visit www.aosmd.com/media/AOSGreenPolicy.pdf for additional information.
Pin Configuration
CH1
VN
CH2
1
5
CH4
4
CH3
2
3
DFN-5
(Top View)
Absolute Maximum Ratings
Exceeding the Absolute Maximum ratings may damage the device.
Parameter
Rating
Storage Temperature (TS)
-65 °C to +150 °C
ESD Rating per IEC61000-4-2, contact
ESD Rating per IEC61000-4-2, air
(1)(3)
±15 kV
(1)(3)
±20 kV
ESD Rating per Human Body Model(2)(3)
±24 kV
Notes:
1. IEC 61000-4-2 discharge with CDischarge = 150pF, RDischarge = 330 Ω.
2. Human Body Discharge per MIL-STD-883, Method 3015 CDischarge = 100 pF, RDischarge = 1.5 kΩ.
Maximum Operating Ratings
Parameter
Rating
Junction Temperature (TJ)
Rev. 1.0 July 2013
-40 °C to +125 °C
www.aosmd.com
Page 2 of 8
AOZ8844
Electrical Characteristics
TA = 25°C unless otherwise specified.
Symbol
Parameter
Diagram
IPP
Maximum Reverse Peak Pulse Current
VCL
Clamping Voltage @ IPP (IEC61000-4-5 8/20 µs pulse)
VRWM
IR
VBR
I
Maximum Reverse Leakage Current
Breakdown Voltage
VCL VBR VRWM
Test Current
VF
Forward Voltage @ IF (IF = 15 mA)
Ppk
Peak Power Dissipation (IEC61000-4-5 8/20 µs pulse)
CJ
Capacitance @ VR = 0 and f = 1 MHz
Device VRWM (V)
Max.
Marking
AOZ8844DT
A
V
IR VF
IT
IT
Device
IF
Working Peak Reverse Voltage
5.0
IPP
VBR (V)
Min.
IT = 100 A
IR (µA)
Max.
VF (V)
Typ.
IPP = 2 A
6.0
1.0
0.85
3.5
VCL Max.(3)
CJ (pF)
IPP = 5 A PPK (W)
6.5
32
Typ.
Max.
0.5
0.6
Notes:
3. These specifications are guaranteed by design and characterization.
Rev. 1.0 July 2013
www.aosmd.com
Page 3 of 8
AOZ8844
Typical Performance Characteristics
Clamping Voltage vs. Peak Pulse Current
8
1.2
Normalized Capacitance
Clamping Voltage (V)
Capacitance vs. Reverse Bias
(IEC61000-4-5 8/20µs pulse current)
7
6
5
4
3
2
1.0
0.8
0.6
0.4
0.2
0
2
2.5
3.0
3.5
4.0
Peak Pulse Current (A)
4.5
5.0
0
0
0
-1
-1
-2
-2
-3
-4
-5
2
3
Reverse Bias (V)
4
5
IO-IO Insertion Loss (S21) vs. Frequency
dB (S21)
dB (S21)
IO-GND Insertion Loss (S21) vs. Frequency
1
-3
-4
1
10
Rev. 1.0 July 2013
100
1000
Frequency (MHz)
10000
-5
www.aosmd.com
1
10
100
1000
Frequency (MHz)
10000
Page 4 of 8
AOZ8844
High Speed PCB Layout Guidelines
Printed circuit board layout is the key to achieving the
highest level of surge immunity on power and data lines.
The location of the protection devices on the PCB is the
simplest and most important design rule to follow. The
AOZ8844DT devices should be located as close as
possible to the noise source. The AOZ8844DT device
should be placed on all data and power lines that enter or
exit the PCB at the I/O connector. In most systems, surge
pulses occur on data and power lines that enter the PCB
through the I/O connector. Placing the AOZ8844DT
devices as close as possible to the noise source ensures
that a surge voltage will be clamped before the pulse can
be coupled into adjacent PCB traces. In addition, the
PCB should use the shortest possible traces. A short
trace length equates to low impedance, which ensures
that the surge energy will be dissipated by the
AOZ8844DT device. Long signal traces will act as
antennas to receive energy from fields that are produced
by the ESD pulse. By keeping line lengths as short as
possible, the efficiency of the line to act as an antenna for
ESD related fields is reduced. Minimize interconnecting
line lengths by placing devices with the most interconnect
as close together as possible. The protection circuits
should shunt the surge voltage to either the reference or
chassis ground. Shunting the surge voltage directly to the
IC’s signal ground can cause ground bounce. The
clamping performance of TVS diodes on a single ground
PCB can be improved by minimizing the impedance with
relatively short and wide ground traces. The PCB layout
and IC package parasitic inductances can cause
significant overshoot to the TVS’s clamping voltage. The
inductance of the PCB can be reduced by using short
trace lengths and multiple layers with separate ground
and power planes. One effective method to minimize
loop problems is to incorporate a ground plane in the
PCB design.
The AOZ8844DT ultra-low capacitance TVS is designed
to protect four high speed data transmission lines from
transient over-voltages by clamping them to a fixed
reference. The low inductance and construction
minimizes voltage overshoot during high current surges.
When the voltage on the protected line exceeds the
reference voltage the internal steering diodes are forward
biased, conducting the transient current away from the
sensitive circuitry. The AOZ8844DT is designed for ease
of PCB layout by allowing the traces to run underneath
the device. The pinout of the AOZ8844DT is designed to
simply drop onto the IO lines of a High Definition
Multimedia Interface (HDMI) or USB 3.0 design without
having to divert the signal lines that may add more
parasitic inductance. Pins 1, 2, 4 and 5 are connected to
the internal TVS devices and pins 6, 7, 9 and 10 are no
connects. The no connects was done so the package can
be securely soldered onto the PCB surface.
Clock
Clock
SSRX+
SSRX+
Data0
Data0
SSRX–
SSRX–
Ground
Ground
Ground
Data1
Data1
SSTX+
SSTX+
Data2
Data2
SSTX–
SSTX–
Ground
Figure 3. Flow Through Layout for HDMI
Figure 4. Flow Through Layout for USB 3.0
.
Rev. 1.0 July 2013
www.aosmd.com
Page 5 of 8
AOZ8844
D
5xL
Package Dimensions, DFN 1.3mm x 0.8mm x 0.4mm, 5L
e1
A1
A
E
e
2
1
A2
5xb
TOP VIEW
SIDE VIEW
BOTTOM VIEW
RECOMMENDED LAND PATTERN
0.45
0.18
0.40
0.25
1.05
0.50
Unit: mm
Dimensions in Millimeters
Symbols
A
A1
A2
b
D
E
e
e1
L
Min.
0.37
0.00
0.13
1.20
0.70
0.20
Nom.
0.40
—
(0.13)
0.18
1.30
0.80
0.45 BSC
0.50 BSC
0.25
Max.
0.43
0.05
0.23
1.40
0.90
0.30
Dimensions in Inches
Symbols
A
A1
A2
b
D
E
e
e1
L
Min.
0.015
0.000
Nom. Max.
0.016 0.017
—
0.002
(0.005)
0.005 0.007 0.009
0.047 0.051 0.055
0.028 0.031 0.035
0.018 BSC
0.020 BSC
0.008 0.010 0.012
Notes:
1. Controlling dimensions are in millimeters. Converted inch dimensions are not necessarily exact.
2. Land pattern dimensions are only for reference.
Rev. 1.0 July 2013
www.aosmd.com
Page 6 of 8
AOZ8844
Tape and Reel Dimensions, DFN 1.3mm x 0.8mm x 0.4mm, 5L
Carrier Tape
P1
T
P2
D1
E1
E2
E
B0
K0
P0
D0
A0
Feeding Direction
UNIT: mm
Package
A0
DFN 1.3x0.8 1.02
±0.05
(8mm)
B0
1.52
±0.05
K0
0.50
±0.05
D0
0.50
±0.05
D1
E1
E
1.50
1.75
8.00
±0.10 +0.3/-0.10 ±0.10
Reel
E2
3.50
±0.05
P0
4.00
±0.10
P1
4.00
±0.10
P2
2.00
±0.05
T
0.20
±0.02
W1
S
G
N
M
K
V
R
H
W
UNIT: mm
Tape Size Reel Size
8mm
ø178
M
ø178.0
±1.0
N
ø60.0
±1.0
W
9.0
±0.5
W1
—
H
ø13.0
+0.5 / –0.2
K
10.25
±0.2
S
2.4
±0.1
E
ø9.8
R
—
R
—
Leader / Trailer & Orientation
Trailer Tape
300mm Min. OR
75 Empty Pockets
Rev. 1.0 July 2013
Components Tape
Orientation in Pocket
www.aosmd.com
Leader Tape
500mm Min. OR
125 Empty Pockets
Page 7 of 8
AOZ8844
Part Marking
AOZ8844DT
(1.3 x 0.8 DFN)
A A
Part Number Code
Month Code
LEGAL DISCLAIMER
Alpha and Omega Semiconductor makes no representations or warranties with respect to the accuracy or
completeness of the information provided herein and takes no liabilities for the consequences of use of such
information or any product described herein. Alpha and Omega Semiconductor reserves the right to make changes
to such information at any time without further notice. This document does not constitute the grant of any intellectual
property rights or representation of non-infringement of any third party’s intellectual property rights.
LIFE SUPPORT POLICY
ALPHA AND OMEGA SEMICONDUCTOR PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL
COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS.
As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant into
the body or (b) support or sustain life, and (c) whose
failure to perform when properly used in accordance
with instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of
the user.
Rev. 1.0 July 2013
2. A critical component in any component of a life
support, device, or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or
effectiveness.
www.aosmd.com
Page 8 of 8
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement