SIDACtor Capacitance Effects

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Transcript SIDACtor Capacitance Effects

Telecom SIDACtor Training
Training Agenda
1.
SIDACtor Definition and Telecom Circuit Protection Needs
2.
SIDACtor Characteristics and Device Physics
3.
SIDACtor Telecom Applications Protection Examples
4.
SIDACtor Telecom Applications Product Selection
5.
Littelfuse SIDACtor Product Road Map
6.
SIDACtor Technology Challenges
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Telecom SIDACtor Training
Section 1 SIDACtor Definition and Telecom Circuit Protection
•
SIDACtor Definition
–
A SIDACtor is a thyristor-based protection device that provides a crowbar current path to
protect electronic components/equipment from transient threats
•
Circuit Protection Needs in Telecom Segment
–
Lightning
–
ESD
–
Inductive
–
Short Circuit/Power-Cross
•
SIDACtor Technology for Telecom Overcurrent Circuit Protection
–
Fast response time
–
Stable electrical characteristics
•
Typical Telecom Test Standards
–
ITU K.20 K.21
–
Bellcore GR1089
–
UL 60950
•
Typical SIDACtor Test Standards
–
IEEE C62.37
–
UL 1449
–
UL 1459
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SIDACtor Definition and Telecom Circuit Protection
SIDACtor Definition
–
SIDACtor is a thyristor-based protection device that provides a crowbar current path to protect
electronic components from transient threats.
–
The SIDACtor functions:
• Bi-directional, voltage-triggered switch
• Normally open circuit (high impedance)
• Turns on with trigger voltage
• On-state becomes low-impedance path
• Turns off when current falls below holding level
–
SIDACtor features as following
• Cannot be damaged by transient voltage.
• Eliminates the hysteresis and heat dissipation typically found with a clamping device.
• Eliminates voltage over-shoot caused by fast rising transients / Extremely fast (<10 ns).
• Non-degenerative, will not fatigue / Rugged (Up to 5,000A surge current ratings).
• Relatively low capacitance, ideal for high speed transmission equipment.
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SIDACtor Definition and Telecom Circuit Protection
Circuit Protection Needs in Telecom Systems
– Thunderstorms around the world deliver 8 million lightning flashes every day. Peak current in
lightning discharges range from a few KA to many hundreds of KA. Induced currents from indirect
strikes range from 10A to 20KA.
–
ESD results from the build up of electrical charge, when two non-conductive materials are brought
together then separated. The potential between a human body & an object can exceed 35,000 volts.
An ESD event can occur to the telecom system or portable devices through human contact and
usage of the telecom devices.
–
Inductive Load Switching is caused when an inductive load is interrupted. It occurs in
factory/industrial environments where motors and relays (inductive loads) are turned on and off.
–
Short Circuit or Power Cross events can occur due to human error (such cutting a phone and power
line simultaneously during construction) or natural disaster such as hurricane, thunderstorm.
–
One or a combination of the above threats can have obvious adverse effects on semiconductor/IC
devices, electro-mechanical contacts, wiring insulation, etc., to cause interruption of telecom
equipment operation, telephone service, and even fire.
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SIDACtor Definition and Telecom Circuit Protection
SIDACtor Technology for Telecom Overvoltage Circuit Protection
Telecom equipment should be protected from overvoltage conditions using SIDACtors, GDTs,
MOVs, or TVS diodes.
–
A SIDACtor device is a PNPN device that can be thought of as a TVS diode with a gate. Upon
exceeding its peak off-state voltage (VDRM), a SIDACtor device will clamp a transient voltage to
within the device's switching voltage (VS) rating. Then, once the current flowing through the
SIDACtor device exceeds its switching current, the device will crowbar and simulate a short-circuit
condition. When the current flowing through the SIDACtor device is less than the device's holding
current (IH), the SIDACtor device will reset and return to its high off-state impedance.
–
SIDACtor devices are primarily used as the principle overvoltage protector in telecommunications
and data communications circuits. Its advantages include:
• Fast response time
• Stable electrical characteristics
• Long term reliability (no wear-out mechanism)
• Low capacitance
• It is difficult to be damaged by voltage and it has extremely high surge current ratings.
–
The SIDACtor is a crowbar device, it cannot be used directly across the AC line; it must be placed
behind a load. Failing to do so will result in exceeding the SIDACtor device's surge current rating,
which may cause the device to enter a permanent short-circuit condition.
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SIDACtor Definition and Telecom Circuit Protection
Telecom Systems Standards
GR 974
GR 1089
GR 974
K.20 YD/T 1082
GR 1089
GR 974
NEC 800
K.21 YD/T 993
K.20 YD/T 950
UL 497
NEC 800
UL 497
UL 497
MDF
SLIC
GR 1089
K.20 YD/T 950
UL 60950
GR 974
K.20/21
YD/T
950/993
UL 497
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SIDACtor Definition and Telecom Circuit Protection
SIDACtor Standards
– Std C62.37 Specification
• Rated parameter values
– The values of the rated parameters are established by the manufacturer.
• Parameter specifications
– Breakover current (IBO)
– Breakover voltage (VBO)
– Holding current (IH)
– Non-repetitive peak on-state current (Itsm)
– Non-repetitive peak pulse current (Ipps)
– Off-state capacitance (CO)
– Off-state (leakage) current (ID)
– Off-state voltage (VD)
– On-state current (IT)
– On-state voltage (VT)
– Repetitive peak off-state current (IDRM)
– Repetitive peak off-state voltage (VDRM)
– Repetitive peak on-state current (ITRM)
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Telecom SIDACtor Training
Section 2
SIDACtor Characteristics and Device Physics
–
Basic SIDACtor Characteristics and test procedures
•
Electrical Characteristics
–
V-I curve Characteristics
–
di/dt, dV/dt
–
Maximum ratings
–
Continuous / Transient
•
Thermal Characteristics
–
Junction Temperature
•
Signal Integrity Characteristics
–
Capacitance
–
SIDACtor Device Physics
•
SIDACtor Construction and V-I Curve Types
•
SIDACtor Thermal Effects/Characteristics
•
SIDACtor Capacitance Effects
•
SIDACtor Peak Pulse Current
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SIDACtor Characteristics and Device Physics
V-I Curve and Device Operation
In the standby mode, SIDACtor devices exhibit a high off-state
impedance, eliminating excessive leakage current and appearing
transparent to the circuits they protect. Upon application of a voltage
exceeding the switching voltage (VS), SIDACtor devices crowbar and
simulate a short circuit condition until the current flowing through the
device is either interrupted or drops below the SIDACtor device's
holding current (IH). Once this occurs, SIDACtor devices reset and
return to their high off-state impedance.
VS (Switching Voltage)
VDRM (Peak Off-state Voltage)
VT (On-state Voltage)
IT (On-state Current )
IS (Switching Current )
IH (Holding Current )
IDRM (Leakage Current )
Maximum voltage prior to
switching to on state
Maximum voltage that can be
applied while maintaining off-state
Maximum voltage measured at
rated on-state current.
Maximum rated continuous onstate current
Maximum current required to
switch to on-state
Minimum current required to
maintain on-state
Maximum peak off-state current
measured at VDRM
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SIDACtor Characteristics and Device Physics
–
di/dt Rate of Rise of Current
-- Maximum value of the acceptable rate of rise in
current over time
The purpose of this test is to verify that the
SIDACtor can survive a fast rising current, as may
occur on the wave front of an impulse. After
applying the di/dt impulse to the device, and when it
has returned to thermal equilibrium conditions, the
device shall not fail any of its specified
characteristics.
–
dV/dt Rate of Rise of Voltage
-- rate of applied voltage over time
The purpose of this test is to verify that the
SIDACtor will not turn on as a result of fast
rising system voltages with peak amplitudes
lass than the Vdrm rating. A specified voltage
ramp equal to the minimum value of critical
dv/dt and of amplitude Vdrm shall be applied to
the un-energized DUT. The peak ramp voltage
shall be maintained for a period of at least
50us. The DUT shall not switch on, even
partially, during the test.
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SIDACtor Characteristics and Device Physics
Maximum Ratings
– IPP
-- Peak Pulse Current
The purpose of this test is to verify that the
SIDACtor can survive a specific impulse wave
shape of short circuit current amplitude IPP with out
failure. The impulse test generator shall be
specified for the open-circuit voltage and shortcircuit current values, or equivalents, of wave
shape and wave shape peak value.
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SIDACtor Characteristics and Device Physics
Thermal Characteristics
– Thermal Resistance
The purpose of this test is to determine the continuous power
capability of the SIDACtor.
Immediately prior to the power being applied, the value of a
temperature dependent characteristic shall be measured at
the reference temperature. A constant value of power is then
applied to the device.
Thermal resistance, junction to ambient
RөJA = (TJPK - TA) / PTOT °C / W
Thermal resistance, junction to case
RөJC = (TJPK - TC) / PTOT °C / W
Thermal resistance, junction to lead
RөJD = (TJPK - TL) / PTOT
°C / W
Where TA = ambient temperature
TC = case temperature
TL = lead temperature
TJPK = peak junction temperature
PTOT = power pulse amplitude
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SIDACtor Characteristics and Device Physics
Off- State Capacitance
– CO
The purpose of this test is to determine the
off-state capacitance of the SIDACtor under
specified conditions.
The DUT off-state capacitance, CO, shall be
measured at specified dc (VD) and ac (VD
and VF) bias levels.
In the absence of special requirements, it is
recommended that an AC bias level of VD =
0.1 VRMS at a frequency of 100kHz to 1 MHz
be used. The DC bias level should be 0 V
and any other levels that are representative
of the intended application.
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SIDACtor Characteristics and Device Physics
SIDACtor Construction
SIDACtors are manufactured by creating a series of N-type and P-type layers in a silicon chip. The basic thyristor
structure has three PN junctions that require four layers (NPNP).
The SIDACtor device started manufacture with an N- slice of silicon. Layers of P material are then created at the top
and the bottom. A further N+ region is then made on the top surface. Finally the top and the bottom metallization
are added to provide contacts.
Transistor TR1 is formed by the N+PN- layers. Similarly transistor TR2 is formed by the PN-P layers. The device
breakdown voltage is determined by the breakdown of the central N-P layers, which form a shared collector-base
junction for TR1 and TR2. The breakdown function is shown as D1. R1 is the lateral resistance of the P layer. R2
together with R1 shunt the base-emitter junction of TR1 to define the value of holding current Ih. R2 has a relatively
low value of resistance and is considered as a localized short circuit between base and emitter.
During the manufacturing process, the emitter N+ diffusion is perforated with a series of dots to create these short
circuits. On the picture, some of the top metallization has been omitted to show the P-type shorting dots.
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SIDACtor Characteristics and Device Physics
SIDACtor Types
Unidirectional Blocking
SIDACtor
The inherent (fixed) voltage
breakdown can be lowered by
gate control, either by use of a
single gate or both together.
In the non-switching quadrant,
current flow will be blocked by the
reverse N-P anode junction.
Unidirectional Conducting
SIDACtor
The inherent (fixed) voltage
breakdown can be lowered by
gate control, either by use of a
single gate or both together.
In the non-switching quadrant,
current flow will be blocked by the
reverse PN diode.
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SIDACtor Characteristics and Device Physics
SIDACtor Types
Bidirectional SIDACtor
Bidirectional TRIAC SIDACtor
The inherent (fixed) voltage breakdown can be
lowered by controlling the appropriate gate or gates.
This bidirectional TRIAC has a special gate structure
that permits control in both quadrants with a single
gate terminal.
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SIDACtor Characteristics and Device Physics
SIDACtor Thermal Effects
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SIDACtor Characteristics and Device Physics
SIDACtor Thermal Effects
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SIDACtor Characteristics and Device Physics
SIDACtor Capacitance Effects
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SIDACtor Characteristics and Device Physics
SIDACtor Non- Repetitive Peak Pulse Current
IPP rating can be expressed as specific peak impulse current -time values or with a graph. If the
designer ensures that the SIDACtor is always operated below this limiting value, protector failure
will not occur.
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Telecom SIDACtor Training
Section 3
SIDACtor Telecom Applications Protection Examples
–
Basic Protection Topology
•
Two Point and Three Terminal Telecom Circuit Protection
–
Circuit Protection based on Telecom Application Requirement
•
Customer Premises Equipment
–
Transformer-Coupled Tip and Ring Circuits
•
High Speed Transmission Equipment & Interfaces
–
ADSL
–
T1/E1 Protection
–
IDSN
•
Analog Line Cards
–
SLIC Protection
•
Data Line Protection
–
LAN/WAN Protectors
–
Littelfuse Global Lab Capabilities
•
Qualification of Products
•
UL-Approved Customer Testing
•
Verification of Standards
•
Customer Application Testing
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SIDACtor Telecom Applications Protection Examples
Basic SIDACtor Topology
Two-terminal parallel
connected unit
Three-terminal parallel
and delta connected unit
Protector with bridge
diodes for wide band
systems
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SIDACtor Telecom Applications Protection Examples
Primary Protection
Primary protection is provided by the local exchange carrier and can be segregated into three distinct categories
as station protection, building entrance protection, and central office (CO) protection.
Protection Requirements
Station protectors must be able to withstand 300A 10x1000 surge events. The building entrance protectors and
CO protectors must be able to withstand 100A 10x1000 surge events. It should meet regulatory standards such
as UL 497, GR974-CORE and ITU K.28.
Example: Primary Protection
Example: Balanced Primary Protection
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SIDACtor Telecom Applications Protection Examples
Customer Premises Equipment (CPE)
CPE is defined as any telephone terminal or network equipment which resides at the customer's site and is
connected to the Public Switched Telephone Network (PSTN)
Protection Requirements:
CPE should be protected against overvoltages that can exceed 800V and against surge currents up to 100A. It
should meet regulatory standards such as TIA -IS-968 and UL 60950
Example: Basic CPE (Phone, Modem) Protection Application
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SIDACtor Telecom Applications Protection Examples
High Speed Transmission Equipment & Interfaces
High speed transmission equipment encompasses a broad range of transmission protocols such as T1/E1, xDSL,
and ISDN. Transmission equipment is located at the central office, customer premises, or remote locations.
Protection Requirements:
High speed transmission equipment should be protected against overvoltages that can exceed 2500V and against
surge currents up to 500A. It should meet regulatory standards such as TIA -IS-968, GR 1089-CORE, ITU
K.20/K.21, and UL 60950
Example: T1/E1 Protection Application
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SIDACtor Telecom Applications Protection Examples
Analog Line Cards
Subscriber Line Interface
Cards (SLICs) are highly
susceptible to transient
voltages that occur at the
central office and in remote
switching locations.
Protection Requirements
It is often necessary to protect Analog
line cards by on-hook (relay) and offhook (SLIC) protection. It should meet
regulatory standards such as TIA -IS968, GR 1089-CORE, ITU K.20/K.21,
and UL 60950.
Example: SLIC Protection
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SIDACtor Telecom Applications Protection Examples
Data Line Protection
In many office and industrial locations, data lines such as RS-232, Ethernet, and AC power lines run in close
proximity to each other, which often results in voltage spikes being induced onto data lines, possibly causing
damage to sensitive equipment.
Protection Requirements
Data lines should be protected against overvoltages that can exceed 1500V and surge currents up to 50A.
Example: 10 Base-T Longitudinal Protection Application
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SIDACtor Telecom Applications Protection Examples
Gate Controlled (Programmable) Protection Thyristor (Battrax)
Unidirectional gate-controlled
protectors
Positive and negative gatecontrolled protection
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SIDACtor Telecom Applications Protection Examples
Global Lab Capabilities
•
•
•
•
Qualification of all LF products
UL-Approved Customer Testing in ISO 17025 Lab (Des Plaines)
– High power (AC/DC up to 1KV/50KA) UL approvals available in DP
– Telcordia approvals in DP planned (2008)
Verification of Telcordia, ITU, IEC, FCC, and other industry, regulatory, and safety standards
– Verification to various OC and OV standards
• Insure application meets standards before submitting for approval
Customer Application testing
– Assistance with design-in and performance verification
• Help with selection of appropriate technology and rating
– Application troubleshooting
• Assistance insuring proper OV/OC and primary/secondary protection coordination
– Competitive evaluations
• Competitive or technology performance comparisons
– Reliability & Tin Whisker data/testing
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Telecom SIDACtor Training
Section 4
•
SIDACtor Telecom Applications Product Selection
SIDACtor Selection
–
Coordination of Protection
–
SIDACtor Unique Advantages Over Other Technologies
•
SIDACtor as a Crowbar Device
•
SIDACtor Fast Response to Transients
–
SIDACtor Device Selection
•
Identify SIDACtor Switching Voltage Requirement
•
Identify SIDACtor IT Requirement
•
Identify SIDACtor De-Rating Requirement
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SIDACtor Telecom Applications Protection Examples
Coordination of Protection
Primary and
secondary
coordination
Coordination
among
secondary
protective
devices
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SIDACtor Telecom Applications Product Selection
SIDACtor Selection
Technology
SIDACtor
GDT
MOV
TVS
Response Time
Fastest
Slowest
Slower
response time
Fast
Capacitance
Low
As low as 1pF
High
Higher
Current
surge rating
High
As high as 500A
for 200 impulses
High
Low
Electrical
Characteristic
Stable
Degrade with time
Fatigue after
multiple
pulses
Stable
Application
Principle over-voltage
in telecom, datacom
circuit
Telecom
applications
Useful in AC
applications
Secondary protection
Overvoltage Protection Comparison
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SIDACtor Telecom Applications Product Selection
SIDACtor Selection
Characteristics of Transient Voltage Suppressor Technology
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SIDACtor Telecom Applications Product Selection
SIDACtor Selection
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SIDACtor Telecom Applications Product Selection
SIDACtor selection
•
•
•
Off-State Voltage (VDRM)
– VDRM of the SIDACtor device must be greater than the maximum operating voltage of the
circuit the SIDACtor device is protecting.
– POTS (Plain Old Telephone Service) Application:
• 150 VRMS (maximum operating voltage) 2 + 56.6 V (maximum DC bias of central
office battery) = 268.8 VPK , VDRM > 268.8V
– ISDN (Integrated Services Digital Network) Application:
–
150 VPK (DC power supply) + 3 VPK (maximum voltage of the transmission signal), VDRM
> 153V
Switching Voltage (VS)
– The VS of the SIDACtor device should be equal to or less than the peak voltage rating of
the component it is protecting
– Example 1: VS < Relay Breakdown Voltage
– Example 2: VS < SLIC (Subscriber Line Interface Circuit) VPK
Peak Pulse Current (IPP)
– The Surge Current Rating (IPP) of the SIDACtor device should be greater than or equal to
the surge currents associated with the lightning immunity tests (IPK)
• IPP > IPK , IPP >= IPK (Available) : IPK (Available) = VPK/RTOTAL
– RTOTAL = RTIP+RSOURCE (Longitudinal) RTOTAL = RTIP +RRING+RSOURCE (Metallic)
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SIDACtor Telecom Applications Product Selection
SIDACtor selection
•
•
•
Peak Pulse Current (IPP)
– Example 1: Type A surge requirement of TIA/EIA-IS-968(FCC Part 68) with out any
series resistance
• IPK = 100A, 10x560 us
• IPP >= 100A, 10X560 us
• We can select "B","C" rated SIDACtor (page 2-4)
– Example 2: Surge requirement of GR 1089 with 30 ohm on Tip and 30 ohm on Ring.
• IPK = 100A, 10x1000 us
• VPK = 1000V, RSOURCE = VPK / IPK = 10 ohm
• RTOTAL = RSOURCE + RTIP = 40 ohm
• IPK (available) = VPK/RTOTAL = 1000V/40 ohm
• IPP >= 25A
Holding Current (IH)
– The holding current (IH) of the SIDACtor device must be greater than the DC current that
can be supplied during an operational and short circuit condition
– Example, TIA/EIA-IS-968 IPK<= 140 mA, IH = 150mA
Off-State Capacitance (CO)
– If Insertion Loss is recommended 70% of the original signal value.
– Example, Speed >= 30MHz, new MC series is highly recommended.
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Telecom SIDACtor Training
Section 5 Littelfuse SIDACtor Product Road Map
–
Teccor Brand
•
SIDACtor Road Map
•
Battrax Road Map
–
Concord Brand
•
Fixed Voltage Protection Thyristor Road Map
•
Variable Voltage Protection Thyristor Road Map
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Telecom SIDACtor Training
Section 6 SIDACtor Technology Challenges
–
SIDACtor VS and tolerance control
–
Higher surge ratings and smaller packaging
–
Multiple devices in one package
–
SIDACtor technology combined with other technologies in the same package
–
Improved de-rating characteristics
–
Higher operating temperatures
–
Development of programmable SIDACtors
–
Lead-frame vs. wire-bonding
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