Introduction to TVS Overvoltage
Protection Devices
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Outline
Overvoltage Protection– The race is on– Clamp vs Crowbar
Key Parameters– Unidirectional vs Bidirectional– Peak Pulse Power PPPM
– Double Exponential Waveforms
– Reverse Stand-Off Voltage VR– Breakdown Voltage VBR– Clampin Voltage VC– Peak Pulse Current IPP
Product Families– Part Number Conventions– Axial Leaded
P4KE, SA, SAC, P6KE 1.5KE, LCE 3KP, 5KP, SLD 15KPA, 20KPA, 30KPA AK6, AK10
– Surface Mount SMAJ, P4SMA, SACB SMBJ, P6SMB, 1KSMB SMCJ, 1.5SMC SMDJ, 5.0SMDJ
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The Race is On!
Overvoltage Protector
Protected Circuit
Overvoltage Event
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Vline
Trigger Voltage
Delatch
Crowbar Devices
Vline
Transient Event
Vline
Clamping Devices
Clamp Voltage
Clamping Devices vs Crowbar Devices
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Outline
Overvoltage Protection– The race is on– Clamp vs Crowbar
Key Parameters– Unidirectional vs Bidirectional– Peak Pulse Power PPPM
– Double Exponential Waveforms
– Reverse Stand-Off Voltage VR– Breakdown Voltage VBR– Clamping Voltage VC– Peak Pulse Current IPP
Product Families– Part Number Conventions– Axial Leaded
P4KE, SA, SAC, P6KE 1.5KE, LCE 3KP, 5KP, SLD 15KPA, 20KPA, 30KPA AK6, AK10
– Surface Mount SMAJ, P4SMA, SACB SMBJ, P6SMB, 1KSMB SMCJ, 1.5SMC SMDJ, 5.0SMDJ
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Key Parameters: Peak Pulse Power
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Key Parameters: Peak Pulse Power
Double Exponential Waveforms– Simulate induced lightning events– Rise time & decay time in microseconds
Underground LineUnderground Line
Transients
Transients
Transients
Transients
10 x 10008 x 20
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Bidirectional vs Unidirectional
Bidirectional TVS Unidirectional TVS
Voltage – Current (V-I) Curve
• Voltage is displayed left to right
• Current is displayed up and down
+I
+V-V
-I
IPP
IT
VR VBR VC
IR
+I
+V-V
-I
IPP
IT
VR VBR VC
IR
+I
+V-V
-I
IPP
IT
VR VBR VC
IR
+I
+V-V
-I
IPP
IT
VR VBR VC
IR
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+I
+V-V
-I
IPP
IT
VR VBR VC
IR
Key Parameters: VR
Reverse Standoff Voltage
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+I
+V-V
-I
IPP
IT
VR VBR VC
IR
Key Parameters: VBR
Breakdown Voltage
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+I
+V-V
-I
IPP
IT
VR VBR VC
IR
Key Parameters: VC
Max Clamping Voltage
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Key Parameters: Ipp
+I
+V-V
-I
IPP
IT
VR VBR VC
IR
Peak Pulse Current
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Question 1: True or False
A TVS Diode is intended to provide continuous voltage regulation to a circuit.
FALSE
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Question 2: True or False
A TVS Diode is a crowbar type of device that brings the protected line close to ground potential.
FALSE
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Question 3: True or False
The continuous power rating of a TVS Diode can be found by multiplying the peak allowable pulse current by the clamping voltage.
FALSE
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Question 4: True or False
A bidirectional TVS Diode can be used on a DC line.
TRUE
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Question 5: True or False
A Unidirectional TVS Diode is symmetrical and has the same clamp voltage regardless of the direction of current flow through the part.
FALSE
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Outline
Overvoltage Protection– The race is on– Clamp vs Crowbar
Key Parameters– Unidirectional vs Bidirectional– Peak Pulse Power PPPM
– Double Exponential Waveforms
– Reverse Stand-Off Voltage VR– Breakdown Voltage VBR– Clamping Voltage VC– Peak Pulse Current IPP
Product Families– Part Number Conventions– Axial Leaded
– P4KE, SA, SAC, P6KE– 1.5KE, LCE– 3KP, 5KP, SLD– 15KPA, 20KPA, 30KPA– AK6, AK10
– Surface Mount– SMAJ, P4SMA, SACB– SMBJ, P6SMB, 1KSMB– SMCJ, 1.5SMC– SMDJ, 5.0SMDJ
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Part Numbering Conventions
• The first portion: Indicates the Peak Pulse Power or the package or both.
• The next portion: Indicates either the VR or the nominal VBR
• Both voltage conventions are industry standards.
• Offering both conventions is a critical driver for sales.
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Part Numbering Conventions
VR – Based Part Numbers – Axial Leaded
SA, SAC, LCE 3KP, 5KP, SLD 15KPA, 20KPA, 30KPA AK6, AK10
– Surface Mount SMAJ, SACB SMBJ, SMCJ, SMDJ, 5.0SMDJ
VBR – Based Part Numbers– Axial Leaded
P4KE, P6KE 1.5KE,
– Surface Mount P4SMA, P6SMB, 1KSMB 1.5SMC
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Axial Leaded TVS Diodes
Available Axial Packages
DO-41 DO-15 DO-201 P-600
AK-6 AK-10
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DO-41 Axial TVS Diodes
P4KE (400W)
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DO-15 Axial TVS Diodes
P6KE (600W) SA (500W) SAC (500W, Low Cap)
TVS Diode
Isolation Diode
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DO-201 Axial TVS Diodes
1.5KE (1500W) LCE (1500W, Low Cap)
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P-600 Axial TVS Diodes
3KP (3000W) 5KP (5000W) 15KPA (15000W) 20KPA (20000W) 30KPA (30000W) SLD (2200W - 100x150000 uS Waveform)
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AK Series TVS Diodes
AK6 (6000A – 8x20 uS Waveform) AK10 (10000A – 8x20 uS Waveform)
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Surface Mount TVS Diodes
Available Surface Mount Packages
DO-214AC(SMA J-Bend)
DO-214AA(SMB J-Bend)
DO-214AB(SMC J-Bend)
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SMA Surface Mount TVS Diodes
SMAJ (400W) P4SMA (400W)
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SMB Surface Mount TVS Diodes
SMBJ (600W) P6SMB (600W) SACB (500W, Low Cap) 1KSMB (1000W)
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SMC Surface Mount TVS Diodes
SMCJ (1500W) 1.5SMC (1500W) SMDJ (3000W) 5.0SMDJ (5000W)
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Axial TVS Diode Summary
Naming Convention
Polarity DO-41 DO-15 DO-201 P-600 AK
Vbr P4KE P6KE 1.5KE
SA
3KP5KP
15KPA20KPA30KPA
SLD
AK6AK10
Low Cap SAC LCE
Vr
Uni / Bi
Littelfuse Axial TVS Diodes
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Surface Mount TVS Diode Summary
Naming Convention
Polarity SMA SMB SMC
Vbr P4SMAP6SMB1KSMB
1.5SMC
SMAJ SMBJSMCJSMDJ
5.0SMDJ
Low Cap SACB
Uni / Bi
Vr
Littelfuse Surface Mount TVS Diodes
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Question 1: True or False
The leakage current of a TVS Diode is measured at its breakdown voltage.
FALSE
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Question 2: True or False
If the same pulse current is allowed to flow through both a low power and a high power TVS Diode, the clamping voltage will be lower on the high power device.
TRUE
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Question 3: True or False
If a narrow 20µS current pulse is allowed to flow through a TVS Diode, the allowable power level can be higher than the 10x1000µS power level indicated on the data sheet.
TRUE
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Question 4: True or False
The AK series of TVS Diodes can handle a million watts of power during a transient event.
TRUE
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Question 5: True or False
TVS Diode part numbers always refer to the actual breakdown voltage of the device.
FALSE
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Thank You!
Introduction to TVSOvervoltage Protection Devices