Silicon Labs has longest TDDB modeled lifetimes
Avago TDDB results: AN-1074,
SiLabs also running long-term dielectric testing
2100+ hours continuous testing @ 1600V without failures
Applied Voltage, Vrms
10ppm Time To Fail, years
Si84xx Si86xx/87xx
90 60 >400 > 400 265 120 10
Avago
>12 >12 >12 12 200 hrs
Silicon Labs Confidential
300
1600V @ 200 hrs
Two common electrical dielectrics are polymer tape and SiO2 Polymer tape: Non-uniform, substantially higher defects than SiO2 Silicon di-oxide (SiO2): Greater dielectric strength and uniformity, very low defect rate Significant maturity and learning over 30+ years Used in trillions of devices sold world wide Si8xxx products use Silicon Dioxide (SiO2) for insulation
Si87xx
TA =150o C
VTEST Device under test for TDDB in a 2 port configuration
14
Silicon Laboratories Confidential
Silicon Labs Confidential
Silabs’ Reliability vs. Optos
Silicon Labs Isolation Products for Sekorm
Silicon Labs Isolation Team, June 2016
Opto-couplers Replacement
What are the key isolation specifications?
Voltage Ratings: ability to withstand high voltage
Silicon Laboratories Confidential
13
Long Term Dielectric Reliability
All dielectrics are subject to aging Modeling is required to predict dielectric lifetimes
Silabs significantly outperforms optos
For Avago - only voltages less than 800V have a lifetime rating
Silabs specifies working voltages up to 1600V
14,391 8722 1310
MTTF
7.9 years 13 years 87 years
Does MTTF matter to customers?
20+ year system lifetime is common target for industrial applications
Top Layer Metal Passivation
Top Layer Metal Top Layer Metal
Passivation
Silicone
LED Die
Insulating Tape
Isolation Capacitor Active Circuit Layers
Isolation Capacitor
1600V lifetime:
Avago - 200 hours* Silabs - 87,600 hours (10 year)
Silabs no isolation field failures: >100M channels shipped
Avago Lifetime Curve
12
Silicon Laboratories Confidential
Silicon Labs Confidential
SiO2 Dielectric Material
SiO2 is the most mature and widely used dielectric available!
SiO2 usage exceeds dielectric tape usage by orders of magnitude
Poor timing characteristics
Long delay times slow system throughput Key parameters (e.g. jitter) often not specified
Marginal common mode transient immunity (CMTI)
Working voltage rating (VIORM)
Continuous lifetime operation
Maximum withstand rating (VIOTM)
1 minute maximum voltage
Si87xx/826x high voltage lifetimes:
`Fast common mode transients can corrupt data
Customers often add BOM to improve CMTI performance
Energy inefficient
Requires high LED drive current – increases overall energy consumption
Silicon Labs Confidential
Optocouplers: 40 Years of Limitations
Poor reliability
Key parameters drift over temperature, VDD and age
CMOS isolator reliability is 10x that of optos
Foundries invested billions in developing and testing SiO2 processes
Proven high reliability in billions of CMOS products in different applications
SiO2
Burried Metal Layer Plate Plate
SiO2
Burried Metal Layer
Active Circuit Layers
DTI
XMITR
RECVR
Detector Die
Si8xxx Isolator Structure with SiO2 Dielectric Optocoupler with polymer insulating tape
Modern low-voltage CMOS ICs subject SiO2 to huge electric fields
Example: 1.8V transistor in a CMOS cell phone chip
Transistor voltage = 1.8V Dielectric thickness = 4nm Electric field = 4.5 MV/cm
Solving these issues requires more BOM, complicating design!
Optocoupler with external clamps to improve CMTI
11
Silicon Labs Confidential
Dielectric Comparisons
>60 years at rated working voltage
Noise performance: ability to resist noise
Common Mode Transient Immunity (CMTI)
Device needs to reject high voltage transients Prevents data errors from these transients
Various models used for predicting lifetimes TF = time to fail
All vendors have done TDDB studies
SilLabs has extensive TDDB testing to prove long lifetimes
Modeled using time dependent dielectric breakdown (TDDB) Various models have been studied E-model is the most widely used and the most conservative TDDB models temperature, E-field and material properties