| ST has been renewing its power rectifiers product range to enlarge
the designer choice and improve the power density of each device.
After the power Schottky range extension to 170V and the avalanche
concept introduction, the next step concerns the reshaping of the
bipolar and ultrafast diode portfolio. |
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| Introduction to bipolar and ultrafast
diodes |
| Bipolar and ultrafast diodes are the workhorse of all power applications,
from adaptor or DVD power supplies to heavy welding converters.
The performance of each bipolar or ultrafast diode has a strong
impact on the final application performance. However, one critical
parameter in an application may be of secondary importance in the
other. Most of these functions can be optimized by using ultrafast
diodes with medium recovery time value, that is to say not exceeding
75ns, and with maximized VF / IR performance. Using a new planar
platinum doping process instead of the previous gold doping technology,
the new 350 STTHxx devices offer optimum solutions in terms of combined
low forward voltage drop (VF), low leakage current (IR) and higher
operating junction temperatures (up to 175°C). |
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| Platinium doping versus gold |
The lower the VF, the higher the reverse recovery time trr, this
rule is true for both platinum and gold doping ultrafast diodes.
Therefore, at a given trr for a diode, the VF can be slightly improved,
to the detriment of the leakage current.
By using the planar platinum doping process, ST has reduced the
leakage current by approximately 10 to 100 times in comparison with
gold doping. Considering the standard reverse recovery time found
on the market with the gold doping technology, ST has optimized
the VF, trr and IR combined performance of its new devices, now
offering the best VF / IR ratio on the market.
Furthermore, the tiny leakage current obtained by this advanced
process results in a significant improvement in thermal dissipation,
and also contributes to the reduction of the power consumption of
the clamping functions in standby mode operation. |
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| STTHxxx series roadmap |
| The new STTHxxx devices are already available from 200 to 1200V.
These new devices replace the STTAxx, BYTxx, BYWxx, BYVxx and STPRxx
series. |
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| New range features, benefits and availability |
| The main advantages of the
STTHxxx series are: |
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high operating temperature
of 175°C |
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leakage current divided by 10 to 100
times |
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low thermal runaway risk by very reduced
IR |
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best VF / IR performance |
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VFP (forward recovery voltage)
specified in datasheets |
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low forward voltage drop: VF
typ. = 1.30V |
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ultrafast recovery diodes: trr
< 80ns (Unitrode conditions) |
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numerous parametric trade-offs to fit
each application (600V) |
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PSPICE parameter available |
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