（2）Metal Sealed Type（ASB, ASL and AHB Series）
a. DC voltage application
MTTFr of the metal sealed type under the actual operating conditions is calculated/estimated from the
reference MTTFs and the acceleration factor as in the case of the resin-coated type. However since
the internal element is sealed from the atmosphere, it is not influenced by the atmospheric humidity.
Therefore, equation（2）below is used.
MTTF
r
=MTTF
s×A
v×A
t
• • • (2)
MTTF
MTTF
r
: Estimated value
s
: Reference value (=36,000h)
2
100
A
A
v
t
: Acceleration factor for drive voltage=
V
r
: Actual operating voltage (V)
V
r
85–T
10
r
:Acceleration factor for ambient temperature=1.5
T
r
: Actual operating temperature (℃)
[Example] The following calculation is made for use at 25(c and 150 V:
2
85–25
10
100
MTTF
r
=36,000×
×1.5
150
=36,000×0.44×11.3
179,000h (20.4years)
b. Pulse voltage application
Like the resin-coated type, it is extremely difficult to estimate reliability by using an equation in the
metal sealed type because of the influence of the pulse waveform, frequency, etc. in addition to the
voltage and ambient temperature.
In NEC TOKINʼs testing on the ASB170C801NP0, there was no failure confirmed up to 1000 hours
（equivalent to 100 million pulses were applied）under the conditions below.
[Conditions for evaluation]
Temperature: 85± 2℃
Humidity: 90 to 95% RH
Load: 200 N to 500 N（20 kgf to 50 kgf）
Drive voltage waveform: Rectangular wave, 30 Hz, 0 V to 100 V, duty ratio at 30%
20 Multilayer Piezoelectric Actuators Vol.06
●All specifications in this catalog and production status of products are subject to change without notice. Prior to the purchase, please contact NEC TOKIN for updated product data.
●Please request for a specification sheet for detailed product data prior to the purchase.
●Before using the product in this catalog, please read "Precautions" and other safety precautions listed in the printed version catalog.
2011.06.22 9307MPAVOL06E1106H2
NEC [ NEC ]
