8
S101DH2 Series
S201DH2 Series
■ Design Considerations
Sheet No.: D4-A01301EN
● Design guide
In order for the SSR to turn off, the triggering current (I
F
) must be 0.1mA or less.
Particular attention needs to be paid when utilizing SSRs that incorporate zero crossing circuitry.
If the phase difference between the voltage and the current at the output pins is large enough, zero crossing
type SSRs cannot be used. The result, if zero crossing SSRs are used under this condition, is that the SSR
may not turn on and off irregardless of the input current. In this case, only a non zero cross type SSR should
be used in combination with the above mentioned snubber circuit selection process.
When the input current (I
F
) is below 0.1mA, the output Triac will be in the open circuit mode. However, if the
voltage across the Triac, V
D
, increases faster than rated dV/dt, the Triac may turn on. To avoid this situation,
please incorporate a snubber circuit. Due to the many different types of load that can be driven, we can
merely recommend some circuit values to start with : Cs=0.022µF and Rs=47Ω. The operation of the SSR
and snubber circuit should be tested and if unintentional switching occurs, please adjust the snubber circuit
component values accordingly.
When making the transition from On to Off state, a snubber circuit should be used ensure that sudden drops
in current are not accompanied by large instantaneous changes in voltage across the Triac.
This fast change in voltage is brought about by the phase difference between current and voltage.
Primarily, this is experienced in driving loads which are inductive such as motors and solenods.
Following the procedure outlined above should provide sufficient results.
For over voltage protection, a Varistor may be used.
Any snubber or Varistor used for the above mentioned scenarios should be located as close to the main
output triac as possible.
All pins shall be used by soldering on the board. (Socket and others shall not be used.)
● Degradation
In general, the emission of the IRED used in SSR will degrade over time.
In the case where long term operation and / or constant extreme temperature fluctuations will be applied to
the devices, please allow for a worst case scenario of 50% degradation over 5years.
Therefore in order to maintain proper operation, a design implementing these SSRs should provide at least
twice the minimum required triggering current from initial operation.
● Recommended Operating Conditions
Parameter Symbol Unit
Input
Output
Input signal current at ON state
Input signal current at OFF state
Load supply voltage
Load supply current
Frequency
Operating temperature
I
F
(ON)
I
F
(OFF)
V
OUT
(rms)
I
OUT
(rms)
f
T
opr
mA
mA
V
mA
Hz
˚C
−
−
−
Locate snubber circuit between output terminals
(Cs=0.022µF, Rs=47Ω)
−
−
Conditions
20
0
−
−
50
−20
25
0.1
120
240
I
T
(rms)×80%(
∗
)
60
80
MIN. MAX.
(
∗
) See Fig.2 about derating curve (I
T
(rms) vs. ambient temperature).
S101DH2
S201DH2
