The LT218D is a miniature 1-Form A solid state relay in a 4 pin SOP package that employs optically coupled MOSFET technology to provide 1500V of input to output isolation. The optically coupled input is controlled by a highly efficient GaAlAs infrared LED and MOS FETs on the output side.



SOP package 4 Pin type in miniature design (4.4×4.3×2.0mm / .173×.169×.083inch)

Low driver power requirements (TTL/CMOS Compatible)

No moving parts

High reliability

Arc-Free with no snubbing circuits

1500Vrms Input/Output isolation

Tape & Reel version available


Telecommunications (PC, Electronic notepad)

Measuring and Testing equipment

Industrial control

Security equipments

High speed inspection machine


Photo DMOS-FET Relay Specifications


Part Name: LT218D

(Load voltage: 40V / Load current: 4.0A/DC)


Absolute Maximum Ratings(Ambient Temperature: 25℃)


InputContinuous LED CurrentIF50mA 
Peak LED CurrentIFP1000mAf=100Hz, duty=1%
LED Reverse VoltageVR5V 
Input Power DissipationPIn75mW 
OutputLoad VoltageVL40V(DC) 
Load CurrentIL4.0A 
Peak Load CurrentIPeak35A300μs(1 pulse)
Output Power DissipationPout250mW 
Total Power DissipationPT2W 
I/O Breakdown VoltageVI/O1500VrmRH=60%, 1min
Operating TemperatureTopr-40 to +85 
Storage TemperatureTstg-40 to +100 
Pin Soldering TemperatureTsol26010 sec max.


Electrical Specifications(Ambient Temperature: 25℃)


InputLED Forward VoltageVF 1.21.4VIF=10mA
Operation LED CurrentIF on 0.55.0mA 
Recovery LED VoltageVF off0.7  V 
OutputOn-ResistanceRon 0.20.6ΩIF=5mA,IL=100mA, Time to flow is within 1 sec.
Off-State Leakage CurrentILeak  0.1uAVL=Rating
Output CapacitanceCout 240 pFVL=0, f=1MHz
TransmissionTurn-On TimeTon 1.03.0msIF=5mA, IL=100mA,
Turn-Off TimeToff 0.030.5Ms
CoupledI/O Isolation ResistanceRI/O1010  ΩDC500V
I/O CapacitanceCI/O 0.81.5pFf=1MHz