The LT211 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: LT211

(Load voltage: 350V / Load current: 120mA)


Absolute Maximum Ratings(Ambient Temperature: 25℃)


InputContinuous LED CurrentIF50mA 
Peak LED CurrentIFP1000mAf=100Hz, duty=1%
LED Reverse VoltageVR5V 
Input Power DissipationPIn75mW 
OutputLoad VoltageVL350V(AC peak or DC) 
Load CurrentIL120mA 
Peak Load CurrentIPeak0.6A100ms(1 pulse)
Output Power DissipationPout300mW 
Total Power DissipationPT350mW 
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 0.51.0mA 
Recovery LED CurrentIF Off 0.350.5mA 
Recovery LED VoltageVF Off0.7  V 
OutputOn-ResistanceROn 1724ΩIF=5mA,IL=100mA, Time to flow is within 1 sec.
Off-State Leakage CurrentILeak  1uAVL=Rating
Output CapacitanceCOut 115 pFVL=0, f=1MHz
TransmissionTurn-On TimeTOn 0.230.5msIF=5mA, IL=100mA,
Turn-Off TimeTOff 0.050.2ms
CoupledI/O Isolation ResistanceRI/O1010  ΩDC500V
I/O CapacitanceCI/O 0.81.5pFf=1MHz