Gas Plasma Voltage Dependent Switches
Switching Gas Discharge Tubes
316 www.littelfuse.com
LT Series
The LT Series is a 2-terminal bi-directional, voltage triggered
switch is designed for ignition circuits used in high pressure HID
lighting. Switching voltages for the devices are fixed depending
on the part number selected. The gas plasma trigger technology
offers very fast switching speeds, resulting in significantly better
di/dt values when compared to silicon based SIDAC devices.
Due to the high switching voltage of the devices, step-up
transformer sizes and specifications can be reduced saving
cost, size and weight.
Features
• RoHS compliant
• Ceramic chamber for ultimate reliability.
• Very high switching speed once switching voltage has
been reached, resulting in high di/dt to be generated
enabling the best performance to be extracted from
ignition transformers.
• Tape and reel to EIA 481-1
Applications
• For switching stored electrical energy (such as capacitive
discharge) at predetermined voltages.
• Designed for ignition circuits used in high pressure
HID lighting.
ORDERING INFORMATION
LT 800
VBO
Package Type
Packaging
A= Axial lead, tape and Reel
SM= Surface Mount
8+0.20
- 0.20
6+0.20
- 0.20
60.0 +4
LT xxx SM
LTxxx A
Mechanical Specifications:
Weight (ballast ciruit only): 1.42g (0.049oz.)
Materials: Electrode Base: Copper alloy
Electrode Plating material: Bright Sn
Body: Ceramic
Device Marking: Littelfuse ‘LF’ marking, voltage and
product code (red print)
Dimensions in mm
RoHS
Switching Gas Discharge Tubes
Gas Plasma Voltage Dependent Switches
317
www.littelfuse.com
7
SWITCH GAS
DISCHARGE TUBES
LT Series
LT device
V
O.C. DC voltage =1000
51KΩ
Fig 1. Recommended breakover voltage test circuit
(Discharge current = 10-20mA, sensitivity of
Peak Voltage Detect = 10-30mA)
P.V.D.
0.22µF
LT device
V
20K
Fig 2. Recommended Life Circuit
Ω
330nF
0.4µH
1000Vdc
Part
Number
Device Ratings and Specifications
VBO(1)
(V) VS
(V)
VT@ 5A
(V) IDRM (2)
(A)
Electrical Life:
Switching Cycles (5) ………………………………………………………… 400,000
Peak Discharge Current (5) ………………………………………………………. 400 A
Maximum Ratings:
Max Switching Frequency ………………………………………………………. 100 Hz
Storage Temperature TSTG ……………………………………………………… -40 - +150˚C
Operating Temperature ……………………………………………………… -40 - +150˚C
Notes:
(1) Measured on recommended test circuit (fig 1.)
(2) Measured @ 100 Volts DC
(3) Current required for transition to on-state
(4) Measured @ 1 MHz, zero Volt bias
(5) Measured on recommended test circuit (fig 2.)
Definitions:
VBO – Breakover Voltage
VS– Switching Voltage
VT@ 5A – Nominal Off-state Voltage at 5A
IDRM – Off-state Current
IBO – Nominal Breakover Current
Co- Max Capacitance
VBO to VT– Max switching time from VBO to VT
IBO (3)
(mA) CO(4)
(pF) VBO to VT
(nS)
LT230 195 –265 184 – 276 15 1.0 50 2.0 25
LT800 680 – 920 640 - 960 15 1.0 50 2.0 25
RoHS
