Gas Plasma Voltage Dependent Switches
Switching Gas Discharge Tubes
320
w w w . l i t t e l f u s e . c o m
XT Series
The XT Series is a 2-terminal bi-directional, voltage triggered
switch designed for Xenon HID 'hot re-strike' circuits such as
those found in automobiles. 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
2 terminal configuration.
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.
High lifetime and stability.
Switching performance is virtually unaffected by changes
in ambient temperature.
Tape and Reel to EIA 481-1
Applications
This product is optimised for Xenon HID `Hot re-strike'
circuits which require a very high number of operations
at high current levels. The switching time is typically
10nS for the best possible efficiency
.
ORDERING INFORMATION
XT
A
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
XT xxx SM.
XT xxx 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
Dimensions in mm
RoHS
Switching Gas Discharge Tubes
Gas Plasma Voltage Dependent Switches
321
w w w . l i t t e l f u s e . c o m
7
SWITCH GAS
DISCHARGE TUBES
XT Series
R1
XT device
C2
V
Recommended
Fig 1.
breakover voltage test circuit
V: open circuit DC voltage =500 (1000V for 600 and 800Vparts)
C1 =220nF
R1 =51K
Discharge current =10 mAmps ( approx )
L
V
R1
XT device
C2
Fig 2. Recommended life test circuit
V: open circuit DC voltage =500 (1000V for 600 and 800V parts)
C1 =680nF
R1 =10K
L =0.5
H
Discharge current =500Amps ( approx )
Part
Number
Device Ratings and Specifications
VBO
(1) (7)
(V)
Max
Ignition
VT
@ 5A
(V)
IDRM
(2)
(A)
IBO
(2)
(mA)
CO
(4)
(pF)
VBO to VT
(nS)
RS
(M)
XT350
297 403
463
15
1.0
5
1.5
25
>1
XT600
510 690
750
15
1.0
5
1.5
25
>1
XT800
680 920
1000
15
1.0
5
1.5
25
>1
Electrical Life:
Switching Cycles (5) .................................................................. 150,000
Maximum Ratings:
Max Switching Frequency(6) ................................................................ 400 Hz
Storage Temperature TSTG ............................................................... -40 - +150C
Operating Temperature ............................................................... -40 - +150C
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.)
(6) Duty Cycle: 1sec on, 10 sec off.
(7) Will retain these limits during life cycle
Definitions:
VBO
Breakover 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
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