Gas Discharge Tubes
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/12/17
SL1021A/B Series
Description
GDT circuit protection devices dissipate electrical
surge energy safely within a contained plasma gas.
Commonly used to help protect sensitive telecom
and networking equipment and lines, GDTs protect
from damage that may result from lightning strikes
and equipment switching operations.
The Littelfuse GDT series described in this document
are available in a variety of leaded and surface mount
forms and offered with and without optional fail-safe
clip. Please refer to the electrical specifications,
dimension and packaging options section of this
document for additional information.
SL1021A/B Series:
SL1021A/B series GDTs are designed to offer high
levels of performance on fast rising transients in the
range of 100V/μS to 1KV/μS, which are those most
likely created by induced lightning disturbances.
These devices feature ultra low capacitance (typically
1.5pF or less) and are extremely robust with SL1021A
devices able to divert a 10,000 Amp pulse without
destruction, and SL1021B suffix devices able to divert
a 20,000 Amp pulse without destruction.
These series offer optimized internal geometry which
provide low insertion loss at high frequencies, ideal
for the protection of broadband and other high speed
transmission equipment.
Features
• RoHS compliant
• Low insertion loss
• Excellent response to
fast rising transients
• Ultra low capacitance
• 10KA (A suffix devices) /
20KA (B suffix devices)
surge capability tested
with 8/20μs pulse as
defined by IEC 61000-4-5
• Available with thermal
failsafe option (add ‘F’
suffix to part number)
Applications
SL1021:
• Broadband equipment
• ADSL equipment
• XDSL equipment
• Satellite and CATV
equipment
• Splitters
• General telecom
equipment
• Telecom network
interfaces
• Telephone line cards
• Repeaters
• Modems
• Line test equipment
AGENCY AGENCY FILE NUMBER
E128662
Agency Approvals
3 Electrode GDT Graphical Symbol
a
e
ba = TIP
b = RING
e = GROUND
(center electrode)
Product Characteristics
Materials Dull Tin Plate 17.5 ± 12.5 Microns.
with ceramic insulator
Product Marking
‘LF’ mark, voltage& date code:
SL1021A - Red/White text
SL1021B - Blue/White text
Glow to arc
transition current ~ 1Amp
Glow Voltage
~60-200 Volts
Storage and Operation
Temperature
-40 to +90°C
Transverse Voltage
(Delay Time)
< 0.2µSec (Tested to ITU-T Rec. K.12)
Arc Voltage
~10 to 35 Volts
Holdover Voltage
<150mS (Tested to ITU-T Rec. K.12)
SL1021A/B Series
RoHS
Gas Discharge Tubes
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/12/17
SL1021A/B Series
Electrical Characteristics
Device Specifications (at 25°C) Life Ratings
Part
Number
DC Voltage
100V/Sec.
DC
Voltage
100 V/
μSec.
DC
Voltage
1kV/
μSec.
Capaci-
tance
(@1Mhz)
Insulation
Resistance
AC
Current
50Hz
1Sec.x101
Surge
Current
8/20μSec
x101
Max
Single
Surge
8/20μSec1
Max Single
Surge
10/350μSec1
Surge Life
10/1000
μSecx3001
MIN TYP MAX MIN
SL1021B075 60 75 90
500
650
<1.5pF
>1010 Ω
(at 50V)
10Amps 10kA2
20kA3
15kA2
25kA3
4kA2
5kA3
200Amps
SL1021A090
SL1021B090 72 90 108
SL1021A145
SL1021B145 116 145 174
600
>1010 Ω
(at 100V)
2.5kA2
5kA3
SL1021A150
SL1021B150 120 150 180
SL1021A200 150 200 250
SL1021A230
SL1021B230 184 230 276 450
650
SL1021A250
SL1021B250 200 250 300 500
SL1021A260
SL1021B260 210 260 310 550 700
SL1021A300
SL1021B300 240 300 360 650 850
SL1021A350
SL1021B350 280 350 420 700 900
SL1021A400
SL1021B400 320 400 480
850 950
SL1021A420
SL1021B420 345 420 500
SL1021A450
SL1021B450 360 450 540 900 1000
SL1021A500
SL1021B500 400 500 600 950 110 0
SL1021A600 480 600 720 1000 1200
NOTES:
1. Total current through centre electrode, tested in accordance with ITU-T Rec K.12
2. SL1021A series
3. SL1021B series
Additional Information
Datasheet Samples
Resources
Datasheet Samples
Resources
SL1021B
SL1021B SL1021B
SL1021A
SL1021A SL1021A
Samples
Samples
SL1021B
SL1021A
Gas Discharge Tubes
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/12/17
SL1021A/B Series
Time vs. Current for Failsafe
0.5
1
2
3
4
5
6
7
8
9
11
12
13
14
15
10
20
30
60
1 2 5 10 15 30
SL102xA with Failsafe
SL102xB or PMT8 500 Volt Higher Melting Point Solder
SL102xB or PMT8 90 Volt Higher Melting Point Solder
SL102xB or PMT8 350 Volt Higher Melting Point Solder
Voltage vs. Time Characteristic
Voltage
(V)
Time (ns)
0 200 400 600 800 1000 1200
Max dynamic breakover
voltage
Hold-over voltage
On-State voltage
Reflow Condition Pb – Free assembly
Pre Heat
- Temperature Min (Ts(min))150°C
- Temperature Max (Ts(max))200°C
- Time (Min to Max) (ts)60 – 180 secs
Average ramp up rate (Liquidus Temp
(TL) to peak 3°C/second max
TS(max) to TL - Ramp-up Rate 5°C/second max
Reflow - Temperature (TL) (Liquidus) 217°C
- Temperature (tL)60 – 150 seconds
Peak Temperature (TP)260+0/-5 °C
Time within 5°C of actual peak
Temperature (tp)10 – 30 seconds
Ramp-down Rate 6°C/second max
Time 25°C to peak Temperature (TP)8 minutes Max.
Do not exceed 260°C
Soldering Parameters - Reflow Soldering (Surface Mount Devices)
Time
Temperature
TP
TL
TS(max)
TS(min)
25
tP
tL
tS
time to peak temperature
(t 25ºC to peak)
Ramp-down
Ramp-up
Preheat
Critical Zone
TL to TP
Soldering Parameters - Wave Soldering (Thru-Hole Devices)
Soldering Parameters - Hand Soldering
Dwell Time
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
Time (Seconds)
Temperature (°C) - Measured on bottom side of board
Cooling Time
Preheat Time
Wave Parameter Lead-Free Recommendation
Preheat:
(Depends on Flux Activation Temperature) (Typical Industry Recommendation)
Temperature Minimum: 100° C
Temperature Maximum: 150° C
Preheat Time: 60-180 seconds
Solder Pot Temperature: 280° C Maximum
Solder Dwell Time: 2-5 seconds
Recommended Process Parameters:
Solder Iron Temperature: 350° C +/- 5°C
Heating Time: 5 seconds max.
Note: Surge Arrestors with a Failsafe mechanism should be
individually examined after soldering
Gas Discharge Tubes
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/12/17
SL1021A/B Series
8.1
[0.319]
10.10
[0.398]
9.9
[0.354]
9.9
[0.354]
10.10
[0.398]
4.4± 0.3
[0.173± 0.12]
4.4± 0.3
[0.173± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
11.8
[0.464]
8.1.
[0.319]
9.9
[0.354]
16.8
[0.661]
11.8
[0.464]
6.35 ± 0.5
[0.25 ± 0.25]
15
[0.590]
1.0 DIA.
[0.039]
8.1 DIA. MAX.
[0.319]
10.10
[0.398]
14.7
[0.579]
6.35 ± 0.5
[0.25 ± 0.25]
9.0
[0.354]
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
Mounting Area
9.0
[0.354]
Mounting Area
9.0
[0.354]
Mounting Area
9.9
[0.354]
10.10
[0.398]
5.5± 0.3
[0.216± 0.12]
5.5± 0.3
[0.216± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
8.1.
[0.319]
0.3mm
Minimum
Gap
9.0
[0.354]
Mounting Area
10.10
[0.398]
22
[0.866] 1.0 DIA..
[0.039]
50 ± 3
[1.968 ± 0.118 ]
8.1 DIA. MAX.
[0.319]
11.8
[0.464]
23.8
[0.937]
9.0
[0.354]
Mounting Area
0.3mm
Minimum
Gap
Type 01 / C
Type 60
Type 06 / Y
Type 14 / X
Type 04 / R
Type 05 / P
PROFILE VIEW
SOLDERING PAD LAYOUT
SIDE VIEW TOP VIEW
7.7 ± 0.3
[0.303 ± 0.019]
10.0 ± 0.3
[0.394 ± 0.019]
Ø7.0 ± 0.1
[0.275 ± 0.004]
8.3 +0.3/-0.0
[0.327
+0.019/-0.00]
8.0 +0.3/-0.1
[0.315
+0.019/-0.004]
8.5 ± 0.0
[0.335 ± 0.000]
2.2 ± 0.0
[0.087 ± 0.000]
6.0 ± 0.0
[0.236 ± 0.000]
10.75 ± 0.0
[0.423 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
Overall Product Space
DO NOT ENCROACH
Device Dimensions
NOTE: Failsafe option dimensions shown in green.
Shaped Radial Leaded Devices: Core Devices:
Straight Radial Leaded Devices:
Straight "T" Leaded Devices:
8.1
[0.319]
10.10
[0.398]
9.9
[0.354]
9.9
[0.354]
10.10
[0.398]
4.4± 0.3
[0.173± 0.12]
4.4± 0.3
[0.173± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
11.8
[0.464]
8.1.
[0.319]
9.9
[0.354]
16.8
[0.661]
11.8
[0.464]
6.35 ± 0.5
[0.25 ± 0.25]
15
[0.590]
1.0 DIA.
[0.039]
8.1 DIA. MAX.
[0.319]
10.10
[0.398]
14.7
[0.579]
6.35 ± 0.5
[0.25 ± 0.25]
9.0
[0.354]
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
Mounting Area
9.0
[0.354]
Mounting Area
9.0
[0.354]
Mounting Area
9.9
[0.354]
10.10
[0.398]
5.5± 0.3
[0.216± 0.12]
5.5± 0.3
[0.216± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
8.1.
[0.319]
0.3mm
Minimum
Gap
9.0
[0.354]
Mounting Area
10.10
[0.398]
22
[0.866] 1.0 DIA..
[0.039]
50 ± 3
[1.968 ± 0.118 ]
8.1 DIA. MAX.
[0.319]
11.8
[0.464]
23.8
[0.937]
9.0
[0.354]
Mounting Area
0.3mm
Minimum
Gap
Type 01 / C
Type 60
Type 06 / Y
Type 14 / X
Type 04 / R
Type 05 / P
PROFILE VIEW
SOLDERING PAD LAYOUT
SIDE VIEW TOP VIEW
7.7 ± 0.3
[0.303 ± 0.019]
10.0 ± 0.3
[0.394 ± 0.019]
Ø7.0 ± 0.1
[0.275 ± 0.004]
8.3 +0.3/-0.0
[0.327
+0.019/-0.00]
8.0 +0.3/-0.1
[0.315
+0.019/-0.004]
8.5 ± 0.0
[0.335 ± 0.000]
2.2 ± 0.0
[0.087 ± 0.000]
6.0 ± 0.0
[0.236 ± 0.000]
10.75 ± 0.0
[0.423 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
Overall Product Space
DO NOT ENCROACH
8.1
[0.319]
10.10
[0.398]
9.9
[0.354]
9.9
[0.354]
10.10
[0.398]
4.4± 0.3
[0.173± 0.12]
4.4± 0.3
[0.173± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
11.8
[0.464]
8.1.
[0.319]
9.9
[0.354]
16.8
[0.661]
11.8
[0.464]
6.35 ± 0.5
[0.25 ± 0.25]
15
[0.590]
1.0 DIA.
[0.039]
8.1 DIA. MAX.
[0.319]
10.10
[0.398]
14.7
[0.579]
6.35 ± 0.5
[0.25 ± 0.25]
9.0
[0.354]
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
Mounting Area
9.0
[0.354]
Mounting Area
9.0
[0.354]
Mounting Area
9.9
[0.354]
10.10
[0.398]
5.5± 0.3
[0.216± 0.12]
5.5± 0.3
[0.216± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
8.1.
[0.319]
0.3mm
Minimum
Gap
9.0
[0.354]
Mounting Area
10.10
[0.398]
22
[0.866] 1.0 DIA..
[0.039]
50 ± 3
[1.968 ± 0.118 ]
8.1 DIA. MAX.
[0.319]
11.8
[0.464]
23.8
[0.937]
9.0
[0.354]
Mounting Area
0.3mm
Minimum
Gap
Type 01 / C
Type 60
Type 06 / Y
Type 14 / X
Type 04 / R
Type 05 / P
PROFILE VIEW
SOLDERING PAD LAYOUT
SIDE VIEW TOP VIEW
7.7 ± 0.3
[0.303 ± 0.019]
10.0 ± 0.3
[0.394 ± 0.019]
Ø7.0 ± 0.1
[0.275 ± 0.004]
8.3 +0.3/-0.0
[0.327
+0.019/-0.00]
8.0 +0.3/-0.1
[0.315
+0.019/-0.004]
8.5 ± 0.0
[0.335 ± 0.000]
2.2 ± 0.0
[0.087 ± 0.000]
6.0 ± 0.0
[0.236 ± 0.000]
10.75 ± 0.0
[0.423 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
Overall Product Space
DO NOT ENCROACH
8.1
[0.319]
10.10
[0.398]
9.9
[0.354]
9.9
[0.354]
10.10
[0.398]
4.4± 0.3
[0.173± 0.12]
4.4± 0.3
[0.173± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
11.8
[0.464]
8.1.
[0.319]
9.9
[0.354]
16.8
[0.661]
11.8
[0.464]
6.35 ± 0.5
[0.25 ± 0.25]
15
[0.590]
1.0 DIA.
[0.039]
8.1 DIA. MAX.
[0.319]
10.10
[0.398]
14.7
[0.579]
6.35 ± 0.5
[0.25 ± 0.25]
9.0
[0.354]
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
0.3mm
Minimum
Gap
Mounting Area
9.0
[0.354]
Mounting Area
9.0
[0.354]
Mounting Area
9.9
[0.354]
10.10
[0.398]
5.5± 0.3
[0.216± 0.12]
5.5± 0.3
[0.216± 0.12]
15
[0.590]
16.8
[0.661]
4.4
[0.173]
1.0 DIA.
[0.039]
12.4 ± 1
[0.488 ± 0.039]
11. 8
[0.464]
8.1.
[0.319]
0.3mm
Minimum
Gap
9.0
[0.354]
Mounting Area
10.10
[0.398]
22
[0.866] 1.0 DIA..
[0.039]
50 ± 3
[1.968 ± 0.118 ]
8.1 DIA. MAX.
[0.319]
11.8
[0.464]
23.8
[0.937]
9.0
[0.354]
Mounting Area
0.3mm
Minimum
Gap
Type 01 / C
Type 60
Type 06 / Y
Type 14 / X
Type 04 / R
Type 05 / P
PROFILE VIEW
SOLDERING PAD LAYOUT
SIDE VIEW TOP VIEW
7.7 ± 0.3
[0.303 ± 0.019]
10.0 ± 0.3
[0.394 ± 0.019]
Ø7.0 ± 0.1
[0.275 ± 0.004]
8.3 +0.3/-0.0
[0.327
+0.019/-0.00]
8.0 +0.3/-0.1
[0.315
+0.019/-0.004]
8.5 ± 0.0
[0.335 ± 0.000]
2.2 ± 0.0
[0.087 ± 0.000]
6.0 ± 0.0
[0.236 ± 0.000]
10.75 ± 0.0
[0.423 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
1.2 ± 0.0
[0.047 ± 0.000]
Overall Product Space
DO NOT ENCROACH
Type “R” is available for SL1021B075 device only.
Gas Discharge Tubes
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/12/17
SL1021A/B Series
Packaging
Part Numbering System and Ordering Information
PMT8 xxx x x
Breakdown Voltage
090 = 90V
230 = 230V
250 = 250V
350 = 350V
400 = 400V
Breakdown Voltage
090 = 90V
145 = 145V
150 = 150V
200 = 200V
230 = 230V
250 = 250V
260 = 260V
300 = 300V
350 = 350V
400 = 400V
420 = 420V
450 = 450V
500 = 500V
600 = 600V
Series
PMT8
Configuration Code
Option Code
Blank = No Failsafe
F = With Failsafe
SL102x x xxx x x
Series
SL1021
SL1024
Surge Capability
A = 10kA
B = 20kA
Configuration Code
(See Device Dimensions section) (See Device Dimensions section)
C
R
P
01
04
05
06
Y
X
10
14
60
Blank = No failsafe
F or G = With Failsafe
Option Code
Device Type Description Quantity
Type C 100pcs/tray x 5 trays per carton 500
Type R 100pcs/tray x 5 trays per carton 500
Type P 100pcs/tray x 5 trays per carton 500
Type Y 100pcs/tray x 5 trays per carton 500
Type X 50pcs/tray x 5 trays per carton 250
* Please contact the factory for further packaging information.
For 'SL1021A/B' device type C, R, P, Y packing
Box (Cardboard)
Tray (PET)
for 50 Pcs.
Sponge (PE Form)
~58
~135
~258
Box (Cardboard)
Tray, Cover (PET)
Tray, Bottom (PET)
for 100 Pcs.
PE Form
~55
~235
For 'SL1021A/B' device type X packing
Box (Cardboard)
Tray (PET)
for 50 Pcs.
Sponge (PE Form)
~58
~135
~258
Box (Cardboard)
Tray, Cover (PET)
Tray, Bottom (PET)
for 100 Pcs.
PE Form
~55
~235
Disclaimer Notice - Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and
test each product selected for their own applications. Littelfuse products are not designed for, and may not be used in, all applications. Read complete
Disclaimer Notice at: www.littelfuse.com/disclaimer-electronics.
