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Surface-Mount ESD protection component by
Firstohm:
ESD Surge Absorber MELF (ESM)
Introduced in 2010, Firstohm Spark Gap Surge
Absorber SGS series as most of you may
already know, is the first non-resistor product
by Firstohm. SGS protects the circuits (and
other components) by acting as a switch and
short-circuiting unwanted electrostatic
discharge (ESD) through the porous layer
when the spark-over voltage is exceeded.
Eliminating gas tubes (or ceramic tubes) and
special gas that are essential for the conventional gas discharge tubes, SGS series would help
reduce surge protection related costs in a network setup. Furthermore, Firstohm SGS has the
advantages of high insulation resistance, low capacitance, and fast response time.
This year, in response to increasing market demand for smaller circuit designs with unaffected,
or sometimes even more powerful, performance, Firstohm further introduced ESD absorber in
surface-mount cylindrical packaging - ESD Surge Absorber MELF (ESM series).
(Comparison with Similar Products)
Firstohm
Glass Surge
Absorber
Transient Voltage
Suppressor (TVS)
Gas Discharge
Tube
Varistor
SGS ESM
Main
Application
ESD Protection Power/ESD Protection
ESD Protection Power Protection Power Protection
Surface Mount
Type
Refer to ESM
Yes
(0204 MELF)
available but few No Yes No Yes No Yes
Cost
Approximately 5% ~ 10% of
TVS
Approximately
20% ~ 30%
of TVS
Approximately
60% ~ 70%
of TVS
Approximately
50% ~ 60%
of TVS
Capacitance
＜1pF ＜1pF ＜2pF ＜1pF 30~30000pF
240~3000pF
Surge Current
Capacity
80A (2/10µs)
[60A (8/20µs)]
500A~3000A
(8/20µs)
2A~143A
(10/1000µs)
6.5A~26.5A
(10/1000µs)
5000A
(8/20µs)
1000A
(8/20µs)
100A~6500A
(8/20µs)
100~200A
(8/20µs)
Surge Test
3000pF/ 10KV/ 0ohm,
300 times
1500pF/ 10KV/ 0ohm
200 times
Spark-Over
Voltage/
Breakdown
Voltage
1550V~3300V
1300V 140V~4500V 6.4V~567V
6V~45V 800V~4000V
75V~400V
22V~1100V
7V~90.2V
Body Size*
6.7 mm (L)
2.4 mm (D)
3.52 mm (L)
1.35 mm (D)
7.0 mm (L)
2.6 mm (D)
7.1 mm (L)
6.2 mm (W)
2.62 mm (H)
4.00 mm (L)
2.18 mm (W)
1.15 mm (H)
6mm (L)
8mm (D)
4.5mm (L)
3mm (D)
5~20mm (D)
3.2 mm (L)
1.6 mm (W)
1.8 mm (H)
Response Time
≦1ns ≦100ns ≦1ns 100~300ns ≦25ns
* D: Diameter, H: Height, L: Length, W: Width
Background
(Top: SGS,
Bottom:
ESM204)
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Surface-Mount ESD protection component by
Firstohm:
ESD Surge Absorber MELF (ESM)
How Does It Work?
Applications of FIRSTOHM SGS/ESM series
1. Differential-Mode Protection
2. Common-Mode Protection
3. Series Connection with Metal-Oxide Varistor
Patents
- Europe (patent no.EP2211357)
- Japan (patent no.3174088)
- Mainland China (patent no. ZL 2010 90000662.4), and
- Korea (20-0462959)
Overvoltage is short-
circuited
via the porous layer when
the spark-over voltage is
exceeded.