
Date: 01 August 2012
Data Sheet Issue: 3
Distributed Gate Thyristor
Type R0878LC18x to R0878LC21x
Absolute Maximum Ratings
VDRM
VDSM
VRRM
VRSM
VOLTAGE RATINGS
Repetitive peak offstate voltage, (note 1)
Nonrepetitive peak offstate voltage, (note 1)
Repetitive peak reverse voltage, (note 1)
Nonrepetitive peak reverse voltage, (note 1)
MAXIMUM
LIMITS
16002100
16002100
16001800
17001900
UNITS
V
V
V
V
IT(AVM)
IT(AVM)
IT(AVM)
IT(RMS)
IT(d.c.)
ITSM
ITSM2
I2t
I2t
(di/dt)cr
VRGM
PG(AV)
PGM
Tj op
Tstg
OTHER RATINGS
Maximum average onstate current, Tsink=55°C, (note 2)
Maximum average onstate current. Tsink=85°C, (note 2)
Maximum average onstate current. Tsink=85°C, (note 3)
Nominal RMS onstate current, Tsink=25°C, (note 2)
D.C. onstate current, Tsink=25°C, (note 4)
Peak nonrepetitive surge tp=10ms, Vrm=0.6VRRM, (note 5)
Peak nonrepetitive surge tp=10ms, Vrm≤10V, (note 5)
I2t capacity for fusing tp=10ms, Vrm=0.6VRRM, (note 5)
I2t capacity for fusing tp=10ms, Vrm≤10V, (note 5)
Critical rate of rise of onstate current (repetitive), (Note 6)
Critical rate of rise of onstate current (nonrepetitive), (Note 6)
Peak reverse gate voltage
Mean forward gate power
Peak forward gate power
Operating temperature range
Storage temperature range
Notes:
1) Derating factor of 0.13% per °C is applicable for Tj below 25°C.
2) Double side cooled, single phase; 50Hz, 180° halfsinewave.
3) Single side cooled, single phase; 50Hz, 180° halfsinewave.
4) Double side cooled.
5) Halfsinewave, 125°C Tj initial.
6) VD=67% VDRM, IFG=2A, tr≤0.5µs, Tcase=125°C.
MAXIMUM
LIMITS
878
583
338
1765
1456
7500
8250
281×103
340×103
1000
1500
5
2
30
40 to +125
40 to +150
UNITS
A
A
A
A
A
A
A
A2s
A2s
A/µs
A/µs
V
W
W
°C
°C
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 1 of 12
August 2012

Characteristics
Distributed Gate Thyristor types R0878LC18x to R0878LC21x
PARAMETER
VTM Maximum peak onstate voltage
VTM Maximum peak onstate voltage
VT0 Threshold voltage
rT Slope resistance
(dv/dt)cr Critical rate of rise of offstate voltage
IDRM Peak offstate current
IRRM Peak reverse current
VGT Gate trigger voltage
IGT Gate trigger current
VGD Gate nontrigger voltage
IH Holding current
tgd Gate controlled turnon delay time
tgt Turnon time
Qrr Recovered charge
Qra Recovered charge, 50% Chord
Irm Reverse recovery current
trr Reverse recovery time
tq Turnoff time (note 2)
RthJK
F
Wt
Thermal resistance, junction to heatsink
Mounting force
Weight
MIN.




200












60


10

TYP. MAX. TEST CONDITIONS (Note 1)
 2.12 ITM=1400A
 2.70 ITM=2650A
 1.447
 0.480
  VD=80% VDRM, Linear ramp, Gate o/c
 70 Rated VDRM
 70 Rated VRRM
 3.0
Tj=25°C
 300
VD=10V, IT=3A
 0.25 Rated VDRM
 1000 Tj=25°C
0.8 2.0 VD=67% VDRM, IT=1500A, di/dt=60A/µs,
1.5 3.5 IFG=2A, tr=0.5µs, Tj=25°C
720 
350 400 ITM=1000A, tp=1000µs, di/dt=60A/µs,
160  Vr=50V
4.4 

65
ITM=1000A, tp=1000µs, di/dt=60A/µs,
Vr=50V, Vdr=80%VDRM, dVdr/dt=20V/µs

70
ITM=1000A, tp=1000µs, di/dt=60A/µs,
Vr=50V, Vdr=80%VDRM, dVdr/dt=200V/µs
 0.032 Double side cooled
 0.064 Single side cooled
 20
340 
UNITS
V
V
V
mΩ
V/µs
mA
mA
V
mA
V
mA
µs
µC
µC
A
µs
µs
K/W
K/W
kN
kg
Notes:
1) Unless otherwise indicated Tj=125°C.
2) The required tq (specified with dVdr/dt=200V/µs) is represented by a ‘#’ in the device part number. See ordering information for
details of tq codes.
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 2 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
Notes on Ratings and Characteristics
1.0 Voltage Grade Table
Voltage Grade
18
20
21
VDRM VDSM
V
1800
2000
2100
VRRM
V
1800
1800
1800
VRSM
V
1900
1900
1900
VD
DC V
1150
1250
1400
VR
DC V
1150
1150
1150
2.0 Extension of Voltage Grades
This report is applicable to other and higher voltage grades when supply has been agreed by
Sales/Production.
3.0 Extension of Turnoff Time
This Report is applicable to other tq/reapplied dv/dt combinations when supply has been agreed by
Sales/Production.
4.0 Repetitive dv/dt
Higher dv/dt selections are available up to 1000V/µs on request.
5.0 Derating Factor
A blocking voltage derating factor of 0.13%/°C is applicable to this device for Tj below 25°C.
6.0 Snubber Components
When selecting snubber components, care must be taken not to use excessively large values of snubber
capacitor or excessively small values of snubber resistor. Such excessive component values may lead to
device damage due to the large resultant values of snubber discharge current. If required, please consult
the factory for assistance.
7.0 Rate of rise of onstate current
The maximum unprimed rate of rise of onstate current must not exceed 1500A/µs at any time during
turnon on a nonrepetitive basis. For repetitive performance, the onstate rate of rise of current must not
exceed 1000A/µs at any time during turnon. Note that these values of rate of rise of current apply to the
total device current including that from any local snubber network.
8.0 Gate Drive
The nominal requirement for a typical gate drive is illustrated below. An open circuit voltage of at least
30V is assumed. This gate drive must be applied when using the full di/dt capability of the device.
IGM
4A/µs
IG
tp1
The magnitude of IGM should be between five and ten times IGT, which is shown on page 2. Its duration
(tp1) should be 20µs or sufficient to allow the anode current to reach ten times IL, whichever is greater.
Otherwise, an increase in pulse current could be needed to supply the necessary charge to trigger. The
‘backporch’ current IG should remain flowing for the same duration as the anode current and have a
magnitude in the order of 1.5 times IGT.
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 3 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
9.0 Frequency Ratings
The curves illustrated in figures 10 to 18 are for guidance only and are superseded by the maximum
ratings shown on page 1.
10.0 Square wave ratings
These ratings are given for load component rate of rise of forward current of 100 and 500 A/µs.
11.0 Duty cycle lines
The 100% duty cycle is represented on all the ratings by a straight line. Other duties can be included as
parallel to the first.
12.0 Maximum Operating Frequency
The maximum operating frequency is set by the onstate duty, the time required for the thyristor to turn off
(tq) and for the offstate voltage to reach full value (tv), i.e.
f max =
1
tpulse + tq + tv
13.0 OnState Energy per Pulse Characteristics
These curves enable rapid estimation of device dissipation to be obtained for conditions not covered by
the frequency ratings.
Let Ep be the Energy per pulse for a given current and pulse width, in joules
Let Rth(JHs) be the steadystate d.c. thermal resistance (junction to sink)
and TSINK be the heat sink temperature.
Then the average dissipation will be:
( )WAV = EP ⋅ f and TSINK (max.) = 125 − WAV ⋅ Rth(J −Hs)
14.0 Reverse recovery ratings
(i) Qra is based on 50% Irm chord as shown in Fig. 1
Fig. 1
(ii) Qrr is based on a 150µs integration time i.e.
(iii)
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 4 of 12
150 µs
∫Qrr = irr .dt
0
K Factor = t1
t2
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
15.0 Reverse Recovery Loss
15.1 Determination by Measurement
From waveforms of recovery current obtained from a high frequency shunt (see Note 1, Page 5) and
reverse voltage present during recovery, an instantaneous reverse recovery loss waveform must be
constructed. Let the area under this waveform be E joules per pulse. A new heat sink temperature can
then be evaluated from the following:
( )TSINK (new) = TSINK (original ) − E ⋅ k + f ⋅ Rth(J −Hs )
Where k=0.227 (°C/W)/s
E = Area under reverse loss waveform per pulse in joules (W.s.)
f = rated frequency Hz at the original heat sink temperature.
Rth(JHs) = d.c. thermal resistance (°C/W).
The total dissipation is now given by:
W(TOT) = W(original) + E ⋅ f
15.2 Determination without Measurement
In circumstances where it is not possible to measure voltage and current conditions, or for design
purposes, the additional losses E in joules may be estimated as follows.
Let E be the value of energy per reverse cycle in joules (curves in Figure 9).
Let f be the operating frequency in Hz
( )TSINK (new) = TSINK (original ) − E ⋅ Rth ⋅ f
Where TSINK (new) is the required maximum heat sink temperature and
TSINK (original) is the heat sink temperature given with the frequency ratings.
A suitable RC snubber network is connected across the thyristor to restrict the transient reverse voltage
to a peak value (Vrm) of 67% of the maximum grade. If a different grade is being used or Vrm is other than
67% of Grade, the reverse loss may be approximated by a pro rata adjustment of the maximum value
obtained from the curves.
NOTE 1 Reverse Recovery Loss by Measurement
This thyristor has a low reverse recovered charge and peak reverse recovery current. When measuring
the charge, care must be taken to ensure that:
(a) a.c. coupled devices such as current transformers are not affected by prior passage of high
amplitude forward current.
(b) A suitable, polarised, clipping circuit must be connected to the input of the measuring oscilloscope
to avoid overloading the internal amplifiers by the relatively high amplitude forward current signal
(c) Measurement of reverse recovery waveform should be carried out with an appropriate critically
damped snubber, connected across diode anode to cathode. The formula used for the calculation
of this snubber is shown below:
R2 = 4 ⋅ Vr
CS
⋅ di
dt
Vr = Commutating source voltage
Where: CS = Snubber capacitance
R = Snubber resistance
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 5 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
16.0 Computer Modelling Parameters
16.1 Calculating VT using ABCD Coefficients
The onstate characteristic IT vs VT, on page 7 is represented in two ways;
(i) the well established VT0 and rT tangent used for rating purposes and
(ii) a set of constants A, B, C, D, forming the coefficients of the representative equation for VT in
terms of IT given below:
VT = A + B ⋅ ln(IT )+ C ⋅ IT + D ⋅ IT
The constants, derived by curve fitting software, are given in this report for hot and cold characteristics
where possible. The resulting values for VT agree with the true device characteristic over a current range,
which is limited to that plotted.
125°C Coefficients
A 1.510816
B 0.01749119
C 4.616469×104
D 2.404072×103
16.2 D.C. Thermal Impedance Calculation
∑rt
=
p=n
rp
p =1
⋅
⎜⎜⎛1
−
e
−t
τp
⎝
⎟⎞
⎟
⎠
Where p = 1 to n, n is the number of terms in the series.
t = Duration of heating pulse in seconds.
rt = Thermal resistance at time t.
rp = Amplitude of pth term.
τp = Time Constant of rth term.
Term
rp
τp
1
0.01771901
0.7085781
D.C. Double Side Cooled
2
4.240625×103
3
6.963806×103
0.1435833
0.03615196
4
3.043661×103
2.130842×103
Term
rp
τp
1
0.03947164
4.090062
D.C. Single Side Cooled
2
0.01022837
3
8.789912×103
1.078983
0.08530917
4
4.235162×103
0.01128791
5
1.907609×103
1.240861×103
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 6 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
Curves
Figure 1  Onstate characteristics of Limit device
10000
R0878LC18x21x
Issue 3
Figure 2  Transient thermal impedance
0.1
R0878LC18x21x
Issue 3
SSC 0.064K/W
Tj = 125°C
0.01
DSC 0.032K/W
1000
0.001
0.0001
100
0
1234
Instantaneous onstate voltage  VT (V)
5
Figure 3  Gate characteristics  Trigger limits
6
R0878LC18x21x
Issue 3
Tj=25°C
5
0.00001
1E05 0.0001 0.001 0.01 0.1 1 10 100
Time (s)
`
Figure 4  Gate characteristics  Power curves
20
R0878LC18x21x
Issue 3
18 Tj=25°C
16
4 Max VG dc
IGT, VGT
3
14
Max VG dc
12
10
8
2 PG Max 30W dc
6
1
IGD, VGD
0
0
Min VG dc
0.2 0.4 0.6 0.8
Gate Trigger Current  IGT (A)
1
4
PG 2W dc
2
Min VG dc
0
0 2 4 6 8 10
Gate Trigger Current  IGT (A)
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 7 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
Figure 5  Total recovered charge, Qrr
10000
R0878LC18x21x
Issue 3
Tj = 125°C
1000
2000A
1500A
1000A
500A
Figure 6  Recovered charge, Qra (50% chord)
1000
R0878LC18x21x
Issue 3
Tj = 125°C
2000A
1500A
1000A
500A
100
10
100
Commutation rate  di/dt (A/µs)
1000
100
10
100
Commutation rate  di/dt (A/µs)
1000
Figure 7  Peak reverse recovery current, Irm
1000
R0878LC18x21x
Issue 3
Tj = 125°C
2000A
1500A
1000A
500A
Figure 8  Maximum recovery time, trr (50% chord)
10
R0878LC18x21x
Issue 3
Tj = 125°C
100
2000A
1500A
1000A
500A
10
10
100
Commutation rate  di/dt (A/µs)
1000
1
10 100 1000
Commutation rate  di/dt (A/µs)
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 8 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
Figure 9 – Reverse recovery energy per pulse
1
R0878LC18x21x
Issue 3
Snubber
0.22µF, 10Ω
Tj = 125°C
Vrm = 67% VRRM
2000A
1500A
1000A
500A
Figure 10  Sine wave energy per pulse
1.00E+02
R0878LC18x21x
Issue 3
Tj=125°C
1.00E+01
4kA
1.00E+00 2kA
1.5kA
1kA
1.00E01
500A
0.1
10
100
Commutation rate  di/dt (A/µs)
1000
1.00E02
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
Figure 11  Sine wave frequency ratings
1.00E+05
500A
R0878LC18x21x
Issue 3
THs=55°C
100% Duty Cycle
1.00E+04 1kA
1.5kA
2kA
Figure 12  Sine wave frequency ratings
1.00E+05
500A
1.00E+04
R0878LC18x21x
Issue 3
100% Duty Cycle
THs=85°C
1kA
1.5kA
2kA
1.00E+03
1.00E+03
4kA
4kA
1.00E+02
1.00E+02
1.00E+01
1.00E+01
1.00E05
1.00E04
1.00E03
Pulse Width (s)
1.00E02
1.00E+00
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 9 of 12
August 2012

Figure 13  Square wave frequency ratings
1.00E+05
500A
1kA
1.00E+04
R0878LC18x21x
Issue 3
THs=55°C
di/dt=100A/µs
100% Duty Cycle
1.5kA
2kA
1.00E+03
4kA
1.00E+02
Distributed Gate Thyristor types R0878LC18x to R0878LC21x
Figure 14  Square wave frequency ratings
1.00E+05
500A
R0878LC18x21x
Issue 3
THs=55°C
di/dt=500A/µs
1.00E+04
1kA
100% Duty Cycle
1.00E+03 2kA
1.5kA
4kA
1.00E+02
1.00E+01
1.00E+01
1.00E+00
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
1.00E+00
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
Figure 15  Square wave frequency ratings
1.00E+05
500A
R0878LC18x21x
Issue 3
THs=85°C
di/dt=100A/µs
1.00E+04
1kA
100% Duty Cycle
1.5kA
2kA
1.00E+03
Figure 16  Square wave frequency ratings
1.00E+05
1.00E+04
500A
R0878LC18x21x
Issue 3
di/dt=500A/µs
THs=85°C
100% Duty Cycle
1kA
1.00E+03
1.5kA
2kA
1.00E+02
4kA
1.00E+02
1.00E+01
4kA
1.00E+01
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
1.00E+00
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 10 of 12
August 2012

Distributed Gate Thyristor types R0878LC18x to R0878LC21x
Figure 17  Square wave energy per pulse
1.00E+03
R0878LC18x21x
Issue 3
di/dt=100A/µs
Tj=125°C
1.00E+02
Figure 18  Square wave energy per pulse
1.00E+03
R0878LC18x21x
Issue 3
di/dt=500A/µs
Tj=125°C
1.00E+02
1.00E+01
4kA
1.00E+00
2kA
1.5kA
1kA
1.00E01
500A
1.00E+01
4kA
2kA
1.00E+00
1.5kA
1kA
500A
1.00E02
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
1.00E01
1.00E05
1.00E04
1.00E03
Pulse width (s)
1.00E02
Figure 19  Maximum surge and I2t Ratings
100000
Gate may temporarily lose control of conduction angle
R0878LC18x21x
Issue 3
Tj (initial) = 125°C
1.00E+07
I2t: VRRM≤10V
I2t: 60% VRRM
10000
1.00E+06
ITSM: VRRM≤10V
ITSM: 60% VRRM
1000
1
3 5 10
Duration of surge (ms)
1
5 10
50 100
Duration of surge (cycles @ 50Hz)
1.00E+05
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 11 of 12
August 2012

Outline Drawing & Ordering Information
Distributed Gate Thyristor types R0878LC18x to R0878LC21x
101A216
ORDERING INFORMATION
(Please quote 10 digit code as below)
R0878
LC
♦♦
♦
Fixed
Type Code
Fixed
Outline Code
Offstate Voltage Code
VDRM/100
1821
tq Code (200V/µs)
K=60µs, L=65µs, M=70µs
Typical order code: R0878LC20L – 2000V VDRM, 1800V VRRM, 65µs tq, 27mm clamp height capsule.
IXYS Semiconductor GmbH
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Tel: +49 6206 5030
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Email: marcom@ixys.de
IXYS UK Westcode Ltd
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Chippenham, Wiltshire, SN15 1GE.
Tel: +44 (0)1249 444524
Fax: +44 (0)1249 659448
Email: sales@ixysuk.com
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Milpitas CA 950357418
Tel: +1 (408) 457 9000
Fax: +1 (408) 496 0670
Email: sales@ixys.net
www.ixysuk.com
www.ixys.com
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IXYS Long Beach, Inc
2500 Mira Mar Ave, Long Beach
CA 90815
Tel: +1 (562) 296 6584
Fax: +1 (562) 296 6585
Email: service@ixyslongbeach.com
The information contained herein is confidential and is protected by Copyright. The information may not be used or
disclosed except with the written permission of and in the manner permitted by the proprietors IXYS UK Westcode Ltd.
In the interest of product improvement, IXYS UK Westcode Ltd reserves the right to change specifications at any time
without prior notice.
Devices with a suffix code (2letter or letter/digit/letter combination) added to their generic code are not necessarily subject
to the conditions and limits contained in this report.
© IXYS UK Westcode Ltd.
Data Sheet. Type R0878LC18x to R0878LC21x Issue 3
Page 12 of 12
August 2012

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