© 2016 Littelfuse, Inc.

Specifications are subject to change without notice.

Revised: 06/14/16

20 / 25 Amp Standard SCRs

Figure 9: Maximum Allowable Ambient Temperature vs. Average On-State Current

0

20

40

60

80

100

120

0.0

0.5

1.01.5

CURRENT WAVEFORM: Sinusoidal

LOAD: Resistive or Inductive

CONDUCTION ANGLE: 180°

FREE AIR RATING

Sxx25L

Sxx25N

Sxx25R

Sxx20L

Average On-State Current [I

Note: xx = voltage

Figure 10: Peak Capacitor Discharge Current

Figure 11: Peak Capacitor Discharge Current Derating

1000

10

100

0.5

1.010.0

50.0

Sxx20L

Sxx25L

Sxx25R

Sxx25N

Pulse Current Duration (t

I

TRM

t

W

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0255075100

125150

Case Temperature (T

10

100

1000

110100

1000

Sxx25L

Sxx25R

Sxx25N

Sxx20L

Surge Current Duration -- Full Cycles

Figure 12: Surge Peak On-State Current vs. Number of Cycles

SUPPLY FREQUENCY: 60 Hz Sinusoidal

LOAD: Resistive

RMS On-State Current: [I

at Specified Case Temperature

Notes:

1. Gate control may be lost during and immediately

following surge current interval.

2. Overload may not be repeated until junction

temperature has returned to steady-state

rated value.