Accuphase E-305 transistor selection help

[stonehome]

Hi,
I have an Accuphase E-305 with a failed transistor I need to replace. (Q10) I am having trouble matching all the parameters. It is high gain with very low output capacitance. 2SA1376 I have KSA1381 but less than half the gain.

Any suggestions?

2SA1376
Collector-Emitter Voltage: -180 V
Collector-Base Voltage: -200 V
Emitter-Base Voltage: -5 V
Collector Current: -0.1 A
Collector Dissipation - 0.75 W
DC Current Gain (hfe) - 135 to 600
Transition Frequency - 120 MHz

thank you
Evan

 

[duncan2]

It was used in TV video and has high speed switching ,not easy finding an exact equivalent and the designer was playing it safe by making sure it was less likely to blow from overvoltage -- 72.6 volts x2=145 volts -both rails .


Its for sale in Ireland but I think its a cheap copy and China is selling an "original " pair (NEC) for about $13 .


Check out high voltage RF BJT,s .

 

[stonehome]

Thanks Duncan,
I have some KSA1220AY I'll use. It's still not ideal but I'll give it a go.

Type - PNP
Collector-Emitter Voltage: -160 V
Collector-Base Voltage: -160 V
Emitter-Base Voltage: -5 V
Collector Current: -1.2 A
Collector Dissipation - 20 W
DC Current Gain (hfe) - 60 to 320
Transition Frequency - 175 MHz

Thanks
Evan

 

[Ian Finch]

Have a look at current HV transistors that replace the 3503/1381 etc. TTC004B, TTA004B may have enough Vbe and Hfe for what you want. TTC004B | Bipolar Transistors / IGBTs | Toshiba Electronic Devices & Storage Corporation | Asia-English
TTA004B | Bipolar Transistors / IGBTs | Toshiba Electronic Devices & Storage Corporation | Asia-English

 

[stonehome]

Hey, thanks Ian

 

[steveu]

Given the +/- 72.5V rails, (145V), you may get away with a 2N5401 (150V). Typically actual samples exceed the spec if you can test and select the best one. But I have to wonder why it failed?