BJT's VCE. - Electronic Circuits Projects Diagrams Free

alphacat · 1st August 2009, 10:49 AM

Hey,

There's something which i dont quite understand about VCE in BJT's datasheet.
I take for example the P2N2222A datasheet.

1.
in the hFE category, for IC = 150mA & VCE = 10V* (2% pulse), hFE is guaranteed to be between 100 to 300.
If I apply continuous 10V voltage on VCE, would hFE remain between 100 to 300?
Do they apply a voltage pulse insead of continuous voltage to keep the BJT cool, and measuring hFE only when the
pulse is at its on state?

2.
In the VCEsat row, they claim that for IC=150mA & VCE = 10V*, VCEsat is 0.3V max.
I dont understand, if they apply 2% 10V pulse on the CE junction, shouldnt VCE be the exact applied pulse?
I dont understand how they reached 0.3V.

Thanks.

crutschow · 1st August 2009, 05:40 PM

1. hFE will be at the values stated for 10V Vce and the indicated collector current and temperature, yes.
They pulse test to limit the power dissipation so it doesn't heat up during the the test, and also to perform the test rapidly in production.

2. You caught an error in the data sheet. The Vce(sat) should be specified at a specific collector and base current. See http://www.eng.yale.edu/ee-labs/mors...ets/2N2222.pdf for example.

alphacat · 1st August 2009, 05:58 PM

Thank you C

audioguru · 1st August 2009, 06:10 PM

I looked at 25 datasheets but did not see the one with the errors about saturation voltages.
I asked before but nobody replied: Whose datasheet is wrong?

mneary · 2nd August 2009, 01:09 AM

Quote:

Originally Posted by audioguru

I looked at 25 datasheets but did not see the one with the errors about saturation voltages.
I asked before but nobody replied: Whose datasheet is wrong?

All of them (except Microsemi). This one is Fairchild PN2222A/MMBT2222A/PZT2222A Rev. 1.0.0 February 2009. Note that Vce cannot be 10V and 0.3V at the same time.

Code:

Collector-Emitter Sat Voltage * IC = 150mA, VCE = 10V    0.3
                              * IC = 500mA, VCE = 10V    1.0

audioguru · 2nd August 2009, 01:31 AM

I looked at one dozen Fairchild datasheets for their PN2222A transistor and found a wrong saturation voltage spec in 2004.
They shouldn't let school kid NOOBs do their datasheets.

Hero999 · 2nd August 2009, 11:29 AM

They've probably outsourced their datasheet department to India.

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1st August 2009, 10:49 AM	#1
alphacat	BJT's VCE. Hey, There's something which i dont quite understand about VCE in BJT's datasheet. I take for example the P2N2222A datasheet. 1. in the hFE category, for IC = 150mA & VCE = 10V* (2% pulse), hFE is guaranteed to be between 100 to 300. If I apply continuous 10V voltage on VCE, would hFE remain between 100 to 300? Do they apply a voltage pulse insead of continuous voltage to keep the BJT cool, and measuring hFE only when the pulse is at its on state? 2. In the VCEsat row, they claim that for IC=150mA & VCE = 10V, VCEsat is 0.3V max. I dont understand, if they apply 2% 10V pulse on the CE junction, shouldnt VCE be the exact applied pulse? I dont understand how they reached 0.3V. Thanks. Attached Thumbnails Last edited by alphacat; 1st August 2009 at 10:51 AM.*

1st August 2009, 05:40 PM	#2
crutschow	1. hFE will be at the values stated for 10V Vce and the indicated collector current and temperature, yes. They pulse test to limit the power dissipation so it doesn't heat up during the the test, and also to perform the test rapidly in production. 2. You caught an error in the data sheet. The Vce(sat) should be specified at a specific collector and base current. See http://www.eng.yale.edu/ee-labs/mors...ets/2N2222.pdf for example. __________________ Carl Curmudgeon Elektroniker

1st August 2009, 06:10 PM	#4
audioguru	I looked at 25 datasheets but did not see the one with the errors about saturation voltages. I asked before but nobody replied: Whose datasheet is wrong? __________________ Uncle $crooge

2nd August 2009, 01:31 AM	#6
audioguru	I looked at one dozen Fairchild datasheets for their PN2222A transistor and found a wrong saturation voltage spec in 2004. They shouldn't let school kid NOOBs do their datasheets. __________________ Uncle $crooge

2nd August 2009, 11:29 AM	#7
Hero999	They've probably outsourced their datasheet department to India. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.