Favorite Cheap and Useful Part? Lemme know.

[Luhan Monat]

Here are some 'hot' parts that I like using (mostly because they are
real cheap). Anybody got any favorites?

http://members.cox.net/berniekm/Hot_Parts.html

 

[Fritz Schlunder]

Here are some 'hot' parts that I like using (mostly because they are
real cheap). Anybody got any favorites?

http://members.cox.net/berniekm/Hot_Parts.html

IRF644N 250V 14A MOSFET (Digikey)
IRF1407 75V 130A MOSFET (Digikey)
IRFZ48V 60V 72A MOSFET (Digikey)
IRL3715 20V 54A MOSFET (Digikey)

IRG4BC40F 600V 49A IGBT (Digikey)

UF4007 1000V 1A Ultrafast recovery diode (Mouser)
TL072 13MHz GBWP Dual Op-amp (Mouser)
LM358 Cheap dual op-amp with inputs to ground (Mouser)

I agree with the TSALXX00 IR Leds. They have some relatively impressive
specifications for their cost.

 

[Paul Burridge]

UF4007 1000V 1A Ultrafast recovery diode (Mouser)

What are these diodes typically used for?

 

[John Larkin]

Here are some 'hot' parts that I like using (mostly because they are
real cheap). Anybody got any favorites?

http://members.cox.net/berniekm/Hot_Parts.html

2N7002 small mosfet

BCX70 and 71 high beta transistors

LM7301 sot-23 opamp

LM1117 regulator

LM1458/so8 ultracheap dual opamp

0.1 uF 0805 ceramic cap

Xilinx Spartan2 FPGAs: fraction of a penny per gate.

John

 

[Stefan Heinzmann]

John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Cheers
Stefan

 

[Fritz Schlunder]

What are these diodes typically used for?
--

I donno. Wherever small high voltage fast recovery diodes are needed I
guess. I use them for things such as:

High output voltage but low current SMPS rectification (IE: small xenon
strobe camera flash chargers), the "D" in an RCD clamp for offline forward
converters, diode for charging the bootstrap capacitor in a bootstrapped
high side MOSFET/IGBT gate drive system, high frequency capable
Cockroft-Walton voltage multipliers, etc.

 

[John Woodgate]

I read in sci.electronics.design that Stefan Heinzmann
online.com>) about 'Favorite Cheap and Useful Part? Lemme know.', on
Mon, 5 Jan 2004:

John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Probably no consensus, but minimum 100 seems a ball-park figure.

Most die lines seem to fall into two groups, those with a minimum beta
of about 100 and those with a maximum beta of about 100. From these die
lines, all sorts of different devices are selected by testing, and
testing may exclude low-beta and/or high-beta devices; the latter may
either be premium product or fall out of Vceo spec., or both. The low-
beta ones are sold as a different device. Like with pig packers, only
the squeak is not used somehow.

 

[John Larkin]

John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Cheers
Stefan

The BCX70K is 380 min at 2 mA, which is pretty good. What's the 3112
like? I can't seem to find a datasheet for that one... looks like the
biggies don't make it any more.

John

 

[Stefan Heinzmann]

John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Cheers
Stefan

The BCX70K is 380 min at 2 mA, which is pretty good. What's the 3112
like? I can't seem to find a datasheet for that one... looks like the
biggies don't make it any more.

2SC3112 is from Toshiba. It comes in the TO92, but versions in other
packages should be available, too.

hFE at 2mA is 600 to 1800 for A version and 1200 to 3600 for B version.

Cheers
Stefan

 

[John Larkin]

John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Cheers
Stefan

The BCX70K is 380 min at 2 mA, which is pretty good. What's the 3112
like? I can't seem to find a datasheet for that one... looks like the
biggies don't make it any more.

2SC3112 is from Toshiba. It comes in the TO92, but versions in other
packages should be available, too.

hFE at 2mA is 600 to 1800 for A version and 1200 to 3600 for B version.

Cheers
Stefan

Toshiba's web sites don't show it... can you find it?

A lot of people have gone out of the gumdrop transistor business.

John

 

[Paul Burridge]

John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Isn't the hfe figure somewhat irrelevant WRT anything other than stuff
like working out the input impedance of a stage and such like?

My nominations would be: LM324 quad op amp, the BC337 and the 2SC1971.

 

[Spehro Pefhany]

On Mon, 05 Jan 2004 22:22:19 +0100, Stefan Heinzmann


John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Cheers
Stefan



The BCX70K is 380 min at 2 mA, which is pretty good. What's the 3112
like? I can't seem to find a datasheet for that one... looks like the
biggies don't make it any more.

2SC3112 is from Toshiba. It comes in the TO92, but versions in other
packages should be available, too.

hFE at 2mA is 600 to 1800 for A version and 1200 to 3600 for B version.

Cheers
Stefan

Toshiba's web sites don't show it... can you find it?
http://www.semicon.toshiba.co.jp/td...Transistors/en_20030328_2SC3112_datasheet.pdf

A lot of people have gone out of the gumdrop transistor business.

Still a big bidness for Toshiba I think.

Best regards,
Spehro Pefhany

 

[John Larkin]

Isn't the hfe figure somewhat irrelevant WRT anything other than stuff
like working out the input impedance of a stage and such like?

I often make precision current sources for stuff like charging caps to
make linear timing ramps. In those cases, Ib and its tempco are
errors. The BCX70/71 are excellent precision current source devices,
with high Hfe, low Cd, and aren't inclined to oscillate.

My nominations would be: LM324 quad op amp,

The 324 is OK for pure DC stuff, but is too slow and has too much
crossover distortion for lots of apps. It also has interesting
parasitic substrate diode behavior and channel-channel interactions.

John

 

[John Larkin]

John Larkin wrote:

On Mon, 05 Jan 2004 22:22:19 +0100, Stefan Heinzmann


John Larkin wrote:
[...]

BCX70 and 71 high beta transistors

[...]

Is there any consensus as to when a transistor qualifies as a high beta
transistor? The hFE of the mentioned transistors doesn't strike me as
extraordinary. A transistor that qualifies more IMHO would be the 2SC3112.

Cheers
Stefan



The BCX70K is 380 min at 2 mA, which is pretty good. What's the 3112
like? I can't seem to find a datasheet for that one... looks like the
biggies don't make it any more.

2SC3112 is from Toshiba. It comes in the TO92, but versions in other
packages should be available, too.

hFE at 2mA is 600 to 1800 for A version and 1200 to 3600 for B version.

Cheers
Stefan

Toshiba's web sites don't show it... can you find it?
http://www.semicon.toshiba.co.jp/td...Transistors/en_20030328_2SC3112_datasheet.pdf

A lot of people have gone out of the gumdrop transistor business.

Still a big bidness for Toshiba I think.

Best regards,
Spehro Pefhany

Thanks, Speff. I did a search on the US Toshiba site, and Google, but
no luck.

That's an impressive part. The Early voltage gets down to something
like -2!

John

 

[Wouter van Ooijen]

Here are some 'hot' parts that I like using (mostly because they are

real cheap). Anybody got any favorites?

PIC12F629
PIC16F676


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

 

[Russell Shaw]

I often make precision current sources for stuff like charging caps to
make linear timing ramps. In those cases, Ib and its tempco are
errors. The BCX70/71 are excellent precision current source devices,
with high Hfe, low Cd, and aren't inclined to oscillate.


The 324 is OK for pure DC stuff, but is too slow and has too much
crossover distortion for lots of apps. It also has interesting
parasitic substrate diode behavior and channel-channel interactions.

The 324 has *no* crossover distortion when used as intended,
and works as good as any 1MHz GBW opamp. Read the schematics.
ICs are *not* black boxes.

 

[Paul Burridge]

The 324 has *no* crossover distortion when used as intended,
and works as good as any 1MHz GBW opamp. Read the schematics.
ICs are *not* black boxes.

Looks like John may be getting mixed-up with some other amp...

 

[Winfield Hill]

Paul Burridge wrote...

Looks like John may be getting mixed-up with some other amp...

Used as an ordinary opamp with split +/- supplies and loads to
ground, the LM324 has serious crossover distortion at moderate
frequencies, as John says. But used in a distinctly single-
supply fashion, e.g. with Vee at ground, AND with a resistive
load to ground, the LM324 will have no crossover distortion,
just as Russell asserted.

The LM324 is an inexpensive, yet very useful part. It's made
by a number of manufacturers: NSC, Fairchild, ST, Philips, TI,
ON Semi, Samsung, etc. Its main appeal is low price, 9 cents
or less. Avnet has TI LM324NSR for 7.5 cents, qty 2k to 10M.
At under 2 cents per opamp, a single transistor costs more.

Now more than 30 years old, surely the LM324 will be readily
available for another 30 years. :>)

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Paul Burridge]

Now more than 30 years old, surely the LM324 will be readily
available for another 30 years. :>)

Hopefully in the same package!

 

[Jim Thompson]

Paul Burridge wrote...

Used as an ordinary opamp with split +/- supplies and loads to
ground, the LM324 has serious crossover distortion at moderate
frequencies, as John says. But used in a distinctly single-
supply fashion, e.g. with Vee at ground, AND with a resistive
load to ground, the LM324 will have no crossover distortion,
just as Russell asserted.

The LM324 is an inexpensive, yet very useful part. It's made
by a number of manufacturers: NSC, Fairchild, ST, Philips, TI,
ON Semi, Samsung, etc. Its main appeal is low price, 9 cents
or less. Avnet has TI LM324NSR for 7.5 cents, qty 2k to 10M.
At under 2 cents per opamp, a single transistor costs more.

Now more than 30 years old, surely the LM324 will be readily
available for another 30 years. :>)

Thanks,
- Win

whill_at_picovolt-dot-com

Back in the Motorola days (I don't know if ON Semi has changed it),
their LM324 had the *worst* crossover distortion known to man. I
actually blacklisted Motorola as an LM324 vendor when I was with
GenRad.

Even with better vendors I always biased the output stages as class-A
when used in active filters.

...Jim Thompson