There a bit of a lead time on these little puppies. I have had a few on order for a couple of weeks now. Anyone have suggestions as to what to use for the darlingtons on the source/sink pins. This will give me an excuse to use those XFO's that I have sitting around that put out too much voltage for a GC. Should be F.U.N!
G.
G.
From the Spec Sheet:
POWER DISSIPATION AND HEAT SINKING
When in “play” mode, the LM4702 draws a constant amount
of current, regardless of the input signal amplitude. Consequently,
the power dissipation is constant for a given supply
voltage and can be computed with the equation PDMAX = Icc
* (Vcc – Vee). For a quick calculation of PDMAX, approximate
the current to be 25mA and multiply it by the total supply
voltage (the current varies slightly from this value over the
operating range).
Constant power draw? This sounds like it's going to be a real hog. Is this Class A?
POWER DISSIPATION AND HEAT SINKING
When in “play” mode, the LM4702 draws a constant amount
of current, regardless of the input signal amplitude. Consequently,
the power dissipation is constant for a given supply
voltage and can be computed with the equation PDMAX = Icc
* (Vcc – Vee). For a quick calculation of PDMAX, approximate
the current to be 25mA and multiply it by the total supply
voltage (the current varies slightly from this value over the
operating range).
Constant power draw? This sounds like it's going to be a real hog. Is this Class A?MikeLewis said:From the Spec Sheet:
POWER DISSIPATION AND HEAT SINKING
When in “play” mode, the LM4702 draws a constant amount
of current, regardless of the input signal amplitude. Consequently,
the power dissipation is constant for a given supply
voltage and can be computed with the equation PDMAX = Icc
* (Vcc – Vee). For a quick calculation of PDMAX, approximate
the current to be 25mA and multiply it by the total supply
voltage (the current varies slightly from this value over the
operating range).
Sounds that way. can't wait until I get my samples. I could use a little help with some suggestion for the Darlingtons.
G.
LM4702
This is the same package as the 3875,76,86 ect..... is a power darlington complimentary output pair with much higher power handling up to +- 70V to as high as 100 +- dissipation is still only 125W quiescent current is 30 ma distortion is .004 at 14RMS out, it actually is not as good overall as its conterparts just handles higher power supply voltages................
This is the same package as the 3875,76,86 ect..... is a power darlington complimentary output pair with much higher power handling up to +- 70V to as high as 100 +- dissipation is still only 125W quiescent current is 30 ma distortion is .004 at 14RMS out, it actually is not as good overall as its conterparts just handles higher power supply voltages................
Re: LM4702
Guys do the maths...
Sure it's Class A, but it's a DRIVER not a power amplifier. To build a complete amplifier you need to add external components for the output stage and that's where the big power disspation will be. The current for the driver IC is 25 mA and the current available model in production is the A grade which means maximum +/- 75 VDC supply. This gives Pmax=(75-(-75))*0.025 W = 3.75 W of dissipation. Yes, that's less than 4 W. No need to worry...
MikeLewis said:From the Spec Sheet:
POWER DISSIPATION AND HEAT SINKING
When in “play” mode, the LM4702 draws a constant amount
of current, regardless of the input signal amplitude. Consequently,
the power dissipation is constant for a given supply
voltage and can be computed with the equation PDMAX = Icc
* (Vcc – Vee). For a quick calculation of PDMAX, approximate
the current to be 25mA and multiply it by the total supply
voltage (the current varies slightly from this value over the
operating range).
tiltedhalo said:
Guys do the maths...
Sure it's Class A, but it's a DRIVER not a power amplifier. To build a complete amplifier you need to add external components for the output stage and that's where the big power disspation will be. The current for the driver IC is 25 mA and the current available model in production is the A grade which means maximum +/- 75 VDC supply. This gives Pmax=(75-(-75))*0.025 W = 3.75 W of dissipation. Yes, that's less than 4 W. No need to worry...
metal said:
MJ11032 from Onsemit should work fine, samples are available. I know I've had a sample request on the 4702 for over a month... it's on backorder... anyone actually play with them yet?
pinkmouse said:
I agree! I actually got that chip, but it is surface mount and incredible small! I can't handle soldering it... anyone else upto the challenge?? I'd be willing to work out some sort of trade/purchase if you could just glue the thing to a piece of cardboard and solder some leads on it!
ElementX -- can you make a PCB good enough for it?
You can use solder paste and a toaster oven to actually solder it on. If that's the only component on the board, I expect you would get it right after only a few tries.
http://www.seattlerobotics.org/encoder/200006/oven_art.htm
Wes
You can use solder paste and a toaster oven to actually solder it on. If that's the only component on the board, I expect you would get it right after only a few tries.
http://www.seattlerobotics.org/encoder/200006/oven_art.htm
Wes
Member
Joined 2004
Funlight
For ElementX: I have successfully soldered the LM4970 device and
tried it out with a picmicro,it's an interesting device if you are interested in adding some "Bling" to your next project...
BTW: I have a stereo microscope that I used while soldering....Those little buggers look like 18 wheelers under the scope!!
Regards Bob C.
For ElementX: I have successfully soldered the LM4970 device and
tried it out with a picmicro,it's an interesting device if you are interested in adding some "Bling" to your next project...
BTW: I have a stereo microscope that I used while soldering....Those little buggers look like 18 wheelers under the scope!!
Regards Bob C.
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