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sot23-6 LED driver

I'm looking for an LDO, single LED driver chip in 6-lead SOT23 form for a blue Cree LED (C405MB290-S0100, for example.) I'd like the following pins: GND, +5, +LED, -LED, current control V (0 to 3.3V is all I have to work with here), OFF. I've got two rails, +3.3 and +5. Small, cheap, and SMT on one side of the board is what I'm looking for.

I need at least 4.1V LED compliance at no less than 65mA drive (no more than 75mA is needed.) It should use negative feedback on the

-LED return line to deal comfortably (foldback not required) with dead shorts across the +LED and -LED. The current control V line should be driven with less than 200uA (the DAC can handle that well.) The DAC, short circuited, provides a typical of 15mA at 3.3V, implying 220 ohm output impedance. The OFF control is to provide a faster way to turn off the LED (the DAC settles in under 20us, but I'd like quicker turn-off) or to hold it off while the DAC settles to a new value I'll use. The OFF control will only be held for periods of around 20-50 microseconds when the DAC output is other than 0V.

I've done the design with discretes which does better than I need in terms of speed and compliances, but it's a SOT143 BCV62, a SOT323 PN3904, and eight 0402 resistors. Inexpensive except for area. Which is a reason why I'm looking for 6-lead SOT23. Cheap is achieved, but unless I put parts on two sides, small is not (and even then...)

I could live with 8-pin or even 12-pin, if small. About 0.1"x0.3" would be acceptable.

Jon

Reply to
Jon Kirwan
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Forgot to add one VERY important point. Precision is NOT required -- the V-control for setting current does NOT need to be precise nor does it need to be stabilized against ambient temperature. It is part of a software PID loop that monitors LED emission at 100Hz, so there is a closed loop control via software. Also, duty cycles (ON time) will be no more than about 50%.

Jon

Reply to
Jon Kirwan

Check for TLE 4240 from Infineon, if it is suitable.

Reply to
kermit

Thanks. That is very close, except that I need to have a way of controlling the current (not with a precision relationship, because it is inside a closed loop control system which will compensate for temperature and time drift and non-linearities [if monotonic.]) I'll look a little further into their parts, though. Maybe something will show up.

Thanks again, Jon

Reply to
Jon Kirwan

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