low noise power supply

You may have to build your own. I work on a system that needs 100 uV long-term stability on the 5 V supply, and it was a HELL of a problem to make it work. We use the Nat Semi 4140 reference and the AD706 op amp which has really low 1/f noise.

Jon

Take a look at HP/Agilent 662X series. (6621A, 6622A, 6623A, 6624A, and

6627A) When new they're $8K to $14K IIRC, but you can get used ones very cheap on Ebay.

lm317,337,350.

Quite - or your own LDO reg cct. If it really must be fully switched mode, the higher the switcher frequency the smaller the gulps of i*t it delivers, and thus the smaller the ripple.

NT

Look at how well this regulates with HV in with loads of ripple and load swing. Maybe it'll give you some ideas.

Version 4 SHEET 1 1400 680 WIRE 64 32 -64 32 WIRE 272 32 64 32 WIRE 560 32 368 32 WIRE 704 32 560 32 WIRE 64 64 64 32 WIRE 560 64 560 32 WIRE 608 64 560 64 WIRE 560 128 560 64 WIRE 608 128 608 64 WIRE 64 192 64 144 WIRE 352 192 352 80 WIRE 352 192 64 192 WIRE 704 192 704 32 WIRE 352 224 352 192 WIRE 560 240 560 192 WIRE 608 240 608 192 WIRE 608 240 560 240 WIRE 560 272 560 240 WIRE 560 272 416 272 WIRE 416 304 416 272 WIRE 416 304 400 304 WIRE 352 352 352 320 WIRE 704 416 704 272 FLAG -64 112 0 FLAG 704 416 0 FLAG 352 352 0 FLAG 560 352 0 SYMBOL voltage -64 16 R0 WINDOW 3 -42 -11 Left 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR Value SINE(155 10 60 0 0 0 1000) SYMATTR InstName V1 SYMBOL res 48 48 R0 SYMATTR InstName R3 SYMATTR Value 100k SYMBOL nmos 272 80 R270 SYMATTR InstName M1 SYMATTR Value BUK9219-55A SYMBOL zener 576 192 R180 WINDOW 0 24 72 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D1 SYMATTR Value 1N5378B SYMATTR Description Diode SYMATTR Type diode SYMBOL res 544 256 R0 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL nmos 400 224 M0 SYMATTR InstName M2 SYMATTR Value FDB2532 SYMBOL load2 704 192 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName I1 SYMATTR Value PULSE(50ma 1a 0 100us 100us 600ms 1200ms 1000) SYMBOL cap 592 128 R0 SYMATTR InstName C1 SYMATTR Value .1µ TEXT 224 8 Left 2 !.tran 0 1 0 startup

Jamie

There is a very low noise SMPS chip by Linear Tech., the LT1533, along with App Note 70 by Jim Williams.

It's a great read even if you don't use it.

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_____________________
Mr.CRC
crobcBOGUS@REMOVETHISsbcglobal.net
SuSE 10.3 Linux 2.6.22.17

missing themodel for the zener?