On Thu, 24 Mar 2011 16:06:23 -0500, John Fields
wrote:
On Thu, 24 Mar 2011 12:33:07 -0400, Bitrex
wrote:
.
.
.
I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.
---
Here's the circuit I'm using to test Linear's NE555 model:
Version 4
SHEET 1 880 748
WIRE 224 192 -128 192
WIRE 544 192 448 192
WIRE -128 256 -128 192
WIRE -80 256 -128 256
WIRE 32 256 0 256
WIRE 64 256 32 256
WIRE 224 256 144 256
WIRE 512 256 448 256
WIRE 32 320 32 256
WIRE 176 320 32 320
WIRE 224 320 176 320
WIRE 608 320 448 320
WIRE 480 384 448 384
WIRE 608 416 608 320
WIRE 176 480 176 320
WIRE 512 480 512 256
WIRE 512 480 176 480
WIRE 544 496 544 192
WIRE -128 512 -128 256
WIRE 480 512 480 384
WIRE 480 512 -128 512
WIRE -128 528 -128 512
WIRE 176 544 176 480
WIRE -128 624 -128 608
WIRE 176 624 176 608
WIRE 176 624 -128 624
WIRE 544 624 544 576
WIRE 544 624 176 624
WIRE 608 624 608 496
WIRE 608 624 544 624
WIRE -128 688 -128 624
FLAG -128 688 0
SYMBOL Misc\\NE555 336 288 M0
SYMATTR InstName U1
SYMBOL voltage -128 512 M0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL res -96 240 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 58 VTop 0
SYMATTR InstName R1
SYMATTR Value 40k
SYMBOL res 48 240 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 19.8k
SYMBOL res 624 400 M0
WINDOW 0 -45 40 Left 0
WINDOW 3 -59 71 Left 0
SYMATTR InstName R3
SYMATTR Value 1000
SYMBOL cap 192 544 M0
WINDOW 0 -33 32 Left 0
WINDOW 3 -39 58 Left 0
SYMATTR InstName C1
SYMATTR Value 1e-7
SYMBOL res 528 480 R0
SYMATTR InstName R4
SYMATTR Value 1
TEXT 88 656 Right 0 !.tran .1 startup uic
TEXT 456 176 Left 0 ;1
TEXT 456 240 Left 0 ;2
TEXT 456 304 Left 0 ;3
TEXT 456 360 Left 0 ;4
TEXT 200 368 Left 0 ;5
TEXT 200 304 Left 0 ;6
TEXT 200 240 Left 0 ;7
TEXT 200 176 Left 0 ;8
I've just posted a query to:
http://groups.yahoo.com/group/LTspice/
for clarification re. the accuracy of the model, and I'll post what
comes back as soon as I get it.
Maybe Helmut will post here first.
The NE555 model in LTspice is virtually all behavioral modeling. Just
a quick observation of the switches (6 Ohms) suggest a whopping spike
;-)
...Jim Thompson
--
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