Re: 74HC4052 Alternative?

On 1 Dec 2006 06:03:34 -0800, jecottrell65@xxxxxxxxx wrote:


Thanks for the suggestions!

No level shifting required. All switching happens between the MCU and
RS232 drivers. System is 3.3V....

I looked at the MAX303 (it's got some funky supply requirements, made
more for higher V's.)

But looking at the category in Digikey (IC analog SW) gave me some good
search criteria and I've found a lot of good options. Nothing yet with
2 x 1:2, but better power than the 4052.

The 74HC4052 Has a maximum Icc of 8 microamps with a Vcc of 6V, so
even if it was running 8µA with your Vcc of 3.3V, that's a quiescent
dissipation of only 26.4 _micro_ watts.

If you can spare the real estate, you can get the current _way_ down
by building the thing out of glue logic.

Here's an LTSPICE circuit file showing one way to do it:


Version 4
*** 1 1092 1384
WIRE -16 -528 -608 -528
WIRE 304 -512 48 -512
WIRE 352 -512 304 -512
WIRE 464 -464 416 -464
WIRE 352 -448 128 -448
WIRE 464 -432 464 -464
WIRE 464 -320 464 -352
WIRE 352 -304 -80 -304
WIRE 464 -256 416 -256
WIRE 304 -240 304 -512
WIRE 352 -240 304 -240
WIRE 464 -224 464 -256
WIRE 464 -112 464 -144
WIRE 208 -48 -432 -48
WIRE 304 0 272 0
WIRE -80 16 -80 -304
WIRE 208 16 -80 16
WIRE 304 32 304 0
WIRE 352 32 304 32
WIRE 464 80 416 80
WIRE -80 96 -80 16
WIRE -16 96 -80 96
WIRE 352 96 304 96
WIRE 128 112 128 -448
WIRE 128 112 48 112
WIRE 208 112 128 112
WIRE 464 112 464 80
WIRE 304 128 304 96
WIRE 304 128 272 128
WIRE 208 176 -256 176
WIRE 464 224 464 192
WIRE -608 240 -608 -528
WIRE -432 240 -432 -48
WIRE -256 240 -256 176
WIRE -80 240 -80 96
WIRE -608 400 -608 320
WIRE -432 400 -432 320
WIRE -432 400 -608 400
WIRE -256 400 -256 320
WIRE -256 400 -432 400
WIRE -80 400 -80 320
WIRE -80 400 -256 400
WIRE -608 448 -608 400
FLAG -608 448 0
FLAG 464 -320 0
FLAG 464 -112 0
FLAG 464 224 0
SYMBOL Digital\\or 16 32 R0
WINDOW 0 4 15 Left 0
SYMATTR InstName A3
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL voltage -80 224 R0
WINDOW 3 24 104 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 5 0 1e-6 1e-6 2 4)
SYMATTR InstName V1
SYMBOL Digital\\or 384 -544 R0
WINDOW 0 -1 12 Left 0
SYMATTR InstName A5
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL Digital\\or 384 -336 R0
WINDOW 0 -4 114 Left 0
SYMATTR InstName A6
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL Digital\\or 16 -592 R0
WINDOW 0 6 107 Left 0
SYMATTR InstName A8
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL res 448 -448 R0
SYMATTR InstName R3
SYMATTR Value 10k
SYMBOL voltage -608 224 R0
WINDOW 3 24 44 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 5 0 1e-6 1e-6 .1 .2)
SYMATTR InstName V3
SYMBOL res 448 -240 R0
SYMATTR InstName R4
SYMATTR Value 10k
SYMBOL Digital\\and 240 -80 R0
SYMATTR InstName A2
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL Digital\\and 240 208 M180
SYMATTR InstName A4
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL Digital\\and 384 0 R0
SYMATTR InstName A7
SYMATTR SpiceLine trise 1e-6 tfall 1e-6 vhigh 5V
SYMBOL voltage -256 224 R0
WINDOW 3 24 44 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 5 0 1e-6 1e-6 .2 .4)
SYMATTR InstName V4
SYMBOL res 448 96 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL voltage -432 224 R0
WINDOW 3 24 44 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 5 0 1e-6 1e-6 .1 .2)
SYMATTR InstName V2
TEXT -408 424 Left 0 !.tran 10
TEXT 72 -552 Left 0 ;TXDATA
TEXT -144 328 Left 0 ;A/B-
TEXT 480 -456 Left 0 ;TXOUT A
TEXT 480 -248 Left 0 ;TXOUT B
TEXT 480 88 Left 0 ;RXIN
TEXT -704 328 Left 0 ;TXOUT
TEXT -536 328 Left 0 ;RXOUTA
TEXT -360 328 Left 0 ;RXOUTB


--
JF
.

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