ac138

[Hul Tytus]

Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

Hul

[Bill Sloman]

Post by Hul Tytus
Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

Two amps is a bit much for a logic ic. Logic can drive MOSFet gates and
eight small surface mount MOSFets might work as open collector buffers.
Back in the day you could an array of this sort of device with a common
emitter/source, but I haven't been paying attention in recent years.

[Don Y]

Post by Hul Tytus
Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

The '138 is a decoder (demultiplexer). What you are looking
for is more likely considered a hammer driver. The two
functions tend not to coexist; if you wanted a low-side
driver that could handle 8 loads, you would likely be looking
to drive any *combination* of those loads... an "octal
driver".

You can probably find something automotive that would give you
8 such outputs in a package (though ***@2A would likely be
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

[Buzz McCool]

On 5/17/2024 10:58 AM, Don Y wrote:
...

Post by Don Y
You can probably find something automotive that would give you
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

These four and six channel devices might be close to what Don is talking
about:

https://www.infineon.com/cms/en/product/power/smart-power-switches/multichannel-spi-switches-controller/spoc-plus-2-multichannel-spi-high-side-power-controller/

[Hul Tytus]

Thanks Buzz. looking for a direct connection to keep the timing on simple basis though.

Hul

Post by Buzz McCool
...

Post by Don Y
You can probably find something automotive that would give you
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

These four and six channel devices might be close to what Don is talking
https://www.infineon.com/cms/en/product/power/smart-power-switches/multichannel-spi-switches-controller/spoc-plus-2-multichannel-spi-high-side-power-controller/

[John Larkin]

On Fri, 17 May 2024 10:58:28 -0700, Don Y

Post by Don Y

Post by Hul Tytus
Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

The '138 is a decoder (demultiplexer). What you are looking
for is more likely considered a hammer driver. The two
functions tend not to coexist; if you wanted a low-side
driver that could handle 8 loads, you would likely be looking
to drive any *combination* of those loads... an "octal
driver".
You can probably find something automotive that would give you
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

There are lots of SPI power drivers, like TPIC6595, but not 6 pins.
Somebody makes a higher-current 4-channel part.

Some logic chip could drive a power buffer, like ULN2003. But 8 loads
at 2 amps each is extreme. Discrete fets make more sense at these
currents.

What's the load?

[piglet]

Post by John Larkin
On Fri, 17 May 2024 10:58:28 -0700, Don Y

Post by Don Y

Post by Hul Tytus
Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

The '138 is a decoder (demultiplexer). What you are looking
for is more likely considered a hammer driver. The two
functions tend not to coexist; if you wanted a low-side
driver that could handle 8 loads, you would likely be looking
to drive any *combination* of those loads... an "octal
driver".
You can probably find something automotive that would give you
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

There are lots of SPI power drivers, like TPIC6595, but not 6 pins.
Somebody makes a higher-current 4-channel part.
Some logic chip could drive a power buffer, like ULN2003. But 8 loads
at 2 amps each is extreme. Discrete fets make more sense at these
currents.
What's the load?

Wouldn’t it be just one load of 2 amps and seven open?

[Hul Tytus]

Yes. One active of 8 at any given time. Aught to be one somewhere.

Hul

Post by John Larkin
On Fri, 17 May 2024 10:58:28 -0700, Don Y

Post by Don Y

Post by Hul Tytus
Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

The '138 is a decoder (demultiplexer). What you are looking
for is more likely considered a hammer driver. The two
functions tend not to coexist; if you wanted a low-side
driver that could handle 8 loads, you would likely be looking
to drive any *combination* of those loads... an "octal
driver".
You can probably find something automotive that would give you
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

There are lots of SPI power drivers, like TPIC6595, but not 6 pins.
Somebody makes a higher-current 4-channel part.
Some logic chip could drive a power buffer, like ULN2003. But 8 loads
at 2 amps each is extreme. Discrete fets make more sense at these
currents.
What's the load?

Wouldn???t it be just one load of 2 amps and seven open?
--
piglet

[Don Y]

Post by Hul Tytus
Aught to be one somewhere.

Why? Can you imagine a variety of other applications where a three-bit-code
(and ONLY a three-bit-code) would need to be resolved to one of 8 high
current drives?

[Jasen Betts]

Post by Don Y

Post by Hul Tytus
Aught to be one somewhere.

Why? Can you imagine a variety of other applications where a three-bit-code
(and ONLY a three-bit-code) would need to be resolved to one of 8 high
current drives?

sprinkler timer, except they usually use AC instead of DC

[Don Y]

Post by Jasen Betts

Post by Don Y

Post by Hul Tytus
Aught to be one somewhere.

Why? Can you imagine a variety of other applications where a three-bit-code
(and ONLY a three-bit-code) would need to be resolved to one of 8 high
current drives?

sprinkler timer, except they usually use AC instead of DC

Electromechanical ones drive the solenoids directly.

And, there is no real NEED for an "electronic" unit to
output a three bit code (plus enable!) instead of 8
discrete outputs (which also allows multiple zones to
be active simultaneously, including a "master valve"
required for ANY of the others to receive water). It's
easier/cheaper to buy an MCU with a few extra pins.

[I use three pins per valve: "pull-in", "hold" and "sense"

Now, where are the "other" applications in that "variety"?

[Hul Tytus]

Probably driving valves on & off but a couple other applications are hoovering
close by. As piglet mentioned, there is only one on at a time.

Hul

Post by John Larkin
On Fri, 17 May 2024 10:58:28 -0700, Don Y

Post by Don Y

Post by Hul Tytus
Anyone know of an ic similar to the hc/ac138/238 (16 pin,
1 input to 8 output multiplexer) but with outputs of the
open collector/drain style that can handle 2 amps at
12 volts?

The '138 is a decoder (demultiplexer). What you are looking
for is more likely considered a hammer driver. The two
functions tend not to coexist; if you wanted a low-side
driver that could handle 8 loads, you would likely be looking
to drive any *combination* of those loads... an "octal
driver".
You can probably find something automotive that would give you
pushing the power dissipation of a normal package) -- but it
would likely have an I2C or SPI interface, requiring you
to do the "decoding"/selection elsewhere.

There are lots of SPI power drivers, like TPIC6595, but not 6 pins.
Somebody makes a higher-current 4-channel part.
Some logic chip could drive a power buffer, like ULN2003. But 8 loads
at 2 amps each is extreme. Discrete fets make more sense at these
currents.
What's the load?