Trying to identify a chip...

Suspect it is a MC145155-2 in the 18-pin DIP package. Datasheet for this
chip shows pin 5 as VDD, and I am wondering, isn't VDD usually the same as
GND? (Don't see any pins labled as GND, although there is VSS ,which I am
thinking is +5 volts). Any help is appreciated...

Thanks,

Dave

Suspect it is a MC145155-2 in the 18-pin DIP package. Datasheet for this
chip shows pin 5 as VDD, and I am wondering, isn't VDD usually the same as
GND?

(Don't see any pins labled as GND, although there is VSS ,which I am
thinking is +5 volts).

On Tue, 17 Nov 2009 08:51:15 -0600, "Dave" <db5151_at_hotmail.com> wrote:

Suspect it is a MC145155-2 in the 18-pin DIP package. Datasheet for this
chip shows pin 5 as VDD, and I am wondering, isn't VDD usually the same as
GND?

---
No, it's the supply voltage.
---

(Don't see any pins labled as GND, although there is VSS ,which I am
thinking is +5 volts).

---
It's GND.


JF

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:0jf5g5d3ghve73ea5618o3rb8r1hcvhedp_at_4ax.com...
On Tue, 17 Nov 2009 08:51:15 -0600, "Dave" <db5151_at_hotmail.com> wrote:

Suspect it is a MC145155-2 in the 18-pin DIP package. Datasheet for this
chip shows pin 5 as VDD, and I am wondering, isn't VDD usually the same as
GND?

---
No, it's the supply voltage.
---

(Don't see any pins labled as GND, although there is VSS ,which I am
thinking is +5 volts).

---
It's GND.


JF

Hah. So I had it backwards. VDD is supply voltage, and VSS is GND. Damn.
Glad I asked.

Thanks much!

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:0jf5g5d3ghve73ea5618o3rb8r1hcvhedp_at_4ax.com...
On Tue, 17 Nov 2009 08:51:15 -0600, "Dave" <db5151_at_hotmail.com> wrote:

Suspect it is a MC145155-2 in the 18-pin DIP package. Datasheet for this
chip shows pin 5 as VDD, and I am wondering, isn't VDD usually the same as
GND?

---
No, it's the supply voltage.
---

(Don't see any pins labled as GND, although there is VSS ,which I am
thinking is +5 volts).

---
It's GND.


JF

Hah. So I had it backwards. VDD is supply voltage, and VSS is GND. Damn.
Glad I asked.

Think in terms of "drain" and "source". For an n-channel FET, the drain

Thanks much!

Dave

On Tue, 17 Nov 2009 09:24:58 -0600, "Dave" <db5151_at_hotmail.com> wrote:


"John Fields" <jfields_at_austininstruments.com> wrote in message
news:0jf5g5d3ghve73ea5618o3rb8r1hcvhedp_at_4ax.com...
On Tue, 17 Nov 2009 08:51:15 -0600, "Dave" <db5151_at_hotmail.com> wrote:

Suspect it is a MC145155-2 in the 18-pin DIP package. Datasheet for
this
chip shows pin 5 as VDD, and I am wondering, isn't VDD usually the same
as
GND?

---
No, it's the supply voltage.
---

(Don't see any pins labled as GND, although there is VSS ,which I am
thinking is +5 volts).

---
It's GND.


JF

Hah. So I had it backwards. VDD is supply voltage, and VSS is GND.
Damn.
Glad I asked.

Thanks much!

---
You're welcome. :-)

One thing... On these electronics groups it's customary to crosspost
instead of multi-posting in that all of the replies will appear in all
the groups when the reply is made in _any_ of the groups.

Makes it much easier to follow the thread and not have to post
individual replies in each group.


JF