I purchased a TLC274cn from Tayda. I populated my board and it doesn't work. My signal essentially stops at the IC in. I checked Mouser and there seems to a variety of TLC274 with different numbers that follow.
You ordered 1?
Murphy's Law dictates that the chip was blown before your order was even assembled!
All the extra letters mean at the end on this chip are Voltage and Temp variables.
Assuming you've checked up on pin orientation and voltages?
I ordered 2. I removed the first and put in the second. I'll check the voltages tomorrow. Just wanted to verify I had the right part.
Where would I find a list of the correct voltages to compare? I've never been clear on that
I had that issue last week.mafter I plugged the pcb power in on the testing rig, things really changed.
Quote from: jimilee on April 09, 2014, 04:10:02 AM
I had that issue last week.mafter I plugged the pcb power in on the testing rig, things really changed.
I laughed so hard at that. But not at you I swear. With you. Cause we've all done it.
Quote from: PhiloB on April 09, 2014, 04:09:19 AM
I ordered 2. I removed the first and put in the second. I'll check the voltages tomorrow. Just wanted to verify I had the right part.
Where would I find a list of the correct voltages to compare? I've never been clear on that
2 is good. That means there's most likely an issue elsewhere. You get the voltages from the schematic and from the Datasheet. You're saying you lose sound at Pin 10. Check voltage across pins 4 and 11 and see what you get. Should be around 5v, IF I can read right at this time of night.
I'm getting 9.33 on PIN 4 and -9.13 on PIN 11
Here are the rest of the values:
1. 12mV 14. -7.6mV
2. 1.3mV. 13. .7mV
3. 1.7mV. 12. .3mV
4. 9.33V. 11. -9.13V
5. 1.8mV. 10. 1.2mV
6. .3mV. 9. 1.7mV
7. -10.2mV. 8. -7.13V
I tried to decipher the datasheet in regard to what the voltages should be. Do these look ok?
Quote from: PhiloB on April 10, 2014, 03:00:58 AM
I tried to decipher the datasheet in regard to what the voltages should be. Do these look ok?
You should have -9V on the V- pin, and +9V on the V+ pin. Everything else on a quad op amp should be halfway between that.
So my voltages suggest a bad IC?
Quote from: PhiloB on April 10, 2014, 06:01:03 PM
So my voltages suggest a bad IC?
Your voltages suggest something is wrong on the pins that aren't close to the voltages I mentioned. Bad parts are one of the last things you should suspect. Wrong component, wrong value, bad soldering, something wrong with the power supply, part put in backwards ...
Thanks Jon
I think a tl074 should work if you have one laying around. At least then you'd know if it's the ic.