The SGA is a high performance SiGe HBT. MMIC Amplifier. NOTE: The recommended operating current in the preliminary datasheet was mA. MOSFET are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for MOSFET. Datasheet, In Stock. SN datasheet, SN circuit, SN data sheet: TI – BIT RANDOM- ACCESS READ/WRITE MEMORY,alldatasheet, datasheet, Datasheet search site.

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schematics – Why are two LEDs on? is broken? – Electrical Engineering Stack Exchange

This IC can sink 12mA max per output pin. The outputs are “active low” – if you write a High 1 to a memory location, you will read back a Low 0. Email Required, but never shown. Datasheeet comment, click on the “add a comment” link by the answer or question your commenting to. I followed the datasheet.

At ohm’s the LED current is only 6mA. The outputs are “open collector” which means that the output transistor’s collector has no connection inside the chip – you need to add a pull-up resistor to see a high output. I don’t know a bunch and I am just trying to learn.

Post as a guest Name. Sign up or log in Sign up using Google. If I connect the ME to high, then this behavior does not change. What MIGHT limit it, is the drive impedance with respect to input capacitance of the input pin; if datasheeet are transmission lines connected, a ohm pullup and ohm pulldown to ground gives good drive circa ohms to 3Vsuitable for the load of the cable.

Yeah I know It’s irrelevant but what the hell! I have also tried inserting pull up resistors 1kOhm to 4.


We Hiif you’re in write mode both controls! ME high regardless of the! I have been learning about the memory chip. Home Questions Tags Users Unanswered.

Post as a guest Name. Ideally only D2 in the schematic would change because D1 is Hi, S1 is the only output that should go low in read mode!

7489 Datasheet

By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. What am I doing wrong? I still can’t get it to work, but I will accept your answer because you dataaheet a general schematics for the chip.

Dstasheet state – and if they’re high they shouldn’t be able to light the LEDs. Can you remember how you wired it up? I had two of these that turned out to be broken see here for previous question on this. That is what I was thinking.

Since the outputs are open collector the output is an NPN transistor with the emitter grounded, and the collector connected only to the output pinyou should use a pull-up resistor of 4K7 or so when connected to a TTL input. Thanks for cleaning up the schematics. I would like to see a schematics for how connect the IC with resistors and other things needed.

Just for the record, I used a in quite successfully. Most of today’s LEDs have a Vdrop of about 3. Does this mean that I am doing something wrong, or have I broken the chip?

I am still new to digital electronics and I am just trying to learn. The following works well! I bought two SN because I wanted to learn how the memory chip works. From this answerI learned the basic idea of how to set up the circuit. Sign up using Email and Password. Remember, both ME and WE need to be active low in order to write data to the chip. Your only using address ‘0’ A0 – A3 are lowso toggling the ME pin has no effect.


For LED drive, you do the same thing: Sign up or log in Sign up using Google. I see that for the question on how big a pull-up resistor in general should be.

By using our site, you acknowledge that you have read and understand our Cookie Policy datashret, Privacy Policyand our Terms of Service. If it is only the LEDs forward voltage 2V and current 0. The SIP network is nice because you can plug it into your breadboard right next to the DIP switch, eliminating a lot of wires. It is my first time using this. If the LEDs drop 2 volts, assume there is 3 volts across the resistors there’s be a bit less, because the can’t 77489 its datashewt quite to groundthen for 20 mA, you’d want Ohms.

You will have better chance of up-votes if you break up your wall of text into small paragraphs. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

ME always low, and hopefully can toggle!