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Part Number: LMC6001
I am designing a signal amplification circuit using LMC6001BIN.
the schematic is like this:
Before I test this current I test my LMC6001, It is ok. And I also check my circuit map and it is just like this schematic.When I power it on, I find the temperature is so high. And it is not work as what I want. So I test it and I find Pin2(-IN) is short-current with Pin4(GND). And I get signal voltage is about 8.5V .And I remove this chip and test it. And yes it is broken.
（Ip[current] on D1 is 0.7uA at most by the way.）
But I don't know why but I am sure I am wrong. So help me, Thanks? If the amplification ratio what I design is too high.
(I am a chinese so my english is not so good, I translate it to Chinese. Thanks)
I am design a signal amplifier circuit. But I don't know why my LMC6001 is broken. And here is the basic schamatic.
I am afriad if I give a such large amplification. Cause my signal Ip is really small, it is 0.6uA max. (Ip is the current of D1 and D1 is a photodiode)
When I powen on my circuit just for a while. I find LMC6001 is really hot, and I don't get a right output. When I power off and take LMC6001 off and test it. I find Pin2(-IN) and Pin4(GND) is short-circuit.
Please help me. Thanks.
By the why, the chip is LMC6001BIN。
In reply to John Henry:
Regards,Ronald MichallickLinear Applications
TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).
In reply to Ron Michallick:
Thanks very much. You are right about the very high gain.
And this design refer to the design in 《Photodioda amplifiers op amp solutions》,Jerald Graeme.
And I use multisim to simulation this design, It is work well.
And I have modified my design. Change R2 from 20K to 10K. And change R3 from 1M to 500k.(Actually, I have two different sense. another have a small If. So I design like this). It seem like ths didn't solve this problem.
Yes, I am sure ESD is important. And I build this circuit by hand and I want to test it first and then design PCB file. Maybe I didn't check every net-connect on my circuit.
I will let you now If I solve it.
I think I need tell U my solution.
When I check my LMC6001, I find mark on this chip is NS not TI. So maybe this is an old product or fake one. Cause I haven't a new one at hand. So I use LM358 to test this circuit. And It worked well.
And I have order some new LMC6001 and LMC6081. And I will test again.
Have a good time. Thanks again.
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