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TLV2333: application in the temperature gun

Zhihong Huang
Intellectual 1550 points
Part Number: TLV2333

Hi team,

In the schematic diagram, tlv2333 is used in the temperature gun to amplify the signal of temperature sensor and then to MCU.

As far as I know, this kind of structure can achieve the goal with one-stage operational amplifier. Why is two-stage operational amplifier used in the temperature gun in this scheme to achieve the function of amplifying temperature signal?  Do you know the reason in this application?

  • 0
    TI__Intellectual 2120 points

    Hi Zhihong,

    The GBW of the TLV2333 is 350kHz. For a single amplifier with gain of 300, this would result in only 1.167kHz of effective bandwidth.

    Instead, the first stage has gain of 10 and thus a bandwidth of 35kHz, while the second stage has a gain of 30 and a BW of 11.67kHz. This means the effective bandwidth of the two-stage setup is 10 times greater than it would be if you only had a single amplifier (11.67kHz vs 1.167kHz).

    Additionally, R9 and C7 allow the implementation of a buffered low-pass filter for noise rejection if needed.

    Hope this helps,

    Jon

  • 0 in reply to JMac
    Guru 48395 points

    The feedback poles indicate no more than maybe 50Hz BW is intended - you probably could do one stage at gain of 300 and get about 1.1KHz in the op amp with a feedback pole at say 60Hz. 

  • 0
    Guru 140200 points

    Hi Zhihong,

    where do you have this circuit from?

    Do you know what kind of temperature sensor this circuit uses?

    Kai

  • 0 in reply to kai klaas69
    TI__Genius 10850 points

    Hello Zhihong,

    We haven't heard from you. We hope the issue is resolved. Closing the thread.