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Several questions about ADCMP582 - High speed comparator

Category: Hardware
Product Number: ADCMP582

Hello Guys,

We are planning to use high speed comparator chips. ADCMP582 seems to be suitable for our application. However, ADCMP582 datasheet leaves several uncertain questions to us. We have to confirm with ADI.

1. The input pins Vtp&Vtn, we can use them as input port Vp&Vn's termination port? Becasue which have intrinsic parallelly 50ohm to ground.

2. Vtt pin must connect to VCCO-2V?

3. How to connect LE and LE-bar to disable Latch function? The datasheet describes this about 580 and 581, but it doesn't have this part for 582.

We draw a roughly schematic of ADCMP582 according to our understand, can you help check it?



"The datasheet describes this about 580 and 581, but it doesn't have this part for 582."
[edited by: coyoo at 7:28 AM (GMT -4) on 27 Mar 2023]
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  • Hi Coyoo,

    Good day! Thank you for considering ADCMP582 for your application! 

    See below for each response:

    1. The input pins Vtp&Vtn, we can use them as input port Vp&Vn's termination port? Becasue which have intrinsic parallelly 50ohm to ground.
    -> Yes. That is exactly the purpose of VTP and VTN. If you connect them to GND, then VP and VN will be terminated to ground through the 50ohm resistor.

    2. Vtt pin must connect to VCCO-2V?
    -> Yes, connect VTT to VCCO-2V for ADCMP582

    3. How to connect LE and LE-bar to disable Latch function? The datasheet describes this about 580 and 581, but it doesn't have this part for 582.
    -> Please refer to figure 22 of the datasheet .

    To proceed in checking your schematic, may I know your target hysteresis and if you will enable latch function?
    Also, what will be your intended application?

    Thanks and Best Regards,
    Sham

Reply
  • Hi Coyoo,

    Good day! Thank you for considering ADCMP582 for your application! 

    See below for each response:

    1. The input pins Vtp&Vtn, we can use them as input port Vp&Vn's termination port? Becasue which have intrinsic parallelly 50ohm to ground.
    -> Yes. That is exactly the purpose of VTP and VTN. If you connect them to GND, then VP and VN will be terminated to ground through the 50ohm resistor.

    2. Vtt pin must connect to VCCO-2V?
    -> Yes, connect VTT to VCCO-2V for ADCMP582

    3. How to connect LE and LE-bar to disable Latch function? The datasheet describes this about 580 and 581, but it doesn't have this part for 582.
    -> Please refer to figure 22 of the datasheet .

    To proceed in checking your schematic, may I know your target hysteresis and if you will enable latch function?
    Also, what will be your intended application?

    Thanks and Best Regards,
    Sham

Children
  • Hi Sham,

    Thanks for u reply.

    Yes, we use this part to replace MAX9601, because we didn't get fine hysteresis. However, ADCMP582 seems can apply lower to 1 or 2mV controlling.

    As a driver, ADCMP582 in our case will be used to drive one OR gate chip (MC100EP01). So, I have a very serious question about how to connect between ADCMP582 and MC100EP01? We can't simply copy our previous design from MAX9601&mc100ep01. Because ADCMP582 introduce one "special" PECL, its Vol range is from VCCO-1.5 to VCCO-1.2 (1.8V~2.1V when VCCO is 3.3V).  However, the receiver, MC100EP01, only has its Vil range from 1.355V~1.675V. They are mismatched.

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    •  Analog Employees 
    •  Super User 
    in reply to coyoo

    Apologies for missing your reply. Do you still need assistance in this one?

    Thanks,

    Mae