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LT1328 powering & photodiode multiplexing

Category: Hardware
Product Number: LT1328

Hello,

I've 2 questions regrding LT1328 frontend.

1. Is it important to uso low-noise LDO for LT1328 powering ?

2.Will LT1328 performance be degraded if connecting 8 different photodiodes with 8 to 1 analog multiplexing... or a better way is to use one LT1328 per photodiode and then multiplex the digital outputs?

Thanks.

Sincerely,

Pavel.

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  • Hi Pavel,

    The LT1328's high-pass filter rejects low frequency noise, however the pin 1 bias voltage is still susceptible to drift from variations to the supply voltage.  Please refer to second TOC on page 3 of the datasheet (Change in Voltage on Pin 1 vs Supply Voltage).  High frequency noise on the supply can lead to jitter on the TTL signals.  If a low noise LDO is not used, I would recommend making sure that the supply pin bypass filter caps can handle any high frequency noise on the supply line.

    Regarding multiplexing, I would recommend multiplexing the digital outputs rather than the analog inputs.

    Regards,

    Omar

  • Hi Omar,

    Thanks. So you think it would be wise to use low-noise LDOs ... like these ones (LDLN025 from ST and LT3045 from Analog Device) ? What about one LDO per one LT1328 ... or one LDO for multiple LT1328 will be also Ok ?

    multiplexing the digital outputs rather than the analog inputs

    Ok

    Sincerely,

    Pavel

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