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How to speed PGA309 startup time?

user561103
Prodigy 50 points
Other Parts Discussed in Thread: PGA309

I use Pga309 in a low-power product.When need to acquisition pressure data,PGA309's power will be turned on ,delay t1 ms;then MCU will acquisition the data and turn off PGA309's Power.

The deley time t1 is the smaller the better in order to save power.How to shorten this time?It seems difficult to achieve by reading  figrue 3-1 in PGA309 user's guide.

Best regards.

  • 0
    TI__Mastermind 27715 points

    Hello,

    The PGA309 must wait 33ms after power-on in order to allow time for digital communication in all modes. Some modes, like 3-Wire (1W connected to Vout) require the 1W functionality to be disabled at all times except immediately after startup.

    The total on-time of the system includes the following:

    • Digital communication wait period - 33ms
    • EEPROM read - 1ms (may vary)
    • Temp ADC conversion - up to 125ms, depending on resolution
    • EEPROM lookup table read - up to 10ms, depending on required location
    • Internal DAC update and Vout enable - 1ms (may vary) 

    This is the best case. If any problems occur with the EEPROM read, the device will wait as indicated in the state machine diagram on Figure 3-1. As you can see, this device was not designed to be used in very fast power-cycling applications. As an alternative, I recommend increasing the off-time (sampling less often) to meet your total power consumption criteria.

    Best regards,

    Ian Williams
    Linear Applications Engineer
    Precision Analog - Op Amps