Questions about HMC860, HMC976, HMC1060

Hi,

I will be adding these parts to the ADIsimPower Linear Regulator design tool, I have some questions about these parts:


HMC860:

Can I short RDx to VRx to get 1.2V output? The datasheet says Vout 2.5V to 5.2V, is this because it's been tested only in this range or is it because of stability due to the loop gain?

Is there an input UVLO at around 2.5V?

I see the resistor values TempCO is specified but what about their accuracy? (not just the ratio accuracy but each resistor accuracy)

Integrated noise is specified from 100Hz to 100KHz at 3.05V. Do you have measured integrated noise specs from 10Hz to 100KHz? what about at other voltages?

HMC976:

Can I short RDx to VRx to get 1.2V output? The datasheet says Vout 1.8V to 5.1V, is this because it's been tested only in this range or is it because of stability due to the loop gain?

Is there an input UVLO at around 3.3V?

I see the resistor values TempCO is specified but what about their accuracy? (not just the ratio accuracy but each resistor accuracy)

Integrated noise is specified from 100Hz to 100KHz at 5V. Do you have measured integrated noise specs from 10Hz to 100KHz?

I see a graph of Drop-out voltage at 5V, No much data at other voltages, is the drop-out load current dependent? Any other datapoints available (3.3V Output for example). I assume the graph shows typ numbers, is there a max guaranteed/tested? what about at other voltages?

Similar questions for the HCM1060.

Thanks,

LucaV

  • Hi Luca,

    We never contemplated a customer wanting to operate the regulator with 1.2V output (reference bias voltage) by directly connecting the VRx and RDx pins. However, it is a good suggestion.  We have no simulation or characterization data for this configuration.  I discussed this with the Designer.  His initial response is that it should work.  However, he needs to further investigate its effects.  The internal circuit requires a minimum of 2.7V (VDD input) to operate, so device output current loading and resulting device power dissipation will need to be considered.  I will follow-up with additional commentary on this configuration.

    Concerning UVLO, none of our regulators have this feature.

    On-die resistor tolerance has a 3-sigma variation of ~18 to 20%.  This has consequences when using external resistors to set output voltage.  The voltage regulation may not match our ~2% tolerance spec in the datasheet when using external resistances even if the external resistor are of very tight tolerance.

    The HMC976LP3E datasheet, page 3 Figure 1 shows the measured noise profile down to 10Hz for 5V output.  We don’t have any measurements for other voltages. HMC976LP3E datasheet available at:  http://www.hittite.com/content/documents/data_sheet/hmc976lp3.pdf

    Drop-out voltages are current dependent.  For the HMC1060LP3E Figures 9 & 10 page 4 of the datasheet show the Vout vs. Vin relationship over temperature (for PTAT enabled & disabled).  These plots were collected at maximum current load.  We don’t have plots for other output voltages or current loading. HMC1060LP3E datasheet available at: http://www.hittite.com/content/documents/data_sheet/hmc1060lp3.pdf

    All plots show typical performance.  Drop-out voltage is guaranteed to be 0.3V maximum for all three regulators.

    The three regulators are of similar internal architecture and design so behavior and performance will be similar across the family.