TLV9061: TLV9061 as LOD

Hi Kai,

Our requirement is 3.6V +/- 50mV @ 60mA max. Some high accuracy LDO (like AnyOut) could meet the requirement but I would like to increase design margin.

As discussed with Eddie, I want to use LM4132 (1.8V) as voltage reference so that I can use the same resistance (with 0.1% accuracy) to get 2*Vin=3.6V and OPA192 to apply those calculated compensation components without stability issue. 

My questions:

1. Can the combination (LM4132+OPA192+0.1% resistors) meet the requirement ? Accuracy and concerns ?

2. You used TPS71750 with high PSRR to supply DAC and OPA in TIDA-01583 in order to guarantee the performance . I only have 5V power in my board and I could need to use LDO to supply OPA and voltage reference. What is recommended V+ of OPA192 for our requirement (3.6V) ? Expected Vout of the OPA should be greater than 3.6V due to Riso and Vbe. If V+ is close to 5V, PSRR of the LDO will be degraded.

3. Could you provide simulation file of TIDA-01583 ? I would like to import it and do some simulations in TINA.

4. For cost consideration, TLV9061 is preferred and may be good enough to meet the requirement. Can you recommend compensation components for TLV9061 ?

Thanks,

Hector Chen

Hector,

To get 60mA , I had to lower Rb to 33 ohms and Riso to 3.3 ohms. At cold temperature and or lower range of the real 5V supply there will be very little headroom and you might not get 60mA.

Here is the test schematic.

IOUT sweep

OUT impedance.

Phase margin

Here are the TI Tina test circuit files.

TLV9061 LDO.TSC

TLV9061 LDO BODE.TSC

TLV9061 LDO OutZ.TSC

Hi Ron,

Thanks for your reply. Need to add one requirement on Cload, in our application, we need to have 2*22uF+ 3*0.1uF decoupling caps for 3.6V power supply pins. Therefore, compensation components need to be recalculated. 

1. R2 should be greater than 100xRiso, R3=R2 (in our application). I would like to double confirm there is no stability issue if R2=R3 > 100x Riso.  

2. I would like to use below reference circuit, however I only have 5V power and I would need to use LDO to provide more clean power supply for OPA and voltage reference. What is minimum V+ of OPA192 you recommend for the reference design ?  

3. If there is no headroom when using lower range of V+, a configuration below is to increase headroom. From customer's point of view, would like to have a solution to overcome headroom issue. Could you provide a solution for our application ?

Thanks,

Hector

Hi Ron,

TIDA-01583 mentioned the reference design can provide voltage output up to 5V @ 75mA max. However, OPA192 output voltage is around 75mA*Riso (10ohm) + 0.65V (VBE typ) + 3.6V (VSUPPLY)=5V.

OPA output voltage is equal to OPA power supply. The OPA can work normally ?

Hi Hector,

do you need an ultra-low-noise regulator in your application at all? In the very most cases the PSRR of OPAmp is totally enough to handle the noise of a voltage regulator. Only the special and very unusual microbolometer detector in the TIDA-01583 needed this ultra-low-noise voltage regulator design.

Such a discrete voltage regulator design has not only advantages but also some disadvantages, like high dropout voltage and the absence of short circuit protection. You can easily barbecue the output transistor during certain short circuit conditions.

Can you explain, what you need the low noise voltage regulator for? Isn't a standard LDO better suited at the end?

Kai

Hi Kai,

I don't need to have ultra-low noise performance. 3.6V +/- 50mV (accuracy 1.38%), RMS noise < 1mV @ 60mA (max). If I use accuracy 1% LDO, then I have 14mV headroom (not sure it is enough or not). 

TIDA-01583 not only provides ultra-low noise but also high accuracy (<10mV) @75mA. Most of voltage reference IC cannot provide such output current. However, I worry about if TIDA-01583 can really provide 3.6V @ 75mA when using 5V power supply. 

TPS7A83A is a candidate without R1 and R2 to adjust Vout. Could you evaluate if I can use the LDO? Any things I need to pay attention? 

Do you recommend other LDO to meet the requirement?

Thanks,

Hector

Hector,

TPS7A83A claims 1% over temperature and load. The output current of 2 amps is far beyond 60mA so so any short would be much higher current than the normal 60mA max. With the internal program resistors and sense feedback, it is very easy to use.