TLV431: Tolerance of Vka(low)

David Dean

Part Number: TLV431

I am using the TLV431 as a comparator in open-loop mode. I know that V_ka(low) is "approximately" 2V. This application note shows the change in V_ka(low) over current and temperature:

https://www.ti.com/lit/an/slva987a/slva987a.pdf

What I cannot find is any mention of the tolerance of V_ka(low) between different parts. My temperature and I_ka will be very consistent, but I want to know the minimum and maximum V_ka(low) that I can expect across multiple units. I plan to make use of the analog output voltage (so, not a matter of converting to a binary output), thus I need to know the min and max voltages.

over 3 years ago

0 Masoud Beheshti61 over 3 years ago

TI__Genius 16251 points

Please kindly refer to the device datasheet for full specification on Vka. Thank you.

https://www.ti.com/lit/ds/symlink/tlv431.pdf

0 David Dean over 3 years ago in reply to Masoud Beheshti61

Expert 2305 points

Could you please point to where in the datasheet the tolerance or range of Vka(low), or "output low level voltage in open-loop/comparator mode" is specified? The the 1.25V VREF I only see mentions of "approximately 1V" or "~1V". For the 2.5V VREF parts it's "approximately 2V" or "~2V". I am looking for the min and max voltages so I know how close to ~1V or ~2V I may see for Vka(low).

0 Masoud Beheshti61 over 3 years ago in reply to David Dean

TI__Genius 16251 points

Sorry I meant the document you had sent:

0 David Dean over 3 years ago in reply to Masoud Beheshti61

Expert 2305 points

This was the figure I had mentioned, showing the change in Vka(low) over current and temperature. But the parameter I still need is the part-to-part variability for Vka(low). For example, in the figure above, if Ika = 0.01A, Temp = 25C, Iref=100uA, the typical Vka is 2.05V. But there must be some min and max that I would see across different parts, correct? Like how a diode has a typical Vf for a given If, but the datasheet also lists the min and max Vf at a few particular values of If.

+1 Marcoo Z over 3 years ago in reply to David Dean

TI__Mastermind 19550 points

Hi David,

We do not have that data for this device. This parameter isn't characterized since its an open loop parameter. I have seen as low as 0.9V in low current cold to as high as 1.105 in high current high heat but that's just my experience. If you are looking characterize a system based for a VILVIH on the comparator output low then that will be tricky. I would recommend to use a voltage supervisor ti.com/svs for something that goes consistently to GND.

0 David Dean over 3 years ago in reply to Marcoo Z

Expert 2305 points

Thank you!

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TLV431: Tolerance of Vka(low)