TLVH431QLPR datasheet(21/50 Pages) TI1

21 / 50 page

Time (ms)

-0.4

-0.2

0.2

0.4

0.6

0.8

D001

Vin~1.24V (+/-5%)

Vo(Vin=1.18V)

Vo(Vin=1.24V)

Vo(Vin=1.30V)

Time (ms)

-0.4

-0.2

0.2

0.4

0.6

0.8

-2

-1

D001

Vo(Vin=5.0V)

Vin=5.0V

TLVH431, TLVH431A, TLVH431B

TLVH432, TLVH432A, TLVH432B

www.ti.com

SLVS555J – NOVEMBER 2004 – REVISED JANUARY 2015

10.2.1.2.2

Overdrive

Slow or inaccurate responses can also occur when the reference pin is not provided enough overdrive voltage.

This is the amount of voltage that is higher than the internal virtual reference. The internal virtual reference

voltage will be within the range of 1.24 V ±(0.5%, 1.0% or 1.5%) depending on which version is being used.

The more overdrive voltage provided, the faster the TLVH431 will respond. This can be seen in figures Figure 25

and Figure 26, where it displays the output responses to various input voltages.

For applications where TLVH431 is being used as a comparator, it is best to set the trip point to greater than the

positive expected error (i.e. +1.0% for the A version). For fast response, setting the trip point to > 10% of the

internal Vref should suffice.

For minimal voltage drop or difference from Vin to the ref pin, it is recommended to use an input resistor <10k

to provide Iref.

10.2.1.2.3

Output Voltage and Logic Input Level

In order for TLVH431 to properly be used as a comparator, the logic output must be readable by the receiving

logic device. This is accomplished by knowing the input high and low level threshold voltage levels, typically

denoted by VIH & VIL.

As shown in Figure 25 and Figure 26, TLVH431's output low level voltage in open-loop/comparator mode is ~1

V, which is sufficient for some 3.3 V supplied logic. However, would not work for 2.5 V and 1.8 V supplied logic.

In order to accommodate this a resistive divider can be tied to the output to attenuate the output voltage to a

voltage legible to the receiving low voltage logic device.

TLVH431's output high voltage is approximately VSUP due to TLVH431 being open-collector. If VSUP is much

higher than the receiving logic's maximum input voltage tolerance, the output must be attenuated to

accommodate the outgoing logic's reliability.

When using a resistive divider on the output, be sure to make the sum of the resistive divider (R1 & R2 in

Figure 24) is much greater than RSUP in order to not interfere with TLVH431's ability to pull close to VSUP when

turning off.

10.2.1.2.3.1

Input Resistance

TLVH431 requires an input resistance in this application in order to source the reference current (IREF) needed

from this device to be in the proper operating regions while turning on. The actual voltage seen at the ref pin will

be VREF=VIN–IREF*RIN. Since IREF can be as high as 0.5 µA it is recommended to use a resistance small enough

that will mitigate the error that IREF creates from VIN.

10.2.1.3 Application Curves

Figure 25. Output Response With Small Overdrive

Figure 26. Output Response With Large Overdrive Voltage

Voltages

Submit Documentation Feedback

Product Folder Links: TLVH431 TLVH431A TLVH431B TLVH432 TLVH432A TLVH432B

TLVH431QLPR 数据表(PDF) 21 Page - Texas Instruments

TLVH431QLPR 数据表(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

数据表下载