0.1

F

m

2.2

F

m

TLV3501-Q1

V

REF

V

OUT

V

IN

V = 5 V

S

R = 51 W

1

R = 10 kW

2

HYST

(V )

R1

V

6 mV

R1 R2

+ ´

=

+

+

TLV3501A-Q1

www.ti.com

SBOS533B – SEPTEMBER 2010 – REVISED OCTOBER 2015

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

9.1.1 Adding External Hysteresis

The TLV3501A-Q1 device has a robust performance when used with a good layout. However, the comparator

inputs have little noise immunity within the range of specified offset voltage (±5 mV). For slow moving or noisy

input signals, the comparator output can cause an undesirable switch state as input signals move through the

switching threshold. In such applications, the 6 mV of internal hysteresis of the TLV3501A-Q1 device might not

be sufficient. In cases where greater noise immunity is desired, external hysteresis can be added by connecting

a small amount of feedback to the positive. Figure 17 shows a typical topology used to introduce 25 mV of

additional hysteresis, for a total of 31-mV hysteresis when operating from a single 5-V supply. Use Equation 1 to

calculate the approximate total hysteresis.

(1)

enlarging the threshold region, thereby reducing sensitivity to noise.

Figure 17. Adding Hysteresis to the TLV3501A-Q1

9.2 Typical Application

9.2.1 Relaxation Oscillator

The TLV3501A-Q1 device can easily be configured as a simple and inexpensive relaxation oscillator. In

circuit, the resistor values are rather low to minimize the effect of parasitic capacitance. The positive input

alternates between 1/3 of V+ and 2/3 of V+ depending on whether the output is low or high. The time to charge

output is calculated to be 10.9 MHz. An implementation of this circuit oscillated at 9.6 MHz. Parasitic capacitance

and component tolerances explain the difference between theory and actual performance.

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