8.1.2 External Hysteresis

The TLV3201 and TLV3202 have a hysteresis transfer curve (shown in Figure 8-3) that is a function of three

components: VTH, VOS, and VHYST.

• VTH: the actual set voltage or threshold trip voltage

• VOS: the internal offset voltage between VIN+ and VIN–. This voltage is added to VTH to form the actual trip

point at which the comparator must respond to change output states.

• VHYST: internal hysteresis (or trip window) that is designed to reduce comparator sensitivity to noise.

V

+ V

V

-

TH

OS

HYST

V

+ V

TH

OS

V

+ V

+ V

TH

OS

HYST

Figure 8-3. TLV320x Hysteresis Transfer Curve

8.1.2.1 Inverting Comparator with Hysteresis

The inverting comparator with hysteresis requires a three-resistor network that is referenced to the comparator

supply voltage (VCC), as shown in Figure 8-4. When VIN at the inverting input is less than VA, the output voltage

is high (for simplicity, assume VO switches as high as VCC). The three network resistors can be represented as

R1 || R3 in series with R2. The lower input trip voltage (VA1) is defined by Equation 1.

V

= V

A1

CC

´

R2

(R1 || R3) + R2

(1)

When VIN is greater than [VA × (VIN > VA)], the output voltage is low, very close to ground. In this case, the three

network resistors can be presented as R2 || R3 in series with R1. The upper trip voltage (VA2) is defined by

Equation 2.

V

= V

A2

CC

´

R2 || R3

R1 + (R2 || R3)

(2)

The total hysteresis provided by the network is defined by Equation 3.

D

-

V = V

V

A

A1

A2

(3)

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TLV3201, TLV3202

SBOS561C – MARCH 2012 – REVISED MAY 2024

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