10

REV1.2

www.3peakic.com.cn

TP2011/TP2012/TP2014

Ultra-Low Power 200nA, 1.6V, RRIO, Push-Pull Output Comparators

Operation

The TP201x family single-supply comparators feature

internal hysteresis, high speed, and low power. Input

signal range extends beyond the negative and positive

power supplies. The output can even extend all the way

to the negative supply. The input stage is active over

different ranges of common mode input voltage.

Rail-to-rail input

voltage

range

and

low-voltage

single-supply operation make these devices ideal for

portable equipment.

Applications Information

Inputs

The TP201x comparator family uses CMOS transistors at the input which prevent phase inversion when the input pins

exceed the supply voltages. Figure 1 shows an input voltage exceeding both supplies with no resulting phase

inversion.

-2

0

2

4

6

Time (100μs/div)

Input Voltage

Output Voltage

Figure 1. Comparator Response to Input Voltage

Chip

1KΩ

1KΩ

Core

+In

-In

Figure 2. Equivalent Input Structure

The electrostatic discharge (ESD) protection input structure of two back-to-back diodes and 1kΩ series resistors are

used to limit the differential input voltage applied to the precision input of the comparator by clamping input voltages

that exceed supply voltages, as shown in Figure 2. Large differential voltages exceeding the supply voltage should be

avoided to prevent damage to the input stage.

Internal Hysteresis

Most high-speed comparators oscillate in the linear region because of noise or undesired parasitic feedback. This

tends to occur when the voltage on one input is at or equal to the voltage on the other input. To counter the parasitic

effects and noise, the TP201x implements internal hysteresis.

The hysteresis in a comparator creates two trip points: one for the rising input voltage and one for the falling input

voltage. The difference between the trip points is the hysteresis. When the comparator’s input voltages are equal, the

hysteresis effectively causes one comparator input voltage to move quickly past the other, thus taking the input out of

the region where oscillation occurs. Figure 3 illustrates the case where IN- is fixed and IN+ is varied. If the inputs were

reversed, the figure would look the same, except the output would be inverted.