5

Application information

Overview

The TS3121 has an embedded fail-safe architecture. This feature allows power saving by dynamically turning on

and off the comparator as needed during operation. Due to the fail-safe design, the input and output pins can stay

biased while the power supply is disconnected (VCC = 0 V). The open-drain output stage allows the comparator to

be used in level shifting applications, where the output voltage range is independent from the supply.

Figure 47. Functional block diagram

Bias

+

–

V+

IN+

IN–

OUT

V-

Operating voltages

The TS3121 can operate from 1.7 V to 5.5 V and parameters are fully specified at 1.8 V, 3.3 V, and 5 V. The

specifications are guaranteed in the extended temperature range of -40 to +125 °C. The TS3121 features an

open-drain output stage that is decoupled from VCC. This allows output voltages from 0 V to 5.5 V, independent of

VCC. The rail-to-rail input stage is also decoupled from VCC, allowing the comparator to sustain input common-

mode voltages from 0 V to 5.5 V and independent of VCC.

Input offset voltage drift versus temperature

The input voltage drift variation versus temperature is defined as the offset variation related to the offset value

measured at 25 °C. The signal chain accuracy at 25 °C can be compensated during the production at the

application level. The maximum input voltage drift over the temperature enables the system designer to anticipate

the effect of temperature variations.

ΔVioΔV=maxVioT −Vio25°C

T−25°C

(1)

Where T = -40 °C and +125 °C. The datasheet maximum value is guaranteed by a measurement on a

representative sample size ensuring a Cpk (process capability index) greater than 1.3. The datasheet reports the

absolute worst-case value between -40 °C and +125 °C.

Resistor values for high-speed design

TS3121, TS3121A

Application information

DS14484 - Rev 2

page 20/34