Overview of analog comparators

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DocID024134 Rev 2

Figure 2. Waveform of a comparator output with and without an hysteresis

1.2

Propagation delay (response time)

Another important feature of the analog comparator is the propagation delay. This delay is

defined as the time between the moment the input signal crosses the threshold and the

trade off between the comparator propagation delay and the power consumption: the faster

the comparator goes, the more it consumes power.

In STM32F302xB/C, STM32F303xB/C and STM32F37x devices, the operation mode

(speed/power consumption) is configurable making it useful for both low-power applications

(such as voltage monitoring) and critical time applications (such as motor control). The

analog comparators in STM32F30x and STM32F37x devices can operate at low speed/low

power with 2 µs/1.2 µA and can also operate at high speed/high power with 50 ns/75 µA.

Table 2. Typical values of an hysteresis

Hysteresis

Typical value

No hysteresis

0 mV

Low hysteresis

8 mV

Medium hysteresis

15 mV

High hysteresis

31 mV