ADT6401/ADT6402

Rev. 0 | Page 10 of 12

Hysteresis

A hysteresis value of 2°C or 10°C can be selected. The digital

comparator ensures excellent accuracy for the hysteresis value.

Hysteresis prevents oscillation on the output pin when the

temperature is approaching the trip point and after the output

pin is activated. For example, if the temperature trip is 45°C and

the hysteresis selected is 10°C, the temperature must go as low

as 35°C before the output deactivates.

TEMPERATURE CONVERSION

The conversion clock for the part is generated internally. No

external clock is required. The internal clock oscillator runs an

automatic conversion sequence. During this automatic conversion

sequence, a conversion is initiated every 600 ms. At this time, the

part powers up its analog circuitry and performs a temperature

conversion.

This temperature conversion typically takes 30 ms, after which

the analog circuitry of the part automatically shuts down. The

analog circuitry powers up again 570 ms later, when the 600 ms

timer times out and the next conversion begins. The result of

the most recent temperature conversion is compared with the

factory-set trip point value. If the temperature measured is

greater than the trip point value, the output is activated. The

output is deactivated once the temperature crosses back over

the trip point threshold, plus whatever temperature hysteresis is

selected. Figure 18 to Figure 21 show the transfer function for

the output trip pin of each generic model.

TTH

TEMP

TOVER

V

2°C

HYSTERESIS

10°C

HYSTERESIS

COLD

HOT

Figure 18. ADT6401 TOVER Transfer Function

TTH

TEMP

TOVER

V

2°C

HYSTERESIS

10°C

HYSTERESIS

COLD

HOT

Figure 19. ADT6402 TOVER Transfer Function

TTH

TEMP

TUNDER

V

COLD

HOT

10°C

HYSTERESIS

2°C

HYSTERESIS

Figure 20. ADT6401 TUNDER Transfer Function

TTH

TEMP

V

COLD

HOT

TUNDER

10°C

HYSTERESIS

2°C

HYSTERESIS

Figure 21. ADT6402 TUNDER Transfer Function