LM81 datasheet(19/32 Pages) NSC

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Functional Description (Continued)

8.2 Temperature Interrupts

INT and T_CRIT_A outputs are provided for temperature in-

terrupt. Temperature interrupts have a normal and an ex-

tended option of operation. Each option has three different

modes of operation: Repetitive Interrupt, One-Time Interrupt

and Comparator.

Normal Repetitive Interrupt Mode is shown in

Figure 11

and operates in the following way: T_CRIT_A is disabled.

Exceeding T

HIGH causes an interrupt that will remain active

indefinitely until reset by reading Interrupt Status Register 1.

Once reset if the temperature remains above the T

HIHYST

setpoint the interrupt will again be activated at the comple-

tion of another conversion cycle. If temperature is less than

or equal to T

HIHYST the interrupt will not be activated.

Normal One-Time Interrupt Mode is shown in

Figure 12

and operates in the following way: T_CRIT_A is disabled.

Exceeding T

HIGH causes an interrupt that will remain active

indefinitely until reset by reading Interrupt Status Register 1.

Another interrupt will not occur until the temperature drops to

less than or equal to T

HIHYST and then exceeds THIGH during

a subsequent conversion. After power up this mode is se-

lected as default.

Normal Comparator Mode is shown in

Figure 13 and oper-

ates in the following way: T_CRIT_A is disabled. Exceeding

HIGH causes an interrupt that will remain activated until the

temperature is less than or equal to T

HIGH.TLOW is disabled.

DS100072-16

*Note: Interrupt resets occur only when interrupt Status Register 1 is read.

FIGURE 11. Normal Repetitive Interrupt Response

Diagram

DS100072-17

*Note: Interrupt resets occur only when interrupt Status Register 1 is read.

FIGURE 12. One-Time Interrupt Response Diagram

DS100072-18

*Note: Interrupt resets occur only when interrupt Status Register 1 is read.

FIGURE 13. Normal Comparator Mode

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