14

TMP108

SBOS663A – APRIL 2013 – REVISED SEPTEMBER 2019

www.ti.com

Product Folder Links: TMP108

Submit Documentation Feedback

Copyright © 2013–2019, Texas Instruments Incorporated

Table 9. Hysteresis Settings

HYS1

HYS0

HYSTERESIS

0

0

0°C

0

1

1°C (default)

1

0

2°C

1

1

4°C

7.5.3.2 Polarity (POL)

The polarity of the ALERT pin can be programmed using the POL bit. If POL = 0 (default), the ALERT is active

low. For POL = 1, the ALERT pin is active high, and the state of the ALERT pin is inverted.

7.5.3.3 Thermostat Mode (TM)

The thermostat mode bit indicates to the device whether to operate in comparator mode (TM = 0, default) or

interrupt mode (TM = 1). For more information on comparator and interrupt modes, see the High- and Low-Limit

Registers section.

7.5.3.4 Temperature Watchdog Flags (FL and FH)

The TMP108 uses temperature watchdog flags in the configuration register that indicate the result of comparing

the device temperature at the end of every conversion to the values stored in the temperature limit registers

(THIGH and TLOW). If the temperature of the TMP108 exceeds the value in the THIGH register, then the flag-high bit

(FH) in the configuration register is set to 1. If the temperature falls below the value in the TLOW register, then the

flag-low bit (FL) is set to 1. If both flag bits remain 0, then the temperature is within the temperature range set by

the temperature limit registers. In interrupt mode, when any of the flags is set by an under- or overtemperature

event, the SMBus ALERT Response only clears the pin and not the flags. Reading the configuration register

clears both the flags and the pin.

7.5.3.5 Conversion Rate

The conversion rate bits, CR1 and CR0, configure the TMP108 for conversion rates of 0.25 Hz, 1 Hz, 4 Hz, or 16

Hz. The default rate is 1 Hz. The TMP108 has a typical conversion time of 27 ms. To achieve different

conversion rates, the TMP108 makes a conversion, and then powers down and waits for the appropriate delay

set by CR1 and CR0. Table 10 shows the settings for CR1 and CR0.

Table 10. Conversion Rate Settings

CR1

CR0

CONVERSION RATE

IQ (TYP)

0

0

0.25 Hz

1 μA

0

1

1 Hz (default)

2 μA

1

0

4 Hz

5 μA

1

1

16 Hz

18 μA