applications attain better overall accuracy with additional series resistance. However, this increased accuracy is

application-specific. When series resistance is added, the total value must not be greater than 1kΩ. If filtering

is required, suggested component values are 100pF differential and 50Ω on each input; exact values are

application-specific.

Additionally, a digital filter is available for the remote temperature measurements to reduce the effect of noise

further. This filter is programmable and has two levels when enabled. Level 1 performs a moving average of

four consecutive samples. Level 1 filtering can be achieved by setting the digital filter control register (read

address 24h, write address 24h) to 01h. Level 2 performs a moving average of eight consecutive samples. Level

2 filtering can be achieved by setting the digital filter control register (read address 24h, write address 24h) to

02h. The value stored in the remote temperature result register is the output of the digital filter, and is the value

that the ALERT and THERM limits are compared to. The digital filter provides additional immunity to noise and

spikes on the ALERT and THERM outputs. The filter responses to impulse and step inputs are shown in Figure

7-2 and Figure 7-3, respectively. The filter can be enabled or disabled by programming the desired levels in the

digital filter register; see Table 8-1. The digital filter is disabled by default and on POR.

0

10

20

30

40

50

60

70

80

90

100

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Samples

Disabled

Level1

Level 2

Figure 7-2. Filter Response to Impulse Inputs

0

10

20

30

40

50

60

70

80

90

100

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Samples

Disabled

Level 1

Level 2

Figure 7-3. Filter Response to Step Inputs

7.3.5 Sensor Fault

The TMP461-EP device can sense a fault at the D+ input resulting from an incorrect diode connection. The

TMP461-EP device can also sense an open circuit. Short-circuit conditions return a value of –64°C. The

detection circuitry consists of a voltage comparator that trips when the voltage at D+ exceeds (V+) – 0.3V

(typical). The comparator output is continuously checked during a conversion. If a fault is detected, then OPEN

(bit 2) in the status register is set to 1.

When not using the remote sensor with the TMP461-EP device, D+ must be connected to D– or GND to prevent

meaningless fault warnings.

7.3.6 ALERT and THERM Functions

Operation of the ALERT (pin 10) and THERM (pin 7) interrupts is shown in Figure 7-4. Operation of the

THERM (pin 7) and THERM2 (pin 10) interrupts is shown in Figure 7-5. The ALERT and THERM pin setting is

determined by bit 5 of the configuration register.

The hysteresis value is stored in the THERM hysteresis register and applies to both the THERM and THERM2

interrupts. The value of the CONAL[2:0] bits in the consecutive ALERT register (see Table 8-1) determines

the number of limit violations before the ALERT pin is tripped. The default value is 000b and corresponds to

one violation, 001b programs two consecutive violations, 011b programs three consecutive violations, and 111b

programs four consecutive violations. The CONAL[2:0] bits provide additional filtering for the ALERT pin state.

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TMP461-EP

SNIS241 – SEPTEMBER 2025

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