SFFS891 June   2024 ISOTMP35-Q1

 

  1.   1
  2.   Trademarks
  3. 1Overview
  4. 2Functional Safety Failure In Time (FIT) Rates
  5. 3Failure Mode Distribution (FMD)
  6. 4Pin Failure Mode Analysis (Pin FMA)

Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the ISOTMP35-Q1. The failure modes covered in this document include the typical pin-by-pin failure scenarios:

  • Pin short-circuited to ground (see Table 4-2)
  • Pin open-circuited (see Table 4-3)
  • Pin short-circuited to an adjacent pin (see Table 4-4)
  • Pin short-circuited to supply (see Table 4-5)

Table 4-2 through Table 4-5 also indicate how these pin conditions can affect the device as per the failure effects classification in Table 4-1.

Table 4-1 TI Classification of Failure Effects
ClassFailure Effects
APotential device damage that affects functionality.
BNo device damage, but loss of functionality.
CNo device damage, but performance degradation.
DNo device damage, no impact to functionality or performance.

Figure 4-1 shows the DFQ package pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the ISOTMP35-Q1 data sheet.

ISOTMP35-Q1 Pin DiagramFigure 4-1 Pin Diagram

Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:

  • Bypass capacitor on the input voltage pin of 0.01µF.
  • Series resistors are sized to limit the input currents to the analog inputs to < 5mA.
  • Capacitive loading on output pin is limited to 1100pF.
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class

VDD

1Device unpowered. Device not functional. Observe that the absolute maximum ratings for all pins of the device are met, otherwise device damage is plausible.

A

NC

2No effect. Normal operation.

D

GND

3No effect. Normal operation.

D

VOUT4

Output stuck low. No analog output present on device.

B

TSENSE

5No effect. Normal operation.D
TSENSE

6

No effect. Normal operation.D
TSENSE

7

No effect. Normal operation.D
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class

VDD

1Device functionality undetermined.

B

NC

2No effect. Normal operation.

D

GND

3Device functionality undetermined. Device is unpowered or connect to ground internally through alternate pin ESD diode and power up.

B

VOUT4No effect. Normal operation.

D

TSENSE

5No effect. Normal operation.

D

TSENSE

6

No effect. Normal operation.

D

TSENSE

7

No effect. Normal operation.

D

Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin No.Shorted toDescription of Potential Failure EffectsFailure Effect Class

VDD

1

NC

No effect. Normal operation.D

NC

2

GND

No effect. Normal operation.

D

GND

3

VOUT

Output stuck low. No analog output present on device.B

TSENSE

5

TSENSENo effect. Normal operation.D
TSENSE

6

TSENSENo effect. Normal operation.D
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
VDD1No effect. Normal operation.

D

NC2No effect. Normal operation.

D

GND3Device functionality undetermined. Observe that the absolute maximum ratings for all pins of the device are met, otherwise device damage is plausible.

A

VOUT4Output stuck high.

B

TSENSE5No effect. Normal operation.D
TSENSE

6

No effect. Normal operation.

D

TSENSE

7

No effect. Normal operation.

D