SFFSAJ0 July   2025 LMR60450-Q1 , LMR60460-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)
  7. 5Revision History

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the LMR60441, LMR60450, LMR60460, LMR60441-Q1, LMR60450-Q1, and LMR60460-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 LMR60441, LMR60450, LMR60460, LMR60441-Q1, LMR60450-Q1, and LMR60460-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the LMR60441, LMR60450, LMR60460, LMR60441-Q1, LMR60450-Q1, and LMR60460-Q1 data sheet.

LMR60441 LMR60450 LMR60460 LMR60441-Q1 LMR60450-Q1 LMR60460-Q1 Pin Diagram Figure 4-1 Pin Diagram

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

  • The application circuit is used according to the LMR60441, LMR60450, LMR60460, LMR60441-Q1, LMR60450-Q1, and LMR60460-Q1 data sheets.
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
VIN1VOUT = 0V.B
PGND2VOUT is normal. D
SW3Damage to high-side FET. A
BOOT4VOUT = 0V. High-side FET does not turn on. B
PG5When not in use, this pin can be left grounded (PG is not a valid signal and VOUT is normal).D
FB6When in adjustable output mode, VOUT approaches VIN. When in fixed output mode, VOUT = 0V. B
MODE/SYNC7Device switches in AUTO mode. VOUT is normal. D
RT8Device stops switching until short to GND is removed.B
EN9VOUT = 0V. Enable is below the VEN-TH and functionality is halted. D
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
VIN1VOUT = 0V.B
PGND2VOUT can be abnormal. C
SW3VOUT = 0V.B
BOOT4VOUT = 0V. High-side FET does not turn on. B
PG5When not in use, this pin can be left open (PGOOD is not a valid signal and VOUT is normal).D
FB6VOUT approaches VIN.C
MODE/SYNC7Mode of operation can toggle between AUTO and FPWM.C
RT8Internal clock does not operate properly and the part does not switch. B
EN9Pin cannot be left floating. Device potentially does not enable. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin No.Shorted toDescription of Potential Failure EffectsFailure Effect Class
VIN1PGNDVOUT = 0V.B
PGND2SWDamage to high-side FET. A
SW3BOOTVOUT = 0V, high-side FET does not turn on and there is not CBOOT.B
BOOT4PGPG damage occurs if BOOT voltage is greater than PG absolute maximum voltage. B
PG5FBIn fixed output mode, VOUT = 0V. In adjustable mode, if a short happens before soft state is complete, output voltage approaches input voltage supply.B
FB6PGNDIn fixed output mode, VOUT = 0V. In adjustable output mode, output voltage approaches the input voltage supply.B
MODE/SYNC7RTDevice operates in FPWM.D
RT8ENInternal clock does not switch at the correct frequency. C
EN9VINDevice is enabled once the voltage between VIN and PGND is greater than VINUVLO(R).D
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
VIN1VOUT is normal. D
PGND2VOUT = 0V.B
SW3Damage to low-side FET.A
BOOT4Damage occurs to BOOT ESD.A
PG5If supply voltage is greater than 20V, damage occurs to PGOOD pin.A
FB6If supply voltage is greater than 16V, damage occurs. A
MODE/SYNC7Device operates in FPWM. D
RT8Internal clock does not switch at the correct frequency. C
EN9VOUT is normal. D