SNVAA06 January   2021 LM5163-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
  4. 3Failure Mode Distribution (FMD)
  5. 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 LM5163-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 LM5163-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the LM5163-Q1 data sheet.

GUID-20210106-CA0I-CLWV-VL0D-BKRMR1DWRBMG-low.pngFigure 4-1 Pin Diagram

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

  • Application circuit, as per the LM5163(-Q1)/LM5164(-Q1) datasheet is used
    • PGOOD is pulled-up to VOUT
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin NoDescription of Potential Failure Effect(s)Failure Effect Class
GND1D
VIN2VOUT = 0 VB
EN/UVLO3VOUT = 0 VB
RON4VOUT unregulated; 0 ≤ VOUT < set voltageB
FB5VOUT >> set voltage. PGOOD can become damaged if VIN > 14 V.A
PGOOD6PGOOD is invalid flag.B
BST7VOUT = 0 VB
SW8Power FET damageA
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin NoDescription of Potential Failure Effect(s)Failure Effect Class
GND1VOUT = 0 VB
VIN2VOUT = 0 VB
EN/UVLO3VOUT = 0 VB
RON4VOUT > set voltageB
FB5VOUT >> set voltage. PGOOD can become damaged if VIN > 14 V.A
PGOOD6PGOOD flag invalidB
BST7VOUT = 0 VB
SW8VOUT = 0 VB
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin NoDescription of Potential Failure Effect(s)Failure Effect Class
GND1VOUT = 0 VB
VIN2D
EN/UVLO3VIN > 5.5 V can lead to device damage.A
RON4VOUT < set voltageB
FB5PGOOD flag invalid. VOUT can be unregulated.A
PGOOD6VOUT = 0 VB
BST7

VOUT = 0 V

B
SW8VOUT = 0 VB
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin NamePin NoDescription of Potential Failure Effect(s)Failure Effect Class
GND1VOUT = 0 VB
VIN2 D
EN/UVLO3D
RON4VIN > 5.5 V can lead to device damage.A
FB5VIN > 5.5 V can lead to device damage.A
PGOOD6VIN > 14 V can lead to device damage.A
BST7VOUT = 0 VB
SW8VOUT = VIN. PGOOD can be damaged if VIN > 14 V.A