SFFS455 May 2022 LM5143A-Q1
This section provides a Failure Mode Analysis (FMA) for the pins of the LM5143A-Q1. The failure modes covered in this document include the typical pin-by-pin failure scenarios:
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.
Class | Failure Effects |
---|---|
A | Potential device damage that affects functionality |
B | No device damage, but loss of functionality |
C | No device damage, but performance degradation |
D | No device damage, no impact to functionality or performance |
Figure 4-1 shows the LM5143A-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the LM5143A-Q1 data sheet.
Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:
Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|
SS2 | 1 | VOUT1 = regulation, VOUT2 = 0 V | B |
COMP2 | 2 | VOUT1 = regulation, VOUT2 = 0 V | B |
FB2 | 3 | If FB = VDDA, VOUT1 and VOUT2 = 0 V. | B |
If FB = GND, VOUT1 = regulation and VOUT2 = 5 V. | B | ||
CS2 | 4 | VOUT1 = regulation, VOUT2 = oscillation | C |
VOUT2 | 5 | VOUT1 = regulation, VOUT2 = 0 V, excessive current from VIN, and enters overcurrent protection | B |
VCCX | 6 | If VCCX = GND, VOUT1 and VOUT2 = regulation. | D |
If VCCX is connected to VOUT2, VOUT1 = regulation, VOUT2 = 0 V, and the internal VCC regulator is used. | B | ||
If VCCX is connected to an external supply, VOUT1 and VOUT2 = regulation. | B | ||
PG2 | 7 | VOUT1 and VOUT2 = regulation, PG2 is forced low. | B |
HOL2 | 8 | VOUT1 and VOUT2 = 0 V, VCC is pulled low through HB2. | B |
HO2 | 9 | VOUT1 and VOUT2 = 0 V, VCC is pulled low through HB2. | B |
SW2 | 10 | VOUT1 = regulation, VOUT2 = 0 V, and excessive current from VIN | A |
HB2 | 11 | VOUT1 and VOUT2 = 0 V, VCC regulator loaded to current limit | B |
LOL2 | 12 | VOUT1 and VOUT2 = regulation | D |
LO2 | 13 | VOUT1 and VOUT2 = regulation | C |
PGND2 | 14 | VOUT1 and VOUT2 = regulation | D |
VCC | 15 | VOUT1 and VOUT2 = 0 V | B |
VCC | 16 | VOUT1 and VOUT2 = 0 V | B |
PGND1 | 17 | VOUT1 and VOUT2 = regulation | D |
LO1 | 18 | VOUT1 and VOUT2 = regulation | C |
LOL1 | 19 | VOUT1 and VOUT2 = regulation | C |
HB1 | 20 | VOUT1 and VOUT2 = 0 V, VCC regulator load to current limit | B |
SW1 | 21 | VOUT1 = regulation, VOUT2 = 0 V, and excessive current from VIN | B |
HO1 | 22 | VOUT1 and VOUT2 = 0 V | B |
HOL1 | 23 | VOUT1 and VOUT2 = 0 V | B |
PG1 | 24 | VOUT1 and VOUT2 = regulation, PG1 forced low | C |
VIN | 25 | VOUT1 and VOUT2 = 0 V | A |
VOUT1 | 26 | VOUT1 = 0 V, VOUT2 = regulation, and excessive current from VIN | B |
CS1 | 27 | VOUT1 = oscillation, VOUT2 = regulation | C |
FB1 | 28 | If FB1 = VDDA, VOUT1 and VOUT2 = 0 V. | B |
If FB1 = GND, VOUT1 = 5 V expected and VOUT2 = regulation. | B | ||
COMP1 | 29 | VOUT1 = 0 V, VOUT2 = regulation | B |
SS1 | 30 | VOUT1 = 0 V, VOUT2 = regulation | B |
EN1 | 31 | VOUT1 = 0 V, VOUT2 = regulation | B |
RES | 32 | VOUT1 and VOUT2 = regulation, cannot exit hiccup mode | B |
DEMB | 33 | If DEMB = VDDA, VOUT1 and VOUT2 = 0 V. | B |
VOUT1 and VOUT2 = regulation | C | ||
MODE | 34 | If MODE = VDDA, VOUT1 and VOUT2 = 0 V. | B |
If MODE = GND, VOUT1 and VOUT2 = regulation. | D | ||
AGND | 35 | VOUT1 and VOUT2 = regulation | D |
VDDA | 36 | VOUT1 and VOUT2 = 0 V, no switching | B |
RT | 37 | VOUT1 and VOUT2 = regulation, operating at the maximum switching frequency | C |
DITH | 38 | VOUT1 and VOUT2 = regulation | C |
SYNCOUT | 39 | VOUT1 and VOUT2 = regulation | D |
EN2 | 40 | VOUT1 = 0 V, VOUT2 = regulation | B |
Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|
SS2 | 1 | VOUT1 and VOUT2 = regulation | D |
COMP2 | 2 | VOUT1 = regulation, VOUT2 = oscillation and does not regulate | C |
FB2 | 3 | VOUT2 = regulation and VOUT2 = does not regulate. The controller is configured for adjustable output. | B |
CS2 | 4 | VOUT1 = regulation, VOUT2 oscillation, and no overcurrent detection | A |
VOUT2 | 5 | VOUT1 = regulation, VOUT2 = oscillation, and does not regulate | A |
VCCX | 6 | VOUT1 and VOUT2 = regulation | D |
PG2 | 7 | VOUT1 and VOUT2 = regulation, no PG2 information | C |
HOL2 | 8 | VOUT1 = regulation, VOUT2 = VIN, does not regulate, and excessive current from VIN | D |
HO2 | 9 | VOUT1 = regulation, VOUT2 = 0 V, and does not regulate | B |
SW2 | 10 | VOUT1 = regulation, VOUT2 = VIN, and high-side FET control floating | A |
HB2 | 11 | VOUT1 = regulation, VOUT2 = 0 V, high-side gate drive floating | B |
LOL2 | 12 | VOUT1 = regulation, VOUT2 = 0 V, and no gate discharge path for the low-side MOSFET | B |
LO2 | 13 | VOUT1 and VOUT2 = regulation, lower efficiency | C |
PGND2 | 14 | VOUT1 and VOUT2 = 0 V, uncontrolled behavior because of the floating ground | B |
VCC | 15 | VOUT1 and VOUT2 = 0 V | B |
VCC | 16 | VOUT1 and VOUT2 = 0 V | B |
PGND1 | 17 | VOUT1 and VOUT2 = 0 V, uncontrolled behavior because of the floating ground | B |
LO1 | 18 | VOUT1 = regulation, lower efficiency, and VOUT2 = regulation | C |
LOL1 | 19 | VOUT1 = 0 V, no discharge path for low-side MOSFET, and VOUT2 = regulation | B |
HB1 | 20 | VOUT1 = regulation, VOUT2 = 0 V, and high-side gate drive floating | B |
SW1 | 21 | VOUT1 = no regulation, high-side FET control floating, and VOUT2 = regulation | A |
HO1 | 22 | VOUT1 = does not regulate, VOUT2 = regulation | B |
HOL1 | 23 | VOUT1 = VIN, does not regulate, excessive current from VIN, and VOUT2 = regulation | C |
PG1 | 24 | VOUT1 and VOUT2 = regulation, no PG1 information | C |
VIN | 25 | VOUT1 and VOUT2 = 0 V | B |
VOUT1 | 26 | VOUT1 = oscillation, does not regulate, and VOUT2 = regulation | A |
CS1 | 27 | VOUT1 = oscillation, no overcurrent detection, and VOUT2 = regulation | A |
FB1 | 28 | VOUT2 = does not regulate. The controller is configured for adjustable output. VOUT2 = regulation | B |
COMP1 | 29 | VOUT1 = oscillation and does not regulate, VOUT2 = regulation | B |
SS1 | 30 | VOUT1 and VOUT2 = regulation | D |
EN1 | 31 | VOUT1 and VOUT2 = 0 V | B |
RES | 32 | VOUT1 and VOUT2 = regulation and exits hiccup mode current limit quickly | C |
DEMB | 33 | VOUT1 and VOUT2 = regulation and there is erratic switching. | C |
MODE | 34 | VOUT1 = regulation, VOUT2 = 0 V, and error amplifier CH2 is set to zero. | B |
AGND | 35 | VOUT1 and VOUT2 = 0 V | B |
VDDA | 36 | VOUT1 and VOUT2 = 0 V, noisy bias rail | B |
RT | 37 | VOUT1 and VOUT2 = 0 V | B |
DITH | 38 | VOUT1 and VOUT2 = regulation, no spread spectrum | C |
SYNCOUT | 39 | VOUT1 and VOUT2 = 0 V, cannot be synchronized to another part | C |
EN2 | 40 | VOUT1 and VOUT2 = 0 V | B |
Pin Name | Pin No. | Shorted to | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|---|
SS1 | 1 | COMP2 | VOUT1 = regulation, VOUT2 = VIN | B |
COMP2 | 2 | FB2 | If FB2 = VDDA, then VOUT1 = regulation and VOUT2 = VIN. | A |
If FB2 = GND, VOUT1 regulation and VOUT2 = 0 V. | B | |||
FB2 | 3 | CS2 | If FB2 = VDDA, then VOUT1 = regulation and VOUT2 = 3.3 V. | B |
If FB2 = GND, VOUT1 = regulation and VOUT = 0 V. | B | |||
CS2 | 4 | VOUT2 | VOUT1 = regulation, VOUT2 = oscillation | B |
VOUT2 | 5 | VCCX | If VOUT2 < 6.5 V, VOUT1 and VOUT2 = regulation. | B |
If VOUT2 > 6.5 V, the device damage exceeds the absolute maximum rating. | A | |||
VCCX | 6 | PG2 | VOUT1 and VOUT2 = regulation, PG2 corrupted | B |
PG2 | 7 | HOL2 | VOUT2 and VOUT2 = regulation, PG2 corrupted | B |
If HOL2 > 6.5 V, the pin exceeds the maximum rating and the PG2 pin is damaged. | A | |||
HOL2 | 8 | HO2 | VOUT1 and VOUT2 = regulation | D |
HO2 | 9 | SW2 | VOUT1 = regulation, VOUT2 < 3 V | B |
SW2 | 10 | HB2 | VOUT1 = regulation, VOUT2 = 0 V | B |
HB2 | 11 | LOL2 | VOUT1 and VOUT2 = 0 V | B |
LOL2 | 12 | LO2 | VOUT1 and VOUT2 = regulation | B |
LO2 | 13 | PGND2 | VOUT1 and VOUT2 = regulation | B |
PGND2 | 14 | VCC | VOUT1 and VOUT2 = 0 V | A |
VCC | 15 | VCC | VOUT1 and VOUT2 = regulation | D |
VCC | 16 | PGND1 | VOUT1 and VOUT2 = 0 V | A |
PGND1 | 17 | LO1 | VOUT1 and VOUT2 = regulation | C |
LO1 | 18 | LOL1 | VOUT1 and VOUT2 = regulation | D |
LOL1 | 19 | HB1 | VOUT1 = 0 V, VOUT2 = regulation | B |
HB1 | 20 | SW1 | VOUT1 = 0 V, VOUT2 = regulation | B |
SW1 | 21 | HO1 | VOUT1 = 0 V, VOUT2 = regulation | B |
HO1 | 22 | HOL1 | VOUT1 and VOUT2 = regulation | D |
HOL1 | 23 | PG1 | VOUT1 = regulation, VOUT2 = regulation, PG1 corrupted | D |
If HOL1 > 6.5 V, the pin exceeds the maximum ratings PG1 and the device is possibly damaged. | A | |||
PG1 | 24 | VIN | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. If VIN > 6.5 V, the pin exceeds the maximum rating of PG1 and the device is damaged. | A |
If VIN > 6.5 V, the pin exceeds the maximum rating of PG1 and the device is damaged. | A | |||
VIN | 25 | VOUT1 | VOUT1 = VIN, there is no switching, and VOUT2 = regulation | B |
VOUT1 | 26 | CS1 | VOUT1 = oscillation, VOUT2 = regulation | B |
CS1 | 27 | FB1 | If FB1 = VDDA, then VOUT1 = 3.3 V and VOUT2 = regulation. | B |
If FB1 = GND, VOUT1 = 0 V and VOUT2 = regulation. | B | |||
FB1 | 28 | COMP1 | If FB1 = VDDA, then VOUT1 = VIN, there is excessive current from VIN, and VOUT2 = regulation. | A |
If FB1 = GND, then VOUT1 = 0 V and VOUT2 = regulation. | B | |||
COMP1 | 29 | SS1 | VOUT1 = VIN, VOUT2 = regulation | B |
SS1 | 30 | EN1 | If EN < 6.5 V, VOUT1 and VOUT2 = regulation. | D |
If EN1 > 6.5 V, this pin exceeds the maximum ratings of SS1 pin and the device is damaged. | A | |||
EN1 | 31 | RES | If EN < 6.5 V, VOUT1 and VOUT2 = regulation. | D |
If EN1 > 6.5 V, this pin exceeds the maximum ratings of RES pin and the device is damaged. | A | |||
RES | 32 | DEMB | VOUT1 and VOUT2 = regulation | B |
DEMB | 33 | MODE | If DEMB = MODE = GND, then the pin is configured as independent dual-output. VOUT1 and VOUT2 = regulation | B |
If DEMB = MODE = VDDA, then the pin is configured as single-output interleaved. VOUT1 and VOUT2 = 0 V | B | |||
MODE | 34 | AGND | If MODE = GND, VOUT1 and VOUT2 = regulation and the pin is always in independent dual-output operation. | D |
AGND | 35 | VDDA | VOUT1 and VOUT2 = 0 V | B |
VDDA | 36 | RT | VOUT1 and VOUT2 = 0 V, no switching | B |
RT | 37 | DITH | VOUT1 = VOUT2 = oscillation | B |
DITH | 38 | SYNCOUT | VOUT1 = regulation, VOUT2 = regulation, and no spread spectrum | C |
SYNCOUT | 39 | EN2 | VOUT1 = regulation, VOUT2 = 0 V | B |
EN2 | 40 | SS2 | If EN < 6.5 V, then VOUT1 and VOUT2 = regulation. | D |
If EN1 > 6.5 V, this pin exceeds the maximum ratings of SS1 pin and the device is damaged. | A |
Pin Name | Pin No. | Description of Potential Failure Effect(s) | Failure Effect Class |
---|---|---|---|
SS1 | 1 | If VIN < 6.5 V, then VOUT1 and VOUT2 = regulation. | D |
If VIN > 6.5 V, then the pin exceeds the SS1 maximum rating and the SS1 pin is damaged. | A | ||
COMP2 | 2 | If VIN > 5 V and < 6.5 V, then VOUT1 and VOUT2 = 0 V. | B |
If VIN > 6.5 V, the pin exceeds the COMP2 maximum rating and the COMP2 pin is damaged. | A | ||
FB2 | 3 | If VIN < 6.5 V and FB2 = VDDA, then VOUT1 = regulation and VOUT2 = 3.3 V. | B |
If VIN < 6.5 V and FB2 = GND, then VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B | ||
If VIN > 6.5 V, the pin exceeds the maximum ratings of the FB2 pin voltage and the FB2 pin is damaged. | A | ||
CS2 | 4 | If VIN < 60 V, VOUT1 = regulation and VOUT2 = VIN. | B |
If VIN > 60 V, the pin exceeds the maximum ratings of the CS2 pin and the CS2 pin is damaged. | A | ||
VOUT2 | 5 | If VIN < 60 V, VOUT1 = regulation and VOUT2 = VIN. | B |
If VIN > 60 V, the pin exceeds the maximum ratings of the VOUT2 pin and the VOUT2 pin is damaged. | A | ||
VCCX | 6 | If VIN < 6.5 V and VCCX = VOUT2, VOUT1 = regulation and VOUT2 = VIN. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the VCCX pin and the VCCX pin is damaged. | A | ||
PG2 | 7 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation and PG2 is forced high. | D |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the PG2 pin and the PG2 pin is damaged. | A | ||
HOL2 | 8 | If VIN < 6.5 V, VOUT1 = regulation, VOUT2 = VIN – dropout, and there is no switching. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the HOL2 pin and the LOL2 pin is damaged. | A | ||
HO2 | 9 | If VIN < 6.5 V, VOUT1 = regulation, VOUT2 = VIN – dropout, and there is no switching. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the HO2 pin and the HO2 pin is damaged. | A | ||
SW2 | 10 | VOUT1 = regulation, VOUT2 = VIN, and there is excessive current from VIN. | B |
HB2 | 11 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation and there is erratic switching on CH2. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the HB2 pin and the HB2 pin is damaged. | A | ||
LOL2 | 12 | If VIN < 6.5 V, VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the LOL2 pin and the LOL2 pin is damaged. | A | ||
LO2 | 13 | If VIN < 6.5 V, VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the LO2 pin and the LO2 pin is damaged. | A | ||
PGND2 | 14 | VOUT and VOUT2 = 0 V and there is excessive current from VIN. | B |
VCC | 15 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | D |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the VCC pin and the VCC pin is damaged. | A | ||
VCC | 16 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | D |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the VCC pin and the VCC pin is damaged. | A | ||
PGND1 | 17 | VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B |
LO1 | 18 | If VIN < 6.5 V, VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the LO1 pin and the LO1 pin is damaged. | A | ||
LOL1 | 19 | If VIN < 6.5 V, VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the LOL1 pin and the LOL1 pin is damaged. | A | ||
HB1 | 20 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | C |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the HB1 pin and the HB1 pin is damaged. | A | ||
SW1 | 21 | VOUT1 = VIN, VOUT2 = regulation, and excessive current from VIN | B |
HO1 | 22 | If VIN < 6.5 V, VOUT1 = VIN – dropout, VOUT2 = regulation, and there is no switching. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the HB1 pin and HO1 pin is damaged. | A | ||
HOL1 | 23 | If VIN < 6.5 V, VOUT1 = VIN – dropout, VOUT2 = regulation, and there is no switching. | B |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the HB1 pin and the HOL1 pin is damaged. | A | ||
PG1 | 24 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation and PG1 is forced high. | D |
If VIN > 6.5 V, the pin exceeds the maximum ratings of the PG1 pin and the PG1 pin is damaged. | A | ||
VIN | 25 | VOUT1 and VOUT2 = regulation | D |
VOUT1 | 26 | If VIN < 60 V, then VOUT1 = VIN and VOUT2 = regulation. | B |
If VIN > 60 V, the pin exceeds the maximum ratings of the VOUT1 pin and the VOUT1 pin is damaged. | A | ||
CS1 | 27 | If VIN < 60 V, then VOUT1 = VIN and VOUT2 = regulation. | B |
If VIN > 60 V, the pin exceeds the maximum ratings of the CS1 pin, CS1 pin damage | A | ||
FB1 | 28 | If VIN < 6.5 V and FB1= VDDA, then VOUT1 = 3.3 V and VOUT2 = regulation. | B |
If VIN < 6.5 V and FB1 = GND, then VOUT1 and VOUT2 = 0 V and there is excessive current from VIN. | B | ||
If VIN > 6.5 V, the pin exceeds the maximum ratings of the FB1 pin voltage and the FB1 pin is damaged. | A | ||
COMP1 | 29 | If VIN > 5 V and < 6.5 V, VOUT1 and VOUT2 = 0 V. | B |
If VIN > 6.5 V, the pin exceeds the COMP1 maximum rating and the COMP1 pin is damaged. | A | ||
SS1 | 30 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | D |
If VIN > 6.5 V, the pin exceeds the SS1 maximum rating and the SS1 pin is damaged. | A | ||
EN1 | 31 | VOUT1 and VOUT2 regulation | D |
RES | 32 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation and no hiccup mode. | C |
If VIN > 6.5 V, the pin exceeds the RES maximum rating and the RES pin is damaged. | A | ||
DEMB | 33 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | B |
If VIN > 6.5 V, the pin exceeds the DEMB maximum rating and the DEMB pin is damaged. | A | ||
MODE | 34 | If MODE = GND, VOUT1 and VOUT2 = 0 V. | B |
If MODE = VDDA and VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | B | ||
If VIN > 6.5 V, the pin exceeds the MODE pin maximum rating and the MODE pin is damaged. | A | ||
AGND | 35 | VOUT1 and VOUT2 = 0 V. Excessive current from VIN | B |
VDDA | 36 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | D |
If VIN > 6.5 V, the pin exceeds the VDDA pin maximum rating and the VDDA pin is damaged. | A | ||
RT | 37 | If VIN < 6.5 V, VOUT1 and VOUT2 = 0 V. | B |
If VIN > 6.5 V, the pin exceeds the RT pin maximum rating and the RT pin is damaged. | A | ||
DITH | 38 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | B |
If VIN > 6.5 V, the pin exceeds the DITH pin maximum rating and the DITH pin is damaged. | A | ||
SYNCOUT | 39 | If VIN < 6.5 V, VOUT1 and VOUT2 = regulation. | B |
If VIN > 6.5 V, the pin exceeds the SYNCOUT pin maximum rating and the SYNCOUT pin is damaged. | A | ||
EN2 | 40 | VOUT1 and VOUT2 = regulation | D |