SFFSA43A December 2024 – September 2025 LM5125-Q1 , LM5125A-Q1
Figure 4-2 shows the LM5125A-Q1 pin diagram for the VQFN package. For a detailed description of the device pins, see the Pin Configuration and Functions section in the LM5125A-Q1 data sheet.
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| DLY | 1 | The average-input-current loop is not activated when the average-input-current loop feature is used. | B |
| D | |||
| SS | 2 | The device does not start; no switching. | B |
| COMP | 3 | VOUT is out of regulation; not switching. | B |
| AGND | 4 | No effect. | D |
| CSN1 | 5 | The device is potentially damaged if the differential voltage exceeds the absolute maximum rating of 0.3V. | A |
| CSP1 | 6 | The device is potentially damaged if the differential voltage exceeds the absolute maximum rating of 0.3V. | A |
| VOUT | 7 | The external components are potentially damaged. The device potentially goes into a latch state or does not start. | B |
| HO1 | 8 | The phase-1 high-side driver is potentially damaged when the device starts switching. | A |
| HB1 | 9 | The device is potentially damaged when BOOT charging starts. | A |
| SW1 | 10 | No energy is transferred from the input to the output. | B |
| LO1 | 11 | The phase-1 low-side driver is potentially damaged when the device starts switching. | A |
| VCC | 12 | There is a loss of VCC regulation; no switching. | B |
| PGND | 13 | No effect. | D |
| LO2 | 14 | The phase-1 low-side driver is potentially damaged when the device starts switching. | A |
| SW2 | 15 | No energy is transferred from the input to the output. | B |
| HB2 | 16 | The device is potentially damaged when BOOT charging starts. | A |
| HO2 | 17 | The phase-2 high-side driver is potentially damaged when the device starts switching. | A |
| BIAS | 18 | The device is not powered, and therefore, not functional. | B |
| UVLO/EN | 19 | The device is disabled. | B |
| CSP2 | 20 | The device is potentially damaged if the differential voltage exceeds the absolute maximum rating of 0.3V. | A |
| CSN2 | 21 | The device is potentially damaged if the differential voltage exceeds the absolute maximum rating of 0.3V. | A |
| RT | 22 | The device goes to the maximum switching frequency of >2.2MHz. | C |
| SYNCOUT | 23 | The device is potentially damaged if the device configuration has the SYNCOUT function enabled. | A |
| D | |||
| SYNCIN | 24 | Clock synchronization is disabled; the device uses the internal clock. | C |
| CFG2 | 25 | Level 1 of the CFG2 pin is forced. | C |
| CFG1 | 26 | Level 1 of the CFG1 pin is forced. | C |
| CFG0 | 27 | Level 1 of the CFG0 pin is forced. | C |
| PGOOD | 28 | The voltage of the output is correct, but there is a loss of functionality at the PGOOD pin. | B |
| MODE | 29 | Diode emulation mode is activated. There is no effect if the device is configured for diode emulation mode (MODE = GND). | C |
| D | |||
| EN2 | 30 | Second phase is disabled if second phase is used. | C |
| D | |||
| ILIM/IMON | 31 | The average-input-current loop is not activated; current monitoring does not work. | B |
| ATRK/DTRK | 32 | There is no output voltage regulation. The device enters BYPASS mode after the soft start completes. | B |
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| DLY | 1 | Delayed programming does not work if the delay pin function is used. | B |
| D | |||
| SS | 2 | There is a short soft-start time. | C |
| COMP | 3 | The device is potentially unstable. | B |
| AGND | 4 | Device damage is possible. | A |
| CSN1 | 5 | There is a loss of the current sense signal for phase 1. Peak-current limit does not work. | B |
| CSP1 | 6 | There is a loss of the current sense signal for phase 1. Peak-current limit does not work. | B |
| VOUT | 7 | The internal feedback voltage for the regulation loop is pulled to GND; VOUT reaches OVPmax. | B |
| HO1 | 8 | There is a loss of the high-side driver. | B |
| HB1 | 9 | There is a loss of boot voltage, and hence, a loss of the high-side driver. | B |
| SW1 | 10 | There is a loss of the high-side driver. | B |
| LO1 | 11 | The low-side MOSFET does not switch for phase 1. | B |
| VCC | 12 | The VCC pin is not stable enough to sustain normal operation. | B |
| PGND | 13 | Device damage is possible. | A |
| LO2 | 14 | The low-side MOSFET does not switch for phase 2. | B |
| SW2 | 15 | There is a loss of the high-side driver. | B |
| HB2 | 16 | There is a loss of boot voltage, and hence, a loss of the high-side driver. | B |
| HO2 | 17 | There is a loss of the high-side driver. | B |
| BIAS | 18 | The device is not powered, and therefore, not functional. | B |
| UVLO/EN | 19 | The device is disabled. | B |
| CSP2 | 20 | There is a loss of the current sense signal for phase 2. Peak-current limit does not work. | B |
| CSN2 | 21 | There is a loss of the current sense signal for phase 2. Peak-current limit does not work. | B |
| RT | 22 | The minimum frequency is set. | C |
| SYNCOUT | 23 | The primary device functions normally. The secondary device does not get a switching clock in a multi-device configuration. | C |
| B | |||
| SYNCIN | 24 | Clock synchronization does not work; the device uses the internal clock. | C |
| CFG2 | 25 | Level 16 of the CFG2 pin is forced. | C |
| CFG1 | 26 | Level 16 of the CFG1 pin is forced. | C |
| CFG0 | 27 | Level 16 of the CFG0 pin is forced. | C |
| PGOOD | 28 | The output voltage is correct, but there is a loss of functionality at the PGOOD pin. | B |
| MODE | 29 | There is no effect if DEM mode is active, otherwise, DEM mode is activated. | D |
| C | |||
| EN2 | 30 | Second-phase enable potentially does not function as intended. | C |
| ILIM/IMON | 31 | The device operates in an average-input-current limit loop operation; VOUT drops, and therefore, VOUT is out of regulation. | B |
| ATRK/DTRK | 32 | The device goes to OVPmax. | B |
| Pin Name | Pin No. | Shorted to | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|---|
| DLY | 1 | SS | There is a loss of the delay function; the average-input-current loop does not function as intended. | B |
| SS | 2 | COMP | The device operates in peak-current limit and the output voltage rises to OVPmax. | B |
| COMP | 3 | AGND | The VOUT regulation loop does not function, the internal supply potentially collapses. | B |
| AGND | 4 | CSN1 | The device is potentially damaged if the differential voltage exceeds the absolute maximum rating of 0.3V. | A |
| CSN1 | 5 | CSP1 | There is a loss of current sense information. The circuit is potentially unstable. | B |
| CSP1 | 6 | VOUT | The output is shorted to the input supply. There is no output regulation. | B |
| VOUT | 7 | HO1 | Device damage is possible as the HO1 pin exceeds the absolute maximum voltage rating to switch. | A |
| HO1 | 8 | HB1 | Device damage is possible when switching starts. | A |
| HB1 | 9 | SW1 | There is a loss of the high-side driver. | B |
| SW1 | 10 | LO1 | Device damage is possible as the absolute maximum rating is exceeded at the LO1 pin. | A |
| LO1 | 11 | VCC | The LO1 pin does not switch. Device damage is possible when switching starts. | A |
| VCC | 12 | PGND | There is no VCC rail; no switching. | B |
| PGND | 13 | LO2 | Device damaged is possible when switching starts. | A |
| LO2 | 14 | SW2 | Device damage is possible as the absolute maximum rating is exceeded at the LO2 pin. | A |
| SW2 | 15 | HB2 | There is a loss of the high-side driver. | B |
| HB2 | 16 | HO2 | Device damage is possible when switching starts. | A |
| HO2 | 17 | BIAS | Device damage is possible as the HO2 pin potentially exceeds the absolute maximum voltage ratings at the pin locations of HO2 to SW2. | A |
| BIAS | 18 | UVLO/EN | There is a loss of the UVLO function; the device is always enabled. | B |
| C | ||||
| UVLO/EN | 19 | CSP2 | There is incorrect current sense information, the current limit is potentially incorrect. | B |
| CSP2 | 20 | CSN2 | There is a loss of current sense information. The circuit is potentially unstable. | B |
| CSN2 | 21 | RT | Device damage is possible. The CSN2 pin exceeds the absolute maximum voltage rating for the RT pin. | A |
| RT | 22 | SYNCOUT | The device operates at the maximum switching frequency at start-up. When the SYNCOUT pin starts switching, switching is unstable. | C |
| SYNCOUT | 23 | SYNCIN | There is a loss of the frequency synchronization function; switching frequency is unstable. | B |
| SYNCIN | 24 | CFG2 | There is a loss of the frequency synchronization function or Configuration 2 is incorrect (or both—loss of function and incorrect configuration). | B |
| CFG2 | 25 | CFG1 | Configuration 1 or Configuration 2 (or both) are incorrect for the device. | B |
| CFG1 | 26 | CFG0 | Configuration 1 or Configuration 2 (or both) are incorrect for the device. | B |
| CFG0 | 27 | PGOOD | The device loses the function of Configuration 0. | B |
| PGOOD | 28 | MODE | The MODE function of the device is effected. The device potentially functions in an operation mode that is incorrect based on the PGOOD output. | C |
| MODE | 29 | EN2 | The incorrect operation MODE or phase 2 enables or disables incorrectly, depending on the voltage that is driven. | B |
| EN2 | 30 | ILIM/IMON | The device is forced to function in average-input-current limit mode if the EN2 pin is driven high. The function of the ILIM/IMON pin is lost if the EN2 pin is driven low. | B |
| ILIM/IMON | 31 | ATRK/DTRK | The voltage of the output is not regulated to target the intended value, and the function of the IMON/ILIM pin is lost. | B |
| ATRK/DTRK | 32 | DLY | The voltage of the output is not regulated to target the intended value. The average-input-current limit does not work as intended. | B |
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| DLY | 1 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| SS | 2 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| COMP | 3 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| AGND | 4 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| CSN1 | 5 | There is a loss of the current sense signal. The circuit is potentially unstable. | B |
| CSP1 | 6 | Normal operation. | D |
| VOUT | 7 | There is a loss of VOUT regulation as the output voltage is forced to VI. | B |
| HO1 | 8 | Device damage is possible as the HO1 pin potentially exceeds the absolute maximum voltage ratings at the pin locations of HO1 to SW1. | A |
| HB1 | 9 | Device damage is possible as the HB1 pin exceeds the absolute maximum voltage ratings at the pin locations of HB1 to SW1. | A |
| SW1 | 10 | Energy is not transferred from input to output. | B |
| LO1 | 11 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| VCC | 12 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| PGND | 13 | Device damage is possible. | A |
| LO2 | 14 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| SW2 | 15 | Energy is not transferred from input to output. | B |
| HB2 | 16 | Device damage is possible as the HB2 pin potentially exceeds the absolute maximum voltage ratings at the pin locations of HB2 to SW2. | A |
| HO2 | 17 | Device damage is possible as the HO2 pin potentially exceeds the absolute maximum voltage ratings at the pin locations of HO2 to SW2. | A |
| BIAS | 18 | Normal operation. | D |
| UVLO/EN | 19 | No UVLO functionality, the device is enabled or disabled with VI. | B |
| C | |||
| CSP2 | 20 | Normal operation. | D |
| CSN2 | 21 | There is a loss of the current sense signal. The circuit is potentially unstable. | B |
| RT | 22 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| SYNCOUT | 23 | The device is potentially damaged; exceeds the absolute maximum voltage rating. | A |
| SYNCIN | 24 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| CFG2/SDA | 25 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| CFG1/SCL | 26 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| CFG0/CFG | 27 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| PGOOD | 28 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| MODE | 29 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| EN2 | 30 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| ILIM/IMON | 31 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |
| ATRK/DTRK | 32 | Device damage is possible; exceeds the absolute maximum voltage rating. | A |