SNVA925E January   2020  – March 2024 LM63610-Q1 , LM63615-Q1 , LM63625-Q1

 

  1.   1
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 HTSSOP Package
    2. 2.2 WSON Package
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 HTSSOP-16 Package
    2. 4.2 WSON Package
  6. 5Revision History

4.1 HTSSOP-16 Package

Figure 4-1 shows the LM636xx-Q1 pin diagram for the HTSSOP-16 package. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the LM63625 data sheet.

GUID-11C76DD3-5C08-47FA-9EE3-5181BD629D0A-low.gif Figure 4-1 Pin Diagram for HTSSOP
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
SW 1, 2 Damage to internal power FET or FETs, other internal circuits, or both A
BOOT 3 Damage to internal circuits A
VCC 4 Fault mode shuts the device off. B
RT 5 Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, no effect is produced. If an RT resistor is used, the frequency is set to 2.1MHz. If a 0Ω jumper is used to connect the RT input to VCC, then the VCC output is pulled to ground; see short to ground on pin 4. B
VSEL 6 Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, VCC is shorted to ground; see short to ground on pin 4. If a VSEL resistor is used or if the VSEL input is pulled to ground with a 0Ω jumper, then the output voltage is set to 3.3V before power up. No effect after power up. B
SYNC/MODE 7 Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, no effect is produced. If a 0Ω jumper is used to connect the SYNC/MODE input to VCC, then the VCC output is pulled to ground; see short to ground on pin 4 B
RESET 8 RESET functionality is lost. B
FB 9 The regulator operates at maximum duty cycle. Output voltage rises to nearly the input voltage (VIN) level. Possible damage to customer load, output stage components, or both, can occur. No effect on device B
AGND 10 No effect D
EN 11 Loss of ENABLE functionality. The device remains in shutdown mode. B
VIN 12, 13 The device does not operate. No output voltage is generated. Output capacitors discharge through input short. Large reverse current can damage the device. A
N/C 14 No effect D
PGND 15, 16 No effect D
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
SW 1, 2 With both pins open – loss of output voltage. With one pin open – some loss of device performance B
BOOT 3 Loss of output voltage regulation; low or no output voltage. Possible damage to the device A
VCC 4 VCC LDO is unstable. Loss of output voltage regulation and possible damage to internal circuits. A
RT 5 Device switching frequency drops to zero or become erratic. Loss of output voltage B
VSEL 6 The device enters ADJ mode when EN or VIN is cycled. Incorrect output voltage if fixed VOUT mode is intended. No effect after power up C
SYNC/MODE 7 Internal pulldown places the device in auto mode. B
RESET 8 RESET functionality is lost. B
FB 9 Loss of output voltage regulation. Output voltage can rise or fall outside of the intended regulation window. B
AGND 10 Loss of output voltage regulation. Possible damage to internal circuits A
EN 11 Loss of ENABLE functionality. Erratic operation; probable loss of regulation B
VIN 12, 13 With both pins open – loss of output voltage. With one pin open – possible device damage A
N/C 14 No effect D
PGND 15, 16 With either one or both pins open, there is possible device damage A
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin Name Pin No. Shorted to Description of Potential Failure Effect(s) Failure Effect Class
SW 1 SW No effect D
SW 2 BOOT Loss of output regulation, possible damage to internal circuits A
BOOT 3 VCC Loss of output regulation, possible damage to internal circuits A
VCC 4 RT Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, VCC is shorted to ground; see short to ground on pin 4. For all other configurations, the effect is either no change or erratic switching frequency with possible damage to device internal circuits. A
RT 5 VSEL Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, VCC is shorted to ground; see short to ground on pin 4. For all other configurations, the effect is either no change or erratic output voltage, switching frequency, or both with possible damage to device internal circuits. A
VSEL 6 SYNC/MODE Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, VCC is shorted to ground; see short to ground on pin 4. For all other configurations, the effect is either no change or erratic operation, switching frequency, or both with possible damage to device internal circuits. A
SYNC/MODE 7 RESET Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, RESET is shorted to ground; see short to ground on pin 8. For all other configurations, the effect is either no change or erratic operation, loss of RESET, SYNC/MODE functionality, or all of the above, with possible damage to device internal circuits. A
FB 9 AGND See short to ground on pin 9 B
AGND 10 EN See short to ground on pin 11 B
EN 11 VIN See short to VIN on pin 11 B
VIN 12, 13 N/C No effect D
N/C 14 PGND No effect D
Table 4-5 Pin FMA for Device Pins Short-Circuited to VIN
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
SW 1,2 Damage to internal power FET or FETs, other internal circuits, or both A
BOOT 3 Damage to internal circuits A
VCC 4 Damage to internal circuits for VIN > 5.5V A
RT 5 Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, no damage occurs. For all other configurations, damage to internal circuits occurs for VIN > 5.5V. A
VSEL 6 Damage to internal circuits for VIN > 5.5V A
SYNC/MODE 7 Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, no damage occurs. For all other configurations, damage to internal circuits occurs for VIN > 5.5V. A
RESET 8 Damage to internal circuits A
FB 9 Depends on exact application configuration. For the application circuit as shown in the Example Application Circuit in the device data sheet, damage to internal circuits occurs for VIN > 16V. For operation in ADJ mode, damage to internal circuits occur for VIN > 5.5V. A
AGND 10 Possible damage to internal circuits or package A
EN 11 No damage to device. Loss of ENABLE functionality B
VIN 12, 13 No effect D
N/C 14 No effect D
PGND 15, 16 Possible damage to internal circuits or package A