SFFS272 September   2022 TPS7B81-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 HVSSOP Package
    2. 2.2 WSON Package
    3. 2.3 TO-252 Package
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 HVSSOP Package
    2. 4.2 WSON Package
    3. 4.3 TO-252 Package

4.1 HVSSOP Package

Figure 4-1 shows the TPS7B81-Q1 pin diagram for the HVSSOP package. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS7B81-Q1 data sheet.

Figure 4-1 Pin Diagram (HVSSOP Package)
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
IN 1 Power is not supplied to the device, resulting in no output voltage. B
EN 2 The device is stuck in shutdown mode, resulting in no output voltage. B
NC 3 No effect. Normal operation. D
GND 4 No effect. Normal operation. D
GND 5 No effect. Normal operation. D
GND 6 No effect. Normal operation. D
NC 7 No effect. Normal operation. D
VOUT 8 The device is not operational when the output is pulled to GND. Current limit is triggered, and the device can repeatedly enter and exit thermal shutdown depending on power dissipation. B
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
IN 1 Power is not supplied to the device, resulting in no output voltage. B
EN 2 The device flips between shutdown mode and normal mode because of the noise on the EN voltage. This condition can result in no output voltage. B
NC 3 No effect. Normal operation. D
GND 4 A floating GND pin can result in incorrect voltage regulation or no output voltage. B
GND 5 A floating GND pin can result in incorrect voltage regulation or no output voltage. B
GND 6 A floating GND pin can result in incorrect voltage regulation or no output voltage. B
NC 7 No effect. Normal operation. D
VOUT 8 The output is disconnected from the load. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin Name Pin No. Shorted to Description of Potential Failure Effects Failure Effect Class
IN 1 EN (pin 2) EN is pulled to the IN supply. Shutdown mode is not possible. The device is powered on as long as the input supply is present. D
EN 2 NC (pin 3) No effect. Normal operation. D
NC 3 GND (pin 4) No effect. Normal operation. D
GND 5 GND (pin 6) No effect. Normal operation. D
GND 6 NC (pin 7) No effect. Normal operation. D
NC 7 VOUT (pin 8) No effect. Normal operation. D
Table 4-5 Pin FMA for Device Pins Short-Circuited to VBAT
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
IN 1 No effect. Normal operation. D
EN 2 EN is pulled to VBAT. Shutdown mode is not possible. The device is powered on as long as VBAT is present. C
NC 3 No effect. Normal operation. D
GND 4 VBAT can discharge if other GND connections on the device are still tied to GND. If all pins are floated to VBAT, this condition can result in VOUT detecting the VBAT voltage. B
GND 5 VBAT can discharge if other GND connections on the device are still tied to GND. If all pins are floated to VBAT, this condition can result in VOUT detecting the VBAT voltage. B
GND 6 VBAT can discharge if other GND connections on device are still tied to GND. If all pins are floated to VBAT, this condition can result in VOUT detecting the VBAT voltage. B
NC 7 No effect. Normal operation. D
VOUT 8 The VOUT pin can be damaged and the load being powered by the TPS7B81-Q1 instead uses the VBAT voltage. A