SFFSAA8 July   2025 TPS7B4256-Q1

 

  1.   1
  2.   Trademarks
  3. 1Overview
  4. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 D Package
    2. 2.2 DDA Package
  5. 3Failure Mode Distribution (FMD)
  6. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 D Package
    2. 4.2 DDA Package
  7. 5Revision History

4.1 D Package

Figure 4-1 shows the TPS7B4256-Q1 pin diagram for the D package. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS7B4256-Q1 data sheet.

Figure 4-1 Pin Diagram (D) Package
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
OUT1Regulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown.B
GND2No effect. Normal operation. D
GND3No effect. Normal operation. D
FB4If FB is directly connected to OUT, regulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown. If FB is connected by a resistor divider, VOUT tracks VIN minus the dropout voltage.B
ADJ/EN5The device is disabled, resulting in no output voltage. B
GND6No effect. Normal operation. D
GND7No effect. Normal operation. D
IN8Power is not supplied to the device. System performance depends on upstream current limiting.B
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
OUT1The device output is disconnected from the load.B
GND2No effect. Normal operation. D
GND3No effect. Normal operation. D
FB4The error amplifier input is not connected. Output voltage is indeterminate.B
ADJ/EN5The device state is unknown. If the device is on, the output voltage is indeterminate. B
GND6Ground loop parasitics are increased and transient performance can be degraded. C
GND7No effect. Normal operation. D
IN8Power is not supplied to the device. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin No.Shorted toDescription of Potential Failure EffectsFailure Effect Class
OUT1GNDRegulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown.B
GND2GNDNo effect. Normal operation.D
GND3FBIf FB is directly connected to OUT, regulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown. If FB is connected by a resistor divider, VOUT tracks VIN minus the dropout voltage.B
ADJ/EN5GNDThe device is disabled, resulting in no output voltage.B
GND6GNDNo effect. Normal operation.D
GND7INPower is not supplied to the device. System performance depends on upstream current limiting.B
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
OUT 1 Regulation is not possible. VOUT = VIN. B
NC 2 No effect. Normal operation. D
GND 3 Power is not supplied to the device. System performance depends on upstream current limiting. B
FB 4 Device channel is closed. If FB is tied to OUT, then VOUT = VIN. If FB is connected with a resistor divider, VOUT equals VIN if there is no loading on the device. If the loading on the device exceeds the leakage through the top feedback resistor, VOUT is pulled to 0V. B
ADJ/EN 5 VOUT tracks VIN minus the dropout voltage. B
GND 6 Power is not supplied to the device. System performance depends on upstream current limiting. B
NC 7 No effect. Normal operation. D
IN 8 No effect. Normal operation. D