SBVA088 August   2022 TPS746-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 DRV Package
    2. 2.2 DRB Package
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 DRV Package
    2. 4.2 DRB Package

4.2 DRB Package

Figure 4-3 and Figure 4-4 show the TPS746-Q1 pin diagram (adjustable and fixed) for the DRB package. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS746-Q1 data sheet.

Figure 4-3 Pin Diagram
(Adjustable TPS746-Q1 DRB Package)
Figure 4-4 Pin Diagram
(Fixed TPS746-Q1 DRB Package)
Table 4-6 Pin FMA for Device Pins Short-Circuited to Ground
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
OUT 1 The output voltage is near or at ground. The device enters current limit. The device may cycle in and out of thermal shutdown depending on power dissipation. B
NC 2 Improved thermal performance. D
FB/NC 3 (Adjustable output.) The device stops regulating. VOUT becomes equal to VIN minus dropout because the pass transistor is driven on as hard as possible.
(Fixed output.) No effect.		 B, D
GND 4 — D
EN 5 The device turns off. B
PG 6 The PG function does not work. D
NC 7 Improved thermal performance. D
IN 8 No output voltage. B
Table 4-7 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
OUT 1 Output voltage is disconnected from the load. B
NC 2 No effect. D
FB/NC 3 (Adjustable output.) The error amplifier input is left floating, the output voltage is not equal to set voltage.
(Fixed output.) No effect.		 B, D
GND 4 The device may be disabled. B
EN 5 The device may be disabled. B
PG 6 The PG function does not work. D
NC 2 No effect. D
IN 8 No output voltage. B
Table 4-8 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin Name Pin No. Short to Description of Potential Failure Effect(s) Failure Effect Class
OUT 1 NC (pin 2) Reduced thermal performance. D
NC 2 FB/NC (pin 3) No effect. D
FB/NC 3 GND (pin 4) (Adjustable output.) The device stops regulating. VOUT becomes equal to VIN minus dropout because the pass transistor is always on.
(Fixed output.) No effect.		 B/D
GND 4 EN (pin 5) The output is forced off, VOUT is 0 V. B
EN 5 PG (pin 6) The device stays off. B
PG 6 NC (pin 7) No effect. D
NC 7 IN (pin 8) Reduced thermal performance. D
Table 4-9 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
OUT 1 The output is not regulated. VOUT = VIN. B
NC 2 No effect. D
FB/NC 3 (Adjustable output.) The FB pin is damaged if VIN is higher than 2 V.
(Fixed output.) No effect.		 A, D
GND 4 No output voltage. Either input supply is at 0 V, or input fuse is blown. B
EN 5 The output is forced on regardless of enable signal. B
PG 6 The PG function does not work. D
NC 7 No effect. D
IN 8 No effect. D