SFFS315 September   2022 TPS7B86-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 TO-252 Package
    2. 2.2 HSOIC Package
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 TO-252 Package
    2. 4.2 HSOIC Package
    3. 4.3 HSOIC Package B Version
    4. 4.4 HSOIC Package D Version

4.1 TO-252 Package

Figure 4-1 shows the TPS7B86-Q1 pin diagram for the TO-252 package. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS7B86-Q1 data sheet.

Figure 4-1 Pin Diagram (TO-252 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. System performance depends on upstream current limiting. B
EN 2 The device is disabled, resulting in no output voltage. B
GND 3 No effect. Normal operation. D
FB/NC 4

(Fixed output.) No effect. Normal operation.

(Adjustable output.) Output voltage is input voltage minus dropout voltage because the error amplifier drives the pass transistor gate to the rail.

 B/D
OUT 5 Regulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown. 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 enable circuit is in an unknown state. The device can be enabled or disabled. B
GND 3 There is no current loop for the supply voltage. The device is not operational and does not regulate. B
FB/NC 4

(Fixed output.) No effect. Normal operation.

(Adjustable output.) The error amplifier input is not connected. The output voltage is indeterminate.

B/D
OUT 5 The device 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) The device is always enabled when the input is powered. B
EN 2 GND (pin 3) The device is forced off. B
GND 3 FB/NC (pin 4)

(Fixed output.) No effect. Normal operation.

(Adjustable output.) Output voltage is input voltage minus dropout voltage because the error amplifier drives the pass transistor gate to the rail.

 B/D
FB/NC 4 OUT (pin 5)

(Fixed output.) No effect. Normal operation.

(Adjustable output.) Output voltage is equal to the internal reference voltage.

 B/D
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
IN 1 No effect. Normal operation. D
EN 2 The device is always enabled when the input is powered. B
GND 3 Power is not supplied to the device. System performance depends on upstream current limiting. B
FB/NC 4

(Fixed output.) No effect. Normal operation.

(Adjustable output.) The error amplifier input can be damaged if the input voltage is above 20 V. The output is not at the target voltage.

 A/D
OUT 5 Damage is possible if the absolute maximum rating is exceeded (20 V max). Reverse current can destroy the device. A