SFFS358 September   2022 TPS784-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 VSON Package
    2. 2.2 SOT-23 Package
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 VSON Package
    2. 4.2 VSON Package B Version
    3. 4.3 SOT-23 Package

4.2 VSON Package B Version

Figure 4-3 shows the TPS784-Q1 pin diagram for the VSON package with a fixed output, and Figure 4-4 shows the TPS784-Q1 pin diagram for the VSON with an adjustable output. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS784-Q1 data sheet.

Figure 4-3 Pin Diagram
(VSON Package B Version), Fixed Version
Figure 4-4 Pin Diagram
(VSON Package B Version), Adjustable Version
Table 4-6 Pin FMA for Device Pins Short-Circuited to Ground
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
OUT 1 Regulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown. B
NC/FB 2

(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.

 D/B
NC 3 No effect. Normal operation. D
NC 4 No effect. Normal operation. D
GND 5 No effect. Normal operation. D
EN 6 The device is disabled, resulting in no output voltage. B
NC 7 No effect. Normal operation. D
IN 8 Power is not supplied to the device, resulting in no output voltage. B
Table 4-7 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
OUT 1 The device output is disconnected from the load. B
NC/FB 2

(Adjustable output.) No effect. Normal operation.

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

 D/B
NC 3 No effect. Normal operation. D
NC 4 No effect. Normal operation. D
GND 5 There is no current loop for the supply voltage. The device is not operational and does not regulate. B
EN 6 The enable circuit is in an unknown state. The device can be enabled or disabled. B
NC 7 No effect. Normal operation. D
IN 8 Power is not supplied to the device, resulting in no output voltage. B
Table 4-8 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin Name Pin No. Shorted to Description of Potential Failure Effects Failure Effect Class
OUT 1 NC/FB (pin 2)

(Fixed output.) No effect. Normal operation.

(Adjustable output.) The output voltage is set to the internal reference voltage.

D/B
NC/FB 2 NC (pin 3) No effect. Normal operation. D
NC 3 NC (pin 4) No effect. Normal operation. D
GND 5 EN (pin 6) The device is always disabled, resulting in no output. B
EN 6 NC (pin 7) No effect. Normal operation. D
NC 7 IN (pin 8) No effect. Normal operation. D
Table 4-9 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
OUT 1 The device does not regulate. B
NC/FB 2

(Fixed output.) No effect. Normal operation.

(Adjustable output.) The absolute maximum rating for the FB pin (2 V max) can be violated, resulting in the device being destroyed. If the absolute maximum rating is not violated, the error amplifier closes the channel and there is no output voltage.

 D/A
NC 3 No effect. Normal operation. D
NC 4 No effect. Normal operation. D
GND 5 No output voltage. Either input supply is at 0 V, or an input fuse is blown. B
EN 6 The device is always enabled. B
NC 7 No effect. Normal operation. D
IN 8 No effect. Normal operation. D