SFFS456 December   2025 TPS785-Q1

 

  1.   1
  2.   Trademarks
  3. 1Overview
  4. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 VSON Package
    2. 2.2 TO-252 Package
  5. 3Failure Mode Distribution (FMD)
  6. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 VSON Package
    2. 4.2 VSON Package B Version
    3. 4.3 TO-252 Package
  7. 5Revision History

4.2 VSON Package B Version

Figure 4-3 shows the TPS785-Q1 pin diagram for the VSON package (B Version) with a fixed output. Figure 4-4 shows the TPS785-Q1 pin diagram for the VSON package (B Version) with an adjustable output. For a detailed description of the device pins, see the Pin Configuration and Functions section in the TPS785-Q1 datasheet.

Figure 4-3 Pin Diagram (VSON Package), Fixed and B Version
Figure 4-4 Pin Diagram (VSON Package), Adjustable and B 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 2 (Fixed output.) There is no effect on the device. The device operates as normal. D
FB (Adjustable output.) The output voltage is input voltage minus dropout voltage because the error amplifier drives the pass transistor gate to the rail. B
NC 3 There is no effect on the device. The device operates as normal. D
NC 4 There is no effect on the device. The device operates as normal. D
GND 5 There is no effect on the device. The device operates as normal. D
EN 6 The device is disabled, resulting in no output voltage. B
NC 7 There is no effect on the device. The device operates as normal. 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 2 (Adjustable output.) There is no effect on the device. The device operates as normal. D
FB (Fixed output.) The error amplifier input is not connected. The output voltage is indeterminate. B
NC 3 There is no effect on the device. The device operates as normal. D
NC 4 There is no effect on the device. The device operates as normal. 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 There is no effect on the device. The device operates as normal. 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 (pin 2) (Fixed output.) There is no effect on the device. The device operates as normal.
(Adjustable output.) The output voltage is set to the internal reference voltage. 		D
FB (pin 2) B
NC/FB 2 NC (pin 3) There is no effect on the device. The device operates as normal. D
NC 3 NC (pin 4) There is no effect on the device. The device operates as normal. D
GND 5 EN (pin 6) The device is always disabled, resulting in no output. B
EN 6 NC (pin 7) There is no effect on the device. The device operates as normal. D
NC 7 IN (pin 8) There is no effect on the device. The device operates as normal. D
Table 4-9 Pin FMA for Device Pins Short-Circuited to Supply (VIN)
Pin Name Pin No. Description of Potential Failure Effects Failure Effect Class
OUT 1 The device does not regulate. A violation of the absolute maximum rating of the downstream device is possible. B
NC 2 (Fixed output.) There is no effect on the device. The device operates as normal. D
FB (Adjustable output.) The absolute maximum rating for the FB pin (2V 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. A
NC 3 There is no effect on the device. The device operates as normal. D
NC 4 There is no effect on the device. The device operates as normal. D
GND 5 There is no output voltage. Either the input supply is at 0V, or an input fuse is blown. B
EN 6 The device is always enabled. B
NC 7 There is no effect on the device. The device operates as normal. D
IN 8 There is no effect on the device. The device operates as normal. D