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

4.3 SOT-23 Package

Figure 4-5 shows the TPS784-Q1 pin diagram for the SOT-23 package with a fixed output, and Figure 4-6 shows the TPS784-Q1 pin diagram for the SOT-23 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 4-5 Pin Diagram
(SOT-23 Package), Fixed Version
Figure 4-6 Pin Diagram
(SOT-23 Package), Adjustable Version
Table 4-10 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, resulting in no output voltage. B
GND 2 No effect. Normal operation. D
EN 3 The device is disabled, resulting in no output voltage. B
NC/FB 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.

 D/B
OUT 5 Regulation is not possible, the device operates at current limit. The device can cycle in and out of thermal shutdown. B
Table 4-11 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
GND 2 There is no current loop for the supply voltage. The device is not operational and does not regulate. B
EN 3 The enable circuit is in an unknown state. The device can be enabled or disabled. B
NC/FB 4

(Fixed output.) No effect. Normal operation.

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

 D/B
OUT 5 The device output is disconnected from the load. B
Table 4-12 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 GND (pin 2) No output voltage. Either input supply is at 0 V, or an input fuse is blown. B
GND 2 EN (pin 3) The device is disabled, resulting in no output voltage. B
NC/FB 4 OUT (pin 5)

(Fixed output.) No effect. Normal operation.

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

 D/B
Table 4-13 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
GND 2 No output voltage. System performance depends on upstream overcurrent protection. B
EN 3 The device is always enabled. B
NC/FB 4

(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
OUT 5 The device does not regulate. B