Figure 4-1 shows the TPS7B81-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 TPS7B81-Q1 data sheet.
Figure 4-3 Pin Diagram (TO-252 Package)
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
EN
2
The device is stuck in shutdown mode,
resulting in no output voltage.
B
GND
3
No effect. Normal operation.
D
DNC
4
No effect. Normal operation.
D
VOUT
5
The device is not operational when the
output is pulled to GND. Current limit is triggered, and the device
can repeatedly enter and exit thermal shutdown depending on power
dissipation.
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
EN
2
The device flips between shutdown mode
and normal mode because of the noise on the EN voltage. This
condition can result in no output voltage.
B
GND
3
A floating GND pin can result in
incorrect voltage regulation or no output voltage.
B
DNC
4
No effect. Normal operation.
D
VOUT
5
The output of the device 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
EN (pin 2)
EN is pulled to the IN supply. Shutdown
mode is not possible. The device is powered on as long as the input
supply is present.
D
EN
2
GND (pin 3)
The device is stuck in shutdown mode,
resulting in no output voltage
B
GND
3
DNC (pin 4)
No effect. Normal operation.
D
DNC
4
VOUT (pin 5)
VOUT can fall out of regulation and
increased quiescent current can be observed.
C
Table 4-13 Pin FMA for Device Pins
Short-Circuited to
VBAT
Pin Name
Pin No.
Description of Potential Failure Effects
Failure Effect Class
IN
1
No effect. Normal operation.
D
EN
2
EN is pulled to VBAT. Shutdown mode is
not possible. The device is powered on as long as VBAT is
present.
C
GND
3
VBAT can discharge if other GND
connections on the device are still tied to GND. If all pins are
floated to VBAT, this condition can result in VOUT detecting the
VBAT voltage.
B
DNC
4
VOUT can fall out of regulation and
increased quiescent current can be observed.
C
VOUT
5
The VOUT pin can be damaged and the load
being powered by the TPS7B81-Q1 instead
uses the VBAT voltage.