SFFS505 July 2022 TPS1HC30-Q1

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the TPS1HC30-Q1. The failure modes covered in this document include the typical pin-by-pin failure scenarios:

Pin short-circuited to Ground (see Table 4-2)
Pin open-circuited (see Table 4-3)
Pin short-circuited to an adjacent pin (see Table 4-4)
Pin short-circuited to VS (see Table 4-5)

Table 4-2 through Table 4-5 also indicate how these pin conditions can affect the device as per the failure effects classification in Table 4-1.

Table 4-1 TI Classification of Failure Effects

Class	Failure Effects
A	Potential device damage that affects functionality
B	No device damage, but loss of functionality
C	No device damage, but performance degradation
D	No device damage, no impact to functionality or performance

Figure 4-1 shows the TPS1HC30-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS1HC30-Q1 data sheet.

Figure 4-1 Pin Diagram

Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:

Follows data sheet recommendation for operating conditions, external components selection, and PCB layout

Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground

Pin Name	Pin No.	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	Resistor, diode network is bypassed if present	B
EN	2	Shutdown of corresponding channel	B
DIAG_EN	3	Diagnostics are disabled	B
FAULT	4	Status being reported can be erroneous	B
LATCH	5	Device defaults to auto-retry mode when encountering thermal fault	B
SNS	6	Sense current not valid from SNS pin	B
ILIM	7	Device defaults to internal open current limit	C
NC	8,11,14	No effect	D
VOUT	9,10	Current limit of device engages	B
VBB	12,13	Device has no input supply and therefore does not function	B

Table 4-3 Pin FMA for Device Pins Open-Circuited

Pin Name	Pin No.	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	Loss of ground detection engages and device shuts off	B
EN	2	Corresponding channel is shutdown and EN is pulled down internally	B
DIAG_EN	3	Internally pulled down. Diagnostics are disabled.	B
FAULT	4	Fault signal not reported	B
LATCH	13	Internally pulled down. Device defaults to auto-retry mode when encountering thermal fault	B
SNS	10	Version B only. Correct sense current cannot be read.	B
ILIM	11	Device defaults to internal current limit	C
NC	8,11,14	No effect	D
VOUT	9,10	No effect. If configured, open load detection triggers	B
VBB	12,13	Device has no input supply and therefore does not function	B

Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin

Pin Name	Pin No.	Shorted to	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	EN	Channel is disabled	B
EN	2	DIAG_EN	EN signal affects DIAG_EN signal and vice versa	B
DIAG_EN	3	FAULT	Fault reporting is erroneous. Diagnostics are enabled if FAULT is pulled high.	B
FAULT	4	LATCH	Fault reporting is erroneous. Device is in auto-retry mode if FAULT is pulled high.	B
LATCH	5	SNS	Current sensing output is erroneous. Device is in auto-retry or latched off depending on the output of the SNS pin.	B
SNS	6	ILIM	Current limit and current sensing output is incorrect	B
NC	8	VOUT	No effect	D
VOUT	10	NC	No effect	D
NC	11	VBB	No effect	D
VBB	13	NC	No effect	D

Table 4-5 Pin FMA for Device Pins Short-Circuited to supply (VBB)

Pin Name	Pin No.	Description of Potential Failure Effect(s)	Failure Effect Class
GND	1	Supply power is bypassed and device does not turn on	B
EN	2	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell	A
DIAG_EN	3	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell	A
FAULT	4	Version B only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
LATCH	5	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell	A
SNS	6	Version B only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell	A
ILIM	7	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell	A
NC	8,11,14	No effect	D
VOUT	9,10	Output is pulled to supply voltage. Short-to-battery detection is triggered if configured.	B