SFFS588 February 2023 TPS4H000-Q1

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the TPS4H000-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

#GUID-59B67224-3CC4-4810-AE39-411866CAB6F7 shows the TPS4H000-Q1 pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the TPS4H000-Q1 data sheet.

Figure 4-1 Pin Diagram (Version A)

Figure 4-2 Pin Diagram (Version B)

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 Effects	Failure Effect Class
INx	1, 2, 3, 4	Shutdown of corresponding channel.	B
STx	5, 6, 7, 8	Version A only. Status being reported erroneous.	B
SEH	5	Version B only. If DIAG_EN is high then only channel 3 or 4's (depending on SEL) sense current output on SNS pin.	B
SEL	6	Version B only. If DIAG_EN is high then only channel 1 or 2's (depending on SEH) sense current output on SNS pin.	B
FAULT	7	Version B only. Status being reported erroneous.	B
CS	8	Version B only. Sense current not valid from CS pin.	B
CL	9	Device defaults to internal current limit.	C
GND	10	Resistor/diode network bypassed if present.	B
DIAG_EN	11	Diagnostics disabled.	B
THER	12	Device defaults to "auto-retry" mode when encountering thermal fault.	B
NC	13, 14	No effect.	D
OUTx	15, 16, 19, 20	Current limit of device engages.	B
VS	17, 18	Device has no input supply and therefore not function.	B

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
INx	1, 2, 3, 4	Corresponding channel shutdown and INx pulled down internally.	B
STx	5, 6, 7, 8	Version A only. STx pin cannot pull high and diagnostics cannot be reported.	B
SEH	5	Version B only. Pulled low internally, however wrong SNS current potentially reported on CS if DIAG_EN is high.	B
SEL	6	Version B only. If DIAG_EN is high then only channel 1 or 2's (depending on SEH) sense current output on SNS pin.	B
FAULT	7	Version B only. Fault signal not reported.	B
CS	8	Version B only. Correct sense current cannot be read.	B
CL	9	Device defaults to internal current limit.	C
GND	10	Loss of ground detection engages and device shuts off.	B
DIAG_EN	11	Internally pulled down. Diagnostics disabled.	B
THER	12	Internally pulled down. Device defaults to "auto-retry" mode when encountering thermal fault.	B
NC	13, 14	No effect.	D
OUTx	15, 16, 19, 20	No effect. If configured, open load detection triggers.	B
VS	17, 18	Device has no input supply and therefore 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 Effects	Failure Effect Class
IN1	1	IN2	IN1 signal affects IN2 signal and vice versa.	B
IN2	2	IN3	IN2 signal affects IN3 signal and vice versa.	B
IN3	3	IN4	IN3 signal affects IN4 signal and vice versa.	B
IN4	4	ST1	Version A only. If ST1 is high then channel 4 is on.	B
IN4	4	SEH	Version B only. IN4 signal affects SEH and vice versa.	B
ST1	5	ST2	Version A only. Fault reporting of channel 1 and channel 2 erroneous.	B
SEH	5	SEL	Version B only. SEH signal affects SEL and vice versa. If DIAG_EN is high only channel 1 or 4 can be read at SNS.	B
ST2	6	ST3	Version A only. Fault reporting of channel 2 and channel 3 erroneous.	B
SEL	6	FAULT	Version B only. If FAULT high and DIAG_EN high, only channel 2 or channel 4 can be read at SNS.	B
ST3	7	ST4	Version A only. Fault reporting of channel 3 and channel 4 erroneous.	B
FAULT	7	CS	Version B only. Fault reporting and current sense reporting erroneous.	B
ST4	8	CL	Version A only. ST4 voltage can cause erroneous current limit to be set on device.	B
CS	8	CL	Version B only. Voltage level on CS can cause erroneous current limit to be set on device.	B
CL	9	GND	Device defaults to internal current limit.	C
DIAG_EN	11	THER	DIAG_EN signal affects THER signal and vice versa.	B
THER	12	NC	No effect	D
NC	14	OUT4	No effect.	D
OUT4	15	OUT3	Output of channel 4 tied to output of channel 3.	B
OUT3	16	VS	Channel 3 cannot be turned off. Short-to-battery detection triggered if configured.	B
VS	17	VS	No effect.	D
VS	18	OUT2	Channel 2 cannot be turned off. Short-to-battery detection triggered if configured.	B
OUT2	19	OUT1	Output of channel 2 tied to output of channel 1.	B

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

Pin Name	Pin No.	Description of Potential Failure Effects	Failure Effect Class
INx	1, 2, 3, 4	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
STx	5, 6, 7, 8	Version A only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
SEH	5	Version B only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell	A
SEL	6	Version B only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
FAULT	7	Version B only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
CS	8	Version B only. Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
CL	9	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
GND	10	Supply power bypassed and device does not turn on.	B
DIAG_EN	11	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
THER	12	Potential violation of absolute maximum rating of pin and possible breakdown of ESD cell.	A
NC	13, 14	No effect.	D
OUTx	15, 16, 19, 20	Output pulled to supply voltage. Short-to-battery detection triggered if configured.	B
VS	17, 18	No effect.	A