SLCA005A Functional safety information

SLCA005A May 2020 – July 2022 LM2903B-Q1

1.4 Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the LM2903B-Q1. The failure modes covered in this document include the typical pin-by-pin failure scenarios:

Pin short-circuited to Ground (see Table 1-6)
Pin open-circuited (see Table 1-7)
Pin short-circuited to supply (see Table 1-8)
Pin short-circuited to an adjacent pin (see Table 1-9)

Table 1-6 through Table 1-9 also indicate how these pin conditions can affect the device as per the failure effects classification in Table 1-5.

Table 1-5 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 1-2 shows the pin diagram. For a detailed description of the device pins please refer to the 'Pin Configuration and Functions' section in the data sheet.

Figure 1-2 Pin Diagram

Table 1-6 Pin FMA for Device Pins Short-Circuited to Ground

Pin No.	Pin Name	Damage	Functionality	Description of Potential Failure Effect(s)	Failure Effect Class
1	OUT1	No	Yes	No change if GND pin is GND node	B
2	1IN-	No	Yes	Output goes high, if other input is positive	C
3	1IN+	No	Yes	Output goes low, if other input is positive	C
4	GND	No	Yes	No change if same node as GND	D
5	2IN+	No	Yes	Output goes low, if other input is positive	C
6	2IN-	No	Yes	Output goes high, if other input is positive	C
7	OUT2	No	Yes	No change if GND pin is GND node	B
8	VCC	No	No	Main supply shorted out (no power to device)	B

Table 1-7 Pin FMA for Device Pins Open-Circuited

Pin No.	Pin Name	Damage	Functionality	Description of Potential Failure Effect(s)	Failure Effect Class
1	OUT1	No	Yes	Output can't drive application load	B
2	1IN-	No	Yes	Output may be low or high	C
3	1IN+	No	Yes	Output may be low or high	C
4	GND	Possible	Affected	Lowest voltage pin will drive GND pin internally (via diode)	B
5	2IN+	No	Yes	Output may be low or high	C
6	2IN-	No	Yes	Output may be low or high	C
7	OUT2	No	Yes	Output can't drive application load	B
8	VCC	No	No	Main supply open (no power to device)	B

Table 1-8 Pin FMA for Device Pins Short-Circuited to VCC

Pin No.	Pin Name	Damage	Functionality	Description of Potential Failure Effect(s)	Failure Effect Class
1	OUT1	Possible	Yes	Thermal stress due to high power dissipation	B
2	1IN-	No	Yes	Output goes low, if other input is less positive	C
3	1IN+	No	Yes	Output goes high, if other input is less positive	C
4	GND	No	No	Main supply shorted out (no power to device)	B
5	2IN+	No	Yes	Output goes high, if other input is less positive	C
6	2IN-	No	Yes	Output goes low, if other input is less positive	C
7	OUT2	Possible	Yes	Thermal stress due to high power dissipation	B
8	VCC	No	Yes	No change if same node as VCC	D

Table 1-9 Pin FMA for Device Pins Short-Circuited to Adjacent Pin

Pin No.	Pin Name	Damage	Functionality	Description of Potential Failure Effect(s)	Failure Effect Class
1 to 2	OUT1 to IN1-	No	Yes	Output may be low or high	C
2 to 3	1IN- to 1IN+	Possible	Yes	Output may be low or high	C
3 to 4	1IN+ to GND	No	Yes	Output goes low, if other input is positive	C
4 to 5	GND to 2IN+	No	Yes	Output goes low, if other input is positive	C
5 to 6	2IN+ to 2IN-	No	Yes	Output may be low or high	C
6 to 7	2IN- to OUT2	No	Yes	Output may be low or high	C
7 to 8	OUT2 to VCC	Possible	Yes	Thermal stress due to high power dissipation	B
8 to 1	VCC to OUT1	Possible	No	Thermal stress due to high power dissipation	B