SFFS178 February   2022 AMC1306M05-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)

4 Pin Failure Mode Analysis (Pin FMA)

This section provides a failure mode analysis (FMA) for the pins of the AMC1306M05-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 supply (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 AMC1306M05-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the AMC1306M05-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:

  • Analog inputs are connected to a resistive signal source.
  • Differential RC filter on INP or INN.
    Series resistors are sized to limit the input currents into INP or INN to <10 mA in all circumstances (for example, if the device is unpowered and the input signal is applied).
  • CLKIN is driven with CMOS-compliant signal levels.
  • DOUT load is only capacitive (no DC connection to DGND or DVDD).
  • For pins on the primary side:
    Short-circuited to ground means short to AGND.
    Short-circuited to supply means short to AVDD.
  • For pins on the secondary side:
    Short-circuited to ground means short to DGND.
    Short-circuited to supply means short to DVDD.

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
AVDD 1 Device primary side unpowered. Device outputs fail-safe state (see data sheet for details).
Observe that the absolute maximum ratings for INP and INN of the device are met, otherwise device damage may be plausible.		 A
INP 2 INP stuck low (AGND).
Value of DOUT output bitstream proportional to voltage difference (VAGND – VINN).		 B
INN 3 INN stuck low (AGND).
Value of DOUT output bitstream proportional to voltage difference (VINP – VAGND).		 B
AGND 4 No effect. Normal operation. D
DGND 5 No effect. Normal operation. D
DOUT 6 DOUT stuck low (DGND). No valid DOUT output bitstream.
DOUT output bitstream looks like fail-safe output response (see data sheet for details).
Excess current consumption from DVDD source when DOUT tries to drive high. Long-term damage plausible.		 A
CLKIN 7 CLKIN stuck low (DGND). Device not functional because of missing clock input.
DOUT stuck in same state (high or low) as when CLKIN stopped. No valid DOUT output bitstream.		 B
DVDD 8 Device secondary side unpowered.
DOUT pin is driven to DGND. No valid DOUT output bitstream.
Observe that the absolute maximum ratings for CLKIN of the device are met, otherwise device damage may be plausible.		 A
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
AVDD 1 Device primary side unpowered. Device outputs fail-safe state (see data sheet for details).
INP and INN have special ESD cells with blocking diodes and no direct connection to internal AVDD. The device does not power up if INP or INN is biased high. However, some input clamp damage can occur if the INP or INN input current exceeds the absolute maximum input current rating.		 B
INP 2 INP undetermined. Value of DOUT output bitstream undetermined. B
INN 3 INN undetermined. Value of DOUT output bitstream undetermined. B
AGND 4 Device primary side unpowered. Device outputs fail-safe state (see data sheet for details). B
DGND 5 Device secondary side periodically powered through ESD diode of the CLKIN pin when CLKIN is driven low.
If the CLK driver can supply 8 mA of current then the device may function and produce a DOUT output bitstream. However, the logic high and low levels of DOUT are not met.
Otherwise, the DOUT output bitstream is undetermined.		 B
DOUT 6 DOUT undetermined. No valid DOUT output bitstream. B
CLKIN 7 CLKIN floating. Device not functional because of missing clock input.
DOUT stuck in same state (high or low) as when CLKIN stopped. No valid DOUT output bitstream.		 B
DVDD 8 Device secondary side periodically powered through ESD diode of the CLKIN pin when CLKIN is driven high.
If the CLK driver can supply 8 mA of current then the device may function and produce a valid DOUT output bitstream. However, the logic high and low levels of DOUT are not met.
Otherwise, the DOUT output bitstream is undetermined.		 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
AVDD 1 INP INP stuck high (AVDD). Value of DOUT output bitstream proportional to voltage difference (VAVDD – VINN).
Overrange or common-mode overvoltage detection is likely to trigger (see data sheet for more details).		 B
INP 2 INN INP shorted to INN, resulting in zero differential input voltage. Value of DOUT output bitstream at mid-scale (50% zeros, 50% ones). B
INN 3 AGND INN stuck low (AGND). Value of DOUT output bitstream proportional to voltage difference (VINP – VAGND). B
AGND 4 DGND Not considered. Corner pin. D
DGND 5 DOUT DOUT stuck low (DGND). No valid DOUT output bitstream.
DOUT output bitstream looks like fail-safe output response (see data sheet for details).
Excess current consumption from DVDD source when DOUT tries to drive high. Long-term damage plausible.		 A
DOUT 6 CLKIN DOUT output bit stream corrupted.
Excess current consumption from DVDD source when DOUT tries to drive high, while CLKIN drives low and vice versa. Long-term damage plausible.		 A
CLKIN 7 DVDD CLKIN stuck high (DVDD). Device not functional because of missing clock input. DOUT stuck in same state (high or low) as when CLKIN stopped. No valid DOUT output bitstream. B
DVDD 8 AVDD Not considered. Corner pin. D
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
Pin Name Pin No. Description of Potential Failure Effect(s) Failure Effect Class
AVDD 1 No effect. Normal operation. D
INP 2 INP stuck high (AVDD). Value of DOUT output bitstream proportional to voltage difference (VAVDD – VINN).
Overrange or common-mode overvoltage detection is likely to trigger (see data sheet for more details).		 B
INN 3 INN stuck high (AVDD). Value of DOUT output bitstream proportional to voltage difference (VINP – VAVDD).
Overrange or common-mode overvoltage detection is likely to trigger (see data sheet for more details).		 B
AGND 4 Device primary side unpowered. Device outputs fail-safe state (see data sheet for details). B
DGND 5 Device secondary side unpowered. DOUT pin is driven to DGND. No valid DOUT output bitstream.
Observe that the absolute maximum ratings for CLKIN of the device are met, otherwise device damage may be plausible.		 A
DOUT 6 DOUT stuck high (DVDD). No valid DOUT output bitstream.
Excess current consumption from DVDD source when DOUT tries to drive low. Long-term damage plausible.		 A
CLKIN 7 CLKIN stuck high (DVDD). Device not functional because of missing clock input.
DOUT stuck in same state (high or low) as when CLKIN stopped. No valid DOUT output bitstream.		 B
DVDD 8 No effect. Normal operation. D