SFFS657 august 2023 AMC1035-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a failure mode analysis (FMA) for the pins of the AMC1035-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 AMC1035-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the AMC1035-Q1 data sheet.
Figure 4-1 Pin DiagramFollowing 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 AINP or AINN.
Series resistors are sized to limit the input currents into AINP and AINN 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).
- Manchester encoding is disabled (MCE pin connected to GND).
- REFOUT is not used (left floating).
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 |
|---|---|---|---|
| MCE | 1 | Manchester encoding disabled. Normal operation for the assumed use case. | D |
| AINP | 2 | AINP stuck low (GND). Value of DOUT output bitstream proportional to voltage difference (VGND – VAINN). | B |
| AINN | 3 | AINN stuck low (GND). Value of DOUT output bitstream proportional to voltage difference VAINP – VAGND . | B |
| REFOUT | 4 | Excess current consumption from VDD source. DOUT bitstream not affected. Long-term damage plausible. | A |
| GND | 5 | No effect. Normal operation. | D |
| DOUT | 6 | DOUT stuck low (GND). No valid DOUT output bitstream. Excess current consumption from VDD source when DOUT tries to drive high. Long-term damage plausible. | A |
| CLKIN | 7 | CLKIN stuck low (GND). Device not functional due to missing clock input. DOUT stuck in the state (high or low) that it was when CLKIN stopped. No valid DOUT output bitstream. | B |
| VDD | 8 | Device is unpowered. DOUT pin is driven to GND. No valid DOUT output bitstream. Observe that the absolute maximum ratings for CLKIN of the device are met, otherwise device damage is 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 |
|---|---|---|---|
| MCE | 1 | Manchester encoding disabled (internal pulldown). Normal operation for the assumed use case. | D |
| AINP | 2 | Value of DOUT output bitstream undetermined. | B |
| AINN | 3 | Value of DOUT output bitstream undetermined. | B |
| REFOUT | 4 | No effect. Normal operation for the assumed use case. | D |
| GND | 5 | Device is periodically powered through ESD diode of the CLKIN pin when CLKIN is driven low. If the CLK driver can supply 8.3 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 due to missing clock input. DOUT stuck in the state (high or low) that it was when CLKIN stopped. No valid DOUT output bitstream. | B |
| VDD | 8 | Device secondary side periodically powered through ESD diode of the CLKIN pin when CLKIN is driven high. If the CLK driver can supply 8.3 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 |
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 |
|---|---|---|---|---|
| MCE | 1 | AINP | Encoding scheme undetermined. | B |
| AINP | 2 | AINN | AINP shorted to AINN resulting in zero differential input voltage. Value of DOUT output bitstream at mid-scale (50% zeros, 50% ones). | B |
| AINN | 3 | REFOUT | AINN stuck at VREFOUT (2.5 V). Value of DOUT output bitstream proportional to voltage difference (VAINP – VREFOUT). | B |
| REFOUT | 4 | GND | Not considered. Corner pin. | D |
| GND | 5 | DOUT | DOUT stuck low (GND). No valid DOUT output bitstream. Excess current consumption from VDD source when DOUT tries to drive high. Long-term damage plausible. | A |
| DOUT | 6 | CLKIN | DOUT output bit stream corrupted. Excess current consumption from VDD source when DOUT tries to drive high, while CLKIN drives low and vice versa. Long-term damage plausible. | A |
| CLKIN | 7 | VDD | CLKIN stuck high (VDD). Device not functional due to missing clock input. DOUT stuck in the state (high or low) that it was when CLKIN stopped. No valid DOUT output bitstream. | B |
| VDD | 8 | MCE | 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 |
|---|---|---|---|
| MCE | 1 | Manchester encoding enabled. Incorrect coding for the assumed use case. | B |
| AINP | 2 | AINP stuck high (VDD). Value of DOUT output bitstream proportional to voltage difference (VVDD – VAINN). Overrange or common-mode overvoltage detection is likely to trigger (see data sheet for more details). | B |
| AINN | 3 | AINN stuck high (VDD). Value of DOUT output bitstream proportional to voltage difference (VAINP – VVDD). Overrange or common-mode overvoltage detection is likely to trigger (see data sheet for more details). | B |
| REFOUT | 4 | Excess current consumption from VDD source. DOUT bitstream not affected. Long-term damage plausible. | A |
| GND | 5 | Device is unpowered. DOUT pin is driven to GND. No valid DOUT output bitstream. Observe that the absolute maximum ratings for CLKIN of the device are met, otherwise device damage is plausible. | A |
| DOUT | 6 | DOUT stuck high (DVDD). No valid DOUT output bitstream. DOUT output bitstream looks like fail-safe output response if MCE = 0 (see data sheet for details). 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 due to missing clock input. DOUT stuck in the state (high or low) that it was when CLKIN stopped. No valid DOUT output bitstream. | B |
| VDD | 8 | No effect. Normal operation. | D |