SFFSB40 February 2026 ISO6421
Figure 4-1 shows the ISO6421 pin diagram for the D-8 SOIC and DWV-8 Wide-SOIC packages. For a detailed description of the device pins, see the Pin Configuration and Functions section in the ISO6421 datasheet.
| Pin Name | Pin Number | Potential Failure Mode | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|---|
| VCC1 | 1 | Short-Circuited to Ground (Side-1) | The device has no power on side-1 (the supply input is shorted to ground). The output state of OUTA is undetermined. The output of OUTB is at the default logic state. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| VCC1 | 1 | Open-Circuited | The device has no power on side-1 (the supply input is open). The output state of OUTA is undetermined. The output of OUTB is at the default logic state. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| VCC1 | 1 | Short-Circuited to Pin2 (OUTA) | The output of OUTA is stuck high. Communication through channel A is corrupted. Device damage is possible if INA is driven low for an extended period of time. | A |
| VCC1 | 1 | Short-Circuited to Supply (Side-1) | The device continues to function as expected. Normal operation. | D |
| OUTA | 2 | Short-Circuited to Ground (Side-1) | The output of OUTA is shorted to ground. Communication through channel A is corrupted. Damage to the device is possible if INA is driven high for an extended period of time. | A |
| OUTA | 2 | Open-Circuited | The output state of OUTA is undetermined. Communication through channel A is corrupted. | B |
| OUTA | 2 | Short-Circuited to Pin3 (INB) | Communication is corrupted for either channel or both channels. With opposite logic states on both channels, high current can flow between signals on INB, supply, and ground in OUTA, and potentially cause damage to the device. | A |
| OUTA | 2 | Short-Circuited to Supply (Side-1) | The output of OUTA is stuck high. Communication through channel A is corrupted. Device damage is possible if INA is driven low for an extended period of time. | A |
| INB | 3 | Short-Circuited to Ground (Side-1) | The input signal is shorted to ground, so the output of OUTB is stuck low. Communication through channel B is corrupted. | B |
| INB | 3 | Open-Circuited | Communication through channel B is not possible. The output of OUTB is at the default state (weak internal pullup or pulldown to the default state). | B |
| INB | 3 | Short-Circuited to Pin4 (GND1) | The input signal is shorted to ground, so the output of OUTB is stuck low. Communication through channel B is corrupted. | B |
| INB | 3 | Short-Circuited to Supply (Side-1) | The input signal is shorted to supply, so the output of OUTB is stuck high. Communication through channel B is corrupted. | B |
| GND1 | 4 | Short-Circuited to Ground (Side-1) | The device continues to function as expected. Normal operation. | D |
| GND1 | 4 | Open-Circuited | There is no power to the device on side-1 (ground is open). The output of OUTA is undetermined. The output of OUTB is at the default logic state. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| GND1 | 4 | Short-Circuited to Pin5 (N/A) | Not applicable (N/A), corner pin. | N/A |
| GND1 | 4 | Short-Circuited to Supply (Side-1) | The device has no power on side-1 (the supply input is shorted to ground). The output of OUTB is at the default logic state. The output state of OUTA is undetermined. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| GND2 | 5 | Short-Circuited to Ground (Side-2) | The device continues to function as expected. Normal operation. | D |
| GND2 | 5 | Open-Circuited | There is no power to the device on side-2 (ground is open). The output of OUTB is undetermined. The output of OUTA is at the default logic state. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| GND2 | 5 | Short-Circuited to Pin6 (OUTB) | The output of OUTB is shorted to ground. Communication through channel B is corrupted. Damage to the device is possible if INB is driven high for an extended period of time. | A |
| GND2 | 5 | Short-Circuited to Supply (Side-2) | The device has no power on side-2 (the supply input is shorted to ground). The output of OUTB is undetermined. The output of OUTA is at the default logic state. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| OUTB | 6 | Short-Circuited to Ground (Side-2) | The output of OUTB is shorted to ground. Communication through channel B is corrupted. Damage to the device is possible if INB is driven high for an extended period of time. | A |
| OUTB | 6 | Open-Circuited | The output state of OUTB is undetermined. Communication through channel B is corrupted. | B |
| OUTB | 6 | Short-Circuited to Pin7 (INA) | Communication is corrupted for either channel or both channels. With opposite logic states on both channels, high current can flow between signals on INA, supply, and ground in OUTB, and potentially cause device damage. | A |
| OUTB | 6 | Short-Circuited to Supply (Side-2) | The output of OUTB is stuck high. Communication through channel B is corrupted. Device damage is possible if INB is driven low for an extended period of time. | A |
| INA | 7 | Short-Circuited to Ground (Side-2) | The input signal is shorted to ground, so the output of OUTA is stuck low. Communication from INA to OUTA is corrupted. | B |
| INA | 7 | Open-Circuited | Communication through channel A is not possible. The output of OUTA is at the default state (weak internal pullup or pulldown to the default state). | B |
| INA | 7 | Short-Circuited to Pin8 (VCC2) | The input signal is shorted to supply, so the output of OUTA is stuck high. Communication through channel A is corrupted. | B |
| INA | 7 | Short-Circuited to Supply (Side-2) | The input signal is shorted to supply, so the output of OUTA is stuck high. Communication through channel A is corrupted. | B |
| VCC2 | 8 | Short-Circuited to Ground (Side-2) | No power to the device on side-2 (the supply input is shorted to ground). The output of OUTA is at the default logic state. The output state of OUTB is undetermined. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| VCC2 | 8 | Open-Circuited | The device has no power on side-2 (the supply input is open). The output of OUTA is at the default logic state. The output state of OUTB is undetermined. Observe that the absolute maximum ratings for all pins of the device are met; otherwise, device damage is possible. | A |
| VCC2 | 8 | Short-Circuited to Pin1 (N/A) | Not applicable (N/A), corner pin. | N/A |
| VCC2 | 8 | Short-Circuited to Supply (Side-2) | The device continues to function as expected. Normal operation. | D |