SFFSAP1 August 2025 LMC7101Q-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a failure mode analysis (FMA) for the pins of the LMC7101Q-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 LMC7101Q-Q1 pin diagram. For a detailed description of the device pins, see the Pin Configuration and Functions section in the LMC7101Q-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:
- Short Circuit to Power and Short Circuit to Supply mean short to V+
- Short Circuit to GND and Short Circuit to Ground mean short to V‒
- V+ is equivalent to VCC
- V‒ is equivalent to VEE
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| OUT | 1 | Depending on the circuit configuration, the device is likely to be forced into a short-circuit condition with the OUT voltage ultimately forced to the V‒ voltage. Prolonged exposure to short-circuit conditions can result in long-term reliability issues. | A |
| V+ | 2 | Op-amp supplies are shorted together, leaving the V+ pin at some voltage between the V+ and V‒ sources (depending on the source impedance). | A |
| IN+ | 3 | Device common-mode is tied to the negative rail. Depending on the circuit configuration, the output likely does not respond because the device is in an invalid common-mode condition. | C |
| IN‒ | 4 | The device does not receive negative feedback. Depending on the circuit configuration, the output most likely moves to the negative supply. | B |
Table 4-3 Pin FMA for Device Pins Open-Circuited
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| OUT | 1 | No negative feedback or ability for OUT to drive the application. | B |
| V+ | 2 | Positive supply is left floating. The op amp ceases to function because no current can source or sink to the device. | A |
| IN+ | 3 | Device common-mode is disconnected. The op amp is not provided with common-mode bias, and the device output can result at the positive or negative rail. The IN+ pin voltage can result at the positive or negative rail because of leakages on the ESD diodes. | B |
| IN‒ | 4 | The inverting pin of the op amp is left floating. Negative feedback is not provided to the device and can result in the device output moving between the positive and negative rails. The IN‒ pin voltage likely ends up at the positive or negative rail because of leakage on the ESD diodes. | B |
| V‒ | 5 | Negative supply is left floating. The op amp ceases to function because no current can source or sink to the device. | 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 |
|---|---|---|---|---|
| OUT | 1 | V+ | Depending on the circuit configuration, the device is likely to be forced into a short-circuit condition with the OUT voltage ultimately forced to the V+ voltage. Prolonged exposure to short-circuit conditions can result in long-term reliability issues. | A |
| V+ | 2 | IN+ | Depending on the circuit configuration, the application is likely not to function because device common-mode voltage is connected to V+. | B |
| IN+ | 3 | IN‒ | Both inputs are tied together. Depending on the offset of the device, the output voltage likely moves to near midsupply. | D |
| IN‒ | 4 | V‒ | The device does not receive negative feedback. Depending on the circuit configuration, the output most likely moves to the negative supply. | B |
| V‒ | 5 | OUT | Depending on the circuit configuration, the device is likely to be forced into a short-circuit condition with the V‒ voltage ultimately forced to the OUT voltage. Prolonged exposure to short-circuit conditions can result in long-term reliability issues. | A |
Table 4-5 Pin FMA for Device Pins Short-Circuited to Supply
| Pin Name | Pin No. | Description of Potential Failure Effects | Failure Effect Class |
|---|---|---|---|
| OUT | 1 | Depending on the circuit configuration, the device can be forced into a short-circuit condition with the OUT voltage ultimately forced to the V+ voltage. Prolonged exposure to short-circuit conditions can result in long-term reliability issues. | A |
| IN+ | 3 | Depending on the circuit configuration, the application is likely not to function because device common-mode voltage is connected to IN+. | B |
| IN‒ | 4 | The device does not receive negative feedback. Depending on the noninverting input voltage and circuit configuration, the output most likely moves to the negative supply. | B |
| V- | 5 | Op-amp supplies are shorted together, leaving the V‒ pin at some voltage between the V‒ and V+ sources (depending on the source impedance). | A |