SFFS013A December 2020 – July 2021 TPS37-Q1 , TPS38-Q1
4 Pin Failure Mode Analysis (Pin FMA)
This section provides a Failure Mode Analysis (FMA) for the pins of the TPS37-Q1 and TPS38-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 TPS37-Q1 and TPS38-Q1 pin diagram. For a detailed description of the device pins please refer to TPS37-Q1 or TPS38-Q1 in the Pin Configuration and Functions section of the data sheet.
Figure 4-1 Pin Diagram DSK Package10-Pin WSONFollowing are the assumptions of use and the device configuration assumed for the pin FMA in this section:
- RESET1_UVOD and RESET2_UVOD are pictured as active high, some configurations (RESET1_UVOD and RESET2_UVOD) will be active low. RESET1_UVOD in Figure 4-1 is shown as open-drain, some configurations will be push-pull. Refer to TPS37-Q1 or TPS38-Q1 Pin Configuration and Functions section of the data sheet.
- At VDD (MIN) ≤ VDD ≤ VDD (MAX), CTR1 / MR = CTR2 / MR = CTS1 = CTS2 = Open
- Output reset Pullup Resistor (RPULLUP) = 10 kΩ, Output reset pullup voltage (VPULLUP = 5.5 V, output reset load (CLOAD) = 10 pF.
- Tables valid over the operating free-air temperature range of – 40°C to 125°C, unless otherwise noted.
- Typical values are at TA = 25°C, VDD = 16 V, and VIT = 6.5 V (VIT refers to VITN or VITP) unless stated otherwise.
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 |
|---|---|---|---|
| VDD | 1 | VDD short to GND Fault | B |
| SENSE1 | 2 | Functionality affected if intent is not to monitor GND | B |
| SENSE2 | 3 | Functionality affected if intent is not to monitor GND | B |
| RESET1_UVOD | 4 | If open drain option: Unreliable device operation if not shorted to VOH | B |
| If push pull option: Not recommended condition | A | ||
| RESET2_UVOD | 5 | Unreliable device operation if not shorted to VOH | B |
| CTR1 / MR | 6 | Normal operation, RESET1_UVOD will be asserted. | D |
| CTS1 | 7 | Normal operation, RESET1_UVOD will be asserted. | D |
| CTS2 | 8 | Normal operation, RESET2_UVOD will be asserted. | D |
| CTR2 / MR | 9 | Normal operation, RESET2_UVOD will be asserted. | D |
| GND | 10 | Normal operation | D |
| Central Pad | PAD | Normal operation, Pad is not internally connected | D |
Table 4-3 Pin FMA for Device Pins Open-Circuited
| PIN NAME | PIN NO. | DESCRIPTION OF POTENTIAL FAILURE EFFECT(S) | FAILURE EFFECT CLASS |
|---|---|---|---|
| VDD | 1 | Device Unpowered | B |
| SENSE1 | 2 | For fixed voltage threshold option where the applied voltage to
SENSE1 is less than 2.7 V, SENSE1 pin will detect a short to GND. For 800 mV SENSE1 voltage option, the input state will be undetermined. | B |
| SENSE2 | 3 | For fixed voltage threshold option where the applied voltage to
SENSE2 is less than 2.7 V, SENSE2 pin will detect a short to GND. For 800 mV SENSE2 voltage option, the input state will be undetermined. | B |
| RESET1_UVOD | 4 | Unreliable RESET1_UVOD | B |
| RESET2_UVOD | 5 | Unreliable RESET2_UVOD | B |
| CTR1 / MR | 6 | Normal operation | D |
| CTS1 | 7 | Normal operation | D |
| CTS2 | 8 | Normal operation | D |
| CTR2 / MR | 9 | Normal operation | D |
| GND | 10 | Device Unpowered | B |
| Central Pad | PAD | Normal operation, pad is not internally connected | D |
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 |
|---|---|---|---|---|
| VDD | 1 | SENSE1 | Functionality affected if intent is not to monitor VDD | B |
| SENSE1 | 2 | SENSE2 | Functionality affected if intent is not to monitor SENSE2 | B |
| SENSE2 | 3 | RESET1_UVOD | Functionality affected if intent is not to monitor RESET1_UVOD | B |
| RESET1_UVOD | 4 | RESET2_UVOD | If open drain option: Unreliable device operation if not shorted to VOH | B |
| RESET1_UVOD | 4 | RESET2_UVOD | If push pull option: Not recommended condition | A |
| CTR1 / MR | 6 | CTS1 | Unreliable timing | B |
| CTS1 | 7 | CTS2 | Unreliable timing | B |
| CTS2 | 8 | CTR2 / MR | Unreliable timing | B |
| CTR2 / MR | 9 | GND | Normal operation, a reset event will be asserted. | D |
| Central Pad | PAD | N/A | N/A | N/A |
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 |
|---|---|---|---|
| VDD | 1 | Normal operation | D |
| SENSE1 | 2 | Functionality affected if intent is not to monitor VDD | B |
| SENSE2 | 3 | Functionality affected if intent is not to monitor VDD | B |
| RESET1_UVOD | 4 | Open drain option: Pullup resistor required. Short directly to VDD will affect pullup voltage functionality | B |
| Push pull option: Not recommended condition | A | ||
| RESET2_UVOD | 5 | Pullup resistor required. Short directly to VDD will affect pullup voltage functionality | B |
| CTR1 / MR | 6 | May damage device if VDD is greater than the pin's recommended operating condition | A |
| CTS1 | 7 | May damage device if VDD is greater than the pin's recommended operating condition | A |
| CTS2 | 8 | May damage device if VDD is greater than the pin's recommended operating condition | A |
| CTR2 / MR | 9 | May damage device if VDD is greater than the pin's recommended operating condition | A |
| GND | 10 | VDD short to GND Fault | B |
| Central Pad | PAD | D |