SFFS957 August   2024 LMR51606-Q1 , LMR51610-Q1

 

  1.   1
  2.   Trademarks
  3. 1Overview
  4. 2Functional Safety Failure In Time (FIT) Rates
    1. 2.1 LMR51606-Q1
    2. 2.2 LMR51610-Q1
  5. 3Failure Mode Distribution (FMD)
  6. 4Pin Failure Mode Analysis (Pin FMA)

Pin Failure Mode Analysis (Pin FMA)

This section provides a Failure Mode Analysis (FMA) for the pins of the LMR51606-Q1 and LMR51610-Q1. The failure modes covered in this document include the typical pin-by-pin failure scenarios:

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
ClassFailure Effects
APotential device damage that affects functionality.
BNo device damage, but loss of functionality.
CNo device damage, but performance degradation.
DNo device damage, no impact to functionality or performance.

Following are the assumptions of use and the device configuration assumed for the pin FMA in this section:

  • Device used within the Recommended Operating Conditions and the Absolute Maximum Ratings found in the appropriate device data sheet.
  • Configuration as shown in the Example Application Circuit found in the appropriate device data sheet.

Figure 4-1 shows the LMR51606-Q1 and LMR51610-Q1 pin diagram for the SOT-23 package. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the appropriate device data sheet.

LMR51606-Q1 LMR51610-Q1 Pin DiagramFigure 4-1 Pin Diagram
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
CB 1 No output voltage. B
GND 2 Normal operation. D
FB 3 The regulator operates at maximum duty cycle. Output voltage rises approximately to the input voltage (VIN) level. Damage to customer load and output stage components are possible. No effect on device. B
EN 4 Loss of ENABLE functionality. Device remains in shutdown mode. B
VIN 5 Device does not operate. No output voltage is generated. Output capacitors discharge through the input short. A large current reversal can damage the device. A
SW 6 Damage to internal FET. A
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
CB 1 No output voltage. B
GND 2 VOUT can be abnormal due to switching noise on analog circuits. B
FB 3 VOUT is higher than the programmed output voltage. B
EN 4 Loss of ENABLE functionality. Erratic operation; loss of regulation is probable. B
VIN 5 No output voltage. B
SW 6 No output voltage. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Pin NamePin No.Shorted toDescription of Potential Failure EffectsFailure Effect Class
CB 1 GND No output voltage. A
GND 2 FB The regulator operates at maximum duty cycle. Output voltage rises approximately to the input voltage (VIN) level. Damage to customer load and output stage components are possible. No effect on device. B
FB 3 GND The regulator operates at maximum duty cycle. Output voltage rises approximately to the input voltage (VIN) level. Damage to customer load and output stage components are possible. No effect on device. B
EN 4 VIN No damage to device. Loss of ENABLE functionality. B
VIN 5 SW Damage to internal FET. A
SW 6 VIN Damage to internal FET. A
Table 4-5 Pin FMA for Device Pins Short-Circuited to VIN
Pin NamePin No.Description of Potential Failure EffectsFailure Effect Class
CB 1 No output voltage. CBOOT ESD clamp runs current to destruction. A
GND 2 No output voltage. Damage to other pins referred to GND. A
FB 3 If VIN exceeds 5.5V, damage occurs. No output voltage. A
EN 4 No damage to device. Loss of ENABLE functionality. B
VIN 5 No effect. D
SW 6 Damage to low side MOSFET. A