SFFS059 January   2023 DRV8145-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)
    1. 4.1 SPI "P" variant in HTSSOP package
    2. 4.2 SPI "S" variant in VQFN-HR package
    3. 4.3 HW variant in VQFN-HR package

4.1 SPI "P" variant in HTSSOP package

Figure 4-2 shows the pin diagram. For a detailed description of the device pins please refer to the Pin Configuration and Functions section in the DRV8145-Q1 data sheet.

Figure 4-2 SPI "P" variants
Table 4-2 Pin FMA for Device Pins Short-Circuited to Ground
Pin Description of Potential Failure Effect(s) Failure Effect Class
No. Name
1 SCLK SPI communication is lost. B
2 nSCS SPI communication is lost. B
3 IN External PWM control is lost. Internal ITRIP regulation is ok. No risk of spin direction reversal. B
4 DRVOFF Pin based shutoff function is lost. B
5 VCP Device damage possible. Device behavior can not be guaranteed. A
6, 7, 8, 21, 22, 23 VM Device is powered off with driver Hi-Z. B
9, 10, 11, 18, 19, 20 OUT If OUT is commanded to be pulled high, short is detected and OUT is Hi-Z. B
12, 13, 14, 15, 16, 17 GND Normal function. D
24 nSLEEP Both "S" & "P" variants: Device will be in SLEEP state and OUT is Hi-Z B
VDD
25 IPROPI IPROPI feedback is lost. ITRIP regulation, if enabled, is also lost. B
26 nFAULT False fault signaling possible. Device will continue to operate as commanded. B
27 SDO SPI communication is lost. B
28 SDI SPI communication is lost. B
Table 4-3 Pin FMA for Device Pins Open-Circuited
Pin Description of Potential Failure Effect(s) Failure Effect Class
No. Name
1 SCLK SPI communication is lost. B
2 nSCS SPI communication is lost. B
3 IN External PWM control is lost. Internal ITRIP regulation is OK. No risk of spin direction reversal. B
4 DRVOFF Pin based shutoff is triggered and OUT is Hi-Z B
5 VCP The driver can't keep up with PWM frequency > 20 KHz B
6, 7, 8, 21, 22, 23 VM Device is powered off with driver Hi-Z. B
9, 10, 11, 18, 19, 20 OUT Load drive capability is lost. B
12, 13, 14, 15, 16, 17 GND Normal function. D
24 nSLEEP Both "S" & "P" variants: Device will be in SLEEP state and OUT is Hi-Z. B
VDD
25 IPROPI IPROPI feedback is lost. Load will be forced to recirculate if ITRIP regulation is enabled. B
26 nFAULT False fault signaling possible. Device will continue to operate as commanded. B
27 SDO SPI communication is lost. B
28 SDI SPI communication is lost. B
Table 4-4 Pin FMA for Device Pins Short-Circuited to Adjacent Pin
Short between pins Description of Potential Failure Effect(s) Failure Effect Class
SCLK SDI SPI communication is lost. B
nSCS SCLK SPI communication is lost. B
IN nSCS SPI communication is affected. External PWM control is lost. Internal ITRIP regulation is OK. No risk of spin direction reversal. B
DRVOFF IN Either OUT is Hi-Z or external PWM control is lost. Internal ITRIP regulation is ok. No risk of spin direction reversal. B
VCP DRVOFF Device damage possible. Device behavior can not be guaranteed. A
VM VCP Pull up path RON (High-side FET) will be much higher. B
OUT VM If OUT is commanded to be pulled low, short is detected and OUT is Hi-Z. B
GND OUT If OUT1 is commanded to be pulled high, short is detected and OUT is Hi-Z. B
nSLEEP VM "S" variant: SLEEP functionality is lost. B
VDD "P" variant: Device damage possible. Device behavior can not be guaranteed. A
IPROPI nSLEEP "S" variant: IPROPI feedback is inaccurate. ITRIP regulation levels, if enabled, will be lower. B
VDD "P" variant: IPROPI feedback is inaccurate. OUT is Hi-Z if ITRIP regulation is enabled.
nFAULT IPROPI False fault signaling possible. IPROPI feedback is inaccurate. ITRIP regulation levels, if enabled, will be lower. B
SDO nFAULT False fault signaling possible. SPI communication will be affected during fault assertion. B
SDI SDO SPI communication is lost. B
Table 4-5 Pin FMA for Device Pins Short-Circuited to supply VM
Pin Description of Potential Failure Effect(s) Failure Effect Class
No. Name
1 SCLK Device damage possible. A
2 nSCS Device damage possible. A
3 IN Device damage possible. A
4 DRVOFF OUT is Hi-Z. B
5 VCP Pull up path RON (High-side FET) will be much higher. B
6, 7, 8, 21, 22, 23 VM Normal function. D
9, 10, 11, 18, 19, 20 OUT If OUT is commanded to be pulled low, short is detected and OUT is Hi-Z. B
12, 13, 14, 15, 16, 17 GND Device is powered off with driver Hi-Z. B
24 nSLEEP Device damage possible. A
VDD Device damage possible. A
25 IPROPI Device damage possible. A
26 nFAULT Device damage possible. A
27 SDO Device damage possible. A
28 SDI Device damage possible. A