Freescale Semiconductor Application Note AN4542 Rev. 2.0, 12/2014 Repetitive Short-circuit Performances for Dual 24 V High-side Switch Family 1 Introduction This application note describes the robustness of the MC06XS4200, MC10XS4200, MC22XS4200, and MC50XS4200 devices. These intelligent high-side switches are designed to be used in 24 V systems, such as trucks and busses. They can be used in some industrial and 12 V applications as well. The low RDS(on) channels can control incandescent lamps, LEDs, solenoids, or DC motors. Control, device configuration, and diagnostics are performed through a 16-bit SPI (serial peripheral interface) interface, allowing for easy integration into existing applications. For a complete feature description, refer to the relevant data sheets. © Freescale Semiconductor, Inc., 2014. All rights reserved. Contents 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2 Short-circuit Protections Features . . . . . . . . . . . . . .2 2.1 Configurable Latched Overcurrent Protection . .2 2.2 Severe Short-circuit Protection . . . . . . . . . . . . . .3 3 Short-circuit Tests . . . . . . . . . . . . . . . . . . . . . . . . . . .3 3.1 Test Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 3.2 Short-circuit Test Results. . . . . . . . . . . . . . . . . . .4 3.3 Overload Test Results . . . . . . . . . . . . . . . . . . . . .7 4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 5 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Short-circuit Protections Features 2 Short-circuit Protections Features These SMARTMOS devices include dual self-protected high-side switches with enhanced diagnostics. In case of a short-circuit from the HSx pin to the ground, the corresponding high-side switch is immediately turned off via two overload protection features: • Configurable latched overcurrent protection • Severe short-circuit protection These protections are preferred over conventional current limitations, to minimize the thermal overstress within the device in an overload condition. The elevation of junction temperature is drastically reduced to a value which does not affect the device’s reliability. Moreover, the availability of the load is guaranteed by the auto-retry feature. According to the SPI configuration, the number of retries is limited to 16, or unlimited. The repetition period of auto-retry is also selectable through the SPI from 17.7 ms to 150 ms (typ.). The high-side switches can be paralleled to drive higher currents. Setting the PARALLEL bit (a bit in the GCR register) is mandatory, to synchronize the turn-off of the outputs, in the event of a short-circuit. If the outputs are not switched concurrently, the device will be damaged, as illustrated in Figure 1. Parallel bit = 0 Parallel bit = 1 DAMAGED PASS Figure 1. Short-circuit Event with Paralleled MC06XS4200 HSx Pins 2.1 Configurable Latched Overcurrent Protection The transient overcurrent profile is adjustable, to account for the variability of load and the energy associated with the expected wire harness current capability. The device incorporates multiple configurable overcurrent profiles, to address lighting and DC motor applications, as illustrated in Figure 2. Repetitive Short-Circuit Performances, Rev. 2.0 2 Freescale Semiconductor Short-circuit Tests DC Motor Load Profile: Dynamic overcurrent window, activated when the IOCLx threshold is crossed Lamp load Profile: Static Overcurrent protection profile activated once per turn-on. Load Current IOCH1 IOCH1 IOCH2 IOCH2 IOCM1 IOCM2 IOCL1 IOCL1 IOCL2 IOCL2 IOCL3 Load curre IOCL3 Time T t OCM2_L t OCM2_M t OCM1_L t OCM1_M t OCH2 t OCH2 t OCH1 t OCH1 Figure 2. Configurable Overcurrent Profile The transient overcurrent profile protects the application, if the load is also driven in the PWM (pulse-width modulation) mode. 2.2 Severe Short-circuit Protection In addition to latched overcurrent protection, a severe short-circuit detection is available during off-to-on switching, to immediately turn off the output. 3 Short-circuit Tests To accelerate the silicon fatigue, the dual 24 V high-side switches are force to switch “on” and “off,” cyclically. The ambient temperature was fixed at 85 °C. This is the worst case for this type of smart power technology. At least five engineering samples were used per test. Repetitive Short-Circuit Performances, Rev. 2.0 Freescale Semiconductor 3 Short-circuit Tests Figure 3. Short-circuit Test Setup 3.1 Test Setup Figure 3 presents the test setup used. Depending on the test that was performed, the test escape condition was: • A severe part damage for the “test to fail” • A defined number of cycles for the “test to pass” 3.2 Short-circuit Test Results 3.2.1 MC06XS4200, MX10XS4200 (PQFN) Test Description High-side Ambient DC Voltage PWM Number of Lsupply Rsupply Lshort Rshort Type of Test Operation temperature source freq. Cycles Short-circuit at the beginning of the load line and occurred in off-state of high-side switch (cold short) 5.0 µH 5.0 m <1.0 µH 12 m test to pass 1.0 k Short-circuit at the beginning Single switch of the load line and occurred with default Lighting in on-state of high-side Profile switch (hot short) 5.0 µH 5.0 m 1.0 µH 15 m test to pass 1.0 k 85 °C Short-circuit at the end of the load line and occurred in off-state of high-side switch (cold short) Short-circuit at the end of the Paralleled load line and occurred in switches off-state of high-side switch with default (cold short) Lighting Profile 32 V 2.0 Hz 3.7 µH 20 m 24 µH 166 m test to fail Figure 4 Figure 5 3.7 µH 20 m 24 µH 166 m test to pass 500 k Repetitive Short-Circuit Performances, Rev. 2.0 4 Freescale Semiconductor Short-circuit Tests For each “test to fail”, the cumulative failures over the number of cycles are presented in Figure 4 and Figure 5. Gumbel’s predictive law, with 95% confidence level, is used to define the number of cycles to failure, down to 10 PPM (parts per million) (1e-5). Figure 4. Predictable MC10XS4200 Failures for a Short-circuit at the End of the Load Line Figure 5. Predictable MC06XS4200 Failures for a Short-circuit at the End of the Load Line Repetitive Short-Circuit Performances, Rev. 2.0 Freescale Semiconductor 5 Short-circuit Tests 3.2.2 MC22XS4200, MC50XS4200 (eSOIC) Test Description High-side Ambient DC Voltage PWM Number of Lsupply Rsupply Lshort Rshort Type of Test Operation temperature source freq. Cycles Short-circuit at the beginning Single switch of the load line and occurred with default Lighting in off-state of high side Profile switch (cold short) 85 °C 32 V 2.0 Hz 3.7 µH 20 m 24 µH 166 m test to fail Figure 6 Figure 7 For each "test to fail", the cumulative failures over the number of cycles are presented in Figure 6 and Figure 7. LogNormal's predictive law, with 95% confidence level, is used to define the number of cycles to failure, down to 100 and 1000 PPM (parts per million) (1e-5). Figure 6. Predictable MC22XS4200 Failures for a Short-circuit at the End of the Load Line Repetitive Short-Circuit Performances, Rev. 2.0 6 Freescale Semiconductor Short-circuit Tests Figure 7. Predictable MC50XS4200 Failures for a Short-circuit at the End of the Load Line 3.3 Overload Test Results Test Description High Side Ambient Operation temperature Overload 80% of OCHI during toch1 (88 A during 8.6 ms for the MC06XS4200 device) Single switch with default Lighting Profile Stalled Wiper DC Motor with freewheeling diode (20 A during 350 ms for the MC06XS4200 device) Single switch with default DC motor Profile 85 °C DC Voltage Source PWM Lsupply Rsupply Lshort freq Rshort Type of Test Number of Cycles 2.0 Hz 5.0 µH 5.0 m 20 µH 350 m test to pass 1.0 k 0.5 Hz 5.0 µH 5.0 m 20 µH stall DC motor test to pass 1.0 k 32 V Repetitive Short-Circuit Performances, Rev. 2.0 Freescale Semiconductor 7 References 4 References Document Number Type MC06XS4200 Data Sheet Dual 24 V High Side Switch (6.0 mOhm) Data Sheet MC10XS4200 Data Sheet Dual 24 V High Side Switch (6.0 mOhm) Data Sheet MC22XS4200 Data Sheet Dual 24 V High Side Switch (22 mOhm) Data Sheet MC50XS4200 Data Sheet Dual 24 V High Side Switch (50 mOhm) Data Sheet AN4516 Application Note IBIS Model File for Dual 24 V High Side Switch Family AN4473 Application Note Compact Thermal Model for Dual 24 V High Side Switch Family AN4474 Application Note EMC and Fast Transient Pulses Performances for Dual 24 V High Side Switch Family Freescale Website Freescale Analog Webpage Freescale Automotive Applications Webpage Description/URL freescale.com freescale.com/analog freescale.com/automotive Repetitive Short-Circuit Performances, Rev. 2.0 8 Freescale Semiconductor Revision History 5 Revision History Revision Date Description of Changes 1.0 10/2012 Initial release 2.0 12/2014 Added short-circuit results for MC22XS4200 and MC50XS4200 Updated document form and style Repetitive Short-Circuit Performances, Rev. 2.0 Freescale Semiconductor 9 How to Reach Us: Information in this document is provided solely to enable system and software implementers to use Freescale products. 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