SBAS920 October 2018 AMC1302-Q1
In a typical traction inverter application, the high-side power supply (VDD1) for the device is derived from the floating power supply of the upper gate driver. For lowest system-level cost, a Zener diode can be used to limit the voltage to 5 V or 3.3 V ± 10%. Alternatively, a low-cost low-dropout (LDO) regulator (for example, the LP2951-XX-Q1) may be used to minimize noise on the power supply. TI recommends a low-ESR decoupling capacitor of 0.1 µF to filter this power-supply path. Place this capacitor (C1 in Figure 56) as close as possible to the VDD1 pin of the AMC1302-Q1 for best performance. Use an additional 2.2-µF decoupling capacitor (C2) for filtering lower-frequency noise. The floating ground reference (GND1) is derived from the end of the shunt resistor, which is connected to the negative input (INN) of the device. If a four-pin shunt is used, the device inputs are connected to the inner leads, and GND1 is connected to one of the outer leads of the shunt.
To decouple the digital power supply on the controller side, use a 0.1-µF capacitor (C3) placed as close to the VDD2 pin of the AMC1302-Q1 as possible, followed by an additional capacitor from 1 µF to 10 µF (C4).