BM28723AMUV
Operational Notes
1. Reverse Connection of Power Supply
Connecting the power supply in reverse polarity can damage the LSI. Take precautions against reverse polarity when
connecting the power supply, such as mounting an external diode between the power supply and the LSI’s power
supply pins.
2. Power Supply Lines
Design the PCB layout pattern to provide low impedance supply lines. Separate the ground and supply lines of the
digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog
block. Furthermore, connect a capacitor to ground at all power supply pins. Consider the effect of temperature and
aging on the capacitance value when using electrolytic capacitors.
3. Ground Voltage
Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. However,
pins that drive inductive loads (e.g. motor driver outputs, DC-DC converter outputs) may inevitably go below ground
due to back EMF or electromotive force. In such cases, the user should make sure that such voltages going below
ground will not cause the LSI and the system to malfunction by examining carefully all relevant factors and conditions
such as motor characteristics, supply voltage, operating frequency and PCB wiring to name a few.
4. Ground Wiring Pattern
When using both small-signal and large-current ground traces, the two ground traces should be routed separately but
connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal
ground caused by large currents. Also ensure that the ground traces of external components do not cause variations
on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance.
5. Recommended Operating Conditions
These conditions represent a range within which the expected characteristics of the LSI can be approximately obtained.
The electrical characteristics are guaranteed under the conditions of each parameter.
6. Inrush Current
When power is first supplied to the LSI, it is possible that the internal logic may be unstable and inrush current may
flow instantaneously due to the internal powering sequence and delays, especially if the LSI has more than one power
supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and
routing of connections.
7. Testing on Application Boards
When testing the LSI on an application board, connecting a capacitor directly to a low-impedance output pin may
subject the LSI to stress. Always discharge capacitors completely after each process or step. The LSI’s power supply
should always be turned OFF completely before connecting or removing it from the test setup during the inspection
process. To prevent damage from static discharge, ground the LSI during assembly and use similar precautions during
transport and storage.
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