a5975d STMicroelectronics, a5975d Datasheet - Page 13

• Manufacturer Part Number: a5975d
• Description: Up To 3 A Step-down Switching Regulator For Automotive Applications
• Manufacturer: STMicroelectronics

A5975D
Functional description
which provides the synchronization signal to the others. Therefore the SYNCH is an I/O pin
to deliver or recognize a frequency signal. The synchronization circuitry is powered by the
internal reference (V
), so a small filtering capacitor (≥ 100 nF) connected between the
REF
V
pin and the signal ground of the master device is recommended for its proper
REF
operation. However, when a set of synchronized devices populate a board it is not possible
to know in advance which is working as master, so the filtering capacitor must be designed
for a whole set of devices.
When one or more devices are synchronized to an external signal, its amplitude must be in
compliance with specifications given in
Table
4. The frequency of the synchronization signal
must be, at a minimum, higher than the maximum guaranteed natural switching frequency of
the device (275 kHz, see
Table
4) while the duty cycle of the synchronization signal can vary
from approximately 10% to 90%. The small capacitor under the V
pin is required for this
REF
operation.
Figure 5.
Oscillator circuit block diagram
Doc ID 018760 Rev 1
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