A5975ADTR STMicroelectronics, A5975ADTR Datasheet - Page 13

• Manufacturer Part Number: A5975ADTR
• Description: IC REG SW STEP-DOWN 2.5A 8SOIC
• Manufacturer: STMicroelectronics
• Series: -r
• Type: Step-Down (Buck), PWMr

Specifications of A5975ADTR

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.235 V ~ 35 V
• Current - Output: 2.5A
• Frequency - Switching: 500kHz
• Voltage - Input: 4 V ~ 36 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width) Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-11425-2

A5975AD
Functional description
The synchronization feature of a set of the A5975AD is simply obtained by connecting
together their SYNCH pins. The device with the highest switching frequency is the master
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 populates a board it is not possible
to know in advance the one 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 V
pin is required for this
REF
operation.
Figure 5.
Oscillator circuit block diagram
Doc ID 018761 Rev 1
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