A5975ADTR STMicroelectronics, A5975ADTR Datasheet - Page 31

• 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
At T
As a consequence, the calculation of the internal power losses must be done for each
specific operating condition given by the final application.
In applications where the current to the output is pulsed, the thermal impedance should be
considered instead of the thermal resistance.
The thermal impedance of the system could be much lower than the thermal resistance,
which is a static parameter. As a consequence, the maximum power losses can be higher
than 2.5 W if a pulsed output power is requested from the load:
Therefore, depending on the pulse duration and its frequency, the maximum output current
can be delivered to the load.
The characterization of the thermal impedance is strictly dependent on the layout of the
board. In
of the A5975AD is provided.
Figure 17. Measurement of the thermal impedance of the demonstration board
As can be seen, for example, for load pulses with a duration of 1 second, the actual thermal
impedance is lower than 20 °C/W. This means that, for short pulses, the device can deliver a
higher output current value.
AMB
=40 °C and V
Figure 17
the measurement of the thermal impedance of the demonstration board
IN
=12 V, the device is no more thermally limited (see
P
Doc ID 018761 Rev 1
MAX
t ( )
=
---------------- -
Z
TH
ΔT
t ( )
=
T
------------------------------------- -
J MAX
Z
TH
–
t ( )
T
AMB
Application information
Figure
16).
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