A5975DTR STMicroelectronics, A5975DTR Datasheet - Page 37
A5975DTR
Manufacturer Part Number
A5975DTR
Description
IC REG SW STEP-DOWN 3A 8SOIC
Manufacturer
STMicroelectronics
Series
-r
Type
Step-Down (Buck), PWMr
Datasheet
1.A5975DTR.pdf
(50 pages)
Specifications of A5975DTR
Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.235 V ~ 35 V
Current - Output
3A
Frequency - Switching
250kHz
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
497-11426-2
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
A5975DTR
Manufacturer:
MICROCHIP
Quantity:
3 000
A5975D
8.7
Figure 25. PCB layout (front side)
Positive buck-boost regulator
The device can be used to implement a step-up/down converter with a positive output
voltage.
The output voltage is given by:
Equation 33
where the ideal duty cycle D for the buck-boost converter is:
Equation 34
However, due to power losses in the passive elements, the real duty cycle is always higher
than this. The real value (that can be measured in the application) should be used in the
following formulas.
The peak current flowing in the embedded switch is:
Equation 35
while its average current is equal to:
Equation 36
This is due to the fact that the current flowing through the internal power switch is delivered
to the output only during the OFF phase.
I
SW
=
Doc ID 018760 Rev 1
I
-------------- -
1 D
LOAD
–
V
+
D
OUT
I
------------------- -
I
RIPPLE
SW
=
2
----------------------------- -
V
=
=
IN
V
V
I
-------------- -
IN
+
1 D
LOAD
OUT
=
V
–
⋅
OUT
I
-------------- -
------------ -
1 D
1 D
LOAD
D
–
–
+
---------- -
2 L
V
⋅
IN
⋅
---------
f
SW
D
Application information
37/50