A5975DTR STMicroelectronics, A5975DTR Datasheet - Page 39

• Manufacturer Part Number: A5975DTR
• Description: IC REG SW STEP-DOWN 3A 8SOIC
• Manufacturer: STMicroelectronics
• Series: -r
• Type: Step-Down (Buck), PWMr

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

A5975D
8.9
Equation 40
Equation 41
An important point to take into account is that the ground pin of the device is connected to
the negative output voltage. Therefore, the device is subjected to a voltage equal to V
which must be lower than 36 V (the maximum operating input voltage).
Figure 27. Negative buck-boost regulator
Floating boost current generator
The A5975D does not support a nominal boost conversion as this topology requires a low
side switch, however, a floating boost can be useful in applications where the load can be
floating. A typical example is a current generator for LED driving, as the LED does not
require a connection to the ground.
Figure 28. Floating boost topology
10V
4.7
6.8
A5975D
Doc ID 018760 Rev 1
I
SW
=
D
I
-------------- -
1 D
LOAD
–
=
--------------- -
5
+
=
5
12
----------------------- -
1 0.706
–
=
0.5
0.706
=
1.7A
Application information
ESR>35m
470
AM09693v1
IN
Ω
39/50
-V
6
O
,