L5983TR STMicroelectronics, L5983TR Datasheet - Page 35

• Manufacturer Part Number: L5983TR
• Description: IC REG SW 1.5A STEPDOWN 8-VFQFPN
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of L5983TR

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 18 V
• Current - Output: 1.5A
• Frequency - Switching: 250kHz ~ 1MHz
• Voltage - Input: 2.9 ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-VFQFN, 8-VFQFPN
• Power - Output: 1.5W
• For Use With: 497-6386 - BOARD EVAL FOR L5983
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6860-2; L5983TR

L5983
Equation 32
where I
To chose the right value of the inductor and to manage transient output current, which for a
short time can exceed the maximum output current calculated by
current in the power MOSFET must also be calculated. The peak current, shown in
33, must be lower than the minimum current limit (2.0 A).
Equation 33
where r is defined as the ratio between the inductor current ripple and the inductor DC
current.
Therefore, in the buck-boost topology the maximum output current depends on the
application conditions (firstly input and output voltage, secondly switching frequency and
inductor value).
In
input voltage from 2.9 V to 18 V.
The dashed line considers a more accurate estimation of the duty cycles given by
34, where power losses across diodes, external power MOSFET, and internal power
MOSFET are taken into account.
Figure 34
SW
is the average current in the embedded power MOSFET in the ON time.
the maximum output current for the above configuration is depicted varying the
Doc ID 13005 Rev 7
I
SW,PK
r
=
I
----------------------------------- -
I
SW
OUT
=
V
------------ -
1 D
=
I
OUT
⋅
OUT
–
L F
------------ -
1 D
I
OUT
⋅
–
⋅
SW
1
<
+
1.5 A
⋅
(
-- -
2
r
1 D
–
<
2.0A
)
2
Equation
Application ideas
32, the peak
Equation
Equation
35/43