EVALA5970D STMicroelectronics, EVALA5970D Datasheet - Page 21

• Manufacturer Part Number: EVALA5970D
• Description: Power Management Modules & Development Tools EVAL BOARD A5970D Auto Grade
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of EVALA5970D

• Input Voltage: 4.4 V to 36 V
• Output Voltage: 1.235 V to 35 V
• Board Size: 23 mm x 20 mm
• Product: Power Management Modules
• Supply Current: 1 A
• Dimensions: 23 mm x 20 mm
• For Use With/related Products: AN1330
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN1330
5.4
Considering the device in an SO-8 package mounted on the board with a good groundplane,
that it has a thermal resistance-junction to-ambient (Rth
ambient temperature of about 70 °C.
Equation 26
Short-circuit protection
In overcurrent protection mode, when the peak current reaches the current limit, the device
reduces the T
frequency to approximately one third of its nominal value (see
protection). In these conditions, the duty cycle is strongly reduced and, in most of
applications, this is enough to limit the current to I
circuit at the output (V
parasitic effect of external components) the current peak could reach values higher than
I
This can be understood considering the inductor current ripple during the ON and OFF
phases:
●
Equation 27
●
Equation 28
where V
inductor.
In short-circuit conditions, V
inductor is very small and it may be that the current ripple in this phase does not
compensate for the current ripple during the T
The maximum current peak can be easily measured through the inductor with V
(short-circuit) and V
circuit condition for an extended period, the external components (mainly the inductor and
diode) must be selected based on this value.
LIM
.
ON phase
OFF phase
D
is the voltage drop across the diode, and DCR
ON
down to its minimum value (approximately 250 ns) and the switching
CC
OUT
=V
IN
=0 V) and depending on the application conditions (V
∆
max. In cases where the application must sustain the short-
∆
OUT
I
I L
L
=
=
T
is negligible. So, during the T
J
(
----------------------------------------------------------------- -
(
-------------------------------------------------------------------- -
V
V
=
D
IN
70
+
–
V
+
V
out
out
0.44 115
L
+
L
–
DCR
ON
•
DCR
.
LIM
L
L
≅
I •
. In any event, in case of heavy short-
121°C
•
I
)
J-A
)
L
•
•
is the series resistance of the
) of about 115 °C/W and an
T
T ON
OFF
OFF
Section 2.4: Current
, the voltage applied to the
Application information
CC
OUT
value and
=0 V
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