EVALA5973D STMicroelectronics, EVALA5973D Datasheet - Page 17

• Manufacturer Part Number: EVALA5973D
• Description: Power Management Modules & Development Tools EVAL BOARD A5973D Auto Grade
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of EVALA5973D

• 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: 2.5 A
• Dimensions: 23 mm x 20 mm
• For Use With/related Products: AN1518
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN1518
9.2
Table 4.
1. POSCAP capacitors have some characteristics which are very similar to tantalum.
●
The inductor value is very important as it fixes the ripple current flowing through the output
capacitor. The ripple current is usually fixed at 20-40% of I
I
Equation 20
where T
V
through the inductor is given by:
Equation 21
and it can be observed that if the inductor value decreases, the peak current (which must be
lower than the current limit of the device) increases. So, when the peak current is fixed, a
higher inductor value allows a higher value for the output current. In the
selection, some inductor manufacturers are listed.
Table 5.
Layout considerations
The layout of switching DC-DC converters is very important to minimize noise and
interference. Power-generating portions of the layout are the main cause of noise and so
high switching current loop areas should be kept as small as possible and lead lengths as
short as possible.
O
AVX
KEMET
Sanyo POSCAP
Sprague
Coilcraft
Coiltronics
BI
Epcos
Wurth Elektronik
OUT
max= 2 A. The approximate inductor value is obtained using the following formula:
Manufacturer
Inductor
Manufacturer
=3.3 V, V
ON
is the ON time of the internal switch, given by D · T. For example, with
Output capacitor selection
Inductor selection
IN
(1)
= 2 V and ∆I
TPA/B/C
Series
T494/5
595D
TPS
O
74456115
=0.6 A, the inductor value is about 17 µH. The peak current
DO3316
HM76-3
B82476
Series
UP1B
L
=
Cap value (µF)
(
----------------------------------
I
V
PK
100 to 470
100 to 470
100 to 470
220 to 390
IN
–
=
∆I
V
I
O
OUT
+
Inductor value (µH)
∆I
---- -
)
2
•
T
15 to 33
22 to 33
15 to 33
15 to 33
15 to 33
ON
Rated voltage (V)
omax
4 to 35
4 to 20
4 to 16
4 to 20
, which is 0.4 - 0.8 A with
Application information
Saturation current (A)
Table 5.: Inductor
2.0 to 3.0
2.0 to 2.4
2.5 to 3.3
2.5 to 3
160 to 650
2 to 3
ESR (mΩ)
50 to 200
30 to 200
40 to 80
17/30