EVALA5973AD STMicroelectronics, EVALA5973AD Datasheet - Page 16

• Manufacturer Part Number: EVALA5973AD
• Description: Power Management Modules & Development Tools EVAL BOARD A5973AD Auto Grade
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of EVALA5973AD

• 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

Application information
16/30
and
Equation 19
Where V
internal PDMOS. Considering the range D
IRMS going through the input capacitor. Capacitors that can be considered are:
Table 3.
●
The output capacitor is very important to meet the output voltage ripple requirement.
Using a small inductor value is useful to reduce the size of the choke but it increases the
current ripple. So, to reduce the output voltage ripple, a low ESR capacitor is required.
Nevertheless, the ESR of the output capacitor introduces a zero in the open loop gain,
which helps to increase the phase margin of the system. If the zero goes to a very high
frequency, its effect is negligible. For this reason, ceramic capacitors and very low ESR
capacitors in general should be avoided.
Tantalum and electrolytic capacitors are usually a good choice for this purpose. A list of
some tantalum capacitor manufacturers is provided in
Electrolytic capacitors:
These are widely used due to their low price and their availability in a wide range of
RMS current ratings.
The only drawback is that, considering ripple current rating requirements, they are
physically larger than other capacitors.
Ceramic capacitors:
If available for the required value and voltage rating, these capacitors usually have a
higher RMS current rating for a given physical dimension (due to very low ESR).
The drawback is the considerably high cost.
Tantalum capacitors:
Very good, small tantalum capacitors with very low ESR are becoming more available.
However, they can occasionally burn if subjected to very high current during charge.
Therefore, it is better to avoid this type of capacitor for the input filter of the device. They
can, however, be subjected to high surge current when connected to the power supply.
Output capacitor
Manufacturer
MURATA
F
TDK
is the freewheeling diode forward voltage and V
List of ceramic capacitors for the L597xD
GRM32
GRM55
Series
C3225
D
MIN
=
MIN
------------------------------------- -
V
INMAX
V
to D
OUT
Capacitor value (µ)
+
MAX
–
V
V
F
SW
, it is possible to determine the max
Table 4.: Output capacitor
10
10
10
SW
the voltage drop across the
Rated voltage (V)
25
25
50
selection.
AN1518