ST5R33DEMOBOARD STMicroelectronics, ST5R33DEMOBOARD Datasheet - Page 11

• Manufacturer Part Number: ST5R33DEMOBOARD
• Description: DEMO BOARD FOR ST5R33MTR
• Manufacturer: STMicroelectronics
• Type: Power Management: DC/DC SMPSr

Specifications of ST5R33DEMOBOARD

• Contents: Fully Assembled Evaluation Board
• For Use With/related Products: ST5R33MTR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5852

ST5R00 SERIES
DIODE SELECTION
A Schottky diode with an high switching speed and a very low Forward Voltage (V
) is needed. Higher V
F
F
may cause lost power as heat in the diode, with a decrease of the Efficiency. Moreover, since the Output
Voltage pin is also used as the device Supply Voltage, the Start-up Voltage (see related plots) is strictly
due to the diode Forward Voltage at the rated Forward Current. A good diode choice is a STPS1L30A.
INPUT/OUTPUT CAPACITORS SELECTION
The Output Ripple Voltage, as well as the Efficiency, is strictly related to the behavior of these elements.
The output ripple voltage is the product of the peak inductor current and the output capacitor Equivalent
Series Resistance (ESR). Best performances are obtained with good high frequency characteristics
capacitors and low ESR. The best compromise for the value of the Output Capacitance is 47µF Tantalum
Capacitor, Lower values may cause higher Output Ripple Voltage and lower Efficiency without
compromising the functionality of the device.
An Input Capacitor is required to compensate, if present, the series impedance between the Supply
Voltage Source and the Input Voltage of the Application.
A value of 4.7µF is enough to guarantee stability for distances less than 2". It could be necessary
(depending on V
, V
, I
values) to proportionally increase the input capacitor value up to 100µA for
IN
OUT
OUT
major distances.
In any case we suggest to connect both capacitors, C
and C
, as close as possible to the device pins.
IN
OUT
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