Application Notes
Ultra High Efficiency 82 - 91%
High Efficiency, Small, Low price, Step-Down DC-DC Converter
5 Watt VSA Series
<Usage>
(A) Standard Connection
Recommended Additional Capacitor
VSA05-2.5S1R2
C1=16ZL330M (Rubycon) or KZE16VB330 (Nippon Chemi-con)
C2=10ZL680M (Rubycon) or KZE16VB680 (Nippon Chemi-con)
VSA24-3.3S1R2
C1=50ZL120M (Rubycon) or KZE50VB120（Nippon Chemi-con）
C2=10ZL470M (Rubycon) or KZE10VB470（Nippon Chemi-con）
VSA24-12S0R6
C1=50ZL120M (Rubycon) or KZE50VB120（Nippon Chemi-con）
C2=16ZL330M (Rubycon) or KZE16VB330（Nippon Chemi-con）
Note 1: If ON/OFF is not controlled, it should be connected to
GND line.
Note 2: When output voltage is rating, please open the terminal V. ADJ
( Figure 4 )
(5 pin)
Note 3: I/O capacitor (C1, C2) must be added. Please put I/O capacitor
to pin close as much as possible and wire with thick pattern.
For C1 & C2, please use low impedance capacitor.
Note 4: For VSA05 model, when the additional capacitor's capacity is
large, startup failure may occur. So please use an additional
capacitor which capacity is 8,200µF or below.
(B) ON/OFF Control
Input voltage is turned on by using ON/OFF control function, and it is
possible for ON/OFF control of output voltage without cutting it.
That is the effective function to compose the sequence of Power
Supply Systems. Also using this function, you can save the electric
power when Power Supply stands by. Please connect the terminal
ON/OFF with GND.
Between the terminal ON/OFF (1 Pin) and GND (3 Pin)
VSA05-2.5S1R2
Output voltage OFF mode : OPEN (2V to +Vin)
Output voltage ON mode : SHORT (-0.2 to 0.7V, 10µA)
( Figure 5 )
VSA24-3.3S1R2
Output voltage OFF mode : OPEN (2.5 to 5.3 V)
Output voltage ON mode : SHORT (-0.2 to 0.5 V, 250µA )
VSA24-12S0R6
Output voltage OFF mode : OPEN (2.5 to 5.3 V)
Output voltage ON mode : SHORT (-0.2 to 0.5 V, 250µA )
Note 1: Use an open collector (or drain) switch element for on/ off control.
Note 2: Set the switch element for on/ off control close to the converter, and lessen the noise effect by parallel patern short loops, or by
using shield wires.
To prevent miss operation caused by noise, it is effective to connect a capacitor between the on/ off pin and GND. However, if this
capacitor is too large, when impressing the input voltage at off, the charged current may flow and momentarily voltage may occur,
so be sure that the max. value is 3300pF.
Note 3: The on/ off pin voltage will be pulled up internally, so it is not necessary to impress voltage externally at off.
Kaga Electronics(USA) Inc.
www.volgen.com
VOLGEN [ VOLGEN KAGA ELECTRONICS INC. ]
