a pp li ca ti on n o t es ultra hi g h efficienc y 82 - 91% high efficiency, small, low price, step-down dc-dc converter 5 w a tt v s a se ri es (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 8,200f 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, 10a) ( 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, 250a ) vsa24-12s0r6 output voltage off mode : open (2.5 to 5.3 v) output voltage on mode : short (-0.2 to 0.5 v, 250a ) 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 volt age 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. ka g a electronics ( usa ) inc. www.vol g en.com
ultra high efficiency 82 - 91% high efficiency, small, low price, step-down dc-dc converter 5 w a tt v s a se ri es (c) output voltage changeable direction please open the terminal v.adj when you use the output voltage with rating, without changing. by connecting resistance between the terminal gnd (3 pin) and v.adj (5 pin), you can change output voltage within the range of voltage in table 1. please refer to the undermentioned equation for the calculation of external resistance. please confirm the output voltage and adjust resistance value after calculating external resistance. ( figure 6 ) to reduce the output voltage model 2.5s 3.3s 12s voltage range (1.5 to 2.5v) (3 to 3.3v) (9 to 12v) rx 2.13k ohm 765 ohm 8.6k ohm ry 1.0k ohm 2.2k ohm 2.2k ohm vref 0.8v 2.45v 2.45v vo = it is your option. to add the output voltage (for 2.5v and 3.3v model) model 2.5s 3.3s 12s voltage range (2.5 to 3.3v) (3.3 to 5v) rx 2.13k ohm 765 ohm ry 1.0k ohm 2.2k ohm vref 0.8v 2.45v vo = it is your option. note 1: when using at rating without adjusting the output voltage, keep the v. adj pin (5pin) open. note 2: v. adj pin (5pin) is a high impedance point, so in a bad environment this wiring may pick up noise and cause bad effect. when energizing, avoid switching the output by opening and shortening or switching the adjustable output resistor(r1, r2). and select a r1, r2 that is accurate and has good temperature characteristics, and mount it by soldering without using connectors or sockets when it is pretty close to the converter. kaga electronics(usa) inc. www.vol g en.com n/ a rxry(vo-vref) rxvref-ry(vo-vref) vr1 = vr2 = open vrefrxry ry(vo-vref)-vrefrx vr2 = vr1 = open
ultra high efficiency 82 - 91% high efficiency, small, low price, step-down dc-dc converter 5 watt v s a s eries note: these test data do not represent all products. |