NJW4184 datasheet(7/13 Pages) NJRC

7 / 13 page

NJW4184

- 7 -

Ver.2012-06-27

*In the case of using a resistance "R" between VIN and control.

If this resistor is inserted, it can reduce the control current when the control voltage is high.

The applied voltage to control terminal should set to consider voltage drop through the resistor “R” and the minimum

control voltage for ON-state.

The VCONT (ON) and ICONT have temperature dependence as shown in the "Control Current vs. Temperature" and "

Control Voltage vs. Temperature" characteristics. Therefore, the resistance "R" should be selected to consider the

temperature characteristics.

*Input Capacitor CIN

Input Capacitor CIN is required to prevent oscillation and reduce power supply ripple for applications when high

power supply impedance or a long power supply line.

Therefore, use the recommended CIN value (refer to conditions of ELECTRIC CHARACTERISTIC) or larger and

should connect between GND and the VIN pin as shortest path as possible to avoid the problem.

*Output Capacitor CO

Output capacitor (CO) will be required for a phase compensation of the internal error amplifier.

The capacitance and the equivalent series resistance (ESR) influence to stable operation of the regulator.

Use of a smaller CO may cause excess output noise or oscillation of the regulator due to lack of the phase

compensation.

On the other hand, Use of a larger CO reduces output noise and ripple output, and also improves output transient

response when rapid load change.

Therefore, use the recommended CO value (refer to conditions of ELECTRIC CHARACTERISTIC) or larger and

should connect between GND and the VOUT pin as shortest path as possible for stable operation

The recommended capacitance depends on the output voltage rank. Especially, low voltage regulator requires larger

CO value.

In addition, you should consider varied characteristics of capacitor (a frequency characteristic, a temperature

characteristic, a DC bias characteristic and so on) and unevenness peculiar to a capacitor supplier enough.

When selecting CO, recommend that have withstand voltage margin against output voltage and superior

temperature characteristic.

NJW4184 Datasheet(PDF) 7 Page - New Japan Radio