XC6216/XE6216
Series
■NOTES ON USE
1． Please use this IC within the stated absolute maximum ratings. The IC is liable to malfunction should the ratings be
exceeded.
2． Where wiring impedance is high, operations may become unstable due to the noise and/or phase lag depending on output
current. Please strengthen VIN and VSS wiring in particular.
3. Phase compensation inside the IC is performed in the XC6216/XE6216 series. Therefore, an abnormal oscillation does not
occur even if there is no output capacitor CL. An input capacitor CIN around 0.1uF~1.0uF between the VIN pin and the
VSS pin is required for input stability. Also, the output voltage fluctuation such as under shoot or over shoot, which occurs
because of the load change can be controlled by placing the output capacitor CL around 0.1uF~1.0uF between the VOUT
pin and VSS pin. The input capacitor (CIN) and the output capacitor (CL) should be placed to the IC as close as possible
with a shorter wiring.
4. Notes on Setting Output Voltage Externally (C type) Ta=25℃
The output voltage can be set externally by the following equation:
VOUT=2.0V x (Rxx + Ryy) / Ryy
……………………………………………………………………… (1)
Although the output voltage can be set freely by the above equation, resistance values can be calculated by the
following equations in case considering output voltage accuracy.
Ixx = IFB + Iyy
Iyy = 2.0V / Ryy
……………………………………………………………………… (2)
……………………………………………………………………… (3)
If the equation (3) is assigned to the equation (2), the equation becomes as below:
Ixx =IFB + 2.0V / Ryy
……………………………………………………………………… (4)
For this, the following equation can be used for setting output voltage externally:
VOUT=2.0V + Rxx・Ixx
……………………………………………………………………… (5)
And the equation (4) will be;
VOUT=2.0V + Rxx・(IFB + 2.0V / Ryy)
………………………………………………………………………
=2.0V x (1 + Rxx / Ryy) + Rxx・IFB ……………………………………………………………………… (6)
The second term of the equation (6), Rxx・IFB, is the cause of the output accuracy error.
The IFB can be calculated by the following equation:
IFB=2.0V / RFB
……………………………………………………………………… (7)
The cause of the output accuracy error, Rxx・IFB can be calculated by the equation below;
Rxx・IFB = Rxx・2.0V / Ryy
= 2.0V x Rxx・RFB
……………………………………………………………………… (8)
Accordingly, if Rxx is smaller than RFB, the output voltage error becomes minute.
●Setting Resistance-Dependant of XC6216 Series’ Output Voltage
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TOREX [ Torex Semiconductor ]
