XC6216 Datasheet, PDF (21/45 Pages) Torex Semiconductor – Voltage Regullators with Stand-by Function-Input Voltage: 30V

■ NOTES ON USE
4. Notes on setting output voltage externally (C type) Ta=25℃
XC6216/XE6216
Series
The output voltage can be set externally by the following equation:
I₂₁=I_FB+I₂₂
……………………………………………………………………… (1)
I₂₂=2.0V/R₂₂
……………………………………………………………………… (2)
I₂₁=I_FB+2.0V/R₂₂
………………………………………………………………………
If the equation (3) is assigned to the equation (2), the equation becomes as below:
V_OUT=2.0V+R₂₁・I₂₁
……………………………………………………………………… (3)
For this, the following equation can be used for setting output voltage externally:
V_OUT=2.0V+R₂₁・I₂₁
……………………………………………………………………… (4)
And the equation (4) will be;
V_OUT=2.0V+R₂₁ ・(I_FB+2.0V/R₂₂)
………………………………………………………………………
=2.0V・(R₂₁ + R₂₂) / R₂₂ + R₂₁・I_FB ……………………………………………………………………… (5)
The second term of the equation (6), R₂₁・I_FB, is the cause of the output accuracy error.
The I_FB can be calculated by the following equation:
I_FB=2.0V / R_FB
……………………………………………………………………… (6)
The cause of the output accuracy error, R₂₁・I_FB can be calculated by the equation below;
R₂₁ï½¥I_FB=R₂₁・2.0V/ R_FB
=2.0V・R₂₁ / R_FB
……………………………………………………………………… (7)
Accordingly, if R₂₁<< R_FB, the output voltage error becomes minute.
●Setting Resistance-Dependant of XC6216 Series C type’s Output Voltage
5. Torex places an importance on improving our products and its reliability.
However, by any possibility, we would request user fail-safe design and post-aging treatment on system or equipment.
21/45