r2j20701np Renesas Electronics Corporation., r2j20701np Datasheet - Page 18

• Manufacturer Part Number: r2j20701np
• Description: Peak Current Mode Synchronous Buck Controller With Power Mosfets
• Manufacturer: Renesas Electronics Corporation.

R2J20701NP
The accuracy of Vout can be estimated by using equation (10).
For example, if Vout (typical) = 1.8 V, resistance variation is 1% (i.e. K1, K2 = 1.01 and 0.99),
and VFB = 594 mV to 606 mV:
Therefore, the output accuracy will be r2.3% under the above conditions.
Figure 5 shows the relationship between the accuracy of the resistance and the accuracy of the output voltage. The
resistor value must have an accuracy of 0.5% if the variation in output voltage from the system is to be kept within two
percent across the voltage range from 0.6 to 3.3 V.
REJ03G1459-0300 Rev.3.00 Jun 20, 2007
Page 18 of 27
Vout (typical)
Vout
=
=
= 2.36%
=
=
or
2.31%
Vout (typical)
3
2
1
0
1
2
3
0.5
606 mV
594 mV
Figure 5 Vout Accuracy vs. Vout Set Voltage
1.8 V
1.8 V
VFB
1.0
Vout (typical)
VFB (typical)
1.5
600 mV
600 mV
1.8 V
1.8 V
R = 0.5%
Vout (typical)
2.0
1
1
1
2.5
1.01
0.99
0.99
1.01
K1
K2
R = 1%
3.0
+ 1
+ 1
+ 1
3.5
1
1
1
100 (%)
100 (%)
100 (%)
(10)