UM3510 Datasheet, PDF (7/10 Pages) Union Semiconductor, Inc. – 1.0A, 1.5MHz, Synchronous Step-Down DC-DC Converter

UM3510
Typical Performance Characteristics (Continued)
(V_IN = 3.6V, V_OUT = 1.8V, T_A = +25°C, unless otherwise noted.)
Output Voltage vs Temperature
1.800
1.798 VIN=3.6V
1.796
1.794
1.792
1.790
1.788
1.786
1.784
1.782
1.780
25
50
75
100
125
Temperature(^oC)
Supply Current VS Supply Voltage
245
240 VOUT=1.2V,I =0mA
O
235
230
225
220
215
210
205
200
195
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Input Voltage(V)
Applications Information
Output Voltage Setting
The external resistor divider sets the output voltage.The feedback resistor R1 also sets the
feedback loop bandwidth with the internal compensation capacitor.
Choose R1 around 300kΩ for optimal transient response. R2 is then given by:
Inductor Selection
A 1µH to 10µH inductor with DC current rating at least 25% higher than the maximum load
current is recommended for most applications.For best efficiency, the inductor DC resistance shall
be<200mΩ.
For most designs, the inductance value can be derived from the following equation:
Where ∆I_L is the inductor ripple current. Choose inductor ripple current approximately 30% of the
maximum load current, 600mA.
The maximum inductor peak current is:
Under light load conditions below 100mA, larger inductance is recommended for improved
efficiency.
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http://www.union-ic.com Rev.02 Dec.2011
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