Summary of Contents for Union Semiconductor UM3501EVB
- Page 1 UM3501 EV Board User’s Guide UM3501 EV Board (Evaluation Kit) User’s Guide V1.0 Version Date Prvoider Approve Note 2012-05-11 Initial version. 1/10 http://www.union-ic.com...
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Page 2: Table Of Contents
UM3501 EV Board User’s Guide Table of Contents 1. Board Information 1.1 Schematic 1.2 PCB Layout 1.3 Interface Define 2. Board Operation 2.1 Power Supply 2.2 Enable 2.3 Output Setting 3. Board Component 3.1 Input Capacitor 3.2 Output Capacitor 3.3 Inductor 3.4 Sampling Resistor 4. -
Page 3: Board Information
UM3501 EV Board User’s Guide 1 . Board Information This UM3501EVB uses a UM3501 adjustable output buck converter to step down 2.5-V or higher input voltages. The EVB operates over an input voltage range of 2.5V to 5.5V. The goal of the EVB is to demonstrate the small size of the UM3501 power supply solution and provide flexibility in interchanging the supporting passive components. - Page 4 UM3501 EV Board User’s Guide Fig 1.2, Fig 1.3 is PCB layout and components location diagram of UM3501 EVB. Fig 1.2 UM3501 EV board PCB top layer Fig 1.3 UM3501 EV board PCB bottom layer 4/10 http://www.union-ic.com...
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Page 5: Interface Define
UM3501 EV Board User’s Guide 1.3 Interface Define Tab 1.1 is the directions of UM3501 EV board interface signals Tab 1.1 UM1661 EVB board interface Interface Function Note Power supply input. 2.5V – 5.5V power supply. Ground. EN=ON (1): enable. Chip enable/disable option. -
Page 6: Power Supply
UM3501 EV Board User’s Guide VOUT Fig 2.1 UM3501 waveform diagram (V =3.6V, V =1.8V, I =300mA) LOAD 2.1 Power Supply UM3501's input supply voltage range from 2.5V – 5.5V, you need to confirm there is sufficient margin with the current limit when use a DC source to supply the device. Input power cable should be thicker to reduce the loss of input voltage when the load current is large. -
Page 7: Board Component
UM3501 EV Board User’s Guide The output voltage of UM3501 is set by the external resistor divider. See Figure 1.1.The output voltage is calculated as V =0.6V × (1+R2/R1) with R1+R2 ≤ 1MΩ. For stability, R1+R2 should not be greater than 1 MΩ. To keep the operating quiescent current to a minimum, the feedback resistor divider should have high impedance. -
Page 8: Output Capacitor
UM3501 EV Board User’s Guide GND is recommended for most application. For optimum noise immunity and low input ripple, the input capacitor value can be increased. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature and DC bias. Ceramic capacitors with Z5U or Y5V temperature characteristics should be avoided. - Page 9 UM3501 EV Board User’s Guide Below formula shows how to calculate the actual peak inductor current under certain application. The saturation inductor current should be higher than the calculated value under the worse case. ΔI )/(V * L *fosc) +ΔI PEAK LOAD Where ΔI...
- Page 10 UM3501 EV Board User’s Guide 2) The input capacitor, as well as the inductor and output capacitor, should be placed as close as possible to the IC pins. In particular, the input capacitor needs to be placed as close as possible to the IC pins, directly across the Vin and GND pin. 3) The feedback resistor network must be routed away from the inductor and switch node to minimize noise and magnetic interference.