EV2109DQ-00A Datasheet, PDF (4/4 Pages) Monolithic Power Systems – Dual 800mA, 6V, 1.2MHz Synchronous Step-Down Converter Evaluation Board

TM
EV2109DQ-00A – DUAL 800mA, 6V, 1.2MHz SYNCHRONOUS STEP-DOWN CONVERTER
EVALUATION BOARD
QUICK START GUIDE
The output voltages of this board are set to 1.8V (VOUT1) and 1.2V (VOUT2). The board layout
accommodates most commonly used inductors and output capacitors.
1. Attach the positive and negative ends of the first load to the VOUT1 and GND pins, respectively.
If using both outputs, attach the positive and negative ends of the second load to the VOUT2
and GND pins, respectively.
2. Attach the input voltage 2.5V ≤ V_IN ≤ 6V and input ground to VIN and GND pins respectively.
3. A 100kΩ pull-up resistor has been connected to both the EN1 and EN2 pins, so both VOUT1
and VOUT2 will turn on without applying any external voltage to the EN1 and EN2 pins.
4. To turn on VOUT1/VOUT2 by using the EN1/EN2 functions, apply a voltage, 1.5V ≤ V_EN1/EN2 ≤
6V, to the EN1/EN2 pin. To disable VOUT1/VOUT2, apply a voltage, V_EN1/EN2 < 0.3V, to the
EN1/EN2 pin.
5. The output voltages V_OUT1 and V_OUT2 can be changed by varying R2 and R4, respectively.
Calculate the new values by the following formulae:
R2 =
R1
⎜⎜⎝⎛
V_OUT1
V_FB
⎟⎟⎠⎞
−
1
R4 =
R3
⎜⎜⎝⎛
V_OUT2
V_FB
⎟⎟⎠⎞
−
1
Where V_FB = 0.6V, R1 = 300kΩ and R3 = 300kΩ.
Example:
For V_OUT1 = 1.8V:
R2 = ^300kΩ = 150kΩ
⎜⎛ ^1.8V ⎟⎞ − 1
⎝ ^0.6V ⎠
Therefore, use a 150kΩ standard 1% value.
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.
Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS
products into any application. MPS will not assume any legal responsibility for any said applications.
EV2109DQ-00A Rev. 1.1
www.MonolithicPower.com
4
10/14/2005
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