LTC3108EDE
2
QUICK START PROCEDURE
Using short twisted pair leads for any power connections and with all loads and power supplies off, refer to Fig-
ure 1 for the proper measurement and equipment setup. The Power Supply (PS1) should not be connected to
the circuit until told to do so in the procedure below.
Two versions of the demo board are available. Assembly build –A uses the LTC3108EDE while Assembly build –
B uses the LTC3108EDE-1. The only difference is the VOUT and VOUT2 voltages.
When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope
probe. Measure the input or output voltage ripple by touching the probe tip directly across the VCC or VOUT and GND
terminals. See Figure 2 for proper scope probe technique.
1.
Jumper, Power Supply and LOAD Settings to start:
PS1= OFF
LOADS = OFF
JP1 (VOUT2) = ON
JP2= VAUX
JP3 = VAUX
2.
Turn on PS1 and slowly increase voltage until the voltage at VIN is 50mV. Monitor input current. If
input current exceeds 50 mA turn off PS1 and look for shorts.
3.
Confirm VLDO = 2.2V
4.
Increase Vin = 100mV
5.
Set LOAD on VLDO to 50μA. Set LOAD on VOUT = 25 μA. Set LOAD on VOUT2 = 25 μA.
6.
For the –A version: Verify VLDO = 2.2V, VOUT
≈
5.0V, VOUT2
≈
5.0V, and VSTORE
≈
5.2V
7.
For the –B version: Verify VLDO = 2.2V, VOUT
≈
4.5V, VOUT2
≈
4.5V, and VSTORE
≈
5.2V
The board is now ready for operation. The voltage on VOUT and VOUT2 can be modified by changing jumpers
JP2 and JP3. The jumper combinations are shown on the demo board.
Several variations of this design are possible, including increasing the energy storage by populating C7, or C9.
Please refer to the datasheet for design equations.
