DC353A DEMO BOARD QUICK START GUIDE
DESCRIPTION
Demonstration circuit DC353A demonstrates the capabilities of the LTC1928-5 doubler
charge pump and linear regulator. The board contains the following:
•
LTC1928-5 doubler charge pump with low noise linear regulator.
•
4.7µF ceramic capacitor on V
OUT
•
4.7µF ceramic capacitor on CPO
•
4.7µF ceramic capacitor on V
IN
•
0.47µF ceramic capacitor between CP and CN/SHDNB
•
N-channel FET type 2N7002 to supply an open-drain pulldown during shutdown
•
50
Ω
termination resistor at the gate of the 2N7002 FET
•
A 100
Ω
current-limit resistor between the drain of the 2N7002 FET and the
CN/SHDNB pin
The LTC1928-5 generates a low noise regulated 5V output from a DC input supply
voltage connected to the V
IN
terminal. The DC supply voltage range is 2.7V to 4.4V. The
small SOT-23 package and small ceramic capacitors minimize board space requirements.
A power supply connected to V
IN
is the only requirement for basic operation of the demo
board. The termination resistor at the gate of the 2N7002 keeps this FET off and the
LTC1928-5 out of shutdown (enabled).
EXTERNAL CONNECTIONS
Refer to Figure 1 for proper power supply and test equipment setup.
Connect a 2.7V to 4.4V DC voltage supply to the V
IN
terminal.
Connect the DC supply ground to the GND terminal.
Connect a pulse generator switching from 0V to 5V to the SHDN terminal (optional).
The part will be enabled when the pulse generator signal is low and disabled when the
pulse generator signal is high. If the pulse generator is not connected the part will be
enabled.
