Connect the load between the V
OUT
and GND terminals directly at the board if noise
measurements are being performed.
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LOAD
GND
VIN
VOUT
SHDN
LTC1928S6-5
DEMO CIRCUIT 353A
LOW NOISE BOOST
DC/DC CONVERTER
Figure 1. DC353 Test and Measurement Setup
OPERATING MODES
DC353A is designed to demonstrate the low noise performance of the LTC1928-5 as well
as its shutdown and current-drive capabilities.
Enable Mode
The device is enabled when the SHDN signal is at 0V. V
OUT
will be between 4.9V and
5.1V. Noise measurements can be performed as outlined in the LTC1928-5 data sheet.
Loads should be applied between the V
OUT
and the GND terminals on the demo board to
avoid ground loops. Ground loops could result in excessive noise generation. A variable
resistor or current source can be applied to the V
OUT
terminal to characterize the output
current drive capabilities.
Shutdown Mode
The 2N7002 FET is required to place the LTC1928-5 in shutdown. Shutdown is achieved
by applying five volts to the SHDN terminal which turns the 2N7002 on. The 50
Ω
termination resistor at the SHDN terminal minimizes ringing when the user controls
