DC391A - Demo Manual

DC391 DEMO BOARD QUICK START GUIDE
INTRODUCTION
The DC391 demo board is used to evaluate the LTC5505 RF power detector with integrated output
buffer and voltage reference. The LTC5505 converts an RF input signal at pin 1(RF) to a DC voltage at
pin 4(Vout). The RF input frequency range is 300MHz to 2700MHz. Maximum input power is 18dBm.
The output voltage at Vout will start at an initial DC value of typically 260mV. When the RF signal is
applied the output voltage will increase.
Additional solder pads have been added for possible evaluation of tuning techniques. L1, L2, C4, C5 are
not included on the board and are not required for typical applications. R2 is included on the board but
again is not required for typical applications. The 68Ω (R1) termination resistor is required and must be
connected to ground. C4 pads are shorted to connect R1 to ground. C1 is used for DC isolation since the
LTC5505 RF input pin 1 is referenced to VCC and the RF input signal at J1 is referenced to ground. In
typical applications the SHDNB pin 3 is controlled by a logic level. A logic high enables the part.
The DC391demo board is easily set up for evaluating the LTC5505 RF power detector performance.
Follow the procedures outlined below and connections on the attached diagram for proper operation.
1.
Connect the input DC power supply (2.7V to 6V) to E1. Connect the power supply ground to E3.
Connect J1 to the RF signal generator via an SMA cable. It is common practice to include a 3dB pad
to minimize reflections back into the signal generator.
2.
The part can be shutdown via switch SW1. When SW1 is connected to ground the part will be in
shutdown. When SW1 is connected to VCC via the 22k resistor the part will be enabled. The
shutdown terminal E4 can also be controlled by a pulse generator to characterize enable times from
the shutdown state. To do this set SW1 to the enable position and connect a 50Ω termination from
E4 to ground. Connect a pulse generator to E4 via a coaxial cable.
3.
With SW1 set to the enable position apply an RF input signal and measure the DC voltage at E2.
LTC CONFIDENTIAL
1
DC391 Connection Diagram
DC Power
Supply
GND
V+
E3
E1
1
DC
Voltmeter
Minus
Plus
RF Signal
Generator
SMA
E2
SW1
J1
E4
DC319 Demo Board
LTC CONFIDENTIAL
2
Similar pages