August 2, 2002
DC489A DEMO BOARD QUICK START GUIDE
INTRODUCTION
The DC489A demo board is used to evaluate the LTC5507 RF power detector with integrated output
buffer and voltage reference. The LTC5507 converts an RF input signal at pin 6 (RF) to a DC voltage at
pin 3 (Vout). The RF input frequency range is 100 KHz to 1000 MHz. The maximum input power is 16
dBm. The DC output voltage at Vout with no RF signal present at the input is typically 260mV. When
the RF signal is applied, the DC output voltage increases proportionately.
The optional 68Ω (R1) termination resistor is not placed on the PCB. Capacitors C1 and C4 are 0.1
µF
for low frequency tests and evaluation (100 KHz to 1 MHz). For higher frequencies, C1 and C4 should
be .01
µF
or less. For frequencies around 800 to 1000 MHz, a 39 pF value is suggested.
A logic HIGH at pin 1 of jumper JP1 enables the part. The jumper inserted in the left position provides
logic HIGH (IC enabled). The jumper inserted in the right position provides logic LOW (IC disabled).
The DC489A demo board is easily set up for evaluating the LTC5507 RF power detector performance.
Follow the procedures outlined below and make the connections on the attached diagram for proper
operation.
1.
Connect a positive DC power supply (2.7V to 6V) to E1. Connect the power supply ground to E3 or
E5. Connect J1 to the RF signal generator via coaxial cable with an SMA connector. It is common
practice to include a 3dB pad to minimize reflections back into the signal generator.
The part can be shutdown via switch JP1. When JP1 is connected to ground, the part will be in
shutdown. When JP1 is connected to VCC via the 22k resistor the part will be enabled. A pulse
generator can also control the shutdown terminal, E4, in order to characterize turn-on delay after
shutdown. To do this, set JP1 to the enable position. Connect a 50Ω termination from E4 to ground.
Connect a pulse generator to E4 via a coaxial cable.
With JP1 set to the enable position, apply an RF input signal and measure the DC output voltage at
E2.
2.
3.
LTC CONFIDENTIAL
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