ADL5500 Analog Devices, Inc., ADL5500 Datasheet - Page 15

• Manufacturer Part Number: ADL5500
• Description: 100 Mhz To 6 Ghz Trupwr Detector
• Manufacturer: Analog Devices, Inc.

VRMS
APPLICATIONS
BASIC CONNECTIONS
Figure 33 shows the basic connections for the ADL5500. The
device is powered by a single supply of between 2.7 V and 5.5 V
with a quiescent current of 1.0 mA. The VPOS pin is decoupled
using 100 pF and 0.1 μF capacitors.
The ADL5500 RF input does not require external termination
components because it is internally matched for an overall
broadband input impedance of 50 Ω.
OUTPUT SWING
At 900 MHz, the output voltage is nominally 6.4 times the input
rms voltage (a conversion gain of 6.4 V/V rms). The output
voltage swings from near ground to 4.9 V on a 5.0 V supply.
Figure 34 shows the output swing of the ADL5500 to a CW
input for various supply voltages. It is clear from Figure 34 that
operating the device at lower supply voltages reduces dynamic
range as the output headroom decreases.
Figure 34. Output Swing for Supply Voltages of 2.7 V, 3.0 V, 5.0 V, and 5.5 V
0.03
0.1
10
1
–25
CFLT
–20
Figure 33. Basic Connections for ADL5500
1
2
–15
VRMS
COMM
ADL5500
–10
INPUT (dBm)
VPOS
RFIN
–5
4
3
0
+V
RFIN
S
5
2.7V TO 5.5V
100pF
3.0V
10
2.7V
5.5V
5.0V
0.1μF
15
Rev. A | Page 15 of 24
LINEARITY
Because the ADL5500 is a linear-responding device, plots of
output voltage vs. input voltage result in a straight line. It is
more useful to plot the error on a logarithmic scale, as shown in
Figure 35. The deviation of the plot for the ideal straight-line
characteristic is caused by output clipping at the high end and
by signal offsets at the low end. However, it should be noted that
offsets at the low end can be either positive or negative; therefore,
this plot could also trend upwards at the low end. Figure 10
through Figure 15 show error distributions for a large
population of devices.
It is also apparent in Figure 35 that the error plot tends to shift
to the right with increasing frequency. The squaring cell has an
input impedance that decreases with frequency. The matching
network compensates for the change and maintains the input
impedance at a nominal 50 Ω. The result is a decrease in the
actual voltage across the squaring cell as the frequency
increases, reducing the conversion gain. Similarly, conversion
gain is less at frequencies near 100 MHz because of the small
on-chip coupling capacitor.
Figure 35. Representative Unit, Error in dB vs. Input Level, V
–1
–2
–3
3
2
1
0
–25
100MHz
450MHz
900MHz
1900MHz
2350MHz
2700MHz
3900MHz
–20
–15
–10
INPUT (dBm)
–5
0
5
ADL5500
10
S
= 5.0 V
15