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ADL5501
Table 4. Waveform and Output Filter Effects on Residual AC
Output
Waveform
C
FILT
, C
OUT
V dc
64QAM
1 nF,
0.5
(7.4 dB CF)
Open
1.0
2.0
Open,
0.5
0.1 μF
1.0
2.0
1 nF,
0.5
0.1 μF
1.0
2.0
W-CDMA RL
1 nF,
0.5
(3.4 dB CF)
Open
1.0
2.0
Open,
0.5
0.1 μF
1.0
2.0
1 nF,
0.5
0.1 μF
1.0
2.0
CDMA2000 DL
1 nF,
0.5
(6.7 dB CF)
Open
1.0
2.0
Open,
0.5
0.1 μF
1.0
2.0
1 nF,
0.5
0.1 μF
1.0
2.0
W-CDMA UL
1 nF,
0.5
TM1-64, 1 CR
Open
1.0
2.0
Open,
0.5
0.1 μF
1.0
2.0
1 nF,
0.5
0.1 μF
1.0
2.0
POWER CONSUMPTION, ENABLE, AND POWER-
ON/-OFF RESPONSE TIME
The quiescent current consumption of the ADL5501 varies with
the size of the input signal from approximately 1.1 mA for no
signal up to 6.2 mA at an input level of 0.7 V rms (10 dBm,
re 50 Ω). If the input is driven beyond this point, the supply
current increases sharply (as shown in Figure 6). There is little
variation in quiescent current with power supply voltage.
The ADL5501 can be disabled either by pulling the ENBL (Pin 5)
to COMM (Pin 4) or by removing the supply power to the device.
Disabling the device via the ENBL function reduces the leakage
current to less than 1 μA.
Rev. 0 | Page 19 of 28
Residual AC
mV p-p
83
175
394
49
98
212
45
93
200
6.4
19
52
4.5
16
36
3.1
9.6
27
67
148
339
28
56
119
26
52
116
204
396
840
60
112
227
56
114
243
mV rms
11
21
47
5.5
11
23
5.5
11
24
0.8
2.6
6.6
0.6
2.2
4.9
0.5
1.4
3.9
8.6
19
43
3.9
7.9
17
3.7
7.7
17
32
64
140
11
21
42
11
21
45
If the input of the ADL5501 is driven while the device is disabled
(ENBL = COMM), the leakage current of less than 1 μA increases
as a function of input level. When the device is disabled, the
output impedance increases to approximately 33.5 kΩ.
The turn-on time and pulse response is strongly influenced by
the size of the square-domain filter and output shunt capacitor.
Figure 45 shows a plot of the output response to an RF pulse on
the RFIN pin, with a 0.1 μF output filter capacitor and no
square-domain filter capacitor. The falling edge is particularly
dependent on the output shunt capacitance, as shown in Figure 45.
2ms/DIV
V
400mV rms RF INPUT
250mV rms
160mV rms
70mV rms
PULSED RFIN
0
Figure 45. Output Response to Various RF Input Pulse Levels,
Supply 3 V, Frequency 900 MHz,
Square-Domain Filter Open, Output Filter 0.1 μF
To improve the falling edge of the enable and pulse responses,
a resistor can be placed in parallel with the output shunt capacitor.
The added resistance helps to discharge the output filter
capacitor. Although this method reduces the power-off time,
the added load resistor also attenuates the output (see the
Output Drive Capability and Buffering section).
2ms/DIV
V
400mV rms RF INPUT
250mV rms
160mV rms
70mV rms
PULSED RFIN
0
Figure 46. Output Response to Various RF Input Pulse Levels,
Supply 3 V, Frequency 900 MHz,
Square-Domain Filter Open, Output Filter 0.1 μF with Parallel 1 kΩ
The square-domain filter improves the rms accuracy for high
crest factors (see the Selecting the Square-Domain Filter and
Output Low-Pass Filter), but it can hinder the response time.
For optimum response time and low ac residual, both the
square-domain filter and the output filter should be used.