ADL5504
Rev. A | Page 17 of 24
POWER CONSUMPTION, ENABLE, AND POWER-
ON/POWER-OFF RESPONSE TIME
The quiescent current consumption of the ADL5504 varies
linearly with the size of the input signal from approximately
1.8 mA for no signal up to 9 mA at an input level of 0.7 V rms
(10 dBm, referred to 50 ). There is little variation in supply
current across power supply voltage or temperature, as shown in
The ADL5504 can be disabled either by pulling the ENBL (Pin 6)
to COMM (Pin 4) or by removing the power supply to the device.
Disabling the device via the ENBL function reduces the leakage
current to less than 1 A. When the device is disabled, the output
impedance increases to approximately 5.5 k on VRMS.
The turn-on time and pulse response is strongly influenced
by the sizes of the square-domain filter and the output shunt
RF pulse on the RFIN pin, with a 0.1 F output filter capacitor and
a no square-domain filter capacitor. The falling edge is particularly
dependent on the output shunt capacitance, as shown i
n Figure 42.70mV rms
160mV rms
250mV rms
1ms/DIV
V
RM
S
(
150mV
/DI
V
)
PULSED RFIN
400mV rms RF INPUT
08437-
042
Figure 42. Output Response to Various RF Input Pulse Levels, 3 V Supply,
900 MHz Frequency, Square-Domain Filter Open, COUT = 0.1 F
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
1ms/DIV
V
RM
S
(
150mV
/DI
V
)
PULSED RFIN
70mV rms
400mV rms RF INPUT
250mV rms
160mV rms
08437-
043
Figure 43. Output Response to Various RF Input Pulse Levels,
3 V Supply, 900 MHz Frequency, Square-Domain Filter Open,
COUT = 0.1 F with Parallel 1 k
The square-domain filter improves the rms accuracy for high
time. For optimum response time and low ac residual, both the
square-domain filter and the output filter should be used. The
square-domain filter at FLTR can be reduced to improve response
time, and the remaining ac residual can be decreased by using
the output filter, which has a smaller time constant.
DEVICE CALIBRATION AND ERROR CALCULATION
Because slope and intercept vary from device to device, board-
level calibration must be performed to achieve high accuracy.
In general, calibration is performed by applying two input power
levels to the ADL5504 and measuring the corresponding output
voltages. The calibration points are generally chosen to be within
the linear operating range of the device. The best-fit line is
characterized by calculating the conversion gain (or slope) and
intercept using the following equations:
Gain = (VVRMS2 VVRMS1)/(VIN2 VIN1)
(3)
Intercept = VVRMS1 (Gain × VIN1)
(4)
where:
VINx is the rms input voltage to RFIN.
VVRMSx is the voltage output at VRMS.
Once gain and intercept are calculated, an equation can be
written that allows calculation of an (unknown) input power
based on the measured output voltage.
VIN = (VVRMS Intercept)/Gain
(5)
For an ideal (known) input power, the law conformance error of
the measured data can be calculated as
ERROR (dB) = 20 × log [(VVRMS, MEASURED Intercept)/
(Gain × VIN, IDEAL)]
(6)