The ADL5507 is a complete, low-power, wide-band logarithmic RF
power detector for the measurement of RF signals in the 10 MHz to
12 GHz frequency range. The device is optimized for accurate RF
signal level measurements over a 55 dB dynamic range, from −56
dBm to −1 dBm at 3.6 GHz, when terminated with 50 Ω. It provides
a wider dynamic range and better accuracy than is possible using
discrete diode detectors. Its high sensitivity allows measurement of
low power levels, thus reducing the amount of power that needs to
be coupled to the detector.
For convenience, the signal input is internally AC-coupled, using a
series 25 pF capacitor. Therefore, the source can be DC grounded.
A broadband 50 Ω match is obtained with an external 51 Ω shunt
resistor. This high-pass coupling, with a corner at approximately 4
MHz, determines the lowest operating frequency.
The DC voltage at the ADL5507 output interface responds linearin-
dB to the RF signal level applied at its input. It is accurately
temperature compensated to provide typically better than ±1 dB
measurement accuracy over the full case operating temperature
range from −40°C to +105°C. The output interface has sufficient
capability to drive a wide range of analog‐to‐digital converters
(ADCs) and other circuitry.
The CFLT interface enables additional ripple and noise filtering of
the output signal, without reducing the drive capability of the VLOG
interface. This is achieved by connecting a capacitor between the
CFLT and VLOG interfaces.
The tri-state ENBL interface switches the device between active
positive output slope mode, active negative output slope mode, and
a low-power shutdown mode. In positive output slope mode, the
ADL5507 output increases approximately from 0.1 V to 1.2 V as the
input signal level increases from 0.35 mV rms (−56 dBm) to 200 mV
rms (−1 dBm). In negative output slope mode, the output decreases
approximately from 1 V to 0 V as the input signal level decreases
from 200 mV rms (−1 dBm) to 0.35 mV rms (−56 dBm). The output
interface becomes high impedance in shutdown to avoid discharge
of external filter capacitors.
The ADL5507 is available in a 6-ball WLCSP package and consumes
12.5 mA from a 3.3 V supply. In shutdown mode, the typical
disable supply current is <100 μA.
APPLICATIONS
- RSSI and TSSI for wired and wireless terminal devices
- RF transmitter or receiver power measurement
- Wide-band Automatic Gain Control
