Datasheet AD8312 (Analog Devices)

50 MHz to 3.5 GHz, 45 dB RF Detector Data Sheet AD8312 FEATURES GENERAL DESCRIPTION Complete RF detector function
The AD8312 is a complete, low cost subsystem for the
Typical range: −45 dBm to 0 dBm, referencing 50 Ω
measurement of radio frequency (RF) signals in the frequency
Frequency response from 50 MHz to 3.5 GHz
range of 50 MHz to 3.5 GHz. It has a typical dynamic range of
Temperature stable linear in dB response
45 dB and is intended for use in a wide variety of cellular handsets
Accurate to 3.5 GHz
and other wireless devices. It provides a wider dynamic range
Rapid response: 85/120 ns (rise/fall)
and better accuracy than possible using discrete diode detectors. In
Low power: 12 mW at 2.7 V
particular, its temperature stability is excellent over the full
APPLICATIONS
operating range of −40°C to +85°C. Its high sensitivity allows measurement at low power levels, thus reducing the amount of
Cellular handsets (GSM, CDMA, WCDMA)
power that needs to be coupled to the detector. It is essentially a
RSSI and TSSI for wireless terminal devices
voltage responding device, with a typical signal range of 1.25 mV
Transmitter power measurement
to 224 mV rms or −45 dBm to 0 dBm, referencing 50 Ω. For convenience, the signal is internally ac-coupled, using a 5 pF capacitor to a load of 3 kΩ in shunt with 1.3 pF. This high- pass coupling, with a corner at approximately 16 MHz, determines the lowest operating frequency. Therefore, the source may be dc grounded. The AD8312 output, VOUT, increases from close to ground to about 1.2 V because the input signal level increases from 1.25 mV to 224 mV. A capacitor may be connected between the VOUT and CFLT pins when it is desirable to increase the time interval over which averaging of the input waveform occurs. The AD8312 is available in a 6-ball, 1.0 mm × 1.5 mm, wafer level chip scale package and consumes 4.2 mA from a 2.7 V to 5.5 V supply.
FUNCTIONAL BLOCK DIAGRAM CFLT V-I VSET – + I-V VOUT DET DET DET DET DET RFIN BAND-GAP 10dB 10dB 10dB 10dB VPOS REFERENCE OFFSET COMPENSATION AD8312 COMM
05260-001 Figure 1.
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Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS GENERAL DESCRIPTION APPLICATIONS INFORMATION BASIC CONNECTIONS TRANSFER FUNCTION IN TERMS OF SLOPE AND INTERCEPT Filter Capacitor Input Coupling Options Increasing the Logarithmic Slope Effect of Waveform Type on Intercept Temperature Drift Operation Above 2.5 GHz Device Handling Evaluation Board OUTLINE DIMENSIONS ORDERING GUIDE