Datasheet AD8318-EP (Analog Devices)

1 MHz to 8 GHz, 70 dB Logarithmic Detector/Control er Enhanced Product AD8318-EP FEATURES FUNCTIONAL BLOCK DIAGRAM Wide bandwidth: 1 MHz to 8 GHz VPSI ENBL TADJ VPSO High accuracy: ±1.0 dB over 55 dB range (f < 5.8 GHz) Stability over temperature: ±0.5 dB TEMP GAIN TEMP SLOPE SENSOR BIAS I V VSET Low noise measurement/controller output (VOUT) Pulse response time: 10 ns/12 ns (fall/rise) I V VOUT Integrated temperature sensor DET DET DET DET Small footprint LFCSP CLPF Power-down feature: <1.5 mW at 5 V INHI Single-supply operation: 5 V @ 68 mA INLO Fabricated using high speed SiGe process
001
CMIP CMOP
10783-
APPLICATIONS
Figure 1.
RF transmitter PA setpoint control and level monitoring 2.4 6 RSSI measurement in base stations, WLAN, WiMAX, and 2.2 5 radars 2.0 4 GENERAL DESCRIPTION 1.8 3 1.6 2
The AD8318-EP is a demodulating logarithmic amplifier,
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capable of accurately converting an RF input signal to a
(V) R ( UT 1.2 0
corresponding decibel-scaled output voltage. It employs the
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progressive compression technique over a cascaded amplifier
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chain, each stage of which is equipped with a detector cel .
0.6 –3
The device is used in measurement or control er mode. The
0.4 –4
AD8318-EP maintains accurate log conformance for signals of
0.2 –5
1 MHz to 6 GHz and provides useful operation to 8 GHz. The
0 –6
input range is typical y 60 dB (re: 50 Ω) with error less than
–65 –60 –55 –50 –45 –40 –35 –30 –25 –20 –15 –10 –5 0 5 10
052
P
±1 dB. The AD8318-EP has a 10 ns response time that enables
IN (dBm)
10783- RF burst detection to beyond 45 MHz. The device provides Figure 2. Typical Logarithmic Response and Error vs. Input Amplitude at 5.8 GHz unprecedented logarithmic intercept stability vs. ambient applications. As a measurement device, Pin VOUT is externally temperature conditions. A 2 mV/°C slope temperature sensor connected to VSET to produce an output voltage, VOUT, which output is also provided for additional system monitoring. is a decreasing linear-in-dB function of the RF input signal A single supply of 5 V is required. Current consumption is amplitude. typically 68 mA. Power consumption decreases to <1.5 mW when the device is disabled. The logarithmic slope is nominally −25 mV/dB but can be adjusted by scaling the feedback voltage from VOUT to the The AD8318-EP can be configured to provide a control voltage VSET interface. The intercept is 20 dBm (re: 50 Ω, CW input) to a VGA, such as a power amplifier or a measurement output, using the INHI input. These parameters are very stable against from Pin VOUT. Because the output can be used for controller supply and temperature variations. applications, wideband noise is minimal. In this mode, the setpoint control voltage is applied to VSET. The AD8318-EP is fabricated on a SiGe bipolar IC process and The feedback loop through an RF amplifier is closed via VOUT, is available in a 4 mm × 4 mm, 16-lead LFCSP. Performance is the output of which regulates the amplifier output to a magnitude specified over a temperature range of –55oC to +105oC. corresponding to VSET. The AD8318-EP provides 0 V to 4.9 V Additional application and technical information can be found output capability at the VOUT pin, suitable for controller in the AD8318 data sheet.
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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 Outline Dimensions Ordering Guide