AD8319_07 Datasheet, PDF (1/20 Pages) Analog Devices – 1 MHz to 10 GHz, 40 dB Log Detector/Controller

FEATURES
Wide bandwidth: 1 MHz to 10 GHz
High accuracy: ±1.0 dB over temperature
>40 dB dynamic range up to 8 GHz
Stability over temperature ±0.5 dB
Low noise measurement/controller output VOUT
Pulse response time: 8 ns/10 ns (fall/rise)
Small footprint 2 mm × 3 mm LFCSP_VD
Supply operation: 3.0 V to 5.5 V @ 22 mA
Fabricated using high speed SiGe process
APPLICATIONS
RF transmitter PA setpoint controls and level monitoring
Power monitoring in radiolink transmitters
RSSI measurement in base stations, WLANs, WiMAX,
and radars
GENERAL DESCRIPTION
The AD8319 is a demodulating logarithmic amplifier, capable
of accurately converting an RF input signal to a corresponding
decibel-scaled output. It employs the progressive compression
technique over a cascaded amplifier chain, each stage of which
is equipped with a detector cell. The device can be used in either
measurement or controller modes. The AD8319 maintains
accurate log conformance for signals of 1 MHz to 8 GHz and
provides useful operation to 10 GHz. The input dynamic range
is typically 40 dB (re: 50 Ω) with error less than ±1 dB. The
AD8319 has 8 ns/10 ns response time (fall time/rise time) that
enables RF burst detection to a pulse rate of beyond 50 MHz.
The device provides unprecedented logarithmic intercept
stability vs. ambient temperature conditions. A supply of 3.0 V
to 5.5 V is required to power the device. Current consumption
is typically 22 mA, and it decreases to 200 μA when the device is
disabled.
The AD8319 can be configured to provide a control voltage to
a power amplifier or a measurement output from the VOUT
pin. Because the output can be used for controller applications,
special attention was paid to minimize wideband noise. In this
mode, the setpoint control voltage is applied to the VSET pin.
1 MHz to 10 GHz, 40 dB
Log Detector/Controller
AD8319
FUNCTIONAL BLOCK DIAGRAM
VPOS
TADJ
GAIN
BIAS
SLOPE
IV
VSET
INHI
INLO
DET
DET
DET DET
COMM
Figure 1.
IV
VOUT
CLPF
The feedback loop through an RF amplifier is closed via VOUT,
the output of which regulates the amplifier’s output to a magnitude
corresponding to VSET. The AD8319 provides 0 V to (VPOS − 0.1 V)
output capability at the VOUT pin, suitable for controller
applications. As a measurement device, VOUT is externally
connected to VSET to produce an output voltage, VOUT, that is a
decreasing linear-in-dB function of the RF input signal amplitude.
The logarithmic slope is −22 mV/dB, determined by the VSET
interface. The intercept is 15 dBm (re: 50 Ω, CW input) using
the INHI input. These parameters are very stable against supply
and temperature variations.
The AD8319 is fabricated on a SiGe bipolar IC process and is
available in a 2 mm × 3 mm, 8-lead LFCSP_VD for an operating
temperature range of −40°C to +85°C.
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
www.analog.com
Fax: [phone] ©2005–2007 Analog Devices, Inc. All rights reserved.