Data Sheet

ADL5513

1 MHz to 4 GHz, 80 dB Logarithmic Detector/Controller

Rev. B

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FEATURES

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Wide bandwidth: 1 MHz to 4 GHz

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80 dB dynamic range (±3 dB)

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Constant dynamic range over frequency

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Stability over −40°C to +85°C temperature range: ±0.5 dB

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Operating temperature range: −40°C to +125°C

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Sensitivity: −70 dBm

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Low noise measurement/controller output (VOUT)

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Pulse response time: 21 ns/20 ns (fall/rise)

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Single-supply operation: 2.7 V to 5.5 V at 31 mA

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Power-down feature: 1 mW at 5 V

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Small footprint LFCSP

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Fabricated using high speed SiGe process

APPLICATIONS

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RF transmitter power amplifier linearization and gain/power con-

trol

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Power monitoring in radio link transmitters

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RSSI measurement in base stations, WLAN, WiMAX, RADAR

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The ADL5513 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 ADL5513 maintains accu-

rate log conformance for signals up to 4 GHz. The input dynamic

range is typically 80 dB (referred to 50 Ω) with error less than ±3

dB and 74 dB with error less than ±1 dB. The ADL5513 has 20

ns response 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

2.7 V to 5.5 V is required to power the device. Current consumption

is 31 mA, and it decreases to 200 μA when the device is disabled.

The ADL5513 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 has been paid to minimize wideband noise. In this mode,

the setpoint control voltage is applied to the VSET pin.

The feedback loop through an RF amplifier is closed via VOUT,

the output of which regulates the amplifier output to a magnitude

corresponding to VSET. The ADL5513 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 con-

nected to VSET to produce an output voltage, VOUT, that increases

linear-in-dB with RF input signal amplitude.

The logarithmic slope is 21 mV/dB, determined by the VSET inter-

face. The intercept is −88 dBm (referred to 50 Ω, continuous wave

input, 900 MHz) using the INHI input. These parameters are very

stable against supply and temperature variations.

The ADL5513 is fabricated on a SiGe bipolar IC process and is

available in a 3 mm × 3 mm, 16-lead LFCSP package for the

−40°C to +125°C operating temperature range. A fully populated

evaluation board is available.