ОБЩЕЕ ОПИСАНИЕ

The LTC5596 is a high accuracy RMS power detector that provides a very wide RF input bandwidth, from 100MHz up to 40GHz. This makes the device suitable for a wide range of RF and microwave applications, such as pointto-point microwave links, instrumentation and power control applications. The DC output voltage of the detector is an accurate representation of the average signal power applied to the RF input. The response is linear-in-dB with 29mV/dB logarithmic slope over a 35dB dynamic range with typically better than ±1dB accuracy. The detector is particularly suited for measurement of waveforms with crest factor (CF) as high as 12dB, and waveforms that exhibit a significant variation of the crest factor during the measurement. To achieve higher accuracy and lower output ripple, the averaging bandwidth can be externally adjusted by a capacitor connected between the FLTR and OUT pins. The enable interface switches the device between active measurement mode and a low power shutdown mode.

 

ОСОБЕННОСТИ

Ultra Wide Matched Input Frequency Range: 100MHz to 40GHz

35dB Linear Dynamic Range (< ±1dB Error)

29mV/dB Logarithmic Slope

±1dB Flat Response from 200MHz to 30GHz

Accurate RMS Power Measurement of High Crest Factors (Up to 12dB) Modulated Waveforms

Low Power Shutdown Mode

Low Supply Current: 30mA at 3.3V (Typical)

Small 2mm × 2mm Plastic DFN8 Package

I-Grade: –40°C to 105°C Rated H-Grade: –40°C to 125°C Rated with Guaranteed Log-Slope and Log-Intercept

ESD Rating: 3500V HBM, 1500V CDM

 

ПРИЛОЖЕНИЯ

Point-to-Point Microwave Links

Instrumentation and Measurement Equipment

Military Radios

LTE, WiFi, WiMax Wireless Networks

RMS Power Measurement

Receive and Transmit Gain Control

RF PA Transmit Power Control

 

ИНФОРМАЦИЯ О ПРИЛОЖЕНИЯХ

The LTC5596 is a true RMS RF power detector, capable of measuring an RF signal over the frequency range from 100MHz to 40GHz, independent of input waveforms with different crest factors such as CW, WCDMA, OFDM (LTE and WiFi) signals. Up to 35dB dynamic range is achieved with a very stable output within the full case temperature range.

RF Input

The single-ended RF input is internally matched to 50Ω, both in active mode and the low power shutdown mode. The DC voltage applied to this pin should be kept below 1V, to avoid damage to the internal circuitry.Together with GND Pin 5 and Pin 7, RFIN (Pin 6) forms

a ground-signal-ground configuration that can interface directly with a co-planar waveguide on the PCB.To minimize reflections at high frequencies, the center strip has been chosen the same width as the RFIN package pin (10mils). Likewise, the center pin of the 40GHz 2.92mm connector terminating the other side of the GCPW has a 10mils width as well. The LTC5596 evaluation board uses a 5mils thick layer of Rogers RO3003 material for the top substrate to achieve low dielectric losses up to 40GHz. The other two substrates on the board are regular FR-4 material. Using this configuration, a 50Ω characteristic impedance is obtained for a 9mils gap width between the center strip and the two ground return conductors. Via’s, connecting the top ground conductors with the second metal ground plane, should be placed along the edge of the GCPW top ground conductors. Via dimensions should be kept as small as possible; the evaluation board uses vias with a diameter of 6mils; 8mils including the metal edge ring (donut).

FLTR Interface (Pin 3):

This pin enables additional suppression of high frequency ripple in the detector output signal, at the expense of a slower detector response (longer rise time, fall time and propagation delay). An external capacitor C3 connected between FLTR and OUT enlarges the amount of feedback capacitance across the output amplifier, and reduces the output filter bandwidth without affecting the current drive capability of the LTC5596. Suitable capacitance values are in the range from 10pF up to 1nF, but the total of feedback and load capacitance (from OUT to signal ground) should not exceed 1nF. Larger capacitance values may result in instability of the output driver.

To avoid permanent damage to the chip, the DC voltage at the FLTR pin should not exceed 0.4V. Similarly, it is not recommended to supply a DC bias current to this pin in excess of about 100μA.