LMH2110_15 Datasheet, PDF (16/36 Pages) Texas Instruments – LMH2110 8-GHz Logarithmic RMS Power Detector with 45-dB Dynamic Range

LMH2110
SNWS022D – JANUARY 2010 – REVISED JUNE 2015
7 Detailed Description
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7.1 Overview
The LMH2110 is a high-performance logarithmic root mean square (RMS) power detector which measures the
actual power content of a signal. The device has a RF input power detection range from –40 dBm to 5 dBm and
provides accurate output voltage that relates linearly to the RF input power in dBm. This output voltage exhibits
high temperature insensitivity ranging ±0.25 dB.
The device has an internal low dropout linear regulator (LDO) making the device insensitive to input supply
variation and allowing operation from a wide input supply range from 2.7 V to 5 V. Additional features include
multi-band operation from 50 MHz to 8 GHz, shutdown functionality to save power, and minimal slope and
intercept variation.
7.2 Functional Block Diagram
V/I
B1 ^RFIN
A1
VDD
LDO
Internal
Supply
EXP
OUT _A2
A
C2 _EN
V/I
EXP
GND
B2,
C1
7.3 Feature Description
7.3.1 Accurate Power Measurement
Detectors have evolved over the years along with the communication standards. Newer communication
standards like LTE and W-CDMA raise the need for more advanced accurate power detectors. To be able to
distinguish the various detector types it is important to understand the ideal power measurement and how a
power measurement is implemented.
Power is a metric for the average energy content of a signal. By definition it is not a function of the signal shape
over time. In other words, the power content of a 0-dBm sine wave is identical to the power content of a 0-dBm
square wave or a 0-dBm W-CDMA signal; all these signals have the same average power content.
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