LMH2120 Datasheet, PDF (1/34 Pages) National Semiconductor (TI) – Linear RMS power detector particularly suited for accurate

LMH2120
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SNWS021C – JULY 2010 – REVISED FEBRUARY 2013
LMH2120 6 GHz Linear RMS Power Detector with 40 dB Dynamic Range
Check for Samples: LMH2120
FEATURES
1
•2 Linear Root Mean Square Response
• 40 dB Linear-in-V Power Detection Range
• Multi-Band Operation from 50 MHz to 6 GHz
• Lin Conformance Better than ±0.5 dB
• Highly Temperature Insensitive
• Modulation Independent Response
• Minimal Slope and Intercept Variation
• Shutdown Functionality
• Wide Supply Range from 2.7V to 5V
• Tiny 6-Bump DSBGA Package
APPLICATIONS
• Multi Mode, Multi Band RF Power Control
– GSM/EDGE
– CDMA/CDMA2000
– W-CDMA
– OFDMA
– LTE
• Infrastructure RF Power Control
DESCRIPTION
The LMH2120 is a 40 dB Linear RMS power detector
particularly suited for accurate power measurement of
modulated RF signals that exhibit large peak-to-
average ratios, i.e, large variations of the signal
envelope. Such signals are encountered in W-CDMA
and LTE cell phones. The RMS measurement
topology inherently ensures a modulation insensitive
measurement.
The device has an RF frequency range from 50 MHz
to 6 GHz. It provides an accurate, temperature and
supply insensitive, output voltage that relates linearly
to the RF input power in volt. The LMH2120's
excellent conformance to a linear response enables
an easy integration by using slope and intercept only,
reducing calibration effort significantly. The device
operates with a single supply from 2.7V to 5V. The
LMH2120 has an RF power detection range from -35
dBm to 5 dBm and is ideally suited for use in
combination with a directional coupler. Alternatively, a
resistive divider can be used.
The device is active for EN = High, otherwise it is in a
low power consumption shutdown mode. To save
power and prevent discharge of an external filter
capacitance, the output (OUT) is high impedance
during shutdown.
The LMH2120 power detector is offered in a tiny 6-
bump DSBGA package.
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RF
PA
COUPLER
ANTENNA
1
50:
V_DD
RF_IN
A1
B1
A2
LMH2120
OUT
EN C2
C1, B2
GND
ADC
0.1
85°C
25°C
-40°C
0.01
-50 -40 -30 -20 -10 0 10
RF INPUT POWER (dBm)
Figure 1. Typical Application
Figure 2. Output Voltage vs. RF Input Power at
1900 MHz
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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