LMV225 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – RF Power Detector for CDMA and WCDMA

March 2005
LMV225/LMV226/LMV228
RF Power Detector for CDMA and WCDMA
General Description
The LMV225/LMV226/LMV228 are 30 dB RF power detec-
tors intended for use in CDMA and WCDMA applications.
The device has an RF frequency range from 450 MHz to 2
GHz. It provides an accurate temperature and supply com-
pensated output voltage that relates linearly to the RF input
power in dBm. The circuit operates with a single supply from
2.7V to 5.5V. The LMV225/LMV226/LMV228 have an inte-
grated filter for low-ripple average power detection of CDMA
signals with 30 dB dynamic range. Additional filtering can be
applied using a single external capacitor.
The LMV225 has an RF power detection range from –30
dBm to 0 dBm and is ideally suited for direct use in combi-
nation with resistive taps. The LMV226/LMV228 have a de-
tection range from –15 dBm to 15 dBm and are intended for
use in combination with a directional coupler. The LMV226 is
equipped with a buffered output which makes it suitable for
GSM, EDGE, GPRS and TDMA applications.
The device is active for Enable = HI, otherwise it is in a low
power consumption shutdown mode. During shutdown the
output will be LOW. The output voltage ranges from 0.2V to
2V and can be scaled down to meet ADC input range re-
quirements.
The LMV225/LMV226/LMV228 power detectors are offered
in the small 1.0 mm x 1.0 mm X 0.6 mm micro SMD pack-
age. The LMV225 and the LMV228 are also offered in the
2.2 mm x 2.5 mm x 0.8 mm LLP package.
Features
n 30 dB linear in dB power detection range
n Output voltage range 0.2 to 2V
n Logic low shutdown
n Multi-band operation from 450 MHz to 2000 MHz
n Accurate temperature compensation
n Packages:
— micro SMD package 1.0 mm x 1.0 mm x 0.6 mm
— LLP package 2.2 mm x 2.5 mm x 0.8 mm (LMV225
and LMV228)
Applications
n CDMA RF power control
n WCDMA RF power control
n CDMA2000 RF power control
n PA modules
Typical Application
LMV225
LMV226/LMV228
20076001
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