LT5504_09 Datasheet, PDF (1/8 Pages) Linear Technology – 800MHz to 2.7GHz RF Measuring Receiver

FEATURES
■ _{RF Frequency Range: 800MHz to 2.7GHz}
■ _{Ultra Wide Dynamic Range: 75dB at 900MHz}
■ _{Wide Power Supply Range: 2.7V to 5.25V}
■ _{Low Supply Current: 14.7mA at 3V}
■ _{8-Lead MS0P Package}
U
APPLICATIO S
■ _{RSSI Measurements}
■ _{Receive AGC}
■ _{Transmit Power Control}
■ _{ASK and Envelope Demodulation}
■ _{GSM/TDMA/CDMA/WCDMA}
TYPICAL APPLICATIO
LT5504
800MHz to 2.7GHz
RF Measuring Receiver
DESCRIPTIO
The LT^®5504 is an 800MHz to 2700MHz monolithic inte-
grated measuring receiver, capable of detecting a wide
dynamic range RF signal from –75dBm to +5dBm. The
logarithm of the RF signal is precisely converted into a
linear DC voltage. The LT5504 consists of RF/IF limiters,
an LO buffer amplifier, a limiting mixer, a 3rd-order
450MHz integrated low pass filter, RF/IF detectors and an
output interface. The ultrawide dynamic range is achieved
by simultaneously measuring the RF signal and a down-
converted IF signal obtained using the on-chip mixer and
an external local oscillator. The RF- and IF-detected sig-
nals are summed to generate an accurate linear DC voltage
proportional to the input RF voltage (or power) in dB. The
output is buffered with a low output impedance driver.
, LTC and LT are registered trademarks of Linear Technology Corporation.
C2
C1
1nF
100pF
LT5504
RF
INPUT
RF
RF+ DETECTOR
R1
82Ω
RF ^–
ENABLE
EN
3V
V_CC
V_{OUT R2}
200Ω
IF
DETECTOR
•••
IF
DETECTOR
C3
10pF
OUTPUT
GND
LO
5504 TA01a
LO
INPUT
Output Voltage and Slope
Variation vs RF Input Power
2.4
6
f_RF = 900MHz
f_IF = 240MHz
2.0 AVERAGE SLOPE:23mV/dB
4
1.6
2
1.2
0
0.8
–2
0.4
–4
0
–6
–80 –70 –60 –50 –40 –30 –20 –10 0 10
PIN (dBm)
5504 TA01b
5504f
1