LT5538_15 Datasheet, PDF (1/12 Pages) Linear Technology – 40MHz to 3.8GHz RF Power Detector with 75dB Dynamic Range

FEATURES
■ _{Frequency Range: 40MHz to 3.8GHz}
■ _{75dB Log Linear Dynamic Range}
■ _{Exceptional Accuracy over Temperature}
■ _{Linear DC Output vs. Input Power in dBm}
■ _{–72dBm Detection Sensitivity}
■ _{Single-ended RF Input}
■ _{Low Supply Current: 29mA}
■ _{Supply Voltage: 3V to 5.25V}
■ _{8-lead DFN 3mm × 3mm package}
APPLICATIONS
■ _{Received Signal Strength Indication (RSSI)}
■ _{RF Power Measurement and Control}
■ _{RF/IF Power Detection}
■ _{Receiver RF/IF Gain Control}
■ _{Envelope Detection}
■ _{ASK Receiver}
LT5538
40MHz to 3.8GHz
RF Power Detector with
75dB Dynamic Range
DESCRIPTION
The LT^®5538 is a 40MHz to 3800MHz monolithic logarith-
mic RF power detector, capable of measuring RF signals
over a wide dynamic range, from –75dBm to 10dBm. The
RF signal in an equivalent decibel-scaled value is precisely
converted into DC voltage on a linear scale. The wide linear
dynamic range is achieved by measuring the RF signal us-
ing cascaded RF limiters and RF detectors. Their outputs
are summed to generate an accurate linear DC voltage
proportional to the input RF signal in dBm. The LT5538
delivers superior temperature stable output (within ±1dB
over full temperature range) from 40MHz to 3.8GHz. The
output is buffered with a low impedance driver.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
40MHz - 3.8GHz Logarithmic RF Detector
RF
INPUT
EN
1nF
56
1nF
LT5538
ENBL
OUT
IN⁺
CAP⁺
IN^–
CAP^–
GND
V_CC
9
5538 TA01
100pF
V_OUT
5V
0.1μF
Output Voltage and Linearity Error
vs Input Power
2.0
3
V_CC = 5V AT 880 MHz
1.7
2
1.4
1
1.1
0
0.8
–1
0.5
T_A = –40°C _–2
T_A = 25°C
T_A = 85°C
0.2
–3
–75 –65 –55 –45 –35 –25 –15 –5 5
INPUT POWER (dBm)
5538 TA02
5538f
1