LTC5583_15 Datasheet, PDF (1/28 Pages) Linear Technology – Matched Dual-Channel 6GHz RMS Power Detector

FEATURES
n _{Frequency Range: 40MHz to 6GHz}
n _{Linear Dynamic Range: Up to 60dB}
n _{±0.5dB (Typ) Accuracy Over Temperature}
n _{40dB Channel-to-Channel Isolation at 2GHz Even}
with Single-Ended RF Inputs
n _{Matched Dual-Channel Outputs: <1.25dB (Typ)}
n _{Single-Ended RF Inputs—No Transformer Required}
n _{Accurate RMS Power Measurement of High Crest}
Factor Modulated Waveforms
n _{Difference Output Provides VSWR Measurement}
n _{Fast Envelope Detector Outputs}
n _{Fast Response Time: 140ns Rise Time}
n _{Small 4mm × 4mm QFN24 Package}
APPLICATIONS
n _{VSWR Monitor}
n _{MIMO Transmit Power Control}
n _{Basestation PA Control}
n _{Transmit and Receive Gain Control}
n _{RF Instrumentation}
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 7262661, 7317357, 7622981.
LTC5583
Matched Dual-Channel
6GHz RMS Power Detector
DESCRIPTION
The LTC^®5583 is a dual-channel RMS power detector,
capable of measuring two AC signals with wide dynamic
range, from –59dBm to 4dBm, depending on frequency.
Each AC signal’s power in decibel-scaled value is precisely
converted to a DC voltage on a linear scale, independent
of the crest factor of the input signal waveforms. The
LTC5583 is suitable for precision power measurement and
level control for a variety of RF standards, including LTE,
EDGE, W-CDMA, CDMA2000, TD-SCDMA, and WiMAX.
Good channel-to-channel isolation is necessary for oper-
ating the dual channels simultaneously. For applications
where the two input signals are at the same frequency (e.g.
measuring VSWR), the LTC5583 provides 40dB isolation
at 2.14GHz even with single-ended inputs. No baluns are
needed. When the two input signals are at different frequen-
cies, the isolation can be as high as 50dB. The isolation
can be improved to >55dB with differential inputs.
The power difference of the two input signals is provided
at a difference output pin. Each channel also has a fast
envelope detector, which tracks the RF input signal’s en-
velope and outputs a voltage directly proportional to the
signal’s instantaneous power. The envelope detectors can
be disabled to reduce power consumption.
TYPICAL APPLICATION
Block Diagram
ENVA
ENVELOPE
DETECT
IN⁺A
IN^–A
RMS
DETECT
ENVB
ENVELOPE
DETECT
LTC5583
RMS
DETECT
IN⁺B
IN^–B
V_OA
+
V_ODF
–
DIFFERENCE
AMPLIFIER _VOB
INV
V_OS
5583 BD
Output Voltage and Linearity Error
vs RF Input Power, 2140MHz CW
Inputs, Single-Ended Drive
2.5
2.5
2.0
2.0
1.5
1.0
1.5
0.5
0
1.0
–0.5
85°C, CH A
85°C, CH B ^–1.0
0.5
25°C, CH A
25°C, CH B
–1.5
–40°C, CH A –2.0
–40°C, CH B
0
–2.5
–65 –55 –45 –35 –25 –15 –5 5
INPUT POWER (dBm)
5583 TA01b
5583fa
1