FEATURES
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LTC1967
Precision Extended
Bandwidth, RMS-to-DC Converter
DESCRIPTIO
The LTC
®
1967 is a true RMS-to-DC converter that uses an
innovative delta-sigma computational technique. The ben-
efits of the LTC1967 proprietary architecture when com-
pared to conventional log-antilog RMS-to-DC converters
are higher linearity and accuracy, bandwidth independent
of amplitude and improved temperature behavior.
The LTC1967 operates with single-ended or differential in-
put signals (for EMI/RFI rejection) and supports crest fac-
tors up to 4. Common mode input range is rail-to-rail. Dif-
ferential input range is 1V
PEAK
, and offers unprecedented
linearity. The LTC1967 allows hassle-free system calibra-
tion at any input voltage.
The LTC1967 has a rail-to-rail output with a separate out-
put reference pin providing flexible level shifting; it oper-
ates on a single power supply from 4.5V to 5.5V. A low power
shutdown mode reduces supply current to 0.1µA.
The LTC1967 is packaged in the space-saving MSOP pack-
age, which is ideal for portable applications.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Protected under U.S. Patent Numbers 6,359,576, 6,362,677 and 6,516,291
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High Linearity:
0.02% Linearity Allows Simple System Calibration
Wide Input Bandwidth:
Bandwidth to 0.1% Additional Gain Error: 40kHz
Bandwidth Independent of Input Voltage Amplitude
No-Hassle Simplicity:
True RMS-DC Conversion with Only One External
Capacitor
Delta Sigma Conversion Technology
Low Supply Current:
330µA Typ
Ultralow Shutdown Current:
0.1µA
Flexible Inputs:
Differential or Single Ended
Rail-to-Rail Common Mode Voltage Range
Up to 1V
PEAK
Differential Voltage
Flexible Output:
Rail-to-Rail Output
Separate Output Reference Pin Allows Level Shifting
Small Size:
Space Saving 8-Pin MSOP Package
APPLICATIO S
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True RMS Digital Multimeters and Panel Meters
True RMS AC + DC Measurements
TYPICAL APPLICATIO
Linearity Performance
LINEARITY ERROR (V
OUT
mV DC – V
IN
mV AC
RMS
)
0.2
LTC1967,
∆Σ
0
–0.2
–0.4
–0.6
–0.8
–1.0
60Hz SINEWAVE
0
100
200
300
V
IN
(mV AC
RMS
)
400
500
1967 TA01b
Single Supply RMS-to-DC Converter
4.5V TO 5.5V
V
+
IN1
DIFFERENTIAL
INPUT
0.1µF
OPT. AC
COUPLING
IN2
EN
OUTPUT
LTC1967
OUT RTN
GND
C
AVE
1µF
+
V
OUT
–
1967 TA01
U
U
U
CONVENTIONAL
LOG/ANTILOG
1967f
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
