LTC1966_11 Datasheet, PDF (1/38 Pages) Linear Technology – Precision Micropower RMS-to-DC Converter

LTC1966
Precision Micropower
∆∑ RMS-to-DC Converter
Features
n _{Simple to Use, Requires One Capacitor}
n _{True RMS DC Conversion Using ∆Σ Technology}
n _{High Accuracy:}
0.1% Gain Accuracy from 50Hz to 1kHz
0.25% Total Error from 50Hz to 1kHz
n _{High Linearity:}
0.02% Linearity Allows Simple System Calibration
n _{Low Supply Current:}
155µA Typ, 170µA Max
n _{Ultralow Shutdown Current:}
0.1µA
n _{Constant Bandwidth:}
Independent of Input Voltage
800kHz –3dB, 6kHz ±1%
n _{Flexible Supplies:}
2.7V to 5.5V Single Supply
Up to ±5.5V Dual Supply
n _{Flexible Inputs:}
Differential or Single-Ended
Rail-to-Rail Common Mode Voltage Range
Up to 1V_PEAK Differential Voltage
n _{Flexible Output:}
Rail-to-Rail Output
Separate Output Reference Pin Allows Level Shifting
n _{Wide Temperature Range:}
–55°C to 125°C
n _{Small Size:}
Space Saving 8-Pin MSOP Package
Typical Application
Single Supply RMS-to-DC Converter
2.7V TO 5.5V
DIFFERENTIAL
INPUT
0.1µF
OPT. AC
COUPLING
V_DD
IN1
OUTPUT
LTC1966
IN2 OUT RTN
EN V_SS GND
C_AVE
1µF
+
–
V_OUT
1966 TA01
Description
The LTC^®1966 is a true RMS-to-DC converter that utilizes
an innovative patented ∆Σ computational technique. The
internal delta sigma circuitry of the LTC1966 makes it sim-
pler to use, more accurate, lower power and dramatically
more flexible than conventional log antilog RMS-to-DC
converters.
The LTC1966 accepts single-ended or differential input
signals (for EMI/RFI rejection) and supports crest factors up
to 4. Common mode input range is rail-to-rail. Differential
input range is 1V_PEAK, and offers unprecedented linearity.
Unlike previously available RMS-to-DC converters, the
superior linearity of the LTC1966 allows hassle free system
calibration at any input voltage.
The LTC1966 also has a rail-to-rail output with a separate
output reference pin providing flexible level shifting. The
LTC1966 operates on a single power supply from 2.7V to
5.5V or dual supplies up to ±5.5V. A low power shutdown
mode reduces supply current to 0.5µA.
The LTC1966 is insensitive to PC board soldering and
stresses, as well as operating temperature. The LTC1966
is packaged in the space saving MSOP package which is
ideal for portable applications.
Applications
n _{True RMS Digital Multimeters and Panel Meters}
n _{True RMS AC + DC Measurements}
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No Latency DS is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents including 6359576, 6362677,
6516291 and 6651036.
Quantum Leap in Linearity Performance
0.2
LTC1966, ∆∑
0
–0.2
–0.4
–0.6
CONVENTIONAL
LOG/ANTILOG
–0.8
60Hz SINEWAVES
–1.0
0 50 100 150 200 250 300 350 400 450 500
V_IN (mV AC_RMS)
1966 TA01b
1966fb
1