LTC1966CMS8#TRPBF Linear Technology, LTC1966CMS8#TRPBF Datasheet
LTC1966CMS8#TRPBF
Specifications of LTC1966CMS8#TRPBF
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LTC1966CMS8#TRPBF Summary of contents
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... True RMS Measurements n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and No Latency 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 ...
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... Maximum Junction Temperature ......................... 150°C Storage Temperature Range ................. –65°C to 150°C Lead Temperature (Soldering, 10 sec) .................. 300°C orDer inForMaTion LEAD FREE FINISH TAPE AND REEL LTC1966CMS8#PBF LTC1966CMS8#TRPBF LTC1966IMS8#PBF LTC1966IMS8#TRPBF LTC1966HMS8#PBF LTC1966HMS8#TRPBF LTC1966MPMS8#PBF LTC1966MPMS8#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. ...
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0.5V unless otherwise noted. ENABLE SYMBOL PARAMETER PSRR Power Supply Rejection V Input Offset Voltage IOS Accuracy vs Crest Factor (CF Input Characteristics ...
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LTC1966 elecTrical characTerisTics temperature range, otherwise specifications are 0.5V unless otherwise noted. ENABLE SYMBOL PARAMETER I ENABLE Pin Current Low IL V ENABLE Threshold Voltage TH V ENABLE Threshold Hysteresis HYS Note 1: Stresses beyond those ...
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Typical perForMance characTerisTics Gain and Offsets vs Input Common Mode 0.5 0 0.4 0 –5V SS 0.3 0.3 0.2 0.2 GAIN ERROR 0.1 0 OOS –0.1 –0.1 V IOS –0.2 –0.2 ...
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LTC1966 Typical perForMance characTerisTics Gain and Offsets vs V Supply SS 0 0.4 0.3 0.2 V IOS V OOS GAIN ERROR 0.1 0 –0.1 –0.2 –0.3 –0.4 –0.5 –6 –5 –4 –3 –2 – ...
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Typical perForMance characTerisTics Quiescent Supply Currents vs Temperature 40 170 –5V 35 160 5V GND 150 140 V = 2.7V GND DD SS ...
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LTC1966 pin FuncTions GND (Pin 1): Ground. A power return pin. IN1 (Pin 2): Differential Input. DC coupled (polarity is irrelevant). IN2 (Pin 3): Differential Input. DC coupled (polarity is irrelevant). V (Pin 4): Negative Voltage Supply. GND to – ...
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READ RMS-TO-DC CONVERSION CONTACT LTC BY PHONE OR AT www.linear.com AND GET SOME NOW READ THE TROUBLESHOOTING GUIDE. IF NECESSARY, CALL LTC FOR APPLICATIONS SUPPORT CONTACT LTC AND PLACE YOUR ORDER START NOT DO YOU SURE NEED TRUE ...
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LTC1966 applicaTions inForMaTion RMS-TO-DC CONVERSION Definition of RMS RMS amplitude is the consistent, fair and standard way to measure and compare dynamic signals of all shapes and sizes. Simply stated, the RMS amplitude is the heating potential of a dynamic ...
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How an RMS-to-DC Converter Works Monolithic RMS-to-DC converters use an implicit com- putation to calculate the RMS value of an input signal. The fundamental building block is an analog multiply/ divide used as shown in Figure 3. Analysis ...
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LTC1966 applicaTions inForMaTion More detail of the LTC1966 inner workings is shown in the Simplified Schematic towards the end of this data sheet. Note that the internal scalings are such that the ∆S output duty cycle is limited to 0% ...
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DESIGN COOKBOOK The LTC1966 RMS-to-DC converter makes it easy to implement a rather quirky function. For many applications all that will be needed is a single capacitor for averaging, appropriate selection of the I/O connections and power supply ...
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LTC1966 applicaTions inForMaTion 0 –0.2 –0 100µF –0.6 –0 47µ 22µF –1.0 –1.2 –1.4 –1.6 –1.8 –2.0 1 Figure 8. Peak Error vs Input Frequency with One Cap Averaging A 1µF capacitor is a ...
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For single-ended DC-coupled applications, simply con- nect one of the two inputs (they are interchangeable) to the signal, and the other to ground. This will work well for dual supply configurations, but for single supply configurations it will ...
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LTC1966 applicaTions inForMaTion In any configuration, the averaging capacitor should be connected between Pins 5 and 6. The LTC1966 RMS DC output will be a positive voltage created at V with respect to OUT RTN (Pin 6). Power Supply Bypassing ...
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C = 1µF AVE 100 0.1 0.2 0.3 TIME (SEC) Figure 11a. LTC1966 Rising Edge with 0.1µ 0.22µF 1 0.1 0.01 0.1 Figure 12. LTC1966 ...
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... However, there are disadvantages to this topology, the first of which is that the op amp input voltage and current errors directly degrade the effective LTC1966 V . The table inset in Figure 13 shows these OOS errors for four of Linear Technology’s op amps. C1 1µ 38.3k ...
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Step Responses with a Post Filter Both of the post filters, shown in Figures 13 and 14, are optimized for additional filtering with clean step responses. The 85kΩ output impedance of the LTC1966 working into a 1µF capacitor ...
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LTC1966 applicaTions inForMaTion 0 –0 10µF –0.4 –0 4.7µF –0.8 –1.0 –1.2 –1.4 –1.6 –1.8 –2.0 1 Figure 17. Peak Error vs Input Frequency with Buffered Post Filter 10µF –0.2 –0 ...
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C = 0.1µ 0.22µF 1 0.1 0.01 0 0.1µ 0.22µF 1 0.1 0.01 0.1 Although the settling times for the post filtered configu- rations shown on Figures 19 and 20 ...
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LTC1966 applicaTions inForMaTion using the same design curves presented in Figures and 18. For the worst-case of square top pulse trains, that are always either zero volts or the peak voltage, base the selection on the lowest ...
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But with 10× less AC input, the error caused by V 100× larger √(20mV AC (0.2mV DC) OUT = 20.001mV = 20mV + 50ppm This phenomena, although small, is one source of the LTC1966’s ...
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LTC1966 applicaTions inForMaTion To do this, inject current into the output. As shown in Figure 21, the charge pump output impedance is 170kΩ, with the computational feedback cutting the closed loop output impedance to the 85kΩ specification. By injecting 30nA ...
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The two 10MΩ resistors not connected to the supply can be any value as long as they match and the feed voltage is changed for 30nA injection. The op amp gain is only 1.00845, so the output is ...
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LTC1966 applicaTions inForMaTion Input Impedance The LTC1966 true RMS-to-DC converter utilizes a 2.5pF capacitor to sample the input at a nominal 100kHz sample frequency. This accounts for the 8MΩ input impedance. See Figure 24 for the equivalent analog input circuit. ...
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However, resistive loading is an issue and the 10MΩ impedance of a DMM or 10× scope probe will drag the output down by –0.85% typ. During shutdown, the switching action is halted and a fixed 30k resistor shunts ...
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LTC1966 applicaTions inForMaTion Interfacing with an ADC The LTC1966 output impedance and the RMS averaging ripple need to be considered when using an analog-to- digital converter (ADC) to digitize the LTC1966 RMS result. The simplest configuration is to connect the ...
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As is shown in Figure 25b, where the LTC2420 is set to continuously convert by grounding the CS pin. The gain error will be less driven at a slower rate, however, the rate should either ...
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LTC1966 applicaTions inForMaTion Whatever calibration scheme is used, the linearity of the LTC1966 will improve the calibrated accuracy over that achievable with older log/antilog RMS-to-DC converters. Additionally, calibration using DC reference voltages are essentially as accurate with the LTC1966 as ...
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The calculations of the error terms for a 200mV full-scale case are: Reading at 200mV – Reading at 20mV Gain = 180mV Reading at 20mV Output Offset = Gain DC, 2 Point DC based calibration is preferable in ...
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LTC1966 applicaTions inForMaTion TROUBLESHOOTING GUIDE Top Ten LTC1966 Application Mistakes 1. Circuit won’t work–Dead On Arrival–no power drawn. – Probably forgot to enable the LTC1966 by pulling Pin 8 low. Solution: Tie Pin 8 to Pin 1. 2. Circuit won’t work, ...
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Output is noisy with >10kHz inputs. – This is a fundamental characteristic of this topol- ogy. The LTC1966 is designed to work very well with inputs of 1kHz or less. It works okay as high as 1MHz, ...
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LTC1966 Typical applicaTions ±5V Supplies, Differential, DC-Coupled RMS-to-DC Converter LTC1966 IN1 V INPUTS OUT (1V PEAK IN2 OUT RTN DIFFERENTIAL) V GND EN SS –5V 1966 TA03 2.7V Single Supply, Single Ended, AC-Coupled RMS-to-DC ...
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V DD GND IN1 2nd ORDER ∆∑ MODULATOR IN2 BIAS CONTROL – – LTC1966 C12 C9 OUTPUT C11 OUT RTN ...
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LTC1966 package DescripTion 0.889 ± 0.127 (.035 ± .005) 5.23 3.20 – 3.45 (.206) (.126 – .136) MIN 0.42 ± 0.038 0.65 (.0165 ± .0015) (.0256) BSC TYP RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT ...
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... Revised entire data sheet to add H- and MP- grades Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
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... V GND EN 100k SS 1966 TA08 100k T1: CR MAGNETICS CR8348-2500-N www.crmagnetics.com , 450pA I OS(MAX) OS(MAX) , 100pA I OS(MAX) , 2nA I OS(MAX) OS(MAX) , 900pA I OS(MAX) OS(MAX) , 75pA I OS(MAX) B(MAX) , 350pA I OS(MAX) OS(MAX) LT 0511 REV B • PRINTED IN USA LINEAR TECHNOLOGY CORPORA TION 2001 /A DC RMS 1966fb ...