Electronic Components Datasheet Search |
|
LT1920CS8 Datasheet(PDF) 11 Page - Linear Technology |
|
LT1920CS8 Datasheet(HTML) 11 Page - Linear Technology |
11 / 12 page 11 LT1920 APPLICATIONS INFORMATION To significantly reduce the effect of these out-of-band signals on the input offset voltage of instrumentation amplifiers, simple lowpass filters can be used at the inputs. This filter should be located very close to the input pins of the circuit. An effective filter configuration is illustrated in Figure 5, where three capacitors have been added to the inputs of the LT1920. Capacitors CXCM1 and CXCM2 form lowpass filters with the external series resis- tors RS1, 2 to any out-of-band signal appearing on each of the input traces. Capacitor CXD forms a filter to reduce any unwanted signal that would appear across the input traces. An added benefit to using CXD is that the circuit’s AC common mode rejection is not degraded due to common mode capacitive imbalance. The differential mode and common mode time constants associated with the capaci- tors are: tDM(LPF) = (2)(RS)(CXD) tCM(LPF) = (RS1, 2)(CXCM1, 2) Setting the time constants requires a knowledge of the frequency, or frequencies of the interference. Once this frequency is known, the common mode time constants can be set followed by the differential mode time constant. Set the common mode time constants such that they do not degrade the LT1920’s inherent AC CMR. Then the differential mode time constant can be set for the band- width required for the application. Setting the differential mode time constant close to the sensor’s BW also mini- mizes any noise pickup along the leads. To avoid any possibility of inadvertently affecting the signal to be pro- cessed, set the common mode time constant an order of magnitude (or more) larger than the differential mode time constant. To avoid any possibility of common mode to differential mode signal conversion, match the common mode time constants to 1% or better. If the sensor is an RTD or a resistive strain gauge, then the series resistors RS1, 2 can be omitted, if the sensor is in proximity to the instrumentation amplifier. N8 1197 0.100 ± 0.010 (2.540 ± 0.254) 0.065 (1.651) TYP 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 0.020 (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.076) 0.125 (3.175) MIN 12 3 4 87 6 5 0.255 ± 0.015* (6.477 ± 0.381) 0.400* (10.160) MAX 0.009 – 0.015 (0.229 – 0.381) 0.300 – 0.325 (7.620 – 8.255) 0.325 +0.035 –0.015 +0.889 –0.381 8.255 () *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) Dimensions in inches (millimeters) unless otherwise noted. PACKAGE DESCRIPTION Figure 5. Adding a Simple RC Filter at the Inputs to an Instrumentation Amplifier is Effective in Reducing Rectification of High Frequency Out-of-Band Signals 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. V – V + IN + IN – 1920 F05 VOUT RG CXCM1 0.001 µF CXCM2 0.001 µF CXD 0.1 µF RS1 1.6k RS2 1.6k EXTERNAL RFI FILTER LT1920 f(–3dB) ≈ 500Hz |
Similar Part No. - LT1920CS8 |
|
Similar Description - LT1920CS8 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |