參數(shù)資料
型號(hào): DC956A
廠商: Linear Technology
文件頁數(shù): 26/40頁
文件大?。?/td> 0K
描述: BOARD DELTA SIGMA ADC LTC2485
軟件下載: QuikEval System
設(shè)計(jì)資源: DC956A Design File
DC956A Schematic
標(biāo)準(zhǔn)包裝: 1
系列: Easy Drive™, QuikEval™
ADC 的數(shù)量: 1
位數(shù): 24
采樣率(每秒): 6.8
數(shù)據(jù)接口: I²C,串行
工作溫度: 0°C ~ 70°C
已用 IC / 零件: LTC2485
已供物品:
相關(guān)產(chǎn)品: LTC2485CDD#TRPBF-ND - IC ADC 24BIT I2C 10-DFN
LTC2485IDD#TRPBF-ND - IC ADC 24BIT I2C 10-DFN
LTC2485IDD#PBF-ND - IC ADC 24BIT I2C 10-DFN
LTC2485CDD#PBF-ND - IC ADC 24BIT I2C 10-DFN
LTC2485
32
2485fc
APPLICATIONS INFORMATION
Using the 2x speed mode of the LTC2485, the device
bypasses the digital offset calibration operation to double
the output data rate. The superior normal mode rejection
is maintained as shown in Figures 31 and 32. However,
the magnied details near DC and fS = 256fN are different,
see Figures 40 and 41. In 2x speed mode, the bandwidth is
11.4Hz for the 50Hz rejection mode, 13.6Hz for the 60Hz
rejection mode and 12.4Hz for the 50Hz/60Hz rejection
mode. Typical measured values of the normal mode rejec-
tion of the LTC2485 operating with the internal oscillator
and 2x speed mode is shown in Figure 42.
When the LTC2485 is congured in 2x speed mode, by
performing a running average, a SINC1 notch is combined
with the SINC4 digital lter, yielding the normal mode
rejection identical as that for the 1x speed mode. The
averaging operation still keeps the output rate with the
following algorithm:
Result 1 = average (sample 0, sample 1)
Result 2 = average (sample 1, sample 2)
……
Result n = average (sample n – 1, sample n)
The main advantage of the running average is that it
achieves simultaneous 50Hz/60Hz rejection at twice the
effective output rate, as shown in Figure 43. The raw output
data provides a better than 70dB rejection over 48Hz to
62.4Hz, which covers both 50Hz ±2% and 60Hz ±2%. With
running average on, the rejection is better than 87dB for
both 50Hz ±2% and 60Hz ±2%.
Complete Thermocouple Measurement System with
Cold Junction Compensation
The LTC2485 is ideal for direct digitization of thermocouples
and other low voltage output sensors. The input has a
typical offset error of 500nV (2.5μV max) offset drift of
10nV/°C and a noise level of 600nVRMS.
Figure 45 (last page of this data sheet) is a complete type
K thermocouple meter. The only signal conditioning is a
simple surge protection network. In any thermocouple
meter, the cold junction temperature sensor must be at
the same temperature as the junction between the ther-
mocouple materials and the copper printed circuit board
traces. The tiny LTC2485 can be tucked neatly underneath
an Omega MPJ-K-F thermocouple socket ensuring close
thermal coupling.
The LTC2485’s 1.4mV/°C PTAT circuit measures the
cold junction temperature. Once the thermocouple volt-
age and cold junction temperature are known, there are
many ways of calculating the thermocouple temperature
including a straight-line approximation, lookup tables or
a polynomial curve t. Calibration is performed by apply-
ing an accurate 500mV to the ADC input derived from an
LT1236 reference and measuring the local temperature
with an accurate thermometer as shown in Figure 44. In
calibration mode, the up and down buttons are used to
adjust the local temperature reading until it matches an
accurate thermometer. Both the voltage and temperature
calibration are easily automated.
The complete microcontroller code for this application is
available on the LTC2485 product webpage at:
http://www.linear.com
It can be used as a template for may different instruments
and it illustrates how to generate calibration coefcients
for the onboard temperature sensor. Extensive comments
detail the operation of the program. The read_LTC2485()
function controls the operation of the LTC2485 and is
listed below for reference.
相關(guān)PDF資料
PDF描述
VE-B21-EY CONVERTER MOD DC/DC 12V 50W
DC571A BOARD DELTA SIGMA ADC LTC2418
MIC2015-1.2YM6 TR IC DISTRIBUTION SW 1.2A SOT23-6
DC570A BOARD DELTA SIGMA ADC LTC2440
DC1012A-A BOARD DELTA SIGMA ADC LTC2499
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DC959A 制造商:Linear Technology 功能描述:BOARD DEMO LTC4257-1 制造商:Linear Technology 功能描述:EVAL BOARD, LTC4257CDD-1 POE
DC95F103V 功能描述:熱敏電阻 - NTC 10KOhms +-.1C Epoxy Coated RoHS:否 制造商:EPCOS 電阻:10 kOhms 功率額定值:150 mW 容差:2 % 端接類型:Radial 系列:B57703M 工作溫度范圍:- 55 C to + 125 C
DC95F103VN 制造商:GE Sensing & Inspection Technologies 功能描述:Thermistor;10;PCB Mount Mtg. Type;1.5In Lead;Bare Tinned Copper 制造商:GE Measurement & Control 功能描述:+/-.1oC (0oC - 70oC) Interchangeable Chip
DC95F103W 功能描述:熱敏電阻 - NTC 10KOhms +-.2C Epoxy Coated RoHS:否 制造商:EPCOS 電阻:10 kOhms 功率額定值:150 mW 容差:2 % 端接類型:Radial 系列:B57703M 工作溫度范圍:- 55 C to + 125 C
DC95F103WN 制造商:GE Sensing & Inspection Technologies 功能描述:Thermistor 10 PCB Mount Mtg Type 1.5Lead Bare Tinned Copper 0 +70 制造商:GE Sensing & Inspection Technologies / Thermometrics 功能描述:THERMISTOR NTC +60 10KOHM 制造商:GE Measurement & Control 功能描述:+/-.2oC (0oC - 70oC) Interchangeable Chip 制造商:GE MEASUREMENT & CONTROL/GE SENSING 功能描述:THERMISTOR, NTC, +60C, 10KOHM; Thermistor Type:NTC; Resistance:10kohm; Thermistor Case Style:Radial Leaded; No. of Pins:2; Operating Temperature Min:-40C; Operating Temperature Max:60C; Operating Temperature Range:-40C to +60C ;RoHS Compliant: Yes