Os motores de busca de Datasheet de Componentes eletrônicos |
|
OP270GP Folha de dados(PDF) 8 Page - Analog Devices |
|
OP270GP Folha de dados(HTML) 8 Page - Analog Devices |
8 / 16 page REV. C OP270 –8– 1/2 OP270 V1 20Vp-p 5k 500 5k 50 V2 1/2 OP270 CHANNEL SEPARATION = 20 log V 1 V 2 /1000 Figure 1. Channel Separation Test Circuit 1/2 OP270 1/2 OP270 7 1 8 5 6 3 2 100k 100k 200k 4 +18V –18V Figure 2. Burn-In Circuit APPLICATIONS INFORMATION VOLTAGE AND CURRENT NOISE The OP270 is a very low noise dual op amp, exhibiting atypical voltage noise of only 3.2 nV/ ÷÷÷÷÷Hz @ 1 kHz. The exceptionally low noise characteristic of the OP270 is achieved in part by operating the input transistors at high collector currents since the voltage noise is inversely proportional to the square root of the collector current. Current noise, however, is directly propor- tional to the square root of the collector current. As a result, the outstanding voltage noise performance of the OP270 is gained at the expense of current noise performance, which is normal for low noise amplifiers. To obtain the best noise performance in a circuit, it is vital to understand the relationship between voltage noise (en), current noise (in), and resistor noise (et). TOTAL NOISE AND SOURCE RESISTANCE The total noise of an op amp can be calculated by: Ee i R e nn n S t = () + () + () 22 2 where: En = total input referred noise en = op amp voltage noise in = op amp current noise et = source resistance thermal noise RS = source resistance The total noise is referred to the input and at the output would be amplified by the circuit gain. Figure 3 shows the relationship between total noise at 1 kHz and source resistance. For RS < 1 k W the total noise is dominated by the voltage noise of the OP270. As RS rises above 1 k W, total noise increases and is dominated by resistor noise rather than by the voltage or current noise of the OP270. When RS exceeds 20 k W, current noise of the OP270 becomes the major contributor to total noise. RS – SOURCE RESISTANCE ( ) 100 100 1k 10k 100k 1 10 OP270 RESISTOR NOISE ONLY OP200 Figure 3. Total Noise vs. Source Resistance (Including Resistor Noise) at 1 kHz Figure 4 also shows the relationship between total noise and source resistance, but at 10 Hz. Total noise increases more quickly than shown in Figure 3 because current noise is inversely proportional to the square root of frequency. In Figure 4, current noise of the OP270 dominates the total noise when RS > 5 k W. Figures 3 and 4 show that to reduce total noise, source resistance must be kept to a minimum. In applications with a high source resistance, the OP200, with lower current noise than the OP270, will provide lower total noise. |
Nº de peça semelhante - OP270GP |
|
Descrição semelhante - OP270GP |
|
|
Ligação URL |
Privacy Policy |
ALLDATASHEETPT.COM |
ALLDATASHEET é útil para você? [ DONATE ] |
Sobre Alldatasheet | Publicidade | Contato conosco | Privacy Policy | roca de Link | Lista de Fabricantes 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 |