Electronic Components Datasheet Search |
|
LTC1419AISW Datasheet(PDF) 11 Page - Linear Technology |
|
LTC1419AISW Datasheet(HTML) 11 Page - Linear Technology |
11 / 20 page 11 LTC1419 many applications. For example, Figure 7 shows a 1000pF capacitor from + AIN to ground and a 100Ω source resistor to limit the input bandwidth to 1.6MHz. The 1000pF capacitor also acts as a charge reservoir for the input sample-and-hold and isolates the ADC input from sam- pling glitch sensitive circuitry. High quality capacitors and resistors should be used since these components can add distortion. NPO and silver mica type dielectric capacitors have excellent linearity. Carbon surface mount resistors can also generate distortion from self heating and from damage that may occur during soldering. Metal film surface mount resistors are much less susceptible to both problems. Input Range The ±2.5V input range of the LTC1419 is optimized for low noise and low distortion. Most op amps also perform well over this same range, allowing direct coupling to the analog inputs and eliminating the need for special transla- tion circuitry. Some applications may require other input ranges. The LTC1419 differential inputs and reference circuitry can accommodate other input ranges often with little or no additional circuitry. The following sections describe the reference and input circuitry and how they affect the input range. Internal Reference The LTC1419 has an on-chip, temperature compensated, curvature corrected, bandgap reference that is factory trimmed to 2.500V. It is connected internally to a reference amplifier and is available at VREF (Pin 3) see Figure 8a. A APPLICATIONS INFORMATION 1 2 3 0.1 µF 10 µF ANALOG INPUT 1419 F08b LT1019A-2.5 VOUT VIN 5V +AIN –AIN VREF LTC1419 AGND REFCOMP 5 4 + Figure 8b. Using the LT1019-2.5 as an External Reference 2k resistor is in series with the output so that it can be easily overdriven by an external reference or other circuitry, see Figure 8b. The reference amplifier gains the voltage at the VREF pin by 1.625 to create the required internal reference voltage. This provides buffering be- tween the VREF pin and the high speed capacitive DAC. The reference amplifier compensation pin (REFCOMP, Pin 4) must be bypassed with a capacitor to ground. The refer- ence amplifier is stable with capacitors of 1 µF or greater. For the best noise performance a 10 µF ceramic or 10µF tantalum in parallel with a 0.1 µF ceramic is recommended. The VREF pin can be driven with a DAC or other means shown in Figure 9. This is useful in applications where the peak input signal amplitude may vary. The input span of the ADC can then be adjusted to match the peak input signal, maximizing the signal-to-noise ratio. The filtering of the internal LTC1419 reference amplifier will limit the bandwidth and settling time of this circuit. A settling time of 5ms should be allowed for after a reference adjustment. Figure 8a. LTC1419 Reference Circuit Figure 9. Driving VREF with a DAC LTC1419 +AIN ANALOG INPUT 1.25V TO 3V DIFFERENTIAL –AIN VREF REFCOMP AGND 1419 F09 1 2 3 4 5 10 µF LTC1450 1.25V TO 3V R2 40k R3 64k REFERENCE AMP 10 µF REFCOMP AGND VREF R1 2k BANDGAP REFERENCE 3 4 5 2.500V 4.0625V LTC1419 1419 F08a |
Similar Part No. - LTC1419AISW |
|
Similar Description - LTC1419AISW |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | 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 |