Motore di ricerca datesheet componenti elettronici |
|
AD8350ARMZ15 Scheda tecnica(PDF) 8 Page - Analog Devices |
|
AD8350ARMZ15 Scheda tecnica(HTML) 8 Page - Analog Devices |
8 / 14 page REV. AD8350 –8– APPLICATIONS Using the AD8350 Figure 1 shows the basic connections for operating the AD8350. A single supply in the range 5 V to 10 V is required. The power supply pin should be decoupled using a 0.1 µF capacitor. The ENBL pin is tied to the positive supply or to 5 V (when VCC = 10 V) for normal operation and should be pulled to ground to put the device in sleep mode. Both the inputs and the outputs have dc bias levels at midsupply and should be ac-coupled. Also shown in Figure 1 are the impedance balancing requirements, either resistive or reactive, of the input and output. With an input and output impedance of 200 Ω, the AD8350 should be driven by a 200 Ω source and loaded by a 200 Ω impedance. A reactive match can also be implemented. 8 7 6 5 1 2 3 4 AD8350 – ENBL (5V) +VS (5V TO 10V) C5 0.1 F C4 0.001 F C3 0.001 F LOAD Z = 200 C2 0.001 F C1 0.001 F SOURCE Z = 100 Z = 100 Figure 1. Basic Connections for Differential Drive Figure 2 shows how the AD8350 can be driven by a single- ended source. The unused input should be ac-coupled to ground. When driven single-endedly, there will be a slight imbalance in the differential output voltages. This will cause an increase in the second order harmonic distortion (at 50 MHz, with VCC = 10 V and VOUT = 1 V p-p, –59 dBc was measured for the second harmonic on AD8350-15). 8 7 6 5 1 2 3 4 AD8350 – ENBL (5V) +VS (5V TO 10V) C5 0.1 F C4 0.001 F C3 0.001 F LOAD Z = 200 C2 0.001 F SOURCE Z = 200 C1 0.001 F Figure 2. Basic Connections for Single-Ended Drive Reactive Matching In practical applications, the AD8350 will most likely be matched using reactive matching components as shown in Figure 3. Matching components can be calculated using a Smith Chart or by using a resonant approach to determine the matching network that results in a complex conjugate match. In either situation, the circuit can be analyzed as a single-ended equivalent circuit to ease calculations as shown in Figure 4. VS 87 6 5 12 34 AD8350 – ENBL (5V) +VS (5V TO 10V) 0.1 F RLOAD CAC CAC CP LS/2 LS/2 RS/2 RS/2 CAC CAC CP LS/2 LS/2 Figure 3. Reactively Matching the Input and Output VS 87 6 5 12 34 AD8350 – ENBL (5V) +VS (5V TO 10V) 0.1 F RLOAD CAC CP LS RS CAC CP LS CAC CAC Figure 4. Single-Ended Equivalent Circuit When the source impedance is smaller than the load impedance, a step-up matching network is required. A typical step-up network is shown on the input of the AD8350 in Figure 3. For purely resistive source and load impedances the resonant approach may be used. The input and output impedance of the AD8350 can be modeled as a real 200 Ω resistance for operating frequencies less than 100 MHz. For signal frequencies exceeding 100 MHz, classi- cal Smith Chart matching techniques should be invoked in order to deal with the complex impedance relationships. Detailed S parameter data measured differentially in a 200 Ω system can be found in Tables II and III. For the input matching network the source resistance is less than the input resistance of the AD8350. The AD8350 has a nominal 200 Ω input resistance from Pins 1 to 8. The reactance of the ac-coupling capacitors, CAC, should be negligible if 100 nF capacitors are used and the lowest signal frequency is greater than 1 MHz. If the series reactance of the matching network inductor is defined to be XS = 2 π f LS, and the shunt reactance of the matching capacitor to be XP = (2 π f CP)–1, then: X RR X XR R RR S S LOAD P PLOAD S LOAD S = × =× where – (1) For a 70 MHz application with a 50 Ω source resistance, and assuming the input impedance is 200 Ω, or RLOAD = RIN = 200 Ω, then XP = 115.5 Ω and X S = 86.6 Ω, which results in the follow- ing component values: CP = (2 π × 70 × 106 × 115.5)–1 = 19.7 pF and LS = 86.6 × (2 π × 70 × 106)–1 = 197 nH B |
Codice articolo simile - AD8350ARMZ15 |
|
Descrizione simile - AD8350ARMZ15 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEETIT.COM |
Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | scambio Link | Ricerca produttore 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 |