Datenblatt-Suchmaschine für elektronische Bauteile |
|
MC13142 Datenblatt(PDF) 10 Page - Motorola, Inc |
|
MC13142 Datenblatt(HTML) 10 Page - Motorola, Inc |
10 / 16 page MC13142 10 MOTOROLA RF/IF DEVICE DATA Figure 5. Ground Side View Mix Lin Cont Mix In VCC LO Buf Out MC13142D Rev A IF Out NOTES: FR4 PCB, 1/32 inch. LNA Output LNA Input V–Cont 1.9 GHz FRONT–END FOR WIRELESS SYSTEMS This application is applicable to both Analog and Digital systems. With the correct VCO tuning and the appropriate filter, it will do the front–end for DECT, PHS or PCS. The MC13142D is available in a SOIC 16 pin package. The part requires minimal external components, leading to a low cost system. A circuit board layout with a circuit diagram to evaluate the IC is shown. Except for the PLL control, all the wireless systems front–ends will look the same and have the same basic performance characteristic as the test circuit. Circuit Operation: LNA Input/Output An LC filter is incorporated before the LNA to provide some selectivity. In addition to selectivity, its other function is to match the antenna impedance (50 Ω) to the LNA input for best gain and sensitivity (low noise figure). The network reflects about a 200 Ω source impedance to the device. The output circuit is a pie network consisting of; the LNA output capacity, the inductance (the bond wire, package pin and L2), and the input capacity of the dielectric filter, along with some added shunt. A 2.4 pF with Toko 4DFA 2 pole filter. The 2.4 pF is for matching the in–band filter impedance to the LNA output and has little effect on tuning. Both networks are tuned to band center by adjusting L1 and L2. L1 and L2, as well as L3, are short length of wire formed in a half loop. Once the correct length is determined in centering the tuning range, adjustment is accomplished by moving the loop toward or away from some conductive surface such as a ground plane. The dielectric filter is referenced to the dc supply which lessen the parts count and adds distributive capacity for high frequency bypassing. DC feed to the LNA is through a low value resistor (220 to 330 Ω) tapped at the filter input, so as not to load the circuit unnecessarily. There is a small voltage drop across the resistor, as well as some signal loss. The signal loss is about 0.73 dB for a 220 Ω resistor and less for larger values. If one can not afford the voltage drop, an inductor could replace the resistor at a somewhat increased cost. Mixer Looking from the dielectric filter’s output, the Mixer input is 50 Ω in series with an inductor. This inductor consists of the printed circuit run, the package pin and bond wire, all in series. It is modified, to some extent, by the package pin distributive capacity, but overall at the bandpass frequency remains inductive. Matching the filter impedance to the Mixer input only requires a capacitor with a value that, when placed in series, will resonate with this inductor at the filter bandpass frequency. The single–ended input signal is converted internally into balanced current signals. The two signals drive the two low impedance inputs (emitters) of a Gilbert Cell. They appear as |
Ähnliche Teilenummer - MC13142 |
|
Ähnliche Beschreibung - MC13142 |
|
|
Link URL |
Privatsphäre und Datenschutz |
ALLDATASHEETDE.COM |
War ALLDATASHEET hilfreich? [ DONATE ] |
Über Alldatasheet | Werbung | Kontakt | Privatsphäre und Datenschutz | Linktausch | Hersteller 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 |