Electronic Components Datasheet Search |
|
ADA4302-4ACPZ-EBSE Datasheet(PDF) 8 Page - Analog Devices |
|
ADA4302-4ACPZ-EBSE Datasheet(HTML) 8 Page - Analog Devices |
8 / 12 page ADA4302-4 Rev. B | Page 8 of 12 APPLICATIONS The ADA4302-4 active splitter is primarily intended for use in the downstream path of television set-top boxes (STBs) that contain multiple tuners. It is located directly after the diplexer in a CATV customer premise unit. The ADA4302-4 provides a differential input and four differential outputs that allow the delivery of the RF signal to up to four different signal paths. These paths can include, but are not limited to, a main picture tuner, the picture-in-picture (PIP) tuner, a digital video recorder (DVR), and a cable modem (CM). The differential nature of the ADA4302-4 allows it to provide composite second-order (CSO) and composite triple beat (CTB) products that are −73 dBc and −66 dBc, respectively. The use of the SiGe process also allows the ADA4302-4 to achieve a noise figure (NF) that is less than 5 dB. CIRCUIT DESCRIPTION The ADA4302-4 has a low noise buffer amplifier that is followed by four parallel amplifiers. This arrangement provides 4.6 dB of gain relative to the RF signal present at the differential inputs of the active splitter. The input and each output must be properly matched to a differential 75 Ω environment in order for distortion and noise performance to match the data sheet specifications. If needed, baluns to convert to single-ended operation can be used. The M/A-COM MABAES0029 is recommended for the input balun and the Mini-Circuit® TC1-1-13M-2 is recommended for the output balun. AC coupling capacitors of 0.01 μF are recommended for all inputs and outputs. Two 1 μH RF chokes, L1 and L2 (Coilcraft chip inductor 0805LS-102X), are used to correctly bias internal nodes of the ADA4302-4 by connecting them between the 5 V supply and ILN and ILP, respectively. EVALUATION BOARDS There are two evaluation boards for the ADA4302-4, a single- ended output board (ADA4302-4 EBSE) and a differential output board (ADA4302-4 EBDI). The single-ended output board has an input balun that converts a signal from a single- ended source to a differential signal. The differential output board uses the same input balun and allows the output signals to run directly to the board connectors. This allows the differential signals at the ADA4302-4’s outputs to be applied directly to a tuner with differential inputs. The schematics for these evaluation boards can be seen in Figure 16 and Figure 17, respectively. Each board has place holders to properly terminate the unused outputs, if needed. On the single-ended output board, they are designated R15 through R18, and 75 Ω resistors should be used here (see Figure 16). On the differential output board, 37.5 Ω resistors should be used for R1, R2, and R4 through R9 when their respective outputs are not in use (see Figure 17). RF LAYOUT CONSIDERATIONS Appropriate impedance matching techniques are mandatory when designing a circuit board for the ADA4302-4. Improper characteristic impedances on traces can cause reflections that can lead to poor linearity. If the stage following the ADA4302-4 is a single-ended load with a 75 Ω impedance, then a balun should be used. The characteristic impedance of the signal trace from each output of a differential pair to the output balun should be 37.5 Ω. In the case of the differential output evaluation board, the output traces should also have a characteristic impedance of 37.5 Ω. POWER SUPPLY The 5 V supply should be applied to each of the VCC pins and RF chokes via a low impedance power bus. The power bus should be decoupled to ground using a 10 μF tantalum capacitor and a 0.01 μF ceramic chip capacitor located close to the ADA4302-4. In addition, the VCC pins should be decoupled to ground with a 0.01 μF ceramic chip capacitor located as close to each of the pins as possible. Pin 3 and Pin 4 can share one capacitor, and Pin 12 and Pin 13 can share one capacitor. |
Similar Part No. - ADA4302-4ACPZ-EBSE |
|
Similar Description - ADA4302-4ACPZ-EBSE |
|
|
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 |