 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SH3000IMLTR Datasheet(PDF) 9 Page - Semtech Corporation |
|
||||||||||||||||||||||||||||||
SH3000IMLTR Datasheet(HTML) 9 Page - Semtech Corporation |
|
|
9 / 24 page  SH3000 MicroBuddy™ SYSTEM MANAGEMENT Copyright ©2003-2005 Semtech Corporation 9 V1.15 www.semtech.com Programmable Spectrum Spreading Most commercial electronic systems must pass regulatory tests in order to determine the degree of their Electromagnetic Interference (EMI) affecting other electronic devices. In some cases compliance with the EMI standards is costly and complicated. The SH3000 offers a technique for reducing the EMI. It can be a part of the initial design strategy, or it can be applied in the prototype stage to fix problems identified during compliance testing. This feature of the SH3000 may greatly reduce the requirements for radiofrequency shielding, and permits the use of simple plastic casings in place of expensive RFI-coated or metal casings. The SH3000 employs Programmable Spectrum Spreading in order to reduce the RF emissions from the processor’s clock. There are five (5) possible settings; please see Table 3 for operating and performance figures in the 8-16 MHz range. Spectrum Spreading is created by varying the frequency of the HF oscillator with a pseudo-random sequence (with a zero-average DC component). The Maximum-Length Sequence (MLS) 8-bit random number generator, clocked by 32 kHz, is used. Only 4, 5, 6, or 7 bits of the generated 8-bit random number are used, according to the configuration setting. Maximum fluctuations of the frequency depend on the selected frequency range and the position within the range. Selecting the HF oscillator frequency to be near the high end of the range limits the peak variations to ±0.1%, ±0.2%, ±0.4%, or ±0.8% (corresponding to the configuration setting). Special Operating Modes The SH3000 can operate stand-alone, without connections to the In and Out terminals of the host’s oscillator. For example, a bank of SH3000 chips can generate several different frequencies for simultaneous use in the system, all controlled by a single micro (and possibly sharing one 32.768 kHz crystal by chaining the CLK32 pin to XIN pin on the next device). In this case the CLKIN pin should be connected to VSS. The clock output on the CLKOUT pin is continuous; the correct operating mode is automatically recognized by the SH3000. Likewise, a microcontroller may not have a STOP command at all. Still, with the help of the SH3000 this controller can do a “simulated” STOP by issuing an instruction to the SH3000 to stop the clock. This command is accepted only if the Periodic Interrupt / Wakeup Timer has started (otherwise, once the system is put to sleep, it would never wake up again). This mode of operations is only possible if the host processor is capable of correct operations with clock frequency down to zero, and keeps all of the internal RAM alive while the clock is stopped. Table 3. EMI reduction with Spectrum Spreading Setting En CFG1 CFG0 Spreading Bandwidth kHz Peak EMI Reduction (guaranteed) db Peak EMI Reduction (measured) db 0 X X Off 0 0 1 0 0 32 -3 -3 1 0 1 64 -6 -7 1 1 0 128 -9 -10 1 1 1 256 -12 -15 |
Similar Part No. - SH3000IMLTR |
|
Similar Description - SH3000IMLTR |
|
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
