| Part | ALC100 |
| Description | Crystal Requirement |
Feature |
www.DataSheet4U.com Avance Logic, Inc. ALC100 Quartz Crystal Requirement for ALC100/ALC100P This document describes the quartz crystal requirements for cl ocking ALC100/P. 1. Frequency and Oscil lation Circuits ALC100/P are designed t o work from a crystal with 24.576MHz. F ig-1 shows the equivalent circuits of c rystal and oscillation circuits within ALC100/P. ALC100/P. |
| Manufacture | Avance Logic |
| Datasheet |
 ALC100; C1 22pF 2. Crystal Requirements Genera l Specifications Holder Type Crystal Fr eq. Oscillation Mode Load Cap. (CL) Fre q. Tolerance(25oC) Effective Series Res istance (Rs) Effective Shunt Capacitanc e (Co) Drive Level Insulation Resistanc e Requirements HC-49 U/S 24.576 MHz Fun damental 16 ~20 pF +/- 50 ppm 40 ohm ma x 7 pF CRYSTAL XTALI Cs Rs Co XTALO 24 .576MHz 10pF 10pF . |
 22pF C2 Ls < 0.1 mW 500 Mohm min. at DC 100V Table-1 Crystal General Specifi cation 3. Load Capacitance (CL) To oper ate between Fs and Fp requires external load capacitance. Although ALC100/P ha s embed internal 10pF capacitors at XTA LI and XTALO, the oscillated frequency may be a little higher than 24.576MHz i f no C1 and C2 placed. To reduce the bi t clock jitter and. |
 get more accurate frequency, the extern al capacitor C1 and C2 most be used. AL C100/P C1 22pF 24.576MHz Y1 XTALI 10pF Fig-1 oscillation circuits The series resonant frequency 1 Fs ≅ 2π Ls * Cs , and parallel resonant frequency Ls * Cs * Co Cs + Co The oscillated frequen cy between Fs and Fp 2π Cs Fo = Fs * 1 + Co + CL where CL=(C1+10pF)//(C2+10pF ) Fp ≅ 1 Clitter XTAL. |