1 multimedia ics clock generator for video cd systems BU2173F the BU2173F is an ic that generates the cpu clock signal, system clock signal and video clock signal used in video cd systems. a single crystal resonator can generate three different oscillation frequencies. applications video cd systems features 1) three frequency clock signals can be generated with a single attached crystal resonator. 2) two internal pll channels. 3) internal loop filter, eliminating the need to attach a loop. 4) single 5.0v power supply. 5) sop 18-pin package. block diagram xtali f out 4 3.375mhz f out 1 40.5mhz f out 2 27.0mhz or 28.6363mhz or 28.375mhz xtalo 13.5mhz ctrlc ctrlb ctrla xtal osc. pll1 a vdd pll2 data1a 1 / 4 1 / 2 1 / 2 data1b data2a data2b data2c data2d m u x m u x m u x vref 1 / 3 a vss v dd v ss v ddio v ssio test tsti tsto f out 3
2 multimedia ics BU2173F pin description pin no. pin name function type 1 v dd digital v dd tsto open in the normal mode (used for testing) 2 xtali reference oscillation input 3 xtalo reference oscillation output 4 ctrla gd-g / vcd clock switching 5 ctrlb stays at the high level when the ic is in the normal mode 6 ctrlc cd-g pal / ntsc clock switching 7 tsti connect to vss when the ic is in the normal mode (used for testing) 8 v ss digital ground 9 a vss analog ground 10 f out 3 not used (open when the ic is in the normal mode) 11 v ssio i / o ground 12 f out 2 clock output 2 13 test setting the test mode (connect to vss when the ic is in the normal mode) 14 v ddio i / o v dd 16 f out 1 clock output 1 15 f out 4 clock output 4 17 a vdd analog v dd 18 b c c a a a a b b a b b absolute maximum ratings (ta = 25?) parameter power supply voltage power dissipation operating temperature storage temperature v dd pd topr tstg 0.3 ~ + 7.0 450 5 ~ + 70 25 ~ + 125 v symbol limits unit mw c c * reduced by 4.5 mw for each increase in ta of 1 c over 25 c. recommended operating conditions (ta = 25?) parameter power supply voltage input high level voltage input low level voltage operating temperature v dd , a vdd , v ddio v ih v il topr 4.75 ~ 5.25 0.8v dd ~ v dd 0.0 ~ 0.2v dd 5 ~ + 70 v symbol limits unit v v c
3 multimedia ics BU2173F input / output circuits pin to inside type a pin pin to inside type c pin from inside type b electrical characteristics (unless otherwise noted, ta = 25?, v dd = 5.0v, a vdd = 5.0v, io vdd = 5.0v) parameter input current, low level input current, high level input voltage, low level input voltage, high level output voltage, low level output voltage, high level operating supply current i il i ih v il v ih v ol v oh i dd m a symbol ?300.0 ?300.0 4.0 2.4 min. 30 0.0 0.0 typ. 50 300.0 300.0 1.0 0.5 ma v v max. unit conditions m a v v f xtal = 13.5 mhz, no load reference frequency f ref 13.5 mhz use with ctrlb at the high level output frequency f 4 3.375 mhz f 4 = f ref 1 / 4 jitter 1.0 ns measure at f 2a , f 2b , f 2c (reference) reference frequency f ref2 14.318 mhz use with ctrlb at the low level output frequency f 1b 40.5 mhz f 1b = f ref2 98 / 35 / 2 output frequency f 4b 3.579 mhz f 4b = f ref2 1 / 4 output frequency f 1 40.5 mhz f 1 = f ref 96 / 16 / 2 output frequency ctrla = h, ctrlb = h, ctrlc = h f 2a 27.000 mhz f 2a = f ref 96 / 16 / 3 output frequency ctrla = h, ctrlb = l, ctrlc = h f 2d 27.000 mhz f 2d = f ref2 98 / 35 / 3 ctrla = l, ctrlb = l, ctrlc = h f 2e 28.636 mhz f 2e = f ref2 80 / 20 / 2 ctrla = l, ctrlb = h, ctrlc = l f 2b 28.375 mhz f 2b = f ref 227 / 54 / 2 ctrla = l, ctrlb = h, ctrlc = h f 2c 28.636 mhz f 2c = f ref 140 / 33 / 2 i ol = 4.0ma i oh = ?4.0ma ( 1 ) ( 2 ) ( 4 ) ( 2 ) ( 1 ) ( 2 ) ( 4 )
4 multimedia ics BU2173F measurement circuit 10pf control a control c c1 x1 f ref = 13.5mhz r2 1m w r1 120 w v dd a vdd tsto f out 4 xtali v ddio xtalo f out 1 ctrla test ctrlb f out 2 ctrlc v ssio tsti f out 3 v ss a vss 10pf c2 clock output (4) clock output (1) clock output (2) 18 17 16 15 14 13 12 11 10 1 2 3 4 5 6 7 8 9 application example 10pf control a control c c1 x1 f ref = 13.5mhz r2 1m w r1 120 w v dd a vdd tsto f out 4 xtali v ddio xtalo f out 1 ctrla test ctrlb f out 2 ctrlc v ssio tsti f out 3 v ss a vss 10pf c2 clock output (4) clock output (1) clock output (2) 18 17 16 15 14 13 12 11 10 1 2 3 4 5 6 7 8 9 * this ic should be used mounted on a pc board. if mounted in a socket, characteristics of the ic may be adversely affected. note: certain crystal resonators may require setting xtali and xtalo to the optimum allowable values. note: certain crystal resonators may require setting xtali and xtalo to the optimum allowable values.
5 multimedia ics BU2173F sop18 0.4 0.1 1.27 0.3min. 0.11 1.8 0.1 5.4 0.2 7.8 0.3 0.15 0.1 18 1 11.2 0.2 10 9 0.15 attached components r1: to keep the voltage of a vdd effectively low, and to enhance signal stability by separating a vdd and d vdd with an impedance. be sure to attach. r2: needed to provide a feedback resistance for the crystal resonator c1 / c2: when f 0 must be adjusted according to the crystal resonator used, or when the crystal resonator results in unnecessary oscillation points, attach a pf and adjust according to the value for this capacitor. x1: use a crystal resonator with an oscillation fre- quency of 13.5 mhz or 14.318 mhz. external dimensions (units: mm)
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