integrated circuit systems, inc. general description features ics9120-46 modem and audio clock generator ics9120-46revb052497p block diagram the ics9120-46 is a high performance frequency generator designed to support the clock requirements of communication and audio interfaces. it offers the clock frequencies required by 28.8 baud modem plus sound system. these frequencies are synthesized from 14.7456 mhz reference oscillator whose buffered output is available for the reference. high accuracy, low-jitter plls meet the -96db signal-to- noise ratios required by 16-bit audio systems. fast output clock edge rates minimize board induced jitter. the on-chip xtal oscillator accuracy is better than 100ppm for an at cut, 18pf load crystal with initial accuracy of ppm plus tc, aging and load variation of 20ppm each assuming 33pf 5% external load capacitors. ? generates 49.92 mhz, 40.32 mhz and 14.7456 mhz ? single 14.7456 mhz crystal reference ? 49.92 mhz accuracy tracks 40.32 mhz reference ? 80ps one sigma jitter maintains 16-bit performance ? output rise/fall times less than 1.5ns ? on-chip loop filter components ? 3.0-5.5v supply range ? 8-pin, 150-mil soic package applications ? specifically designed to support the high performance requirements of communication and audio interfaces. ics reserves the right to make changes in the device data identified in this publication without further notice. ics advises its customers to obtain the latest version of all device data to verify that any information being relied upon by the customer is current and accurate.
2 ics9120-46 pin configuration pin descriptions for ics9120-46 functionality x1 (mhz) pd# clk1 (mhz) clk2 (mhz) ref (mha) - 0 low low low 14.7456 1 49.92 40.32 14.7456 8-pin soic pin num ber pin name type description 1 x1 input crystal or external clock source. has feedback bias for crystal. nominally 14.7456mhz input applied. (no internal load cap; must connect external load cap to ground for crystal oscillator.) 2 vdd power +power supply input. 3 gnd power ground return for pin 2. 4 clk1 output 49.92 mhz target output clock (with nominal 14.7456 mhz input). 5 pd# output power-down input. all outputs shut off and driven to low output state when this pin is at logic low level. has pull-up. 6 clk2 output 40.32 mhz target output clock. 7 ref output 14.7456 mhz reference clock buffered output (with nominal 14.7456 mhz input). 8 x2 output crystal output drive (leave this pin unconnected when using an external clock). (no internal load cap; must connect external load cap to ground for crystal oscillator). functionality the ics9120-46 incorporates a crystal oscillator circuit designed to provide 50% duty cycle over a range of operating conditions, including the addition of external crystal load capacitors to pins x1 and x2. for the crystal oscillator, the crystal load capacitance must be connected externally by adding a capacitor from each of the x1 and x2 pins to ground. a parallel resonant 14.7456 mhz crystal is recommended. duty cycle is also maintained when using an external clock source (connected to x1, x2 left unconnected) as long as the external clock has good duty cycle.
3 ics9120-46 absolute maximum ratings electrical characteristics at 5 v v dd = +4.5 to +5.5 v, t a = 0 to 70 o c unless otherwise stated * parameter is guaranteed by design and characterization. not 100% tested in production. avdd, vdd referenced to gnd .......................................................................... 7v operating temperature under bias .................................................... 0 o c to +70 o c storage temperature ..................................................................... -65 o c to +150 o c voltage on i/o pins referenced to gnd ...................... gnd -0.5v to vdd +0.5v power dissipation ...................................................................................... 0.5 watts stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect product reliability. dc characteristics parameter symbol test conditions min typ max units input low voltage v il - - 0.8v input high voltage v ih 2.0 - - v input low current i il v in =0v -18.0 -8.3 - a input high current i ih v in =v dd - - 5.0 a output low voltage v ol iol=+10ma - 0.15 0.4 v output high voltage v oh ioh=-30ma 2.4 3.7 - v output low current i ol v ol =0.8v 25.0 45.0 - ma output high current i oh v oh =2.4v - -53.0 -35.0 ma supply current i dd unloaded - 27.0 50.0 ma supply current power-down i ddpd unloaded; pin 5=0v - 500.0 800.0 a pull-up resistor value rpu - 400.0 800.0 k ohm ac characteristics rise time t r 15pf load 0.8 to 2.0v - 0.8 2.0 ns fall time t f * 15pf load 2.0 to 0.8v - 0.6 1.5 ns rise time t r 15pf load 20% to 80% - 1.7 3.0 ns fall time t f 15pf load 80% to 20% - 1.1 2.5 ns duty cycle d t 15pf load @ 50% of vdd; except refclk 45.0 50.0 55.0 % duty cycle d t 15pf load @ 50% of vdd; refclk only 40.0 45.0 60.0 % jitter, one sigma t jis for all frequencies except refclk - 70.0 90.0 ps jitter, absolute t jab for all frequencies except refclk 300.0 270 300.0 ps jitter, one sigma t jis refclk only - 350.0 500.0 ps jitter absolute t jab refclk only -1.0 0.8 1.0 ns input frequency range f i 11.0 14.0 17.0 mhz output frequency range f o 11.0 - 58.0 mhz power-up time t pu 0 to 40.3 mhz - 5.5 12.0 ms crystal input capacitance c inx x1 (pin 1),x2 (pin 8) - 5 - pf
4 ics9120-46 electrical characteristics at 3.3 v v dd = +3.0 to +3.7 v, t a = 0 o c-70 o c unless otherwise stated * parameter is guaranteed by design and characterization. not 100% tested in production. dc characteristics parameter symbol test conditions min typ max units input low voltage v il - - 0.2v dd v input high voltage v ih 0.7v dd - - v input low current i il v in =0v -8.0 -3.6 - a input high current i ih v in =vdd - - 5.0 a output low voltage v ol i ol =6.0ma - 0.05v dd 1.1 v output high voltage v oh i oh =4.0ma 0.85v dd 0.94v dd -v output low current i ol v o l=0.2v dd 15.0 24.0 - ma output high current i oh v oh =0.7v dd - -13.0 -8.0 ma supply current i dd unloaded - 20.0 40.0 ma supply current power- down i ddpd unloaded; pin 5=0v - 200.0 400.0 a pull-up resistor value rpu - 620.0 900.0 k ohm ac characteristics rise time t r 15pf load 0.8 to 2.0v - 2.2 3.5 ns fall time t f * 15pf load 2.0 to 0.8v - 1.2 2.5 ns rise time t r 15pf load 20% to 80% - 2.3 4.0 ns fall time t f 15pf load 80% to 20% - 1.2 3.0 ns duty cycle d t 15pf load @ 50% of vdd; except refclk 45.0 50.0 55.0 % duty cycle d t 15pf load @ 50% of vdd; refclk only 40.0 45.0 60.0 % jitter, one sigma t j1s for all frequencies except refclk - 80.0 100.0 ps jitter absolute t jab for all frequencies except refclk -350.0 300.0 350.0 ps jitter, one sigma t j1s refclk only - 380.0 500.0 ps jitter, absolute t jab refclk only -1.0 0.8 1.0 ns input frequency range f i 11.0 14.745 15.0 mhz output frequency range f o 14.0 - 51.0 mhz power-up time t pu 0 to 40.3 mhz - 5.5 12.0 ms crystal input capacitance c inx x1 (pin 1), x2 (pin 8) - 5 - pf
5 ics9120-46 ordering information ics9120m-46 ics reserves the right to make changes in the device data identified in this publication without further notice. ics advises its customers to obtain the latest version of all device data to verify that any information being relied upon by the customer is current and accurate. 8 pin soic package ics xxxx m-ppp example: package type m=soic device t ype (consists of 3 or 4 digit numbers) ics=standard device prefix pattern number(2 or 3 digit number for parts with rom code patterns)
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