STIWI* A IMISC405 SYSTEM CLOCK CHIP May 1993 PRODUCT FEATURES m@ Generates All Essential Clock Signals for the Motherboards. m@ 4V to 7V Operating Supply Range. m Supports 80286, 80386 and 80486 Based Designs. w Integrates Keyboard Clock, CPU Clocks and Buffered 14.318 MHz Output. m@ Wide Range of Selectable Output Frequencies Including 88, 80, 66.6, 50, 40, 32, 24, 16 and 8 MHz. m@ 1 NS Maximum Skew Between MCLK1 and MCLK2 CPU Clock Outputs. @ Single, Low Cost Crystal (14.318 MHz) Used as Reference Frequency. @ Two Independent Clock Generators. w Glitch-Free Switching tor Both Clock Generators. m@ 50% Duty Cycle. m Power Down Mode for Low Power Consumption. m@ Two Turbo Modes with Turbo Output. m@ TTL or CMOS Compatible Outputs with 12 mA Drive Capability. g On-Chip Buffers Can Be Used to Replace External FCT244 Devices. @ Low, Short and Long Term Jitter. B 28 PDIP and 28 Pin SSOP (209 Mil Body) Package Options. CLOCK GEN CLOCK GEN IMISC405 BLOCK DIAGRAM INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571 CMOS LSI PLL FREQUENCY SYNTHESIZER PRODUCT DESCRIPTION The IMISC405 is a clock chip for Motherboards. The IMISC405 includes two independent VCOs and uses a single 14.318 MHz external crystal to generate all essential clock signals. The IMISC405 is designed to generate CPU clock options of 88 MHz, 80 MHz, 66.6 MHz, 50 MHz, 40 MHz, 32 MHz, 24 MHz, 16 MHz and 8 MHz as well as the resultant frequencies from dividing these frequencies by 2, giving flexibility to the user. The frequency selection on the CPU clock outputs is determined by the SO-S3 and Turbo pins. The user can use the 32 MHz and 16 MHz as fixed frequencies and select the variable frequencies using SO-S3 pins for the CPU clock. S3 pin selects single or double frequency on the MCLK2 output determined by S0-S2. Turbo pins allow the user to easily switch CPU clock frequencies. When TURBO1 pin goes low, the MCLK2 output goes to 16 or 8 MHz depending on the status of S3 pin. When TURBO2 pin goes low, the output frequency steps down to the next lower frequency selected by SO-S2. MCLK1 output frequency is half of MCLK2. Both VCOs can be turned off in the standby mode, reducing the current consumption to a few microamperes. In the standby mode, all outputs except 14.318 MHz output are low and both phase detectors are tri-stated. B1 and B2 pins provide additional buffers needed for signal buffering on a typical board design. These buffers can be used to replace FCT244 buffers and reduce component cost and board space. Each output provides 12mA sink and source capability and can be used for TTL or GMOS signal buffering. APPLICATIONS IMISC405 eliminates the need for multiple oscillators and generates ail the essential clock signals for the Personal Computer Motherboards. Supports 8086, 80286, 80386SX, 80386DX and 80486 based designs. IMISC405 can be used with laptop or notebook computers to save power by running the system slower then normal CPU speeds or completely disabling the clocks in standby mode. Page 1IMISC405 SYSTEM CLOCK CHIP PIN DESCRIPTION Xin, Xout - These pins form an on-chip reference oscillator when connected to terminals of an external parallel resonant crystal (nominally 14.31818 MHz). Xin may also serve as input for an externally generated reference signal. SO, $1, S2, and S3 - Frequency select inputs. These inputs control the MCLK2 frequency selection. SO-S2 inputs control the CPU clock frequencies. S3 selects single or double frequency determined by SO-S2. All these inputs have internal pull-ups. Table 1 shows the output frequency selection conditions. MCLK2 FREQUENCY SELECTION MCLK2 INPUTS (MHz) T = = TuRBO1| s21s1| so URBO2=1 TURBO2=0 S3=0 | S$3=1 | S3=0 | S3=1 0 x |X |X 8 16 8 16 1 o;0]0 12 24 8 16 1 QO; 0]; 1 16 32 12 24 1 0 1 0 20 40 16 32 1 0 1 1 25 50 20 40 1 1 0 | 0 | 33.3 | 66.6 25 50 1 1 0 1 40 80 33.3 | 66.6 1 1 4 0 44 88 40 80 Power 1 1 4 1 | TEST Down 44 88 TABLE 1: When Power Down address is selected, all VCOs are turned off and the device goes to standby mode. All outputs except 14.318 MHz output are set to low. Phase detectors are in tri-state mode. TURBO1 and TURBO2 - Turbo function select inputs. These inputs are used to slow down the System Clock. When TURBO1 goes low, MCLK2 output is set to 16 MHz or 8 MHz depending on the state of S3 pin. When TURBO2 goes low, MCLK2 output is stepped down to next lower frequency selected by SO-S2. Both of these inputs have internal pull-ups. Bilin and B2in - Buffer input pins. These are on-chip, two independent buffers that can be used for additional signal buffering. Each input has a pull-up and can be Page 2 used to buffer TTL or CMOS signals. B1 is a single buffer, and its output is B1OUT. B2 is a triple buffer with three parallel outputs. Each output is capable to sink or source 12 mA. TS - Tri-State input pin. When high, all outputs except TURBO output are tri-stated. When low, outputs are enabled. This pin has an internal pull-down. MCLK@2 - Master clock output. Programmable output frequencies can be selected using SO-S3 and TURBO1 and TURBO2 inputs shown on Table 1. MCLK1 - MCLK2 divided by two output. 32 MHz - 32 MHz !SA clock output. 16 MHz - 16 MHz AT Bus Clock output. 14.318 MHz - 14.31818 MHz output. Buffered output of on-chip reference oscillator or externally provided reference. 7.159 MHz - 7.159 MHz output. This output is the divided by 2 result of 14.318 MHz output. It can be used as keyboard clock. TURBO - Turbo output pin. This is an open drain output. If either TURBO1 or TURBO2 is low the output will be in Tri-State. When both TURBO1 and TURBO2 are high, output goes low as shown on Table 2. This pin can be used to drive the TURBO LED. It can sink 12 mA. PD1 and PD2 - These are the phase detector outputs for the clock generators. They are single-ended, tri-state outputs for use as loop error signal. A 0.1uF capacitor to ground should be connected from each pin to form the loop filter. VSS - Circuit ground. VDD - Positive power supply. TURBO INPUT OUTPUT TURBO TURBO2 TURBO 0 0 Hi-Z 0 1 Hi-Z 1 0 Hi-Z 1 1 0 TABLE 2 INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571IMISC405 SYSTEM CLOCK CHIP BLOCK DIAGRAM TURBO 1 TURBO 2 $o $1 $2 Bi IN JN COUNTER 81 OUT B2 IN B2 OUT 1 82 OUT 2 Be OUT3 TS VOD vob VSS vss (19) v& v8 IMI SC405 BLOCK DIAGRAM 1261/81 14.318 MHz 7.159 MHz TURBO PDI MCLK1 MCLK2 Poe 32 MHz 16 MHz INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571 Page 3IMISC405 SYSTEM CLOCK CHIP MAXIMUM RATINGS Voltage Relative to VSS : -0.3V to 7V Voltage Relative to VDD : 0.3V Storage Temperature : Ambient Temperature : -65C to 150C -55C to 125C Recommended Operating Range: 4V - 7V This device contains circuitry to protect the inputs against damage due to high static voltages or electric field; however, precautions should be taken to avoid application of any voltage higher than the maximum rated voltages to this circuit. For proper operation, Vin and Vout should be constrained to the range: Vss < (Vin or Vout) < VDD Unused inputs must always be tied to an appropriate logic voltage level (either Vss or VDD). ELECTRICAL CHARACTERISTICS Characteristic Symbol Min Typ Max Units input Low Voltage VIL - - 0.8 Vdc Input High Voltage VIH 2.0 - - Vdc Input Low Current tL _ ; 5 UA With Pull-up or Pull-down +50 Input High Current tH ; ; 5 UA With Pull-up or Pull-down +50 Output Low Voltage 7 IOL = 12mA VOL - 0.4 Vdc Output High Voltage loH= 12mA VOH 2.4 - - Vdc Tri-State Leakage Current loz - - 10 uA Static Supply Current IDD - - 10 uA Dynamic Supply Current loc - - 0.3 mA/MHz/VCO mA Short Circuit Current Isc 25 - - mA VDD = 5V +10%, TA = 0C to +70C SWITCHING CHARACTERISTICS Characteristic Symbol Min Typ Max Units Output Rise and Fall Time tTLH, tTHL - - 2 ns Output Enable TS to All Outputs tu - - 35 ns Duty Cycle All Outputs - 45/55 50/50 45/55 % Jitter One Sigma - - - 100 ps Input Rise and Fall Times OSCIN tTLH, tTHL - 3 1 us VDD = 5V +10%, TA = 0C ta +70C Page 4 INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571IMISC405 9" + _ 3 _+ SO-S3 OR alt2 |e | TURBO INPUTS XT t F | | MCLK OUTPUTS PLA Changing Outputs t : Current cycle time t1: time to first positive edge after address change t2: Output high time. t3 = 4t t3: Lock time. 7ms max tz af TS a ANY OUTPUT Ai-z TURBO INPUTS OY 2 TURBO OUTPUT Hi-Z INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. Page 5 MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571IMISC405 SYSTEM CLOCK CHIP CONNECTION DIAGRAMS PLASTIC DIP PACKAGE SSOP PACKAGE i Oo xout a 27 ; Prout us Xin d1O ~~ ae b> 14.318 MHe Blin 3 261> VOD Xout q2 27 > Biout vss qj 25> PD2 Brin qs 26 > VOD vss q4 25 > PD2 B2out 3 qs 24D 16 MHz TURBO2 6 23 > 32MHz B2out 3 qs 24 [> 16MHz 7.150MHz 7 22 TURBO! TURBO2 46 29 > 32 MHz so qs 21D Bout 2 7.159MHz 7 22 [> TURBO 1 B2in ado 20 [> B2outt so qs 21D B2out2 PDt <110 19D vss B2in qo 20 [> B2out1 vpp aii 18> MCLK2 PDI 10 19 [> VSS $1 12 7D $2 vDD qu 18 p> MCLK 2 $3 q13 16D TS $1 12 17 $2 MCLK1 14 15> TURBO $3 413 16> TS MCLK 1 14 18 TURBO EXTERNAL CONNECTIONS v ci 4.7 UF C12 . F Ct 033u 10 pf XTALIN 14.318 MHz XTALOUT = Bitout Biin VoD vss PD2 B2out3 16 MHz TURBO2 32 MHz 7 ASQMHz TURBO1 so B2out2 B2in B2out1 PD1 vss VDD MCLK2 $1 $2 $3 TS MCLK1 TURBO 14.318 MHz C2 10 pf C3 0.1 uF 12/31/91 DIP-8 IMISC405 Page 6 INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571IMISC405 SYSTEM CLOCK CHIP PACKAGE DRAWINGS AND DIMENSIONS 28 PIN SKINNY PLASTIC DIP DIMENSIONS INCHES MILLIMETERS SYMBOL MIN | NOM | MAX | MIN | NOM | MAX ren A - ~- | 480] - - | 4.57 w/e a Al 0.020 - - 0.51 - - B 0.015 | 0.018 | 0.020 | 0.38 | 0.46 | 0.51 >. AA AAAAAAAAAAA B1 0.045 | 0.050 | 0.055 | 1.14 | 1.27 | 1.40 8 had B2 0.035 | 0.040 | 0.045 | 0.89 | 1.02 | 1.14 E Pp EI C 0.008 | 0.010 | 0.012 | 0.20 | 0.25 | 0.30 10 14 | D 1.360 | 1.365 | 1.370 | 34.54 | 34.67 | 34.80 a EV VV VV VUE YS D E 0.300 - 0.325 | 7.62 - 8.255 ary Ble! Le 402 + ren E1 0.280 | 0.282 | 0.284] 7.11 | 7.16 | 7.21 eH E2 0.282 | 0.284 | 0.286 | 7.16 | 7.21 | 7.26 _-| dl ! L et 0.100 BSC 2.54 BSC set at 8 L 0.125 | 0.130 | 0.135 | 3.18 | 3.30 | 3.43 26 PLASTIC SKINNY DIP a C 7 15 0 7 15 (300 mil narrow body) Q1 0.055 | 0.060 | 0.065 | 1.40 | 1.52 | 1.65 Q2 - 130 - - 3.30 - s 0.028 | 0.033 | 0.038 | 0.71 | 0.84 | 0.97 28 PIN SSOP OUTLINE DIMENSIONS INCHES MILLIMETERS ot SYMBOL wy MIN | NOM | MAX | MIN | NOM | MAX HAAR AA = Tt | A 0.068 | 0.073 | 0.078 | 1.73 | 1.86 | 1.99 Ll Al 0.002 | 0.005 | 0.008 | 0.05 | 0.13 | 0.21 A2 0.066 | 0.068 | 0.070 | 1.68 | 1.73 | 1.78 a SaEE Too B 0.010 | 0.012 | 0.015 | 0.25 | 0.30 | 0.38 C 0.005 | 0.006 | 0.009 | 0.13 | 0.15 | 0.22 | . D 0.397 | 0.402 | 0.407 | 10.07 | 10.20 | 10.33 Ss Apap 14 VY y 4 E 0.205 | 0.209 | 0.212 | 5.20 | 5.30 | 5.38 A a, be >, be e 0.0256 BSC 0.65 BSC H 0.301 | 0.307 | 0.311 | 7.65 | 7.80 | 7.90 SSOP PACKAGE a 0 4 . 8 0 4 8 L 0.022 | 0.030 | 0.037 | 0.55 | 0.75 | 0.95 INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. Page 7 MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-657 1IMISC405 SYSTEM CLOCK CHIP ORDERING INFORMATION Part Number Package Type Production Flow IMISC405xPB Plastic Dip Commercial, 0C to +70C IMISC405xXB SSOP Commercial, 0C to +70C Note: The "x" following the IMI Device Number denotes the device revision. The ordering part number is formed by a combination of device number, device revision, package style, and screening as shown below. Marking: Example: IMI SC405xPB Date Code, Lot # IMISC405xPB i B = Commercial, 0C to +70C Package P = Plastic Dip X = SSOP Revision IMI Device Number Page 8 INTERNATIONAL MICROCIRCUITS INC. 525 LOS COCHES ST. MILPITAS, CA 95035 TEL :408-263-6300 FAX : 408-263-6571