CGS74B304 Octal Divide-by-2 Skew Clock Driver General Description Features These minimum skew clock drivers are designed for high frequency Clock Generation & Support (CGS) applications. These devices are ideal for duty cycle recovery applications with internal frequency divide-by-2 circuitry. The devices guarantee minimum skew across the outputs of a given device. Skew parameters are also provided as a means to measure duty cycle requirements as those found in high speed clocking systems. Y Y Y Y Y Functional Description Y The CGS74B304 contains eight flip-flops designed to have low skew between outputs. The eight outputs (eight inphase with CLK) toggle on successive CLK pulses. PRE and CLR inputs are provided to set Q and Q outputs high or low independent of CLK pin. Logic Diagram Y Clock Generation & Support (CGS) devices ideal for high frequency signal generation or clock distribution applications Fabricated on National’s Advanced Bipolar FASTTM LSl process 900 ps pin-to-pin output skew Specification for transition skew to meet duty cycle requirements Current sourcing 24 mA and current sinking of 48 mA Low dynamic power consumption above 20 MHz Guaranteed 4 kV ESD protection Connection Diagram Pin Assignment SOIC (M) TL/F/11750 – 1 TL/F/11750 – 3 Pin Description Truth Table Pin Names Description CLK Q0 – Q 7 PRE CLR Clock Input Outputs Preset Clear Inputs Outputs CLR PRE CLK Q0 –Q7 L H L H H H L L H H X X X L H L* Q0 Q0 u L *This state will not persist when CLR/PRE returns to high. FASTTM is a trademark of National Semiconductor Corporation. C1996 National Semiconductor Corporation TL/F/11750 RRD-B30M86/Printed in U. S. A. http://www.national.com CGS74B304 Octal Divide-by-2 Skew Clock Driver July 1996 Absolute Maximum Ratings (Note) Recommended Operating Conditions If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage (VCC) Input Voltage (VI) Operating Free Air Temperature Storage Temperature Range Typical iJA Airflow (LFM) 0 Jedec SOIC (M) Package 118 Supply Voltage (VCC) 225 96 500 86 4.5V to 5.5V Input Rise and Fall Times 2 ns max (0.8V to 2.0V) Free Air Operating Temperature (TA) 0§ C to 70§ C NOTE: The Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the DC and AC Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The Recommended Operating Conditions will define the conditions for actual device operation. 7.0V 7.0V 0§ C to a 70§ C b 65§ C to a 150§ C § C/W § C/W DC Electrical Characteristics CGS64/74B304 Over recommended operating conditions unless specified otherwise. All typical values are measured at VCC e 5V, TA e 25§ C Symbol Parameter VIK Input Clamp Voltage VIH Minimum Input High Level Voltage VIL Maximum Input Low Level Voltage VOH High Level Output Voltage Conditions Typ Max Units b 1.2 V 2.0 V 0.8 IOH e b2 mA, VCC e 4.5V VCC b 2 IOH e 24 mA, VCC e 4.5V 2.0 VOL Low Level Output Voltage VCC e 4.5V, IOL e 48 mA II Input Current @ Max Input Voltage VCC e 5.5V, VIH e 7V IIH High Level Input Current VCC e 5.5V, VIH e 2.7V IIL Low Level Input Current VCC e 5.5V, VIL e 0.4V IO Output Drive Current VCC e 5.5V, VO e 2.25V ICC Supply Current VCC e 5.5V CIN Input Capacitance VCC e 5V http://www.national.com Min VCC e 4.5V, II e b18 mA V V 0.35 b 0.1 b 50 0.5 V 0.1 mA 20 mA b 0.50 mA b 150 mA Outputs High 20 30 mA Outputs Low 42 55 mA 5 2 pF AC Electrical Characteristics Over recommended operating conditions unless specified otherwise. All typical values are measured at VCC e 5V, TA e 25§ C CGS74B304 Symbol VCC e 4.5V to 5.5V TA e 0§ C to a 70§ C CL e 0 pF –50 pF RL e 500X Parameter Min Typ Units Max fMAX Maximum Input Frequency (Note 2) 110 MHz tPLH, tPHL Propagation Delay CLKn to On (Note 2) 4 8.5 ns tPLH, tPHL Propagation Delay PRE/CLR (Note 2) 4 11 ns tSU Set Up Time before CLK 5 ns tW CLK HI CLK LO CLR/PRE 4 4 4 ns Extended AC Electrical Characteristics Over recommended operating conditions unless specified otherwise. All typical values are measured at VCC e 5V, TA e 25§ C CGS74B304 VCC e 4.5V to 5.5V TA e 0§ C to a 70§ C CL e 0 pF –50 pF RL e 500X Symbol Parameter tOSHL Q Maximum Skew Common Edge Output-to-Output Variation (Notes 1, 2) 0.5 ns tOSLH Q Maximum Skew Common Edge Output-to-Output Variation (Notes 1, 2) 0.5 ns tPS Maximum Skew. Pin (Signal) Transition Variation (Note 1) 1.1 ns trise, tfall Rise/Fall Time (from 0.8V/2.0V to 2.0V/0.8V) 0 pF–30 pF Loads (Note 2) 2.0 2.0 ns Min Typ 1.1 0.9 Units Max Note 1: Output-to-Output Skew is defined as the absolute value of the difference between the actual propagation delay for any outputs within the same packaged device. The specifications apply to any outputs switching in the same direction either HIGH to LOW (tOSHL) or LOW to HIGH (tOSLH) or in opposite directions both HL and LH (tOST). Parameters tOST and tPS guaranteed by design. Note 2: This device is sensitive to noise due to the large transient currents which occur during multiple switching of the outputs. VCC bypass capacitor(s), chip types, must be placed as closely as possible to the VCC pin. Note 3: Refer to Minimum Skew Parameters Measurement Information Chart for definitions of each skew specification. Note 4: All input pulses are from 3.5V to 0.3V with rise and fall times of 2.0 ns. Note 5: Load capacitance includes the test jig. 3 http://www.national.com Timing Diagrams Minimum Skew Divide-by-2 Clock Drivers CGS74B304 TL/F/11750 – 4 TL/F/11750 – 5 Test Circuit RL is 500X CL is 50 pF for all prop delays and skew measurements. CL is 30 pF for trise and tfall measurements. TL/F/11750 – 6 Ordering Information Contact NSC Marketing for specific data of availability TL/F/11750 – 13 http://www.national.com 4 Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Small Outline Integrated Circuit (S) NS Package Number M16A 5 http://www.national.com CGS74B304 Octal Divide-by-2 Skew Clock Driver Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Plastic Dual-In-Line Package (P) NS Package Number N16E LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. 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