DATASHEET LOW SKEW 1 TO 4 CLOCK BUFFER ICS553 Description Features The ICS553 is a low skew, single input to four output, Extremely low skew outputs (50 ps maximum) TM clock buffer. Part of IDTs ClockBlocks family, this is Packaged in 8-pin SOIC our lowest skew, small clock buffer. Pb (lead) free package See the ICS552-02 for a 1 to 8 low skew buffer. For Low power CMOS technology more than eight outputs, see the MK74CBxxx TM Operating voltages of 2.5 V to 5 V Buffalo series of clock drivers. Output Enable pin tri-states outputs IDT makes many non-PLL and PLL based low skew output devices as well as Zero Delay Buffers to 5 V tolerant input clock synchronize clocks. Contact us for all of your clocking Commercial (0 to +70C) and Industrial (-40 to needs. +85C) temperature ranges available Block Diagram Q0 Q1 ICLK Q2 Q3 Output Enable IDT LOW SKEW 1 TO 4 CLOCK BUFFER 1 ICS553 REV N 051310ICS553 LOW SKEW 1 TO 4 CLOCK BUFFER FAN OUT BUFFER Pin Assignment VDD 1 8 OE Q0 2 7 Q3 Q1 3 6 Q2 GND 4 5 ICLK 8-pin SOIC Pin Descriptions Pin Pin Pin Pin Description Number Name Type 1 VDD Power Connect to +2.5 V, +3.3 V or +5.0 V. 2 Q0 Output Clock output 0. 3 Q1 Output Clock output 1. 4 GND Power Connect to ground. 5 ICLK Input Clock input, 5 V tolerant input. 6 Q2 Output Clock Output 2. 7 Q3 Output Clock Output 3. 8 OE Input Output Enable. Tri-states outputs when low. Connect to VDD for normal operation. External Components A minimum number of external components are required for proper operation. A decoupling capacitor of 0.01 F should be connected between VDD on pin 1 and GND on pin 4, as close to the device as possible. A 33 series terminating resistor may be used on each clock output if the trace is longer than 1 inch. To achieve the low output skew that the ICS553 is capable of, careful attention must be paid to board layout. Essentially, all four outputs must have identical terminations, identical loads and identical trace geometries. If they do not, the output skew will be degraded. For example, using a 30 series termination on one output (with 33 on the others) will cause at least 15 ps of skew. IDT LOW SKEW 1 TO 4 CLOCK BUFFER 2 ICS553 REV N 051310