Texas Instruments has added a new high speed PLL, TLC2933, to the TLC29XX PLL product family. The TLC2933 is a 100 MHz high precision standalone CMOS PLL with external frequency divider and a loop filter for low jitter and added design flexibility. TLC2933 provides an easy upgrade path to the TLC2932 with a higher lock frequency. This device locks a frequency up to 100 MHz with less than 100 ps jitter when operating at 5 V. It is pin-for-pin compatible with its predecessor, TLC2932, except it does not feature the no select pin for a ½ frequency output option.
The TLC2933 contains two key functional blocks; an edge triggered phase/frequency detector (PFD) and a voltage controlled oscillator (VCO).
The PFD is used to detect the phase difference between the input reference frequency and the variable input frequency from the VCO. This difference is filtered by an external filter and then fed back to the VCO to adjust (lock) the VCO output frequency. The PFD includes an internal charge pump to drive the output. The PFD and VCO have independent inhibit pins to allow use of each function individually. The inhibit pins can also shut down the VCO and/or the PFD to achieve different power down schemes for power sensitive applications. Output frequency is easily manipulated by external counters, which may be part of the controller or ASIC in the system. The external PFD output filtering circuitry allows the system designer maximum control over the filter type and complexity.
With its flexible partitioning, high frequency locking and low jitter, the TLC2933 provides a cost effective, high speed clock/phase recovery and clock distribution solution. Applications include advanced consumer products such as high quality video, hard disk drive, CD ROM drive and set top box systems.
Telecommunication switches, wireless network and mobile communication devices can also benefit from its stability. This highly integrated device is available in a small 14-pin TSSOP package. The TLC2933IPW can operate from either 5-V or 3-V supply.
TLC2932
Vol 17, June, 1996
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