Advance Data Sheet

LCK4972 Low-Voltage PLL Clock Driver

March 26, 2004

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2

Agere Systems Inc.

Table of Contents

Contents

Page

1 Features ............................................................................................................................................................................. 1

2 Description .......................................................................................................................................................................... 1

3 Pin Information ................................................................................................................................................................... 4

3.1 Pin Diagram .................................................................................................................................................................4

4 Functional Description ........................................................................................................................................................ 7

4.1 Device Programming ................................................................................................................................................... 8

4.2 Application Examples .................................................................................................................................................. 9

4.3 Typical Skew Example ................................................................................................................................................ 9

4.4 SYNC Output .............................................................................................................................................................10

4.5 Output Freeze Circuitry .............................................................................................................................................12

4.6 On-Board Crystal Oscillator .......................................................................................................................................12

4.7 Power Supply Filtering ...............................................................................................................................................13

4.8 Driving Transmission Lines .......................................................................................................................................14

5 Absolute Maximum Ratings ..............................................................................................................................................15

5.1 Handling Precautions ................................................................................................................................................15

5.2 Thermal Parameters (Definitions and Values) ...........................................................................................................15

6 Electrical Characteristics ..................................................................................................................................................17

6.1 dc Characteristics ......................................................................................................................................................17

6.2 ac Characteristics ......................................................................................................................................................18

7 Outline Diagram ................................................................................................................................................................19

8 Ordering Information .........................................................................................................................................................20

Figures

Page

Figure 2-1. Logic Diagram ...................................................................................................................................................... 4

Figure 3-1. 52-Pin TQFPT ...................................................................................................................................................... 5

Figure 4-1. 100 MHz from 50 MHz Example ........................................................................................................................10

Figure 4-2. Pentium Compatible Clocks Example ................................................................................................................10

Figure 4-3. 20 MHz Source Example ...................................................................................................................................10

Figure 4-4. Skew Relative to Qa...........................................................................................................................................10

Figure 4-5. Phase Delay Example Using Two LCK4972s ....................................................................................................11

Figure 4-6. LCK4972 Timing ................................................................................................................................................12

Figure 4-7. Freeze Data Input Protocol ................................................................................................................................13

Figure 4-8. Power Supply Filter ............................................................................................................................................14

Figure 4-9. Dual Transmission Lines....................................................................................................................................15

Figure 4-10. Single vs. Dual Waveforms ..............................................................................................................................15

Figure 4-11. Optimized Dual Transmission Lines.................................................................................................................15

Tables

Page

Table 3-1. Pin Description....................................................................................................................................................... 5

Table 4-1. Function Table for Qa, Qb, and Qc ........................................................................................................................ 7

Table 4-2. Function Table for QFB.......................................................................................................................................... 7

Table 4-3. Function Table for Logic Selection......................................................................................................................... 7

Table 4-4. Programmable Output Frequency Relationships for Qa, Qb, and Qc (VCO_Sel = 1) ...........................................8

Table 4-5. Programmable Output Frequency Relationships for QFB (VCO_Sel = 1)............................................................. 8

Table 4-6. Crystal Recommendations...................................................................................................................................12

Table 5-1. Absolute Maximum Ratings .................................................................................................................................15

Table 5-2. ESD Tolerance.....................................................................................................................................................15

Table 5-3. Thermal Parameter Values ..................................................................................................................................16

Table 6-1. PLL Input Reference Characteristics (TA = –40 °C to +85 °C) ............................................................................17

Table 6-2. dc Characteristics (TA = –40 °C to+85 °C, VDD = 3.3 V ± 5%) ...........................................................................17

Table 6-3. dc Characteristics (TA = –40 °C to +85 °C, VDD = 2.5 V ± 5%) ..........................................................................17

Table 6-4. ac Characteristics (TA = –40 °C to +85 °C, VDD = 3.3 V/2.5 V ± 5%).................................................................18

Table 8-1. LCK4972 Ordering Information............................................................................................................................20