CDC706PW集成电路（IC）的时钟发生器PLL频率合成器规格书PDF中文资料

1FEATURES

2• High Performance 3:6 PLL Based Clock

Synthesizer / Multiplier / Divider

• User Programmable PLL Frequencies

• Easy In-Circuit Programming via SMBus Data Interface

• Wide PLL Divider Ratio Allows 0-PPM Output

Clock Error

• Clock Inputs Accept a Crystal or a

Single-Ended LVCMOS or a Differential Input

Signal

• Accepts Crystal Frequencies from 8 MHz up to

54 MHz

• Accepts LVCMOS or Differential Input

Frequencies up to 200 MHz

• Two Programmable Control Inputs [S0/S1] for

User Defined Control Signals

• Six LVCMOS Outputs with Output Frequencies

up to 300 MHz

• LVCMOS Outputs can be Programmed for

Complementary Signals

• Free Selectable Output Frequency via

Programmable Output Switching Matrix [6x6]

Including 7-Bit Post-Divider for Each Output

• PLL Loop Filter Components Integrated

• Low Period Jitter (Typical 60 ps)

• Features Spread Spectrum Clocking (SSC) for

Lowering System EMI

• Programmable Output Slew-Rate Control

(SRC) for Lowering System EMI

• 3.3-V Device Power Supply

• Industrial Temperature Range –40°C to 85°C

• Development and Programming Kit for Easy

PLL Design and Programming

(TI Pro-Clock™)

• Packaged in 20-Pin TSSOP

• Factory Programmable for Customized Default

Settings are Available. Contact TI Sales for

More Details.

APPLICATIONS

• Wireless Base Stations

• Network Line Cards

• Datacom / Telecom

DESCRIPTION

The CDC706 is one of the smallest and powerful PLL synthesizer / multiplier / divider available today. Despite its

small physical outlines, the CDC706 is very flexible. It has the capability to produce an almost independent

output frequency from a given input frequency.

The input frequency can be derived from a LVCMOS, differential input clock, or a single crystal. The appropriate

input waveform can be selected via the SMBus data interface controller.

To achieve an independent output frequency the reference divider M and the feedback divider N for each PLL

can be set to values from 1 up to 511 for the M-Divider and from 1 up to 4095 for the N-Divider. The PLL-VCO

(voltage controlled oscillator) frequency than is routed to the free programmable output switching matrix to any of

the six outputs. The switching matrix includes an additional 7-bit post-divider (1-to-127) and an inverting logic for

each output.

The deep M/N divider ratio allows the generation of zero ppm clocks from any reference input frequency (e.g., a

27-MHz).

The CDC706 includes three PLLs of those one supports SSC (spread-spectrum clocking). PLL1, PLL2, and

PLL3 are designed for frequencies up to 300 MHz and optimized for zero-ppm applications with wide divider

factors.

PLL2 also supports center-spread and down-spread spectrum clocking (SSC). This is a common technique to

reduce electro-magnetic interference. Also, the slew-rate controllable (SRC) output edges minimize EMI noise.

Based on the PLL frequency and the divider settings, the internal loop filter components will be automatically

adjusted to achieve high stability and optimized jitter transfer characteristic of the PLL.

The device provides customized applications. It is preprogrammed with a factory default configuration (see

Figure 13) and can be reprogrammed to a different application configuration via the serial SMBus Interface.

Two free programmable inputs, S0 and S1, can be used to control for each application the most demanding logic

control settings (outputs disable to low, outputs 3-state, power down, PLL bypass, etc).

The CDC706 has three power supply pins, VCC, VCCOUT1, and VCCOUT2. VCC is the power supply for the device. It

operates from a single 3.3-V supply voltage. VCCOUT1 and VCCOUT2 are the power supply pins for the outputs.

VCCOUT1 supplies the outputs Y0 and Y1 and VCCOUT2 supplies the outputs Y2, Y3, Y4, and Y5. Both outputs

supplies can be 2.3 V to 3.6 V. At output voltages lower than 3.3 V, the output current drive is limited.

The CDC706 is characterized for operation from –40°C to 85°C.