The ispClock5610 and ispClock5620 are in-system-programmable high-fanout PLL-based clock drivers designed for use in high performance communications and computing applications. The ispClock5610 provides up to 10 single-ended or five differential clock outputs, while the ispClock5620 provides up to 20 single-ended or 10 differential clock outputs. Each pair of outputs may be independently configured to support separate I/O standards (LVDS, LVPECL, LVTTL, LVCMOS, SSTL, HSTL) and output frequency. In addition, each output provides independent programmable control of termination, slew-rate, and timing skew. All configuration information is stored on-chip in nonvolatile E2 CMOS memory. The ispClock5600’s PLL and divider systems supports the synthesis of clock frequencies differing from that of the reference input through the provision of programmable input and feedback dividers. A set of five post-PLL V-dividers provides additional flexibility by supporting the generation of five separate output frequencies. Loop feedback may be taken internally from the output of any of the five V-dividers, or externally through FBKA+/- or FBKB+/- pins. The core functions of all members of the ispClock5600 family are identical, the differences between devices being restricted to the number of inputs and outputs, as shown in the following table. Figures 1 and 2 show functional block diagrams of the ispClock5610 and ispClock5620.

Features

■ 10MHz to 320MHz Input/Output Operation

■ Low Output to Output Skew (<50ps)

■ Low Jitter Peak-to-Peak (<60ps)

■ Up to 20 Programmable Fan-out Buffers

• Programmable output standards and individual enable controls

- LVTTL, LVCMOS, HSTL, SSTL, LVDS,LVPECL

• Programmable output impedance

- 40 to 70Ω in 5Ω increments

• Programmable slew rate

• Up to 10 banks with individual VCCO and GND

- 1.5V, 1.8V, 2.5V, 3.3V

■ Fully Integrated High-Performance PLL

• Programmable lock detect

• Multiply and divide ratio controlled by

- Input divider (5 bits)

- Feedback divider (5 bits)

- Five output dividers (5 bits)

• Programmable On-chip Loop Filter

■ Precision Programmable Phase Adjustment (Skew) Per Output

• 16 settings; minimum step size 195ps

- Locked to VCO frequency

• Up to +/- 12ns skew range

• Coarse and fine adjustment modes

■ Up to Five Clock Frequency Domains

■ Flexible Clock Reference and External Feedback Inputs

• Programmable input standards

- LVTTL, LVCMOS, SSTL, HSTL, LVDS,LVPECL

• Clock A/B selection multiplexer

• Feedback A/B selection multiplexer

• Programmable termination

■ Four User-programmable Profiles Stored in E2

CMOS Memory

• Supports both test and multiple operating configurations

■ Full JTAG Boundary Scan Test In-System

Programming Support

■ Exceptional Power Supply Noise Immunity

■ Commercial (0 to 70°C) and Industrial

(-40 to 85°C) Temperature Ranges

■ 100-pin and 48-pin TQFP Packages

Applications

• Circuit board common clock generation and distribution

• PLL-based frequency generation

• High fan-out clock buffer

• Zero-delay clock buffer