The ispClock5406D and ispClock5410D are in-system-programmable differential clock distribution ICs designed for use in high performance communications and computing applications. The ispClock5400D family features the CleanClock™ ultra-low phase noise, third generation PLL. The FlexiClock™ output section supports multiple logic standards and dual skew control features.
The configuration of each device is held in on-chip non-volatile memory that is reprogrammable through a JTAG interface. Certain aspects of the device can be modified on the fly via an I2C interface.
Please select a document category from the selection on the left-hand side of this page for more information on ispClock5400D.
Applications
- Low-cost clock source for SERDES
- ATCA, MicroTCA, AMC, PCI Express
- Differential clock distribution
- Generic source synchronous clock management
- High fan-out clock buffer
- Zero-delay clock buffer
SERDES Reference Clock
The need for a reference clock source for FPGAs and ASICs with SERDES, such as the LatticeECP3, traditionally has been addressed by expensive crystal oscillators with differential outputs. The ispClock5400D enables the use of a lower cost, lower frequency CMOS oscillator clock source, reducing the overall cost of implementation.

Affordable CMOS Oscillator and ispClock5400D Combination
Clock Management for High-Speed Source Synchronous Interfaces
Converts edge-aligned clock output from FPGA to data-centered clock (90° phase skew) for receiver. Use Time Skew feature to dynamically adapt to PVT variation of setup and hold times.

Edge-Aligned to Data-Centered Clocking
Timing Margin Measurement
The ispClock5400D can be used to measure timing margin in a given system. In order to ensure that the data transfer between transmitter and receiver takes place reliably across device voltage and operating temperature, system designers usually measure the timing margin indirectly by increasing or decreasing the operating frequency. This is called frequency margining.
The ispClock5400D provides accurate and very fine timing skew control which can be controlled by the I2C bus interface. Using this feature, the receiving clock can be skewed independently from the transmit clock. By adjusting clock skew hold time (tH), setup time (tSU), and clock-to-out (tCO) margins measurements can be obtained.

Timing Margin Measurement
Features
CleanClock™ PLL Performance
- Ultra Low Cycle-to-Cycle Jitter (29ps p-p)
- Ultra Low Period Jitter (2.5ps)
- Low Output to Output Skew (<100ps)
Fully Integrated High-Performance PLL
- Programmable lock detect
- Four output dividers
- Programmable on-chip loop filter
- Compatible with spread spectrum clocks
- Internal/external feedback
Flexible Clock Reference and External Feedback Inputs
- Programmable differential input reference / feedback standards: LVDS, LVPECL, HSTL, SSTL, HCSL
- Programmable termination
- Clock A/B selection multiplexer
FlexiClock™ I/O
- 50MHz to 400MHz Input/Output operation
- Dual programmable skew per output
- Dynamic skew control through I2C
- Low output to output skew (<100ps)
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Up to 10 Programmable Fan-Out Buffers
- Programmable differential output standards and individual enable controls: LVDS, LVPECL, HSTL, SSTL, HCSL, MLVDS
- Up to 10 banks with individual VCCO and GND: 1.5V, 1.8V, 2.5V, 3.3V
- All inputs and outputs are hot socket compliant
Operating Modes
- Fan-out buffer with programmable output skew control
- Zero delay buffer with dual programmable skew controls
Programmability and Packaging
- Full JTAG Boundary Scan Test In-System Programming Support
- Commercial (0 to 70°C) and Industrial (-40 to 85°C) Temperature Ranges
- 48-Pin and 64-pin QFNS Package
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Selector Guide
ispClock5400D Product Family Selector Guide
| Feature |
ispClock5400D Family |
| 5410D |
5406D |
| |
|
|
| Outputs |
10 |
6 |
| Input Operating Frequency Range |
40 to 400MHz |
| Output Operating Frequency Range |
50 to 400MHz
|
| VCO Operation |
400 to 800MHz |
| Spread-Spectrum Compatibility |
Yes |
| Programmable Input Types |
LVDS, LVPECL, HSTL, SSTL, HCSL |
Programmable Output and
Feedback Interface Types |
LVDS, LVPECL, HSTL, SSTL, HCSL, MLVDS |
| Type of PLL Feedback |
Internal/External |
| Number of V Dividers |
4 |
| V Divider Count Range |
2 to 16 (power of 2) |
| Maximum Cycle-Cycle Jitter |
29ps (peak-peak) |
| Maximum Period Jitter (RMS) |
2.5ps |
| Typical Phase Jitter (RMS) |
6ps |
| Maximum Static Phase Offset |
0ps to 100ps |
| Frequencies Generated |
4 |
| Programmable Skew |
156ps to 12ns |
| Fan-out Buffer Mode |
Yes |
Evaluation Board
The ispClock 5400D evaluation board allows the designer to quickly configure and evaluate the ispPAC-CLK5406D device on a fully assembled printed-circuit board.
- The ispClock-5400D Evaluation Board includes
- ispClock5406D programmable clock (ispPAC-CLK5406D-01SN48I)
- Crystal oscillator circuits
- ispDOWNLOAD Cable (HW-DLN-3C)
- Universal power supply kit
- Can oscillator circuits
- Resistor networks
- SMA connectors
- Power jack
- I2C, JTAG, and test interface headers
- Programmable with PAC-Designer and ispVM System software
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