描述 Description

The 8V79S683 is a fully integrated, clock and SYSREF signal fanout

buffer for JESD204B/C applications. It is designed as a

high-performance clock and converter synchronization solution for

wireless base station radio equipment boards with JESD204B/C

subclass 0, 1, and 2 compliance. The main function of the device is the

distribution and fanout of high-frequency clocks and low-frequency

system reference signals generated by a JESB204B clock generator

such as the IDT 8V19N490, extending its fanout capabilities and

providing additional phase-delay. The 8V79S683 is optimized to deliver

very low phase noise clocks and precise, phase-adjustable SYSREF

synchronization signals. Low-skew outputs, low device-to-device skew

characteristics and fast output rise/fall times help the system design to

achieve deterministic clock and SYSREF phase relationship across

devices.

The device distributes the input clock (CLK) and JESD204B SYSREF

signals (REF) to four fanout channels. Input clock signals can be

frequency divided and are fanned-out to multiple clock (QCLK_y) and

SYSREF (QREF_r) outputs. Configurable phase-delay circuits are

available for both clock and SYSREF signals. The propagation delays in

all signal paths are fully deterministic to support fixed phase

relationships between clock and SYSREF signals within one device. The

device facilitates synchronization between frequency dividers within the

device and across multiple devices, removing phase ambiguity

introduced in dividers between power and configuration cycles.

特性 Features

? Distribution, fanout, phase-delay of clock and SYSREF signals

? Very low output noise floor: -158.8dBc/Hz noise floor

(245.76MHz)

? Supports clock frequencies up to 3GHz, including clock output

frequencies of 983.04MHz, 491.52MHz, 245.76MHz, and

122.88MHz

? Four output channels with a total of 16 differential outputs

? Each channel contains frequency dividers and clock phase delay

circuits

? Phase alignment mode across multiple buffers with any frequency

divider setting

? Flexible differential outputs (LVDS/LVPECL/amplitude

configurable)

? Configuration through 3-wire SPI interface

? Supply voltage:

— 3.3V core and signal I/O

— 1.8V Digital control SPI I/O (3.3V-tolerant inputs)

? 64-VFQFPN package (9 × 9 × 0.85 mm)

? Ambient temperature range: -40°C to +105°C (case)