1 Features

• High-performance LVDS clock buffer family: up to

2 GHz

– Dual 1:2 differential buffer

– Dual 1:4 differential buffer

• Supply voltage: 1.71 V to 3.465 V

• Fail-safe input operation

• Low additive jitter: < max 60 fs RMS in 12-kHz to

20-MHz @ 156.25 MHz

– Very low phase noise floor: -164 dBc/Hz

(typical)

• Very low propagation delay < 575 ps max

• Output skew of 20 ps max

• Universal inputs accept LVDS, LVPECL, LVCMOS,

HCSL and CML signal levels.

• LVDS reference voltage, VAC_REF, available for

capacitive coupled inputs

• Industrial temperature range: –40°C to 105°C

• Packaged in

– LMK1D2102: 3-mm x 3-mm, 16-Pin VQFN

– LMK1D2104: 5-mm x 5-mm, 28-Pin VQFN

2 Applications

• Telecommunications and networking

• Medical imaging

• Test and measurement

• Wireless infrastructure

• Pro audio, video and signage

3 Description

The LMK1D210x clock buffer distributes two clock

inputs (IN0 and IN1) to a total of up to 8 pairs of

differential LVDS clock outputs (OUT0, OUT7) with

minimum skew for clock distribution. Each buffer block

consists of one input and up to 4 LVDS outputs. The

inputs can either be LVDS, LVPECL, HCSL, CML or

LVCMOS.

The LMK1D210x is specifically designed for driving

50-Ω transmission lines. In case of driving the inputs

in single-ended mode, the appropriate bias voltage as

shown in Figure 9-6 must be applied to the unused

negative input pin.

Using the control pin (EN), output banks can either

be enabled or disabled. If this pin is left open, two

buffers with all outputs are enabled, if switched to

a logic 0, both banks with all outputs are disabled

(static logic 0), if switched to a logic 1, one bank

and its outputs are disabled while another bank with

its outputs are enabled. The part supports a fail-safe

function. The device further incorporates an input

hysteresis which prevents random oscillation of the

outputs in the absence of an input signal.

The device operates in 1.8-V or 2.5-V or 3.3-V

supply environment and is characterized from –40°C

to 105°C (ambient temperature). The LMK1D210x

package variant is shown in the table below: