Microchip SY89847U Handleiding

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 2018 Microchip Technology Inc. DS20006101A-page 1

SY89847U

Features

• Selects Between Two Sources and Provides 5

Precision LVDS Copies

• Fail Safe Input Prevents Outputs from Oscillating

when Input is Invalid

• Guaranteed AC Performance over Temperature

and Supply Voltage:

- DC-to >1.5 GHz Throughput

- <1000 ps Propagation Delay (IN-to-Q)

- <210 ps Rise/Fall Times

• Ultra-Low Jitter Design:

- <1 psRMS Random Jitter

- <1 psRMS Cycle-to-Cycle Jitter

- <10 psPP Total Jitter (Clock)

- <0.7 psRMS MUX Crosstalk Induced Jitter

• Unique, Patented MUX Input Isolation Design

Minimizes Adjacent Channel Crosstalk

• Unique, Patented Internal Termination and VT Pin

Accepts DC- and AC-Coupled Inputs (CML,

PECL, LVDS)

• Wide Input Voltage Range VCC to GND

• 2.5V ±5% Supply Voltage

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

• Available in 32-Pin (5 mm x 5 mm) QFN Package

Applications

• Fail Safe Clock Protection

• Ultra-Low Jitter LVDS Clock Distribution

• Rack-Based Telecom/Datacom

Markets

• LAN/WAN

• Enterprise Servers

• ATE

• Test and Measurement

General Description

The SY89847U is a 2.5V, 1:5 LVDS fanout buffer with a

2:1 differential input multiplexer (MUX). A unique fail

safe input (FSI) protection prevents metastable output

conditions when the selected input clock fails to a DC

voltage (voltage between the pins of the differential

input drops significantly below 100 mV).

The differential input includes Microchip’s unique, 3-pin

internal termination architecture that can interface to

any differential signal (AC- or DC-coupled) as small as

100 mV (200 mVPP) without any level shifting or

termination resistor networks in the signal path. The

outputs are LVDS compatible with very fast rise/fall

times guaranteed to be less than 210 ps.

The SY89847U operates from a 2.5V ±5% supply and

is guaranteed over the full industrial temperature range

of –40°C to +85°C. The SY89847U is part of

Microchip’s high-speed, Precision Edge® product line.

Package Type

SY89847U

5 mm x 5 mm QFN-32 (M)

(Top View)

VT0

IN0

/IN0

SEL

IN1

/IN1

VT1

VCC

GND

VREF-AC1

/Q4

VCC

9 10 11 12 13 14 15 16

32 31 30 29 28 27 26 25

/Q1

VCC

/Q2

VCC

/Q3

VCC

GND

VREF-AC0

/Q0

VCC

1.5 GHz Precision LVDS 1:5 Fanout with 2:1 MUX

and Fail Safe Input with Internal Termination

SY89847U

DS20006101A-page 2  2018 Microchip Technology Inc.

Functional Block Diagram

SEL

IN0

/IN0

VT0

ȍ

IN1

/IN1

VT1

ȍ

VREF-AC0

VREF-AC1

Enable

Logic

/Q0

/Q1

/Q2

/Q3

/Q4

 2018 Microchip Technology Inc. DS20006101A-page 3

SY89847U

1.0 ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings †

Supply Voltage (VCC) ................................................................................................................................ –0.5V to +4.0V

Input Voltage (VIN) ....................................................................................................................................... –0.5V to V

LVPECL Output Current (IOUT)

Continuous...................................................................................................................................................50 mA

Surge .........................................................................................................................................................100 mA

Current (VT)

Source or Sink on V

T Pin .........................................................................................................................±100 mA

Input Current

Source or Sink Current on IN, /IN ..............................................................................................................±50 mA

Current (VREF)

Source or Sink Current on VREF-AC (Note 1)............................................................................................ ±0.5 mA

Operating Ratings ††

Supply Voltage (VCC) ........................................................................................................................ +2.375V to +2.625V

† Notice: Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only