SY89645LK4GTR - Micrel, Inc.

SY89645L

Precision Low Skew , 1-to-4

LVCMOS/LVTTL-to-LVDS Fanout Buffer

Precision Edge is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

General Description

The SY89645L is a 3.3V, fully differential, low skew, 1:4

LVDS fanout buffer that accepts LVTTL or LVCMOS

inputs. It is capable of processing clock signals as fast as

650MHz. The LVDS signals are optimized to provide less

than 40ps of output skew.

The single-ended input takes a 3.3V LVTTL or LVCMOS,

with a signal swing as small as 1.2V. The outputs are

280mV LVDS, with fast rise and fall times, guaranteed to

be less than 400ps.

The SY89645L operates from a 3.3V + 5% power supply

and is guaranteed over the full industrial temperature

range (–40°C to +85°C). The SY89645L is part of Micrel’s

Precision Edge® product line.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Block Diagram

Precision Edge®

Features

• Four identical LVDS outputs

• CLKIN accepts LVCMOS or LVTTL input levels

• Maximum output frequency: 650MHz

• Translates LVCMOS/LVTTL input signals to LVDS levels

• <40ps output-to-output skew

• <3ns propagation delay

• <400ps rise/fall times

• 3.3V ±5% operating supply

• Industrial temperature range: –40°C to +85°C

• Available in 20-pin TSSOP

Applications

• Communications

• High-performance computing

• Clock and data distribution

Markets

• Datacom

• Telecom

• Storage

• ATE

• Test and Measurement

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Ordering Information

Part Number Package Type Operating Range Packag e Marking Lead Finish

SY89645LK4G K4-20-1 Industrial SY89645LK4G with

Pb-Free bar-line indicator

NiPdAu

Pb-Free

SY89645LK4GTR(2) K4-20-1 Industrial SY89645LK4G with

Pb-Free bar-line indicator

NiPdAu

Pb-Free

Notes:

1. Contact factory for die availability. Dice are guaranteed at TA = 25°C, DC Electricals only.

2. Tape and Reel.

Pin Configur ation

20-Pin TSSOP (K4-20-1)

Pin Description

Pin Number Pin Name Pin Function

1, 9, 13 GND Power Supply Ground.

2 CLK_EN

Clock Enable. When LOW, Q outputs are forced low, /Q outputs are forced high. The synchronous

nature of the enable function forces the output clocks to enable or disable following a rising and a

falling edge of the input clock. When HIGH, clock outputs follow input clock. Internal 50k pull-up

resistor. VTH = VCC/2. See “Clock Enable (CLK_EN) Description” section.

3, 5, 6, 7, 8 NC No Connect.

4 CLKIN

LVCMOS/LVTTL Clock Input. This is the input to the device. Input accepts single-ended input signals

as small as 1.2V. VTH = VCC/2. Internal 50k pull-down resistor.

10, 18 VCC Positive Supply Pins. Connect to 3.3V supply, bypass with low ESR capacitors, as close to pins as

possible.

11, 12

14, 15

16, 17

19, 20

/Q3, Q3

/Q2, Q2

/Q1, Q1

/Q0, Q0

LVDS Differential Output Pairs: Differential buffered copies of the input signal. The output swing is

typically 280mV. Normally terminated with 100 across the output pairs (Q and /Q). See “LVDS

Output Termination” section.

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Absolute Maximum Ratings(1)

Supply Voltage (VCC)............................... –0.5V to +4.6V

Input Voltage (VIN)............................ –0.5V to VCC +0.3V

LVDS Output Current (IOUT)..................................±10mA

Lead Temperature (soldering, 20sec.).................. 260°C

Storage Temperature (Ts) ....................–65°C to +150°C

Operating Ratings(2)

Supply Voltage (VIN)............................. +3.135V to +3.465V

Ambient Temperature (TA) ..........................–40°C to +85°C

Package Thermal Resistance(3)

TSSOP

Junction-to-Ambient (θJA)

Still-Air, Multi-Layer Board..............................75°C/W

Junction-to-Case (θJC)...........................................21°C/W

DC Electrical Characteristics(4)

VDD = 3.3V ±5%, TA = –40°C to +85°C, unless otherwise stated.

Symbol Parameter Condition Min. Typ. Max. Units

VCC Positive Supply Voltage Range 3.135 3.3 3.465 V

ICC Power Supply Current No Load 43 60 mA

LVCMOS/LVTTL DC Electrical Characteristics(4)

VCC = 3.3V ±5%, TA = –40°C to +85°C, unless otherwise stated.

Symbol Parameter Condition Min. Typ. Max. Units

VIH Input HIGH Voltage

CLKIN, CLK_EN

VCC+0.15 V

VIL Input LOW Voltage

CLKIN, CLK_EN

-0.3

0.8 V

IIH

Input HIGH Current

CLKIN

CLK_EN

VCC = VIN = 3.465V

150

µA

IIL

Input LOW Current

CLKIN

CLK_EN

VCC = 3.465V, VIN = 0V

-70

-150

µA

LVDS Outputs DC Electrical Characteristics(4)

VCC = 3.3V ±5%, RL = 100 across the outputs, TA = –40°C to +85°C, unless otherwise stated.

Symbol Parameter Condition Min. Typ. Max. Units

VOUT Output Voltage Swing See Figure 1a 200 280 mV

VDIFF_OUT Differential Output Voltage Swing See Figure 1b 400 560 mV

VOCM Output Common Mode Voltage 1.125 1.25 1.375 V

VOCM Change in Common Mode

Voltage 5 25 mV

Notes:

1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied

at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum ratings conditions for extended

periods may affect device reliability.

2. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings.

3. ψJB and θJA values are determined for a 4-layer board in still-air number, unless otherwise stated.

4. The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established.

Micrel, Inc. SY89645L

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AC Electrical Characteristics(5)

VCC = +3.3V ±5%, RL = 100 across the outputs, TA = –40°C to +85°C, unless otherwise stated.

Symbol Parameter Condition Min. Typ. Max. Units

fMAX Maximum Frequency VOUT > 140mV 650 MHz

tPD Propagation Delay fMAX  650MHz, Note 6 1.0 1.8 3.0 ns

Output Skew Note 7 40 ps

tSKEW Part-to-Part Skew Note 8 500 ps

tr, tf Output Rise/Fall Times

(20% to 80%) fMAX  266MHz 150 250 400 ps

fMAX  266MHz 45 55 %

Duty Cycle fMAX > 266MHz 40 60 %

Notes:

5. All parameters measured at fMAX  650MHz, unless otherwise stated.

6. Measured from VCC/2 of the input to the differential output crossing point.

7. Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VCC/2 of the input to the differential

output crossing point.

8. Defined as skew between outputs on different devices operating at the same supply voltages and with equal load conditions. Using the same type

of inputs on each device, the outputs are measured at the differential cross points.

Timing Diagram

Clock Enable (CLK_EN) Description

The enable function is synchronous so that the clock

outputs will be enabled or disabled following a rising and

a falling edge of the input clock.

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Typical Operating Te chniques

VCC = 3.3V ± 5%; VIN > 2V; TA = 25°C, RL = 100 across output pair; unless otherwise stated.

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Single-Ended and Differential Swings

Figure 1a. Single-Ended Voltage Swing

Figure 1b. Differential Voltage Swing

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LVDS Output Interface Applications

LVDS specifies a small swing of 280mV typical, on a

nominal 1.25V common mode above ground. The

common mode voltage has tight limits to permit large

variations in ground between an LVDS driver and

receiver. Also, change in common mode voltage, as a

function of data input, is kept to a minimum, to keep EMI

low.

Figure 2a. LVDS Differential Measurement

Figure 2b. LVDS Common-Mode Measurement

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Package Information

20-Pin TSSOP (MM)

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com

Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This

information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,

specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual

property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability

whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties

relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product

reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical impla

into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A

Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully

indemnify Micrel for any damages resulting from such use or sale.

can nt

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