Datasheet MK74CB44R, MK74CB44RTR Datasheet (ICST)

PRELIMINARY INFORMATION

Quad 1 to 4 Buffalo™ Clock Driver

MK74CB44

Description

The MK74CB44 Buffalo™ is a monolithic
CMOS high speed clock driver. It consists of
four identical single input to four low-skew
output, non-inverting clock drivers. When
combined with ICS’s MK series of low jitter
clock synthesizers, the chips form an unequaled
high performance clocking scheme. This
monolithic solution can eliminate concern for
part-to-part skew matching. The MK74CB44 is
packaged in the tiny 28 pin SSOP, which uses the
same board space as the narrow 16 pin SOIC.

Block Diagram

INA

Features

• Tiny 28 pin SSOP (150 mil) package

• Quad one input to four output clock drivers

• Outputs are skew matched to within 250ps

• A, B, C and D banks matched to 250ps

• 3.3V±10% and/or 5V±10% supply voltage

• Clock speeds up to 200 MHz

• For tighter skew matching, more outputs, or
other speeds, consult ICS for other solutions

Family of ICS Parts

The MK74CB44 Buffalo™ is designed to be used
with ICS’s clock synthesizer devices. The inputs
of the Buffalo are matched to the outputs of ICS
clock synthesizers. Consult ICS for applications
support.

VDD
4

IND

QA0

QA1
QA2

QA3

QB0
QB1
QB2

QB3
INB INC

4

GND

MDS 74CB44 B 1 Revision 022000 Printed 11/17/00

Integrated Circuit Systems, Inc. • 525 Race St. • San Jose • CA • 95126 • [phone]tel • www.icst.com

QD0
QD1

QD2
QD3
QC0

QC1
QC2
QC3

PRELIMINARY INFORMATION

Quad 1 to 4 Buffalo™ Clock Driver

MK74CB44

Pin Assignment

1

INA

2

QA0
QA1

3

QA2

4

QA3
QB0

QB1
QB2
QB3

INB

5
6
7

8
9

10
11
12
13
14

VDD
VDD

GND
GND

28
27

26
25

24
23
22

21
20
19

18
17
16

15

IND

QD0
QD1
QD2

VDD
VDD

QD3
QC0
GND
GND
QC1

QC2
QC3
INC

0.01µF

Suggested Layout

V

G

For simplicity,series terminating resistors (required) are not
shown for the outputs, but should be placed as close to the
device as possible. It is most critical to have the 0.01µF
decoupling capacitors closest.

= connect to VDD

V

= connect to GNDG

V

0.01µF

G

Pin Descriptions

Number Name Type Description

1 INA I Clock input for four A outputs.

2, 3, 4 QA0, QA1, QA2 O Clock A outputs.

5, 6 VDD P Power supply. Connect to +3.3 V or +5 V. Must be the same as pins 23, 24.

7 QA3 O Clock A output.
8 QB0 o Clock B output.

9, 10 GND P Connect to ground.

11, 12, 13 QB1, QB2, QB3 O Clock B outputs.

14 INB I Clock input for four B outputs.
15 INC I Clock input for four C outputs.

16, 17, 18 QC3, QC2, QC1 O Clock C outputs.

19, 20 GND P Connect to ground.

21 QC0 O Clock C output.
22 QD3 O Clock D output.

23, 24 VDD P Power supply. Connect to +3.3 V or +5 V. Must be the same as pins 5, 6.

25, 26, 27 QD2, QD1, QD0 O Clock D outputs.

28 IND I Clock input for four D outputs.

Type: I = Input, O = output, P = power supply connection

MDS 74CB44 B 2 Revision 022000 Printed 11/17/00

Integrated Circuit Systems, Inc. • 525 Race St. • San Jose • CA • 95126 • [phone]tel • www.icst.com

PRELIMINARY INFORMATION

ABSOLUTE MAXIMUM RATINGS (Note 1)

DC CHARACTERISTICS (VDD = 3.3 V unless noted)

AC CHARACTERISTICS (VDD = 3.3 V unless noted)

MK74CB44

Quad 1 to 4 Buffalo™ Clock Driver

Electrical Specifications

Parameter Conditions Minimum Typical Maximum Units

Supply Voltage, VDD Referenced to GND 7 V
Inputs Referenced to GND 0.5 VDD+0.5 V
Clock Outputs Referenced to GND 0.5 VDD+0.5 V
Ambient Operating Temperature 0 70 °C
Soldering Temperature Max of 20 seconds 260 °C
Storage Temperature -65 150 °C

Operating Voltage, VDD 3.0 3.3 5.5 V
Input High Voltage, VIH VDD-1 VDD/2 V
Input Low Voltage, VIL VDD/2 1 V
Output High Voltage IOH=-8mA VDD-0.4 V
Output High Voltage IOH=-12mA 2.4 V
Output Low Voltage IOL=12mA 0.8 V
Operating Supply Current, IDD, at 100 MHz No Load 55 mA
Output Impedance 14 Ω
Short Circuit Current Each output 50 mA
Input Capacitance 7 pF

Input Clock Frequency Note 4, 5 0 200 MHz
Propagation Delay with load=15pF 1.4 3 ns
Output Clock Rise Time 0.8 to 2.0V 2 ns
Output Clock Fall Time 2.0 to 0.8V 2 ns
Output Clock Rising Edge Skew At VDD/2. Note 2 100 250 ps
Output Clock Bank to Bank Skew At VDD/2. Note 3 100 250 ps

Notes:

1. Stresses beyond those listed under Absolute Maximum Ratings could cause permanent damage to the device. Prolonged exposure
to levels above the operating limits but below the Absolute Maximums may affect device reliability.

2. Within any bank of four outputs, with equal loading.

3. Between any two banks of four with their inputs connected together, and equal loading.

4. At VDD = 3.3 V, 70°C, series termination of 33 Ω per pin, 8 pF load per pin.

5. See discussion and graph of speed versus load.

MDS 74CB44 B 3 Revision 022000 Printed 11/17/00

Integrated Circuit Systems, Inc. • 525 Race St. • San Jose • CA • 95126 • [phone]tel • www.icst.com

PRELIMINARY INFORMATION

MK74CB44

Quad 1 to 4 Buffalo™ Clock Driver

Maximum Speed/Application Notes

The maximum speed at which the chip can operate is limited by power dissipation of the package. Graph 1
shows the operating frequency plotted against load capacitance per pin for a die temperature of 125°C. This is
at VDD = 3.3 V, 70°C and with 33 Ω series termination resistor. The termination resistors are essential
because they allow a large proportion of the total power to be dissipated outside the package. Reducing or
eliminating the series termination will cause an increase in die temperature. It is not recommended to operate
the chip at die temperature greater than 125°C. Also note that the load capacitance per pin must include PC
board parasitics such as trace capacitance. ICS has other buffers specified to 250 MHz with heavier loads.

If not all outputs of the chip are used, it is possible to operate the chip faster with larger loads. Unused outputs
should be left unconnected. Consult ICS for your specific requirement.

300

250

Do not operate in this area .

200

150

100

50

0

Load Capacitance/per pin (pF), all 16 outputs loaded

Graph 1

MK74CB44

Maximum Speed at 3.3 V

806040200

MDS 74CB44 B 4 Revision 022000 Printed 11/17/00

Integrated Circuit Systems, Inc. • 525 Race St. • San Jose • CA • 95126 • [phone]tel • www.icst.com

PRELIMINARY INFORMATION

Inches

Millimeters

Quad 1 to 4 Buffalo™ Clock Driver

Package Outline and Package Dimensions
(For current dimensional specifications, see JEDEC Publication No. 95.)

28 pin SSOP

Symbol Min Max Min Max

A 0.053 0.069 1.35 1.75

E1 E

D

A1 0.004 0.010 0.102 0.254

b 0.008 0.012 0.203 0.305

c 0.007 0.010 0.191 0.254

D 0.386 0.394 9.804 10.008

e

E 0.228 0.244 5.791 6.198

E1 0.150 0.157 3.810 3.988

L 0.016 0.050 0.406 1.270

MK74CB44

A1 c

A

e

b

L

Ordering Information

Part/Order Number Marking Package Temperature

MK74CB44R MK74CB44R 28 pin SSOP 0-70°C

MK74CB44RTR MK74CB44R Add Tape & Reel 0-70°C

While the information presented herein has been checked for both accuracy and reliability, ICS Incorporated assumes no responsibility for either its use or for the infringement of
any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal
commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not
recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS
product for use in life support devices or critical medical instruments.

Buffalo is a trademark of ICS Incorporated

MDS 74CB44 B 5 Revision 022000 Printed 11/17/00

Integrated Circuit Systems, Inc. • 525 Race St. • San Jose • CA • 95126 • [phone]tel • www.icst.com