Datasheet MK74CB218R, MK74CB218RTR Datasheet (ICST)

PRELIMINARY INFORMATION

Dual 1 to 8 Buffalo™ Clock Driver

MK74CB218

Description

The MK74CB218 Buffalo™ is a monolithic
CMOS high speed clock driver. It consists of two
identical single input to eight low-skew output,
non-inverting clock drivers. This eliminates
concerns of part to part matching in many
systems. The MK74CB218 is packaged in the
tiny 28 pin SSOP, which uses the same board
space as the narrow 16 pin SOIC. The inputs can
be connected together for a 1 to 16 fanout buffer.

A quad 1 to 4, and PECL versions, are also
available. Consult ICS for more details.

The MK74CB218 can also act as a voltage
translator, since it is possible to run the inputs at

3.3 V and the outputs at 2.5 V.

Block Diagram

Features

• Tiny 28 pin SSOP (150 mil) package

• Dual one input to eight output clock drivers

• Outputs are skew matched to within 250 ps

• A outputs and B outputs matched to 250 ps

• 2.5 V, 3.3 V or 5 V supply voltages

• Output Enable tri-states each bank of eight

• Clock speeds up to 200 MHz

Family of ICS Parts

The MK74CB218 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

VDDVDDA

VDDB

INA

QA0
QA1

QA2
QA3

QA4
QA5

QA6
QA7

GND

OE (all outputs)

MDS 74CB218 A 1 Revision 021600 Printed 11/16/00

IntegratedCircuit Systems, Inc. • 525 Race Street • San Jose •CA •95126•[phone]tel • www.icst.com

INB

QB0
QB1
QB2

QB3
QB4

QB5
QB6

QB7

PRELIMINARY INFORMATION

Dual 1 to 8 Buffalo™ Clock Driver

MK74CB218

Pin Assignment

INA

1

QA0

2

QA1

3

QA2

4

QA3
QA4

QA5
QA6

QA7

OE

5
6
7

8
9

10
11
12
13

14

VDDA
VDDA

GND
GND

28
27

26
25

24
23
22

21
20
19

18
17
16

15

INB

QB0
QB1

QB2
VDDB

VDDB
QB3
QB4

GND
GND

QB5
QB6
QB7

VDD

Suggested Layout

A

0.01µF
G

V

For simplicity, series terminating resistors 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 VDDA

A

= connect to VDDB

B

B

0.01µF
G

0.01µF
G

= connect to VDD

V

Pin Descriptions

Number Name Type Description

1 INA I Clock input for eight A outputs.

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

5, 6 VDDA P Power supply for QA outputs. Connect to a voltage from 2.5V to 5V. Cannot exceed VDD.
7, 8 QA3, QA4 O Clock A outputs.

9, 10 GND P Connect to ground.

11, 12, 13 QA5, QA6, QA7 O Clock A outputs.

14 OE I Output Enable. Tri-states all clock outputs when this input is low. Internal pull-up to VDD.
15 VDD P Power supply for inputs.

16, 17, 18 QB7, QB6, QB5 O Clock B outputs.

19, 20 GND P Connect to ground.
21, 22 QB4, QB3 O Clock B outputs.
23, 24 VDDB P Power supply for QB outputs. Connect to a voltage from 2.5V to 5V. Cannot exceed VDD.

25, 26, 27 QB2, QB1, QB0 O Clock B outputs.

28 INB I Clock input for eight B outputs.

= connect to low

G

inductance ground plane

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

MDS 74CB218 A 2 Revision 021600 Printed 11/16/00

IntegratedCircuit Systems, Inc. • 525 Race Street • 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)

MK74CB218

Dual 1 to 8 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
Operating Voltage, VDDA or VDDB 2.375 VDD V
Input High Voltage, VIH (INA, INB pins) VDD-1.0 VDD/2 V
Input Low Voltage, VIL (INA, INB pins) VDD/2 1.0 V
Input High Voltage, VIH (OE pin) 2.0 V
Input Low Voltage, VIL (OE pin) 0.8 V
Output High Voltage, 3.3V and 5V IOH=-12mA VDD-0.4 V
Output High Voltage, 3.3V and 5V IOH=-25mA 2.4 V
Output Low Voltage, 3.3V and 5V IOL=25mA 0.8 V
Output High Voltage, 2.5V IOH=-16mA 2 V
Output Low Voltage, 2.5V IOL=16mA 0.5 V
Operating Supply Current, IDD, at 100 MHz No Load 55 mA

Output Impedance

Short Circuit Current Each output 100 mA
On-Chip Pull-up Resistor OE 250 kΩ
Input Capacitance 7 pF

14 Ω

Input Clock Frequency Note 4 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 A to B Skew At VDD/2. Note 3 100 250 ps
Output Enable Time, OE high to output on 20 ns
Output Disable Time, OE low to tri-state 20 ns

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. Between any two A outputs, or any two B outputs, with equal loading.

3. Between any clock A output and any clock B output with INA connected to INB, and equal loading.

4. See discussion and graph of speed versus load.

MDS 74CB218 A 3 Revision 021600 Printed 11/16/00

IntegratedCircuit Systems, Inc. • 525 Race Street • San Jose •CA •95126•[phone]tel • www.icst.com

PRELIMINARY INFORMATION

MK74CB218

Dual 1 to 8 Buffalo™ Clock Driver

Maximum Speed

The maximum speed at which the chip can operate is limited by power dissipation in 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 = VDDA = VDDB = 3.3 V, 70°C and with 33 Ω series termination resistors. 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 temperatures greater than 125°C. Also note
that the load capacitance per pin must include PC board parasitics such as trace capacitance.

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

300

250

200

150

100

Do not operate in this area .

50

0

806040200

Load Capacitance/per pin (pF)

Graph 1

MK74CB218

Maximum Speed with all VDDs at 3.3V

MDS 74CB218 A 4 Revision 021600 Printed 11/16/00

IntegratedCircuit Systems, Inc. • 525 Race Street • San Jose •CA •95126•[phone]tel • www.icst.com

PRELIMINARY INFORMATION

Inches

Millimeters

Dual 1 to 8 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

A1 0.004 0.010 0.10 0.25

b 0.008 0.012 0.20 0.30

c 0.007 0.010 0.18 0.25

D 0.337 0.344 8.55 8.75

e

E 0.228 0.244 5.80 6.20

E1 0.150 0.157 3.80 4.00

L 0.016 0.050 0.40 1.27

INDEX

AREA

E1 E

1 2

MK74CB218

D

A

A1 c

e

b

L

Ordering Information

Part/Order Number Marking Package Temperature

MK74CB218R MK74CB218R 28 pin SSOP 0-70 °C

MK74CB218RTR MK74CB218R 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 74CB218 A 5 Revision 021600 Printed 11/16/00

IntegratedCircuit Systems, Inc. • 525 Race Street • San Jose •CA •95126•[phone]tel • www.icst.com