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MK74CB214
Dual 1 to 7 Buffalo™ Clock Driver
Description
The MK74CB214 Buffalo™ is a monolithic
CMOS high speed clock driver which is ideal for
Pentium™, 486, and RISC processor systems. It
consists of two identical single input to seven lowskew output, non-inverting clock drivers. When
combined with MicroClock’s MK14xx series of
low jitter clock synthesizers, the two chips form an
unequaled high performance clocking scheme for
new processors. This is the only solution on the
market that meets Intel’s specs for skew and jitter.
Many new Pentium systems require up to seven
outputs each of two low-skew clocks. This
monolithic solution eliminates any concern for
part-to-part skew matching. The MK74CB214 is
packaged in the tiny 20 pin SSOP, which uses the
same board space as the narrow 14 pin SOIC. An
added feature of the chip is the ability to produce
both 3.3V and 5V amplitude clocks by connecting
different voltages to VDDA and VDDB. See
MAN03 for dual voltage operation.
Features
• Tiny 20 pin SSOP (150 mil) package
• Dual one input to seven output clock drivers
• Outputs are skew matched to within 250ps
• A outputs and B outputs matched to 500ps
• 3.3V±10% and/or 5V±10% supply voltage
• Each set of seven clock drivers can run from
different supply voltages, making it possible to
have 3.3V and 5V amplitude clock outputs from
the same chip
• Clock speeds up to 66.67 MHz
Family of MicroClock Parts
The MK74CB214 Buffalo™ is designed to be
used with MicroClock’s clock synthesizer devices,
which will produce the CPU, memory, and local
bus clocks. The inputs of the Buffalo are matched
to the outputs of MicroClock clock synthesizers.
Consult MicroClock for applications support.
Block Diagram
INA
QA0
QA1
QA2
QA3
QA4
QA5
QA6
VDDA
GNDA
VDDB
INB
QB0
QB1
QB2
QB3
QB4
QB5
QB6
GNDB
MDS 74CB214 B 1 Revision 051396 Printed 11/16/00
MicroClock Incorporated•1171 North Fourth St.•San Jose•CA•95112•(408)295-9800tel•(408)295-9818fax
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MK74CB214
Dual 1 to 7 Buffalo™ Clock Driver
Pin Assignment
INA
QA0
QA1
VDDA
QA2
QA3
GNDA
QA4
QA5
QA6
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
INB
QB0
QB1
VDDB
QB2
QB3
GNDB
QB4
QB5
QB6
Suggested Layout
V
0.1µF
G
For simplicity, terminating resistors (if needed) are not
shown for the outputs, but should be placed as close to the
device as possible. It is most critical to have the 0.1µF
decoupling capacitors closest.
= connect to VDD
V
= connect to GNDG
V
0.1µF
G
Pin Descriptions
Number Name Type Description
1 INA I Clock input for seven A outputs.
2, 3 QA0, QA1 O Clock A outputs.
4 VDDA P Power supply for seven A buffers. Connect to +3.3V or +5V. Clock amplitude will match.
5, 6 QA2, QA3 O Clock A outputs.
7 GNDA P Connect to ground.
8, 9, 10 QA4, QA5, QA6 O Clock A outputs.
11, 12, 13 QB6, QB5, QB4 O Clock B outputs.
14 GNDB P Connect to ground.
15, 16 QB3, QB2 O Clock B outputs.
17 VDDB P Power supply for seven B buffers. Connect to +3.3V or +5V. Clock amplitude will match.
18, 19 QB1, QB0 O Clock B outputs.
20 INB I Clock input for sevent B outputs.
Type: I = Input, O = output, P = power supply connection
MDS 74CB214 B 2 Revision 051396 Printed 11/16/00
MicroClock Incorporated•1171 North Fourth St.•San Jose•CA•95112•(408)295-9800tel•(408)295-9818fax
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MK74CB214
ABSOLUTE MAXIMUM RATINGS (Note 1)
DC CHARACTERISTICS (VDD = 5V unless noted)
AC CHARACTERISTICS (VDD = 5V unless noted)
Dual 1 to 7 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 10 seconds 260 °C
Storage Temperature -65 150 °C
Operating Voltage, VDD 3.0 5.5 V
Input High Voltage, VIH (INA, INB pins) VDD-1 VDD/2 V
Input Low Voltage, VIL (INA, INB pins) VDD/2 1 V
Output High Voltage, 3.3V and 5V IOH=-8mA VDD-0.4 V
Output High Voltage, 3.3V and 5V IOH=-12mA 2.4 V
Output Low Voltage, 3.3V and 5V IOL=12mA 0.8 V
Operating Supply Current, IDD, at 66.6MHz No Load 20 mA
Short Circuit Current Each output ±70 mA
Short Circuit Current at 3.3V Each output ±35 mA
Input Capacitance 7 pF
Input Clock Frequency 67 MHz
Propagation Delay with load=10pF 2 3.5 5 ns
Propagation Delay with load=10pF At VDD=3.3V 2.5 4.5 6.5 ns
Output Clock Rise Time, 3.3V and 5V 0.8 to 2.0V 1.5 ns
Output Clock Fall Time, 3.3V and 5V 2.0 to 0.8V 1.5 ns
Output Clock Rising Edge Skew, 3.3V and 5V At VDD/2. Note 2 50 250 ps
Output Clock A to B Skew, 3.3V and 5V At VDD/2. Note 3 100 500 ps
Maximum load per output pin At 66.66 MHz 25 pF
Maximum load per side of 7 outputs Note 4 105 pF
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. With VDDA=VDDB and equal loading.
Combined with the 250ps uncertainty of MicroClock’s Clock Synthesizers, this adds to a 750ps total.
4. This is the load sum of all A outputs, or all B outputs, at 66.66MHz. The formula for per side load is CL (F) =
-3
7 x 10
f (in Hz)
MDS 74CB214 B 3 Revision 051396 Printed 11/16/00
MicroClock Incorporated•1171 North Fourth St.•San Jose•CA•95112•(408)295-9800tel•(408)295-9818fax
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MK74CB214
Inches
Millimeters
Dual 1 to 7 Buffalo™ Clock Driver
Package Outline and Package Dimensions
E H
h x 45°
D
Q
e
c
b
20 pin SSOP
Symbol Min Max Min Max
A 0.061 0.068 1.55 1.73
b 0.008 0.012 0.203 0.305
c 0.007 0.010 0.191 0.254
D 0.337 0.344 8.560 8.740
E 0.150 0.160 3.810 4.064
H 0.230 0.245 5.842 6.223
e
h 0.016 0.406
Q 0.005 0.01 0.127 0.254
A
Ordering Information
Part/Order Number Marking Package Temperature
MK74CB214R 74CB214R 20 pin SSOP 0-70°C
MK74CB214RTR 74CB214R Add Tape & Reel 0-70°C
While the information presented herein has been checked for both accuracy and reliability, MicroClock 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 MicroClock. MicroClock reserves the right to change any circuitry or specifications without notice. MicroClock does not
authorize or warrant any MicroClock product for use in life support devices or critical medical instruments.
Buffalo is a trademark of MicroClock Incorporated
Pentium is a trademark of Intel Corporation
MDS 74CB214 B 4 Revision 051396 Printed 11/16/00
MicroClock Incorporated•1171 North Fourth St.•San Jose•CA•95112•(408)295-9800tel•(408)295-9818fax
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