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Issue A

ML12079

2.8 GHz Prescaler

MECL PLL Components

÷64/128/256 Prescaler

Legacy Device: Motorola MC12079

The ML12079 is a single modulus divide by 64, 128, 256 prescaler

for low power frequency division of a 2.8 GHz (typical) high frequen-

cy input signal. Divide ratio control inputs SW1 and SW2 select the

required divide ratio of ÷64, ÷128, or ÷256.

An external load resistor is required to terminate the output. A 1.2

kΩ resistor is recommended to achieve a 1.6 Vpp output swing, when

dividing a 1.1 GHz input signal by the minimum divide ratio of 64,

assuming a 12 pF load. Output current can be minimized dependent

on conditions such as output frequency, capacitive load being driven,

and output voltage swing required. Typical values for load resistors

are included in the Vout specification for various divide ratios at 2.8

GHz input frequency.

• 2.8 GHz Toggle Frequency

• Supply Voltage 4.5 to 5.5 V

• Low Supply Current 9mA Typical at VCC = 5.0 V

• Operating Temperature Range of TA = –40 to 85°C

P DIP 8 = PP

PLASTIC PACKAGE

CASE 626

SO 8 = -5P

PLASTIC PACKAGE

CASE 751

8

1

1

8

CROSS REFERENCE/ORDERING INFORMATION

MOTOROLA

P DIP 8

MC12079P

ML12079PP

SO 8

MC12079D

ML12079-5P

LANSDALE

PACKAGE

Note: Lansdale lead free (Pb) product, as it

becomes available, will be identified by a part

number prefix change from

ML to MLE.

PIN CONNECTIONS

IN

(Top View)

8

IN

VCC

SW1

OUT

NC

SW2

Gnd

7

6

5

1

2

3

4

FUNCTIONAL TABLE

SW1

SW2

Divide Ratio

H

H

64

H

L

128

L

H

128

L

L

256

NOTE: SW1 & SW2: H = VCC, L = Open.

MAXIMUM RATINGS

Characteristic

Symbol

Range

Unit

Power Supply Voltage, Pin 2

VCC

–0.5 to 7.0

Vdc

Operating Temperature Range

TA

–40 to 85

°C

Storage Temperature Range

Tstg

–65 to 150

°C

Maximum Output Current, Pin 4

IO

4.0

mA