1.8V to 3.3V PicoPLL

47745 Fremont Blvd., Fremont, California 94538 Tel (510) 492-0990 Fax (510) 492-0991 www.phaselink.com Rev 2/25/07 Page 3

FUNCTIONAL DESCRIPTION

PL611s-27 is a highly featured, very flexible, advanced programmable PLL design for high performance, low-

power, small form-factor applications. The PL611s-27 accepts a reference clock input of 1MHz to 200MHz and is

capable of producing two outputs up to 55MHz. This flexible design allows the PL611s-27 to deliver any PLL

of the PL611s-27 are mentioned below:

PLL Programming

The PLL in the PL611s-27 is fully programmable.

The PLL is equipped with an 8-bit input frequency

divider (R-Counter), and an 11-bit VCO frequency

feedback loop divider (M-Counter). The output of

the PLL is transferred to a 5-bit post VCO divider (P-

Counter). The output frequency is determined by

the following formula [FOUT = FREF * M / (R * P) ].

Clock Output (CLK0)

CLK0 is the main clock output. The output of CLK0

output. The output drive level can be programmed to

Low Drive (4mA), Standard Drive (8mA) or High Drive

(16mA). The maximum output frequency is 125MHz.

Clock Output (CLK1)

The CLK1 feature allows the PL611s-27 to have an

additional clock output. This output can be

programmed to one of the following:

CLK0

CLK0 / 2

When using the OE function CLK1 will remain

“Always On” and will not be disabled when OE is

pulled low. When using the PDB function CLK1 will

be disabled along with CLK0. The output drive level

can be programmed to Low Drive (4mA), Standard

Drive (8mA) or High Drive (16mA). The maximum

output frequency is 125MHz.

Output Enable (OE)

The Output Enable feature allows the user to enable

and disable the clock output(s) by toggling the OE

pin. The OE pin incorporates a 60k

pull up

resistor giving a default condition of logic “1”.

The OE feature can be programmed to allow the

output to float (Hi Z), or to operate in the ‘Active low’

mode.

Power-Down Control (PDB)

The Power Down (PDB) feature allows the user to

put the PL611s-27 into “Sleep Mode”. When

activated (logic ‘0’), PDB ‘Disables the PLL, the

oscillator circuitry, counters, and all other active

circuitry. In Power Down mode the IC consumes

<10 A of power. The PDB pin incorporates a 60k

pull up resistor giving a default condition of logic “1”.

The PDB feature can be programmed to allow the

output to float (Hi Z), or to operate in the ‘Active low’

mode.

Frequency Select (FSEL)

The Frequency Select (FSEL) feature allows the

PL611s-27 to switch between two pre-programmed

outputs allowing the device “On the Fly” frequency

switching. The FSEL pin incorporates a 60k

pull

up resistor giving a default condition of logic “1”.