(Preliminary) Analog Frequency Multiplier

PL565-68 VCXO

PRODUCT DESCRIPTION

The Analog Frequency Multiplier (AFM) is the

industry’s first ‘Balanced Oscillator’ utilizing analog

multiplication of the fundamental frequency (at

quadruple frequency), combined with an attenuation

of the fundamental of the reference crystal, without

the use of a phase-locked loop (PLL), in CMOS

technology.

Micrel’s world’s best performing AFM products can

achieve up to 800 MHz output frequency with little

jitter or phase noise deterioration. In addition, the

low frequency input crystal requirement makes the

AFM the most affordable high-performance timing-

source in the market.

PL565-68 product utilizes low-power CMOS

technology and is housed in Green / RoHS

compliant 16-pin TSSOP, and 16-pin 3x3 QFN

packages.

QFN PACKAGE PIN-OUT

FEATURES

Non-PLL frequency multiplication by 2.

Input frequency from 62.5-160 MHz

Output frequency

o PL565-68: 125-320MHz

Low phase noise and jitter (equivalent to fundamental

crystal at the output frequency)

Ultra-low jitter

o RMS phase jitter < 100 fs (12kHz-20MHz)

o RMS random period jitter < 2 ps

Low phase noise

o -142 dBc/Hz @100kHz offset from the carrier

o -155 dBc/Hz @10MHz offset from the carrier

High linearity pull range (typ. 5%)

VCXO, set pullability ±100ppm ~ ±200ppm

Low input frequency eliminates the need for expensive

crystals

Differential output levels: LVPECL

Single 3.3V, ±10% power supply

Optional industrial temperature range (-40C to +85C)

Available in 16-pin Green/RoHS compliant 3x3 QFN

packages and as die.

VDDANA

OESEL

VDDOSC

L2X

12

13

11 10

9

8

14 P565-68 7

15 6

16 5

123 4

GNDANA

DNC

OE

XOUT

VCON

XIN

XOUT

PL565-68 BLOCK DIAGRAM

L2X

Oscillator

Amplifier

Frequency

X2

OE

QBAR

Q

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1(408) 9 44-0800 • fax +1(408) 474-1000 • www.micrel.com Rev 12/08/11 Page 1

(Preliminary) Analog Frequency Multiplier

PL565-68 VCXO

PHASE NOISE PERFORMANCE

Part

Number

Input

Freq.

Range

(MHz)

Output

Freq.

Range

(MHz)

Phase Noise at Frequency Offset From Carrier (dBc/Hz)

Carrier

Freq.

(MHz)

10 100 1 10 100 1 10

Hz Hz kHz kHz kHz MHz MHz

PL565-68 62.5 - 160 125 - 320 311.04

Phase noise was measured using Agilent E5052B.

-59 -93 -122 -137 -143 -149 -155

Phase

Jitter

12KHz ~

20MHz

(ps)

0.07

SUB-HARMONIC PERFORMANCE

Part

Number

Input

Output

Frequency Frequency

(MHz)

(MHz)

Spectral Specifications / Sub-harmonic Content (dBc), Freq. (MHz)

Carrier Frequency

(Fc)

@ -50%

(Fc)

@ +50%

(Fc)

PL565-68

155.52

311.04

311.04

Note: Spectral specifications were obtained usin g Agilent E7401A

-60

-60

AFM MULTIPLYING TECHNIQUE

The analog frequency multiplication is achieved through a “squaring” operation.

The math is as follows: SIN²(x) = 0.5 - 0.5×COS(2x)

A very important property of this processing is that the result is a pure sin e wave with double frequency. In theory

there are no sub harmonics but in practice the squaring operation is not perfect and a low level of sub harmonics

is present anyway. The key is that the resulting sub harmonics are very low and simple filtering with only one

inductor per squarer is adequate for excellent performance.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1(408) 9 44-0800 • fax +1(408) 474-1000 • www.micrel.com Rev 12/08/11 Page 4

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(Preliminary) Analog Frequency Multiplier

PL565-68 VCXO

INDUCTOR VALUE OPTIMIZATION

The required inductor values for the best performance depend on the operating frequency, and the board layout

or module specifications. The listed values in this datasheet are based on the calculated parasitic values from

Micrel’s evaluation board design. These inductor values provide the user with a starting point to determine the

optimum inductor values. Additional fine-tuning may be required to determine the optimal solution.

The inductor is recommended to be a high Q small size 0402 or 0603 SMD component, and must be placed

between L2X and adjacent VDDOSC pin. Place inductor as close to the IC as possible to minimize parasitic

effects and to maintain inductor Q.

To assist with the inductor value optimization, Micrel has developed AFM “Tuning Assistant” documents. You can

download these documents from Micrel’s web site (www.micrel.com). The documents consist of tables with

recommended inductor values for certain output frequency ranges.

Figure 10: Diagram Representation of the Related System Inductance and Capacitance

DIE SIDE

- Cinternal at L2X = 7.625 pF

- Cpad = 1.0 pF, Bond pad and its ESD circuitry

- C11 = 0.4 pF, The following amplifier stage

PCB side

- LWB1 = 2 nH, (2 places), Stray inductance

- Cstray = 0.5 pF, Stray capacitance

- L2X = 2x inductor

- C2X = range (0.1 to 2.7 pF), Fine tune

the tank, if used.

Work out the resonance of this network and you have a good first guess for the required inductor values for

optimum performance. Non-linear behavior at large signal amplitudes can shift the tank resonance significantly,

especially at the L2X side, to a lower frequency than the calculation suggests. The Tuning Assistant documents

are based upon actual lab tests and are corrected for the non -linear behavior.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1(408) 9 44-0800 • fax +1(408) 474-1000 • www.micrel.com Rev 12/08/11 Page 7

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