HMC832LP6GETR datasheet(47/49 Pages) AD

47 / 49 page

HMC832

Data Sheet

Rev. A | Page 46 of 48

EVALUATION PRINTED CIRCUIT BOARD (PCB)

Figure 53. Silk Screen and PCB Traces Top Layer

Figure 54. Silk Screen and PCB Traces Bottom Layer

The circuit board used in the application uses RF circuit design

techniques. Signal lines have 50 Ω impedance whereas the

package ground leads and exposed paddle are connected

directly to the ground plane similar to that shown in Figure 53

and Figure 54. Use a sufficient number of via holes to connect

the top and bottom ground planes. The evaluation circuit board

shown Figure 53 and Figure 54 is available from Analog Devices

upon request.

CHANGING EVALUATION BOARD REFERENCE

FREQUENCY AND CP CURRENT CONFIGURATION

The evaluation board is provided with a 50 MHz on board

reference oscillator, and Type 1 loop filter configuration, as

shown in Figure 52 (~127 kHz bandwidth, see Table 12).

The default register configuration file included in the Analog

Devices PLL evaluation software sets the comparison frequency

to 50 MHz (R = 1, that is, Register 0x02 = 1).

As with all PLLs and PLL with integrated VCOs, modifying the

comparison frequency or charge pump (CP) current results in

changes to the loop dynamics and ultimately, phase noise

performance. When making these changes there are several

items to keep in mind:



CP offset current setting: refer to the Charge Pump (CP)

and Phase Detector (PD) section.



LD configuration: refer to the Lock Detect section.

To redesign the loop filter for a particular application,

download the PLL design software tool by clicking on the

software download link on the HMC832 product page. Analog

Devices PLL design enables users to accurately model and

analyze performance of all Analog Devices PLLs, PLLs with

integrated VCOs, and clock generators. It supports various loop

filter topologies, and enables users to design custom loop filters

and accurately simulate resulting performance. For more

information, see the Loop Filter and Frequency Changes

section.

For evaluation purposes, the HMC832 evaluation board is

shipped with an on-board, low cost, low noise (100 ppm),

50 MHz VCXO, enabling evaluation of most parameters

including phase noise without any external references.

Exact phase or frequency measurements require the HMC832

to use the same reference as the measuring instrument. To

accommodate this requirement, the HMC832 evaluation board

includes the HMC1031MS8E; a simple low current integer-N

PLL that can lock the on-board VCXO to an external 10 MHz

reference input commonly provided by most test equipment. To

lock the HMC832 to an external 10 MHz reference, connect the

external reference output to the J5 input of the HMC832 evaluation

board and change the HMC1031MS8E integer divider value to

5 by changing the switch settings, D1 = 1 (SW1 to SW4 closed),

and D0 = 0 (SW2 to SW3 open), for more information see the

HMC1031MS8E data sheet.

EVALUATION KIT CONTENTS

The evaluation kit contains one HMC832LP6GE evaluation

PCB, a USB interface board, a six-foot USB A-male to USB

B-female cable, a CD ROM that contains the user manual,

evaluation PCB schematic, evaluation software, and Analog

Devices PLL design software. To order the evaluation kit, see

the Ordering Guide section for the product number.

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