SM34 Data Sheet #:

TM095

Page 23

Rev:

05 Date: 11/19/12

© Copyright 2012 The Connor-Winfield Corp. All Rights Reserved

Specifications subject to change without notice

SM34 Initialization:

Power-up:

1. If possible, always start up in master mode. After the module is powered up, hold the reset pin low for 10ms. Wait 1200ms

and read the contents of register 0x33. If it reads1 then the module came up properly. If it reads 0 then reset the module and re-read

register 0x33 after 1200ms. The contents of 0x33 must read 1 before continuing.

2. Remain in the default free-run mode for 10 seconds then read the value of bit 1 of register 0x11 or pin 2, the LOL alarm output.

If the LOL alarm is set, the reset pin must be pulled low as in 1 above. In the free-run mode the LOL alarm should never be set. This

indicates the module is in an invalid state. If there is no LOL alarm in free-run the module is ready.

Operation:

On power up or after a reset all the registers are loaded with their default values. The default values of some important registers

are given below assuming the SM34 module operates as a Master

Address(Hex)

Register Name

Value(Binary MSB first)

Notes

0x03

Bandwidth_PBO

00000111

Bandwidth = 0.098Hz

0x04

Ctl_Mode

0000r010

r - Read Only

0x05

Op_Mode

00010000

Indicates Free run mode

0x06

Max_Pullin_Range

01100100

0x0b

Ref_Mask

00000000

0x0d

Ref_Rev_Delay

00000101

0x0e

Phase_Offset

00000000

0x0f

Calibration

00000000

0x11

DPLL_Status

00000000

Indicates No Active Reference

0x13

Intr_Enable

00000000

Indicates Interrupts are disabled

0x1c-0x23

Ref(1-8)_Frq_Priority

xxxx0000

Frequencies are auto detected

0x33

Chksum

xxxxxxx1

Bit0 should be high to indicate that

data has been loaded

correctly from the EEPROM.

Performance Specifications continued

Capture range and Lock range – Capture range and lock range are the maximum frequency errors on the reference input within

which the phase locked loop is able to achieve lock and hold lock, respectively. The SM34 Stratum 3 performance is shown below:

Characteristic

SM34

Requirement

Capturerange

±25.5ppmmaximum

GR-1244-CORE,Sec3.4

Holdrange

±25.5ppmmaximum

GR-1244-CORE,Sec3.4

This is the minimum capability, and guarantees the ability to capture and lock with a reference that is offset the maximum allowed in

one direction in the presence of a clock that is offset the maximum in the opposite direction (4.6 ppm + 4.6 ppm = 9.2 ppm).

Master/Slave Skew and Reference switch settling time– Master/Slave Skew and Reference switch settling time performance

are shown below:

Characteristic

SM34

Requirement

Master/Slavephaseskew

<2nS

N/A

Referenceswitchsettlingtime

Stratum3:<100sec.upto20ppm

Stratum3:<100sec.up

frequencyoffset

to+/-4.6ppmfrequencyoffset