STC5428 Datasheet, PDF (44/66 Pages) Connor-Winfield Corporation – Synchronous Clock for SETS

User_Specified_History, 0x31 (R/W)
STC5428
Synchronous Clock for SETS
DATASHEET
Address
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
0x31
0x32
0x33
Bits 0 - 7 of 32 bit User Holdover History
Bits 8 - 15 of 32 bit User Holdover History
Bits 16 - 23 of 32 bit User Holdover History
0x34
Bits 24 - 31 of 32 bit User Holdover History
User defined history of fractional frequency offset can be written/read to/from this register. The value is in 2’s
complement and the resolution is 0.745x10^-3 ppb. The bit HO_Usage of the register Control Mode determine
the usage of user specified history.
Default value: 0
History_Ramp, 0x35 (R/W)
Address
0x35
Bit7
Bit6
Bit5
Bit4
Long Term History Accumulator Bandwidth
Bit3
Bit2
Short Term History Accu-
mulator Bandwidth
Bit1
Bit0
Ramp Control
Holdover history bandwidth selection and ramp control.
Long-term history -3dB bandwidth is selected at Bit7~Bit4.
As described in section Device Holdover History, after the clock output is synchronized to the selected refer-
ence input for a period of History Settling Time, the device holdover history will begin and be continuously
updated by the long-term history. The time duration of the History Settling Time varies with a choice of the long-
term history -3dB bandwidth. For bandwidth of 1.3Hz to 9.9mHz, the History Settling Time is 2s to 256s as
shown in the table below. For 4.9mHz to 0.15mHz, the History Settling Time is only 256s as a result of an inter-
nal fast settling mode temporarily being applied.
Short-term history -3dB bandwidth is selected at Bit3~Bit2.
Ramp control (Bit1~Bit0) selects the maximum rate of frequency change to ensure the smooth frequency tran-
sition in and out of freerun or holdover mode.
Bits 7 ~ 4
0
1
2
3
4
5
6
7
8
9
Long Term
History -3dB
Bandwidth
1.3Hz
0.64Hz
0.32Hz
0.16Hz
79mHz
40mHz
20mHz
9.9mHz
4.9 mHz
2.5 mHz
History Settling Time
2s
4s
8s
16s
32s
64s
128s
256s
256s (with fast settling mode)
256s (with fast settling mode)
Page 44 of 66
Preliminary
Rev: 0.2
© Copyright the Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Date: April 3, 2014