MT9046
T1/E1 System Synchronizer
with Holdover
Data Sheet
Features
•
February 2005
Supports AT&T TR62411 and Bellcore GR-1244CORE, Stratum 4 Enhanced and Stratum 4 timing
for DS1 interfaces
•
Supports ETSI ETS 300 011, TBR 4, TBR 12 and
TBR 13 timing for E1 interfaces
•
Selectable 19.44 MHz, 1.544 MHz, 2.048 MHz or
8kHz input reference signals
•
Provides C1.5, C2, C4, C6, C8, C16, and C19
(STS-3/OC3 clock divided by 8) output clock
signals
Ordering Information
MT9046AN
MT9046ANR
MT9046AN1
MT9046ANR1
*Pb
48 Pin SSOP
48 Pin SSOP
48 Pin SSOP*
48 Pin SSOP*
Free Matte Tin
Tubes
Tape & Reel
Tubes
Tape & Reel
-40°C to +85°C
Applications
•
Synchronization and timing control for Customer
Premises Equipment (CPE)
•
ST-BUS clock and frame pulse sources
•
Provides 5 styles of 8 KHz framing pulses
•
Holdover frequency accuracy of 0.2 PPM
•
Holdover indication
Description
•
Attenuates wander from 1.9 Hz
•
Fast lock mode
•
Provides Time Interval Error (TIE) correction
•
Accepts reference inputs from two independent
sources
•
JTAG Boundary Scan
The MT9046 T1/E1 System Synchronizer contains a
digital phase-locked loop (DPLL), which provides timing
and synchronization signals for multitrunk T1 and E1
primary rate transmission links. The device has
reference switching and frequency holdover capabilities
to help maintain connectivity during temporary
synchronization interruptions.
OSCi
OSCo
Master Clock
TCK
TDI
TMS
TRST
TDO
IEEE
1149.1a
PRI
SEC
Reference
Select
MUX
TIE
Corrector
Circuit
TIE
Corrector
Enable
VDD
DPLL
State
Select
Output
Interface
Circuit
Input
Impairment
Monitor
State
Select
Control State Machine
Feedback
MS1 MS2
VSS
Virtual
Reference
Selected
Reference
Reference
Select
RSEL
LOCK
TCLR
RST HOLDOVER PCCi FLOCK
Frequency
Select
MUX
FS1
FS2
Figure 1 - Functional Block Diagram
Zarlink Semiconductor US Patent No. 5,602,884, UK Patent No. 0772912,
France Brevete S.G.D.G. 0772912; Germany DBP No. 69502724.7-08
1
Zarlink Semiconductor Inc.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 2003-2005, Zarlink Semiconductor Inc. All Rights Reserved.
C19o
C1.5o
C2o
C4o
C6o
C8o
C16o
F0o
F8o
F16o
RSP
TSP
MT9046
Data Sheet
The MT9046 generates ST-BUS clock and framing signals that are phase locked to either a 19.44 MHz,
2.048 MHz, 1.544 MHz, or 8 kHz input reference.
The MT9046 is compliant with AT&T TR62411 and Bellcore GR-1244-CORE Stratum 4 Enhanced, and Stratum 4
and ETSI ETS 300 011 interfaces. It will meet the jitter tolerance, jitter transfer, intrinsic jitter, frequency accuracy,
capture range, phase change slope frequency and MTIE requirements for these specifications.
VSS
RST
TCLR
NC
SEC
PRI
Vdd
OSCo
OSCi
Vss
F16o
F0o
RSP
TSP
F8o
C1.5o
Vdd
LOCK
C2o
C4o
C19o
FLOCK
Vss
IC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
SSOP
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
TMS
TCK
TRST
TDI
TDO
NC
IC
FS1
FS2
IC
RSEL
MS1
MS2
Vdd
IC
IC
NC
Vss
PCCi
HOLDOVER
Vdd
C6o
C16o
C8o
Figure 2 - Pin Connections
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Pin Description
Pin #
Name
Description
1,10,
23,31
VSS
Ground. 0 Volts. (Vss pads).
2
RST
Reset (Input). A logic low at this input resets the MT9046. To ensure proper operation, the
device must be reset after reference signal frequency changes and power-up. The RST pin
should be held low for a minimum of 300 ns. While the RST pin is low, all frame pulses
except RST and TSP and all clock outputs except C6o, C16o and C19o are at logic high.
The RST, TSP, C6o and C16o are at logic low during reset. The C19o is free-running
during reset. Following a reset, the input reference source, output clocks and frame pulses
are phase aligned as shown in Figure 13.
3
TCLR
TIE Circuit Reset (Input). A logic low at this input resets the Time Interval Error (TIE)
correction circuit resulting in a realignment of input phase with output phase as shown in
Figure 13. The TCLR pin should be held low for a minimum of 300 ns. This pin is internally
pulled down to VSS.
4
NC
5
SEC
Secondary Reference (Input). This is one of two (PRI & SEC) input reference sources
(falling edge) used for synchronization. One of four possible frequencies (8 kHz, 1.544 MHz,
2.048 MHz or 19.44 MHz) may be used. The selection of the input reference is based upon
the MS1, MS2, RSEL, and PCCi control inputs.This pin is internally pulled up to VDD.
6
PRI
Primary Reference (Input). See pin description for SEC. This pin is internally pulled up to
VDD.
7,17
28,35
VDD
Positive Supply Voltage. +3.3 VDC nominal.
8
OSCo
Oscillator Master Clock (CMOS Output).
For crystal operation, a 20 MHz crystal is
connected from this pin to OSCi, see Figure 9. For clock oscillator operation, this pin is left
unconnected, see Figure 8.
9
OSCi
Oscillator Master Clock (CMOS Input). For crystal operation, a 20 MHz crystal is
connected from this pin to OSCo, see Figure 9. For clock oscillator operation, this pin is
connected to a clock source, see Figure 8.
11
F16o
Frame Pulse ST-BUS 8.192 Mb/s (CMOS Output). This is an 8 kHz 61 ns active low framing
pulse, which marks the beginning of an ST-BUS frame. This is typically used for ST-BUS
operation at 8.192 Mb/s. See Figure 14.
12
F0o
Frame Pulse ST-BUS 2.048 Mb/s (CMOS Output). This is an 8 kHz 244 ns active low
framing pulse, which marks the beginning of an ST-BUS frame. This is typically used for STBUS operation at 2.048 Mb/s and 4.096 Mb/s. See Figure 14.
13
RSP
Receive Sync Pulse (CMOS Output). This is an 8 kHz 488 ns active high framing pulse,
which marks the beginning of an ST-BUS frame. This is typically used for connection to the
Siemens MUNICH-32 device. See Figure 15.
14
TSP
Transmit Sync Pulse (CMOS Output). This is an 8 kHz 488 ns active high framing pulse,
which marks the beginning of an ST-BUS frame. This is typically used for connection to the
Siemens MUNICH-32 device. See Figure 15.
15
F8o
Frame Pulse (CMOS Output). This is an 8 kHz 122 ns active high framing pulse, which
marks the beginning of a frame. See Figure 14.
16
C1.5o
No Connection. Leave open Circuit
Clock 1.544 MHz (CMOS Output). This output is used in T1 applications.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Pin Description (continued)
Pin #
Name
Description
18
LOCK
Lock Indicator (CMOS Output). This output goes high when the PLL is frequency locked to
the input reference.
19
C2o
Clock 2.048 MHz (CMOS Output). This output is used for ST-BUS operation at 2.048 Mb/s.
20
C4o
Clock 4.096 MHz (CMOS Output). This output is used for ST-BUS operation at 2.048 Mb/s
and 4.096 Mb/s.
21
C19o
Clock 19.44 MHz (CMOS Output). This output is used in OC3/STS3 applications.
22
FLOCK
24
IC
25
C8o
26
C16o
Clock 16.384 MHz (CMOS Output). This output is used for ST-BUS operation with a
16.384 MHz clock.
27
C6o
Clock 6.312 Mhz (CMOS Output). This output is used for DS2 applications.
29
HOLD
OVER
Holdover (CMOS Output). This output goes to a logic high whenever the PLL goes into
holdover mode.
30
PCCi
Phase Continuity Control Input (Input). The signal at this pin affects the state changes
between Primary Holdover Mode and Primary Normal Mode, and Primary Holdover Mode and
Secondary Normal Mode. The logic level at this input is gated in by the rising edge of F8o.
See Table 4.
32
NC
No connection. Leave open circuit
33,34
IC
Internal Connection. Tie low for normal operation.
36
MS2
Mode/Control Select 2 (Input). This input determines the state (Normal, Holdover or
Freerun) of operation. The logic level at this input is gated in by the rising edge of F8o. See
Table 3.
37
MS1
Mode/Control Select 1 (Input). The logic level at this input is gated in by the rising edge of
F8o. See pin description for MS2. This pin is internally pulled down to VSS.
38
RSEL
Reference Source Select (Input). A logic low selects the PRI (primary) reference source as
the input reference signal and a logic high selects the SEC (secondary) input. The logic level
at this input is gated in by the rising edge of F8o. See Table 2. This pin is internally pulled
down to VSS.
39
IC
40
FS2
Frequency Select 2 (Input). This input, in conjunction with FS1, selects which of four
possible frequencies (8 kHz, 1.544 MHz, 2.048 MHz or 19.44 MHz) may be input to the PRI
and SEC inputs. See Table 1.
41
FS1
Frequency Select 1 (Input). See pin description for FS2.
42
IC
Internal Connection. Tie low for normal operation.
43
NC
No Connection. Leave open Circuit
44
TDO
Fast Lock Mode (Input). Set high to allow the PLL to quickly lock to the input reference
(less than 500 ms locking time).
Internal Connection. Tie low for normal operation.
Clock 8.192 MHz (CMOS Output). This output is used for ST-BUS operation at 8.192 Mb/s.
Internal Connection. Tie low for normal operation.
Test Serial Data Out (CMOS Output). JTAG serial data is output on this pin on the falling
edge of TCK. This pin is held in high impedance state when JTAG scan is not enable.
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MT9046
Data Sheet
Pin Description (continued)
Pin #
Name
Description
45
TDI
46
TRST
Test Reset (Input). Asynchronously initializes the JTAG TAP controller by putting it in the
Test-Logic-Reset state. If not used, this pin should be held low.
47
TCK
Test Clock (Input): Provides the clock to the JTAG test logic. This pin is internally pulled up to
VDD.
48
TMS
Test Mode Select (Input). JTAG signal that controls the state transitions of the TAP
controller. This pin is internally pulled up to VDD.
Test Serial Data In (Input). JTAG serial test instructions and data are shifted in on this pin.
This pin is internally pulled up to VDD.
Functional Description
The MT9046 is a Multitrunk System Synchronizer with frequency holdover capability, providing timing (clock) and
synchronization (frame) signals to interface circuits for T1 and E1 Primary Rate Digital Transmission links. Figure 1
is a functional block diagram which is described in the following sections.
Reference Select MUX Circuit
The MT9046 accepts two simultaneous reference input signals and operates on their falling edges. Either the
primary reference (PRI) signal or the secondary reference (SEC) signal can be selected as input to the TIE
Corrector Circuit. The selection is based on the Control, Mode and Reference Selection of the device. See Table 1
and Table 4.
Frequency Select MUX Circuit
The MT9046 operates with one of four possible input reference frequencies (8 kHz, 1.544 MHz, 2.048 MHz or
19.44 MHz). The frequency select inputs (FS1 and FS2) determine which of the four frequencies may be used at
the reference inputs (PRI and SEC). Both inputs must have the same frequency applied to them. A reset (RST)
must be performed after every frequency select input change. See Table 1.
FS2
FS1
Input Frequency
0
0
19.44 MHz
0
1
8 kHz
1
0
1.544 MHz
1
1
2.048 MHz
Table 1 - Input Frequency Selection
Time Interval Error (TIE) Corrector Circuit
The TIE corrector circuit, when enabled, prevents a step change in phase on the input reference signals (PRI or
SEC) from causing a step change in phase at the input of the DPLL block of Figure 1.
During reference input rearrangement, such as during a switch from the primary reference (PRI) to the secondary
reference (SEC), a step change in phase on the input signals will occur. A phase step at the input of the DPLL
would lead to unacceptable phase changes in the output signal.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
TCLR
Resets Delay
Control
Circuit
Control Signal
Delay Value
PRI or SEC
from
Reference
Select Mux
Programmable
Delay Circuit
Virtual
Reference
to DPLL
Compare
Circuit
TIE Corrector
Enable
from
State Machine
Feedback
Signal from
Frequency
Select MUX
Figure 3 - TIE Corrector Circuit
As shown in Figure 3, the TIE Corrector Circuit receives one of the two reference (PRI or SEC) signals, passes the
signal through a programmable delay line, and uses this delayed signal as an internal virtual reference, which is
input to the DPLL. Therefore, the virtual reference is a delayed version of the selected reference.
During a switch from one reference to the other, the State Machine first changes the mode of the device
from Normal to Holdover. In Holdover Mode, the DPLL no longer uses the virtual reference signal, but generates an
accurate clock signal using storage techniques. The Compare Circuit then measures the phase delay between the
current phase (feedback signal) and the phase of the new reference signal. This delay value is passed to the
Programmable Delay Circuit (See Figure 3). The new virtual reference signal is now at the same phase position as
the previous reference signal would have been if the reference switch not taken place. The State Machine then
returns the device to Normal Mode.
The DPLL now uses the new virtual reference signal, and since no phase step took place at the input of the DPLL,
no phase step occurs at the output of the DPLL. In other words, reference switching will not create a phase change
at the input of the DPLL, or at the output of the DPLL.
Since internal delay circuitry maintains the alignment between the old virtual reference and the new virtual
reference, a phase error may exist between the selected input reference signal and the output signal of the DPLL.
This phase error is a function of the difference in phase between the two input reference signals during reference
rearrangements. Each time a reference switch is made, the delay between input signal and output signal will
change. The value of this delay is the accumulation of the error measured during each reference switch.
The programmable delay circuit can be zeroed by applying a logic low pulse to the TIE Circuit Reset (TCLR) pin. A
minimum reset pulse width is 300 ns. This results in a phase alignment between the input reference signal and the
output signal as shown in Figure 14. The speed of the phase alignment correction is limited to 5 ns per 125 us, and
convergence is in the direction of least phase travel.
The state diagram of Figure 7 indicates which state changes the TIE Corrector Circuit is activated.
Digital Phase Lock Loop (DPLL)
As shown in Figure 4, the DPLL of the MT9046 consists of a Phase Detector, Limiter, Loop Filter, Digitally
Controlled Oscillator, and a Control Circuit.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Phase Detector - the Phase Detector compares the virtual reference signal from the TIE Corrector circuit with the
feedback signal from the Frequency Select MUX circuit, and provides an error signal corresponding to the phase
difference between the two. This error signal is passed to the Limiter circuit. The Frequency Select MUX allows the
proper feedback signal to be externally selected (e.g., 8 kHz, 1.544 MHz, 2.048 MHz or 19.44 MHz).
Virtual Reference
from
TIE Corrector
Phase
Detector
Feedback Signal
from
Frequency Select MUX
Limiter
Loop Filter
State Select
from
Input Impairment Monitor
Digitally
Controlled
Oscillator
DPLL Reference
to
Output Interface Circuit
Control
Circuit
State Select
from
State Machine
Figure 4 - DPLL Block Diagram
Limiter - the Limiter receives the error signal from the Phase Detector and ensures that the DPLL responds to all
input transient conditions with a maximum output phase slope of 5 ns per 125 us. This is well within the maximum
phase slope of 7.6 ns per 125 us or 81 ns per 1.326 ms specified by AT&T TR62411 and Bellcore GR-1244-CORE,
respectively.
Loop Filter - the Loop Filter is similar to a first order low pass filter with a 1.9 Hz cutoff frequency for all four
reference frequency selections (8 kHz, 1.544 MHz, 2.048 MHz or 19.44 MHz). This filter ensures that the jitter
transfer requirements in ETS 300 011 and AT&T TR62411 are met.
Control Circuit - the Control Circuit uses status and control information from the State Machine and the Input
Impairment Circuit to set the mode of the DPLL. The three possible modes are Normal, Holdover and Freerun.
Digitally Controlled Oscillator (DCO) - the DCO receives the limited and filtered signal from the Loop Filter, and
based on its value, generates a corresponding digital output signal. The synchronization method of the DCO is
dependent on the state of the MT9046.
In Normal Mode, the DCO provides an output signal which is frequency and phase locked to the selected input
reference signal.
In Holdover Mode, the DCO is free running at a frequency equal to the last (less 30 ms to 60 ms) frequency the
DCO was generating while in Normal Mode.
In Freerun Mode, the DCO is free running with an accuracy equal to the accuracy of the OSCi 20 MHz source.
Lock Indicator - If the PLL is in frequency lock (frequency lock means the center frequency of the PLL is identical to
the line frequency), and the input phase offset is small enough such that no phase slope limiting is exhibited, then
the lock signal will be set high. For specific Lock Indicator design recommendations see the Applications - Lock
Indicator section.
Output Interface Circuit
The output of the DCO (DPLL) is used by the Output Interface Circuit to provide the output signals shown in Figure
5. The Output Interface Circuit uses four Tapped Delay Lines followed by a T1 Divider Circuit, an E1 Divider Circuit,
and a DS2 Divider Circuit to generate the required output signals.
Four tapped delay lines are used to generate 16.384 MHz, 12.352 MHz, 12.624 MHz and 19.44 MHz signals.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
The E1 Divider Circuit uses the 16.384 MHz signal to generate four clock outputs and three frame pulse outputs.
The C8o, C4o and C2o clocks are generated by simply dividing the C16o clock by two, four and eight respectively.
These outputs have a nominal 50% duty cycle.
The T1 Divider Circuit uses the 12.384 MHz signal to generate the C1.5o clock by dividing the internal C12 clock
by eight. This output has a nominal 50% duty cycle.
The DS2 Divider Circuit uses the 12.624 MHz signal to generate the clock output C6o. This output has a nominal
50% duty cycle.
T1 Divider
C1.5o
12 MHz
Tapped
Delay
Line
From
DPLL
Tapped
Delay
Line
Tapped
Delay
Line
Tapped
Delay
Line
E1 Divider
C2o
C4o
C8o
C16o
F0o
F8o
F16o
DS2 Divider
C6o
16 MHz
12 MHz
19 MHz
C19o
Figure 5 - Output Interface Circuit Block Diagram
The frame pulse outputs (F0o, F8o, F16o, TSP, and RSP) are generated directly from the C16 clock.
The T1 and E1 signals are generated from a common DPLL signal. Consequently, all frame pulse and clock outputs
are locked to one another for all operating states, and are also locked to the selected input reference in Normal
Mode. See Figures 14 & 16.
All frame pulse and clock outputs have limited driving capability, and should be buffered when driving high
capacitance (e.g., 30 pF) loads.
Input Impairment Monitor
This circuit monitors the input signal to the DPLL and automatically enables the Holdover Mode (Auto-Holdover)
when the frequency of the incoming signal is outside the Auto-Holdover capture range. (See AC Electrical
Characteristics - Performance). This includes a complete loss of incoming signal, or a large frequency shift in the
incoming signal. When the incoming signal returns to normal, the DPLL is returned to Normal Mode with the output
signal locked to the input signal. The holdover output signal in the MT9046 is based on the incoming signal 30 ms
minimum to 60 ms prior to entering the Holdover Mode. The amount of phase drift while in holdover is negligible
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
because the Holdover Mode is very accurate (e.g., ±0.2 ppm).
and output after switching back to Normal Mode is preserved.
Consequently, the phase delay between the input
State Machine Control
As shown in Figure 1, this state machine controls the Reference Select MUX, the TIE Corrector Circuit and the
DPLL. Control is based on the logic levels at the control inputs RSEL, MS1, MS2 and PCCi (See Figure 6). When
switching from Primary Holdover to Primary Normal, the TIE Corrector Circuit is enabled when PCCi = 1, and
disabled when PCCi = 0.
All state machine changes occur synchronously on the rising edge of F8o. See the Control and Mode of Operation
section for full details.
To
Reference
Select MUX
To TIE
Corrector
Enable
To DPLL
State
Select
Control
State Machine
RSEL
PCCi
MS2
MS1
Figure 6 - Control State Machine Block Diagram
Master Clock
The MT9046 can use either a clock or crystal as the master timing source. For recommended master timing
circuits, see the Applications - Master Clock section.
Control and Mode of Operation
The active reference input (PRI or SEC) is selected by the RSEL pin as shown in Table 2.
RSEL
Input Reference
0
PRI
1
SEC
Table 2 - Input Reference Selection
MS2
MS1
Mode
0
0
NORMAL
0
1
HOLDOVER
1
0
FREERUN
1
1
Reserved
Table 3 - Operating Modes and States
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
The MT9046 has three possible modes of operation, Normal, Holdover and Freerun.
As shown in Table 3, Mode/Control Select pins MS2 and MS1 select the mode and method of control. Refer to
Table 4 and Figure 7 for details of the state change sequences.
Normal Mode
Normal Mode is typically used when a slave clock source, synchronized to the network is required.
In Normal Mode, the MT9046 provides timing (C1.5o, C2o, C4o, C8o, C16o and C19o) and frame synchronization
(F0o, F8o, F16o, TSP and RSP) signals, which are synchronized to one of two reference inputs (PRI or SEC). The
input reference signal may have a nominal frequency of 8 kHz, 1.544 MHz, 2.048 MHz or 19.44 MHz.
From a reset condition, the MT9046 will take up to 30 seconds (see AC Electrical Characteristics) of input reference
signal to output signals which are synchronized (phase locked) to the reference input.
The selection of input references is control dependent as shown in state Table 4. The reference frequencies are
selected by the frequency control pins FS2 and FS1 as shown in Table 1.
Fast Lock Mode
Fast Lock Mode is a submode of Normal Mode, it is used to allow the MT9046 to lock to a reference more quickly
than Normal Mode will allow. Typically, the PLL will lock to the incoming reference within 500 ms if the FLOCK pin is
set high.
Holdover Mode
Holdover Mode is typically used for short durations (e.g., 2 seconds) while network synchronization is temporarily
disrupted.
In Holdover Mode, the MT9046 provides timing and synchronization signals, which are not locked to an external
reference signal, but are based on storage techniques. The storage value is determined while the device is in
Normal Mode and locked to an external reference signal
When in Normal Mode, and locked to the input reference signal, a numerical value corresponding to the MT9046
output reference frequency is stored alternately in two memory locations every 30 ms. When the device is switched
into Holdover Mode, the value in memory from between 30 ms and 60 ms is used to set the output frequency of the
device.
The frequency accuracy of Holdover Mode is ±0.2 ppm, which translates to a worst case 1 frame (125 us) slip in 10
minutes.
Two factors affect the accuracy of Holdover Mode. One is drift on the Master Clock while in Holdover Mode, drift on
the Master Clock directly affects the Holdover Mode accuracy. Note that the absolute Master Clock (OSCi)
accuracy does not affect Holdover accuracy, only the change in OSCi accuracy while in Holdover. For example, a
±32 ppm master clock may have a temperature coefficient of ±0.1ppm per degree C. So a ±10 degree change in
temperature, while the MT9046 is in Holdover Mode may result in an additional offset (over the ±0.2 ppm) in
frequency accuracy of ±1 ppm.
The other factor affecting accuracy is large jitter on the reference input prior (30 ms to 60 ms) to the mode switch.
For instance, jitter of 7.5 UI at 700 Hz may reduce the Holdover Mode accuracy from ±0.2 ppm to ±0.25 ppm.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Freerun Mode
Freerun Mode is typically used when a master clock source is required, or immediately following system power-up
before network synchronization is achieved.
In Freerun Mode, the MT9046 provides timing and synchronization signals which are based on the master clock
frequency (OSCi) only, and are not synchronized to the reference signals (PRI and SEC).
The accuracy of the output clock is equal to the accuracy of the master clock (OSCi). So if a ±32 ppm output clock
is required, the master clock must also be ±32 ppm. See Applications - Crystal and Clock Oscillator sections.
MT9046 Measures of Performance
The following are some synchronizer performance indicators and their corresponding definitions.
Intrinsic Jitter
Intrinsic jitter is the jitter produced by the synchronizing circuit and is measured at its output. It is measured by
applying a reference signal with no jitter to the input of the device, and measuring its output jitter. Intrinsic jitter may
also be measured when the device is in a non-synchronizing mode, such as free running or holdover, by measuring
the output jitter of the device. Intrinsic jitter is usually measured with various bandlimiting filters depending on the
applicable standards. In the MT9046, the intrinsic Jitter is limited to less than 0.02 UI on the 2.048 MHz and
1.544 MHz clocks.
Jitter Tolerance
Jitter tolerance is a measure of the ability of a PLL to operate properly (i.e., remain in lock and or regain lock in the
presence of large jitter magnitudes at various jitter frequencies) when jitter is applied to its reference. The applied
jitter magnitude and jitter frequency depends on the applicable standards.
Jitter Transfer
Jitter transfer or jitter attenuation refers to the magnitude of jitter at the output of a device for a given amount of jitter
at the input of the device. Input jitter is applied at various amplitudes and frequencies, and output jitter is measured
with various filters depending on the applicable standards.
For the MT9046, two internal elements determine the jitter attenuation. This includes the internal 1.9 Hz low pass
loop filter and the phase slope limiter. The phase slope limiter limits the output phase slope to 5 ns/125 us.
Therefore, if the input signal exceeds this rate, such as for very large amplitude low frequency input jitter, the
maximum output phase slope will be limited (i.e., attenuated) to 5 ns/125 us.
The MT9046 has twelve outputs with three possible input frequencies (except for 19.44 MHz, which is internally
divided to 8 KHz) for a total of 36 possible jitter transfer functions. Since all outputs are derived from the same
signal, the jitter transfer values for the four cases, 8 kHz to 8 kHz, 1.544 MHz to 1.544 MHz and 2.048 MHz to
2.048 MHz can be applied to all outputs.
It should be noted that 1 UI at 1.544 MHz is 644 ns, which is not equal to 1 UI at 2.048 MHz, which is 488 ns.
Consequently, a transfer value using different input and output frequencies must be calculated in common units
(e.g., seconds) as shown in the following example.
What is the T1 and E1 output jitter when the T1 input jitter is 20UI (T1 UI Units) and the T1 to T1 jitter attenuation is
18 dB?
Using the above method, the jitter attenuation can be calculated for all combinations of inputs and outputs based on
the three jitter transfer functions provided.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
A
–----- 20
OutputT1 = InputT1 ×10
OutputT1 = 20 ×10
18-
–------- 20
= 2.5UI ( T1 )
( 1UIT1 )
OutputE1 = OutputT1 × ---------------------( 1UIE1 )
( 644ns )
OutputE1 = OutputT1 × ------------------- = 3.3UI ( T1 )
( 488ns )
Note that the resulting jitter transfer functions for all combinations of inputs (8 kHz, 1.544 MHz, 2.048 MHz) and
outputs (8 kHz, 1.544 MHz, 2.048 MHz, 4.096 MHz, 8.192 MHz, 16.384 MHz, 19.44 MHz) for a given input signal
(jitter frequency and jitter amplitude) are the same.
Since intrinsic jitter is always present, jitter attenuation will appear to be lower for small input jitter signals than for
large ones. Consequently, accurate jitter transfer function measurements are usually made with large input jitter
signals (e.g., 75% of the specified maximum jitter tolerance).
Frequency Accuracy
Frequency accuracy is defined as the absolute tolerance of an output clock signal when it is not locked to an
external reference, but is operating in a free running mode. For the MT9046, the Freerun accuracy is equal to the
Master Clock (OSCi) accuracy.
Holdover Accuracy
Holdover accuracy is defined as the absolute tolerance of an output clock signal, when it is not locked to an external
reference signal, but is operating using storage techniques. For the MT9046, the storage value is determined while
the device is in Normal Mode and locked to an external reference signal.
The absolute Master Clock (OSCi) accuracy of the MT9046 does not affect Holdover accuracy, but the change in
OSCi accuracy while in Holdover Mode does.
Capture Range
Also referred to as pull-in range. This is the input frequency range over which the synchronizer must be able to pull
into synchronization. The MT9046 capture range is equal to ±230 ppm minus the accuracy of the master clock
(OSCi). For example, a 32 ppm master clock results in a capture range of 198 ppm.
Lock Range
This is the input frequency range over which the synchronizer must be able to maintain synchronization. The lock
range is equal to the capture range for the MT9046.
Phase Slope
Phase slope is measured in seconds per second and is the rate at which a given signal changes phase with respect
to an ideal signal. The given signal is typically the output signal. The ideal signal is of constant frequency and is
nominally equal to the value of the final output signal or final input signal.
Time Interval Error (TIE)
TIE is the time delay between a given timing signal and an ideal timing signal.
12
Zarlink Semiconductor Inc.
MT9046
Data Sheet
Maximum Time Interval Error (MTIE)
MTIE is the maximum peak to peak delay between a given timing signal and an ideal timing signal within a
particular observation period.
MTIE ( S ) = TIEmax ( t ) – TIEmin ( t )
Phase Continuity
Phase continuity is the phase difference between a given timing signal and an ideal timing signal at the end of a
particular observation period. Usually, the given timing signal and the ideal timing signal are of the same frequency.
Phase continuity applies to the output of the synchronizer after a signal disturbance due to a reference switch or a
mode change. The observation period is usually the time from the disturbance, to just after the synchronizer has
settled to a steady state.
In the case of the MT9046, the output signal phase continuity is maintained to within ±5 ns at the instance (over
one frame) of all reference switches and all mode changes. The total phase shift, depending on the switch or type
of mode change, may accumulate up to 200 ns over many frames. The rate of change of the 200 ns phase shift is
limited to a maximum phase slope of approximately 5 ns/125 us. This meets the AT&T TR62411 maximum phase
slope requirement of 7.6 ns/125 us and Bellcore GR-1244-CORE (81 ns/1.326 ms).
Phase Lock Time
This is the time it takes the synchronizer to phase lock to the input signal. Phase lock occurs when the input signal
and output signal are not changing in phase with respect to each other (not including jitter).
Lock time is very difficult to determine because it is affected by many factors which include:
•
initial input to output phase difference
•
initial input to output frequency difference
•
synchronizer loop filter
•
synchronizer limiter
Although a short lock time is desirable, it is not always possible to achieve due to other synchronizer requirements.
For instance, better jitter transfer performance is achieved with a lower frequency loop filter which increases lock
time. And better (smaller) phase slope performance (limiter) results in longer lock times. The MT9046 loop filter and
limiter were optimized to meet the AT&T TR62411 jitter transfer and phase slope requirements. Consequently,
phase lock time, which is not a standards requirement, may be longer than in other applications. See AC Electrical
Characteristics - Performance for Maximum Phase Lock TIme.
MT9046 provides a fast lock pin (FLOCK), which, when set high enables the PLL to lock to an incoming reference
within approximately 500 ms.
MT9046 Measures of Performance
The following are some synchronizer performance indicators and their corresponding definitions.
Intrinsic Jitter
Intrinsic jitter is the jitter produced by the synchronizing circuit and is measured at its output. It is measured by
applying a reference signal with no jitter to the input of the device, and measuring its output jitter. Intrinsic jitter may
also be measured when the device is in a non-synchronizing mode, such as free running or holdover, by measuring
the output jitter of the device. Intrinsic jitter is usually measured with various bandlimiting filters depending on the
applicable standards. In the MT9046, the intrinsic Jitter is limited to less than 0.02 UI on the 2.048 MHz and
1.544 MHz clocks.
13
Zarlink Semiconductor Inc.
MT9046
Data Sheet
Jitter Tolerance
Jitter tolerance is a measure of the ability of a PLL to operate properly (i.e., remain in lock and or regain lock in the
presence of large jitter magnitudes at various jitter frequencies) when jitter is applied to its reference. The applied
jitter magnitude and jitter frequency depends on the applicable standards.
Jitter Transfer
Jitter transfer or jitter attenuation refers to the magnitude of jitter at the output of a device for a given amount of jitter
at the input of the device. Input jitter is applied at various amplitudes and frequencies, and output jitter is measured
with various filters depending on the applicable standards.
For the MT9046, two internal elements determine the jitter attenuation. This includes the internal 1.9 Hz low pass
loop filter and the phase slope limiter. The phase slope limiter limits the output phase slope to 5 ns/125 us.
Therefore, if the input signal exceeds this rate, such as for very large amplitude low frequency input jitter, the
maximum output phase slope will be limited (i.e., attenuated) to 5 ns/125 us.
The MT9046 has twelve outputs with three possible input frequencies (except for 19.44 MHz, which is internally
divided to 8 KHz) for a total of 36 possible jitter transfer functions. Since all outputs are derived from the same
signal, the jitter transfer values for the four cases, 8 kHz to 8 kHz, 1.544 MHz to 1.544 MHz and 2.048 MHz to
2.048 MHz can be applied to all outputs.
It should be noted that 1 UI at 1.544 MHz is 644 ns, which is not equal to 1 UI at 2.048 MHz, which is 488 ns.
Consequently, a transfer value using different input and output frequencies must be calculated in common units
(e.g., seconds) as shown in the following example.
What is the T1 and E1 output jitter when the T1 input jitter is 20 UI (T1 UI Units) and the T1 to T1 jitter attenuation is
18 dB?
A
–----- 20
OutputT1 = InputT1 ×10
OutputT1 = 20 ×10
18
–------- 20
= 2.5UI ( T1 )
( 1UIT1 )
OutputE1 = OutputT1 × ---------------------( 1UIE1 )
( 644ns )
OutputE1 = OutputT1 × ------------------- = 3.3UI ( T1 )
( 488ns )
Using the above method, the jitter attenuation can be calculated for all combinations of inputs and outputs based on
the three jitter transfer functions provided.
Note that the resulting jitter transfer functions for all combinations of inputs (8 kHz, 1.544 MHz, 2.048 MHz) and
outputs (8 kHz, 1.544 MHz, 2.048 MHz, 4.096 MHz, 8.192 MHz, 16.384 MHz, 19.44 MHz) for a given input signal
(jitter frequency and jitter amplitude) are the same.
Since intrinsic jitter is always present, jitter attenuation will appear to be lower for small input jitter signals than for
large ones. Consequently, accurate jitter transfer function measurements are usually made with large input jitter
signals (e.g., 75% of the specified maximum jitter tolerance).
Frequency Accuracy
Frequency accuracy is defined as the absolute tolerance of an output clock signal when it is not locked to an
external reference, but is operating in a free running mode. For the MT9046, the Freerun accuracy is equal to the
Master Clock (OSCi) accuracy.
14
Zarlink Semiconductor Inc.
MT9046
Data Sheet
Holdover Accuracy
Holdover accuracy is defined as the absolute tolerance of an output clock signal, when it is not locked to an external
reference signal, but is operating using storage techniques. For the MT9046, the storage value is determined while
the device is in Normal Mode and locked to an external reference signal.
The absolute Master Clock (OSCi) accuracy of the MT9046 does not affect Holdover accuracy, but the change in
OSCi accuracy while in Holdover Mode does.
Capture Range
Also referred to as pull-in range. This is the input frequency range over which the synchronizer must be able to pull
into synchronization. The MT9046 capture range is equal to ±230 ppm minus the accuracy of the master clock
(OSCi). For example, a 32 ppm master clock results in a capture range of 198 ppm.
Lock Range
This is the input frequency range over which the synchronizer must be able to maintain synchronization. The lock
range is equal to the capture range for the MT9046.
Phase Slope
Phase slope is measured in seconds per second and is the rate at which a given signal changes phase with respect
to an ideal signal. The given signal is typically the output signal. The ideal signal is of constant frequency and is
nominally equal to the value of the final output signal or final input signal.
Time Interval Error (TIE)
TIE is the time delay between a given timing signal and an ideal timing signal.
Maximum Time Interval Error (MTIE)
MTIE is the maximum peak to peak delay between a given timing signal and an ideal timing signal within a
particular observation period.
MTIE ( S ) = TIEmax ( t ) – TIEmin ( t )
Phase Continuity
Phase continuity is the phase difference between a given timing signal and an ideal timing signal at the end of a
particular observation period. Usually, the given timing signal and the ideal timing signal are of the same frequency.
Phase continuity applies to the output of the synchronizer after a signal disturbance due to a reference switch or a
mode change. The observation period is usually the time from the disturbance, to just after the synchronizer has
settled to a steady state.
In the case of the MT9046, the output signal phase continuity is maintained to within ±5 ns at the instance (over
one frame) of all reference switches and all mode changes. The total phase shift, depending on the switch or type
of mode change, may accumulate up to 200 ns over many frames. The rate of change of the 200 ns phase shift is
limited to a maximum phase slope of approximately 5 ns/125 us. This meets the AT&T TR62411 maximum phase
slope requirement of 7.6 ns/125 us and Bellcore GR-1244-CORE (81 ns/1.326 ms).
15
Zarlink Semiconductor Inc.
MT9046
Data Sheet
Phase Lock Time
This is the time it takes the synchronizer to phase lock to the input signal. Phase lock occurs when the input signal
and output signal are not changing in phase with respect to each other (not including jitter).
Lock time is very difficult to determine because it is affected by many factors which include:
•
initial input to output phase difference
•
initial input to output frequency difference
•
synchronizer loop filter
•
synchronizer limiter
Although a short lock time is desirable, it is not always possible to achieve due to other synchronizer requirements.
For instance, better jitter transfer performance is achieved with a lower frequency loop filter which increases lock
time. And better (smaller) phase slope performance (limiter) results in longer lock times. The MT9046 loop filter and
limiter were optimized to meet the AT&T TR62411 jitter transfer and phase slope requirements. Consequently,
phase lock time, which is not a standards requirement, may be longer than in other applications. See AC Electrical
Characteristics - Performance for Maximum Phase Lock TIme.
MT9046 provides a fast lock pin (FLOCK), which, when set high enables the PLL to lock to an incoming reference
within approximately 500 ms.
Description
State
Input Controls
Freerun
Normal
(PRI)
Normal
(SEC)
Holdover
(PRI)
Holdover
(SEC)
MS2
MS1
RSEL
PCCi
S0
S1
S2
S1H
S2H
0
0
0
0
S1
-
S1 MTIE
S1
S1 MTIE
0
0
0
1
S1
-
S1 MTIE
S1 MTIE
S1 MTIE
0
0
1
X
S2
S2 MTIE
-
S2 MTIE
S2 MTIE
0
1
0
X
/
S1H
/
-
/
0
1
1
X
/
S2H
S2H
/
-
1
0
X
X
-
S0
S0
S0
S0
Legend:
No Change
/
Not Valid
MTIE
State change occurs with TIE Corrector Circuit
Refer to Control State Diagram for state changes to and from Auto-Holdover State
Table 4 - Control State Table
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
S0
Freerun
(10X)
S1
Normal
Primary
(000)
{A}
(PCCi=0)
(PCCi=1)
S1A
Auto-Holdover
Primary
(000)
S2A
Auto-Holdover
Secondary
(001)
S1H
Holdover
Primary
(010)
S2H
Holdover
Secondary
(011)
{A}
S2
Normal
Secondary
(001)
NOTES:
(XXX)
MS2 MS1 RSEL
Phase Re-Alignment
{A}
Invalid Reference Signal
Phase Continuity Maintained (without TIE Corrector Circuit)
Phase Continuity Maintained (with TIE Corrector Circuit)
Movement to Normal State from any
state requires a valid input signal
Figure 7 - Control State Diagram
MT9046 and Network Specifications
The MT9046 fully meets all applicable PLL requirements (intrinsic jitter/wander, jitter/wander tolerance,
jitter/wander transfer, frequency accuracy, frequency holdover accuracy, capture range, phase change slope and
MTIE during reference rearrangement) for the following specifications.
1. Bellcore GR-1244-CORE June 1995 for Stratum 4 Enhanced and Stratum 4
2. AT&T TR62411 (DS1) December 1990 for Stratum 4 Enhanced and Stratum 4
3. ANSI T1.101 (DS1) February 1994 for Stratum 4 Enhanced and Stratum 4
4. ETSI 300 011 (E1) April 1992 for Single Access and Multi Access
5. TBR 4 November 1995
6. TBR 12 December 1993
7. TBR 13 January 1996
8. ITU-T I.431 March 1993
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Applications
This section contains MT9046 application specific details for clock and crystal operation, reset operation, power
supply decoupling, and control operation.
Master Clock
The MT9046 can use either a clock or crystal as the master timing source.
In Freerun Mode, the frequency tolerance at the clock outputs is identical to the frequency tolerance of the source
at the OSCi pin. For applications not requiring an accurate Freerun Mode, tolerance of the master timing source
may be ±100 ppm. For applications requiring an accurate Freerun Mode, such as AT&T TR62411, the tolerance of
the master timing source must be no greater than ±32 ppm.
Another consideration in determining the accuracy of the master timing source is the desired capture range. The
sum of the accuracy of the master timing source and the capture range of the MT9046 will always equal 230 ppm.
For example, if the master timing source is 100 ppm, then the capture range will be 130 ppm.
Clock Oscillator - when selecting a Clock Oscillator, numerous parameters must be considered. This includes
absolute frequency, frequency change over temperature, output rise and fall times, output levels and duty cycle.
MT9046
OSCi
+3.3 V
+3.3 V
20 MHz OUT
GND
0.1 uF
OSCo
No Connection
Figure 8 - Clock Oscillator Circuit
For applications requiring ±32 ppm clock accuracy, the following clock oscillator module may be used.
FOX F7C-2E3-20.0 MHz
Frequency:
Tolerance:
Rise & Fall Time:
Duty Cycle:
20 MHz
25 ppm 0C to 70C
10 ns (0.33 V 2.97 V 15 pF)
40% to 60%
The output clock should be connected directly (not AC coupled) to the OSCi input of the MT9046, and the OSCo
output should be left open as shown in Figure 8.
18
Zarlink Semiconductor Inc.
MT9046
Data Sheet
Crystal Oscillator - Alternatively, a Crystal Oscillator may be used. A complete oscillator circuit made up of a
crystal, resistor and capacitors is shown in Figure 9.
MT9046
OSCi
20 MHz
1 MΩ
56 pF
39 pF
3-50 pF
OSCo
100 Ω
1 uH
1 uH inductor: may improve stability and is optional
Figure 9 - Crystal Oscillator Circuit
The accuracy of a crystal oscillator depends on the crystal tolerance as well as the load capacitance tolerance.
Typically, for a 20 MHz crystal specified with a 32 pF load capacitance, each 1 pF change in load capacitance
contributes approximately 9 ppm to the frequency deviation. Consequently, capacitor tolerances, and stray
capacitances have a major effect on the accuracy of the oscillator frequency.
The trimmer capacitor shown in Figure 9 may be used to compensate for capacitive effects. If accuracy is not a
concern, then the trimmer may be removed, the 39 pF capacitor may be increased to 56 pF, and a wider tolerance
crystal may be substituted.
The crystal should be a fundamental mode type - not an overtone. The fundamental mode crystal permits a simpler
oscillator circuit with no additional filter components and is less likely to generate spurious responses. The crystal
specification is as follows.
Frequency:
20 MHz
Tolerance:
As required
Oscillation Mode:
Fundamental
Resonance Mode:
Parallel
Load Capacitance:
32 pF
Maximum Series Resistance:
35 Ω
Approximate Drive Level:
1 mW
e.g., R1B23B32-20.0 MHz
(20 ppm absolute, ±6 ppm 0C to 50C, 32 pF, 25 Ω)
TIE Correction (using PCCi)
When Primary Holdover Mode is entered for short time periods, TIE correction should not be enabled. This will
prevent unwanted accumulated phase change between the input and output.
For instance, 10 Normal to Holdover to Normal mode change sequences occur, and in each case Holdover was
entered for 2s. Each mode change sequence could account for a phase change as large as 350 ns. Thus, the
accumulated phase change could be as large as 3.5 us, and, the overall MTIE could be as large as 3.5 us.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Phase hold = 0.2ppm × 2s = 400ns
Phase state = 50ns + 200ns = 250ns
Phase 10 = 10 × ( 250ns + 400ns ) = 6.5us
•
0.2 ppm is the accuracy of Holdover Mode
•
50 ns is the maximum phase continuity of the MT9046 from Normal Mode to Holdover Mode
•
200 ns is the maximum phase continuity of the MT9046 from Holdover Mode to Normal Mode (with or
without TIE Corrector Circuit)
When 10 Normal to Holdover to Normal mode change sequences occur without MTIE enabled, and in each case
holdover was entered for 2s, each mode change sequence could still account for a phase change as large as
650 ns. However, there would be no accumulated phase change, since the input to output phase is re-aligned after
every Holdover to Normal state change. The overall MTIE would only be 650 ns.
Reset Circuit
A simple power up reset circuit with about a 50 us reset low time is shown in Figure 10. Resistor RP is for protection
only and limits current into the RST pin during power down conditions. The reset low time is not critical but should
be greater than 300 ns.
MT9046
+3.3 V
R
10 kΩ
RST
RP
1 kΩ
C
10 nF
Figure 10 - Power-Up Reset Circuit
Lock Indicator
The LOCK pin toggles at a random rate when the PLL is frequency locked to the input reference. In Figure 11 the
RC-time-constant circuit can be used to hold the high state of the LOCK pin.
Once the PLL is frequency locked to the input reference, the minimum duration of LOCK pin’s high state would be
32 ms and the maximum duration of LOCK pin’s low state would not exceed 1 second. The following equations can
be used to calculate the charge and discharge times of the capacitor.
tC =
- RD C ln(1 – VT+ /VDD) = 240 µs
tC = Capacitor’s charge time
RD = Dynamic resistance of the diode (100 Ω)
C = Capacitor value (1 µF)
VT+ = Positive going threshold voltage of the
Schmitt Trigger (3.0 V)
20
Zarlink Semiconductor Inc.
MT9046
Data Sheet
VDD = 3.3 V
tD =
- R C ln(VT- /VDD) = 1.65 seconds
tD = Capacitor’s discharge time
R = Resistor value (3.3 MΩ)
C = Capacitor value (1 µF)
VT- = Negative going threshold voltage of the
Schmitt Trigger (2.0 V)
VDD = 3.3 V
MT9046
R=3.3 M
74HC14
74HC14
Lock
LOCK
IN4148
+
C=1 µf
Figure 11 - Time-constant Circuit
A digital alternative to the RC-time-constant circuit is presented in Figure 12. The circuit in Figure 12 can be used to
generate a steady lock signal. The circuit monitors the MT9046’s LOCK pin, as long as it detects a positive pulse
every 1.024 seconds or less, the Advanced Lock output will remain high. If no positive pulse is detected on the
LOCK output within 1.024 seconds, the Advanced LOCK output will go low.
MT9046
Figure 12 - Digital Lock Pin Circuit
21
Zarlink Semiconductor Inc.
MT9046
Data Sheet
Absolute Maximum Ratings* - Voltages are with respect to ground (VSS) unless otherwise stated.
Parameter
Symbol
Min.
Max.
Units
1
Supply voltage
VDD
-0.3
7.0
V
2
Voltage on any pin
VPIN
-0.3
VDD+ 0.3
V
3
Current on any pin
IPIN
30
mA
4
Storage temperature
TST
125
° C
200
5 48 SSOP package power dissipation
PPD
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
mW
-55
Recommended Operating Conditions - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
1
Supply voltage
2
Operating temperature
Sym.
Min.
Max.
Units
VDD
3.0
3.6
V
TA
-40
85
° C
DC Electrical Characteristics* - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
1
Supply current with:
2
Sym.
OSCi = 0 V
OSCi = Clock
Max.
Units
IDDS
1.8
mA
Outputs unloaded
IDD
50
mA
Outputs unloaded
3
CMOS high-level input voltage
VCIH
4
CMOS low-level input voltage
VCIL
5
Input leakage current
6
7
Min.
0.7VDD
IIL
-15
High-level output voltage
VOH
2.4
Low-level output voltage
VOL
V
OSCi
0.3VDD
V
OSCi
15
µA
VI=VDD or 0 V
V
IOH= 10 mA
V
IOL= 10 mA
0.4
* Supply voltage and operating temperature are as per Recommended Operating Conditions.
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Zarlink Semiconductor Inc.
Conditions/Notes
MT9046
Data Sheet
AC Electrical Characteristics - Performance
Characteristics
1
Sym.
±0 ppm
Freerun Mode accuracy with OSCi at:
Conditions/
Notes†
Min.
Max.
Units
-0
+0
ppm
5-9
2
±32 ppm
-32
+32
ppm
5-9
3
±100 ppm
-100
+100
ppm
5-9
-0.2
+0.2
ppm
1,2,4,6-9,41
4
± 0 ppm
Holdover Mode accuracy with OSCi at:
5
±32 ppm
-0.2
+0.2
ppm
1,2,4,6-9,41
6
±100 ppm
-0.2
+0.2
ppm
1,2,4,6-9,41
-230
+230
ppm
1-3,6-9
7
±0 ppm
Capture range with OSCi at:
8
±32 ppm
-198
+198
ppm
1-3,6-9
9
±100 ppm
-130
+130
ppm
1-3,6-9
30
s
1-3,6-15
reference switch
200
ns
1-3,6-15
12
mode switch to Normal
200
ns
1-2,4-15
13
mode switch to Freerun
200
ns
1-,4,6-15
14
mode switch to Holdover
50
ns
1-3,6-15
10
Phase lock time
11
Output phase continuity with:
15
MTIE (maximum time interval error)
600
ns
1-15,28
16
Output phase slope
45
us/s
1-15,28
17
Reference input for Auto-Holdover with: 8kHz,
19.44 MHz
-30 k
+30 k
ppm
1-3,6,9,10-12
18
1.544 MHz
-30 k
+30 k
ppm
1-3,7,10-12
19
2.048 MHz
-30 k
+30 k
ppm
1-3,8,10-12
† See “Notes” following AC Electrical Characteristics tables.
AC Electrical Characteristics - Timing Parameter Measurement Voltage Levels* - Voltages are
with respect to ground (VSS) unless otherwise stated
Characteristics
1
Threshold Voltage
2
Rise and Fall Threshold Voltage High
Sym.
CMOS
Units
VT
0.5 VDD
V
VHM
0.7 VDD
V
0.3 VDD
V
3
Rise and Fall Threshold Voltage Low
VLM
* Supply voltage and operating temperature are as per Recommended Operating Conditions.
* Timing for input and output signals is based on the worst case result of the CMOS thresholds.
* See Figure 12.
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
Timing Reference Points
V HM
VT
V LM
ALL SIGNALS
tIRF, tORF
tIRF, tORF
Figure 13 - Timing Parameter Measurement Voltage Levels
tR8D
PRI/SEC
8kHz
tRW
tR15D
PRI/SEC
1.544MHz
tR2D
PRI/SEC
2.048MHz
VT
tRW
VT
tRW
tR19D
PRI/SEC
19.44MHz
VT
tRW
VT
F8o
VT
NOTES:
1. Input to output delay values
are valid after a TCLR or RST
with no further state changes
Figure 14 - Input to Output Timing (Normal Mode)
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Zarlink Semiconductor Inc.
MT9046
Data Sheet
AC Electrical Characteristics - Input/Output Timing
Characteristics
Sym.
Min.
100
1
Reference input pulse width high or low
tRW
2
Reference input rise or fall time
tIRF
3
8kHz reference input to F8o delay
tR8D
4
1.544 MHz reference input to F8o delay
5
Max.
Units
ns
10
ns
-21
6
ns
tR15D
337
363
ns
2.048 MHz reference input to F8o delay
tR2D
222
238
ns
6
19.44 MHz reference input to F8o delay
tR19D
46
57
ns
7
F8o to F0o delay
tF0D
111
130
ns
8
F16o setup to C16o falling
tF16S
25
40
ns
9
F16o hold to C16o rising
tF16H
-10
10
ns
10
F8o to C1.5o delay
tC15D
-45
-25
ns
11
F8o to C6o delay
tC6D
-10
10
ns
12
F8o to C2o delay
tC2D
-11
5
ns
13
F8o to C4o delay
tC4D
-11
5
ns
14
F8o to C8o delay
tC8D
-11
5
ns
15
F8o to C16o delay
tC16D
-11
5
ns
16
F8o to TSP delay
tTSPD
-6
10
ns
17
F8o to RSP delay
tRSPD
-8
8
ns
18
F8o to C19o delay
tC19D
-15
5
ns
19
C1.5o pulse width high or low
tC15W
309
339
ns
20
C6o pulse width high or low
tC6W
70
86
ns
21
C2o pulse width high or low
tC2W
230
258
ns
22
C4o pulse width high or low
tC4W
111
133
ns
23
C8o pulse width high or low
tC8W
52
70
ns
24
C16o pulse width high or low
tC16WL
24
35
ns
25
TSP pulse width high
tTSPW
478
494
ns
26
RSP pulse width high
tRSPW
474
491
ns
27
C19o pulse width high
tC19WH
25
35
ns
28
C19o pulse width low
tC19WL
17
25
ns
29
F0o pulse width low
tF0WL
234
254
ns
30
F8o pulse width high
tF8WH
109
135
ns
31
F16o pulse width low
tF16WL
47
75
ns
32
Output clock and frame pulse rise or fall time
9
ns
33
Input Controls Setup Time
tS
100
ns
34
Input Controls Hold Time
tH
100
ns
tORF
25
Zarlink Semiconductor Inc.
MT9046
Data Sheet
tF8WH
VT
F8o
tF0WL
tF0D
VT
F0o
tF16WL
tF16D
VT
F16o
tF16S
tC16WL
tF16H
tC16D
VT
C16o
tC8W
tC8W
tC8D
VT
C8o
tC4W
tC4W
tC4D
VT
C4o
tC2W
tC2D
VT
C2o
tC6W
tC6D
tC6W
VT
C6o
tC15W
tC15D
VT
C1.5o
tC19W
tC19W
C19o
tC19D
VT
Figure 15 - Output Timing 1
26
Zarlink Semiconductor Inc.
MT9046
Data Sheet
F8o
VT
VT
C2o
tRSPD
VT
RSP
tRSPW
tTSPW
TSP
VT
tTSPD
Figure 15 - Output Timing 2
VT
F8o
tS
MS1,2,
RSEL, PCCi
tH
VT
Figure 16 - Input Controls Setup and Hold Timing
AC Electrical Characteristics - Intrinsic Jitter Unfiltered
Characteristics
Sym.
Max.
Units
Conditions/Notes†
1
Intrinsic jitter at F8o (8 kHz)
0.0002
UIpp
1-15,22-25,29
2
Intrinsic jitter at F0o (8 kHz)
0.0002
UIpp
1-15,22-25,29
3
Intrinsic jitter at F16o (8 kHz)
0.0002
UIpp
1-15,22-25,29
4
Intrinsic jitter at C1.5o (1.544 MHz)
0.030
UIpp
1-15,22-25,30
5
Intrinsic jitter at C2o (2.048 MHz)
0.040
UIpp
1-15,22-25,31
6
Intrinsic jitter at C6o (6.312 MHz)
0.120
UIpp
1-15,22-25,32
7
Intrinsic jitter at C4o (4.096 MHz)
0.080
UIpp
1-15,22-25,33
8
Intrinsic jitter at C8o (8.192 MHz)
0.104
UIpp
1-15,22-25,34
9
Intrinsic jitter at C16o (16.384 MHz)
0.104
UIpp
1-15,22-25,35
10
Intrinsic jitter at TSP (8 kHz)
0.0002
UIpp
1-15,22-25,35
11
Intrinsic jitter at RSP (8 kHz)
0.0002
UIpp
1-15,22-25,35
12
Intrinsic jitter at C19o (19.44 MHz)
0.27
UIpp
1-15,22-25,36
† See “Notes” following AC Electrical Characteristics tables.
27
Zarlink Semiconductor Inc.
MT9046
Data Sheet
AC Electrical Characteristics - C1.5o (1.544 MHz) Intrinsic Jitter Filtered
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Intrinsic jitter (4 Hz to 100 kHz filter)
0.015
UIpp
1-15,22-25,30
2
Intrinsic jitter (10 Hz to 40 kHz filter)
0.010
UIpp
1-15,22-25,30
3
Intrinsic jitter (8 kHz to 40 kHz filter)
0.010
UIpp
1-15,22-25,30
4
Intrinsic jitter (10 Hz to 8 kHz filter)
0.005
UIpp
1-15,22-25,30
† See “Notes” following AC Electrical Characteristics tables.
AC Electrical Characteristics - C2o (2.048 MHz) Intrinsic Jitter Filtered
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Intrinsic jitter (4 Hz to 100 kHz filter)
0.015
UIpp
1-15,22-25,31
2
Intrinsic jitter (10 Hz to 40 kHz filter)
0.010
UIpp
1-15,22-25,31
3
Intrinsic jitter (8 kHz to 40 kHz filter)
0.010
UIpp
1-15,22-25,31
4
Intrinsic jitter (10 Hz to 8 kHz filter)
0.005
UIpp
1-15,22-25,31
† See “Notes” following AC Electrical Characteristics tables.
AC Electrical Characteristics - 8 kHz Input to 8 kHz Output Jitter Transfer
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Jitter attenuation for 1 Hz@0.01 UIpp input
0
6
dB
1-3, 6, 10 -15,
22-23, 25, 29, 37
2
Jitter attenuation for 1 Hz@0.54 UIpp input
6
16
dB
1-3,6,10 -15,
22-23, 25, 29, 37
3
Jitter attenuation for 10 Hz@0.10 UIpp input
12
22
dB
1-3, 6,10 -15,
22-23,25,29,37
4
Jitter attenuation for 60 Hz@0.10 UIpp input
28
38
dB
1-3,6,10-15,
22-23,25,29,37
5
Jitter attenuation for 300 Hz@0.10 UIpp input
42
dB
1-3,6,10 -15,
22-23,25,29,37
6
Jitter attenuation for 3600 Hz@0.005 UIpp input
45
dB
1-3,6,10 -15,
22-23,25,29,37
† See “Notes” following AC Electrical Characteristics tables.
28
Zarlink Semiconductor Inc.
MT9046
Data Sheet
AC Electrical Characteristics - 1.544 MHz Input to 1.544 MHz Output Jitter Transfer
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Jitter attenuation for 1 Hz@20 UIpp input
0
6
dB
1-3,7,10 -15,
22-23,25,30,37
2
Jitter attenuation for 1 Hz@104 UIpp input
6
16
dB
1-3,7,10 -15,
22-23,25,30,37
3
Jitter attenuation for 10 Hz@20 UIpp input
12
22
dB
1-3,7,10 -15,
22-23,25,30,37
4
Jitter attenuation for 60 Hz@20 UIpp input
28
38
dB
1-3,7,10 -15,
22-23,25,30,37
5
Jitter attenuation for 300 Hz@20 UIpp input
42
dB
1-3,7,10-15,
22-23,25,30,37
6
Jitter attenuation for 10 kHz@0.3 UIpp input
45
dB
1-3,7,10-15,
22-23,25,30,37
7
Jitter attenuation for 100 kHz@0.3 UIpp input
45
dB
1-3,7,10-15,
22-23,25,30,37
† See “Notes” following AC Electrical Characteristics tables.
29
Zarlink Semiconductor Inc.
MT9046
Data Sheet
AC Electrical Characteristics - 2.048 MHz Input to 2.048 MHz Output Jitter Transfer
Characteristics
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Sym.
Min.
Jitter at output for 1 Hz@3.00 UIpp input
with 40 Hz to 100 kHz filter
Jitter at output for 3 Hz@2.33 UIpp input
with 40 Hz to 100 kHz filter
Jitter at output for 5 Hz@2.07 UIpp input
with 40 Hz to 100 kHz filter
Jitter at output for 10 Hz@1.76 UIpp input
with 40 Hz to 100 kHz filter
Jitter at output for 100 Hz@1.50 UIpp input
with 40 Hz to 100 kHz filter
Jitter at output for 2400 Hz@1.50 UIpp input
with 40 Hz to 100 kHz filter
Jitter at output for 100 kHz@0.20 UIpp input
with 40 Hz to 100 kHz filter
† See “Notes” following AC Electrical Characteristics tables.
30
Zarlink Semiconductor Inc.
Max.
Units
Conditions/Notes†
2.9
UIpp
1-3,8,10 -15,
22-23,25,31,37
0.09
UIpp
1-3,8,10 -15,
22-23,25,31,38
1.3
UIpp
1-3,8,10 -15,
22-23,25,31,37
0.10
UIpp
1-3,8,10 -15,
22-23,25,31,38
0.80
UIpp
1-3,8,10-15,
22-23,25,31,37
0.10
UIpp
1-3,8,10-15,
22-23,25,31,38
0.40
UIpp
1-3,8,10-15,
22-23,25,31,37
0.10
UIpp
1-3,8,10-15,
22-23,25,31,38
0.06
UIpp
1-3,8,10-15,
22-23,25,31,37
0.05
UIpp
1-3,8,10-15,
22-23,25,31,38
0.04
UIpp
1-3,8,10-15,
22-23,25,31,37
0.03
UIpp
1-3,8,10-15,
22-23,25,31,38
0.04
UIpp
1-3,8,10-15,
22-23,25,31,37
0.02
UIpp
1-3,8,10-15,
22-23,25,31,36
MT9046
Data Sheet
AC Electrical Characteristics - 8 kHz Input Jitter Tolerance
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Jitter tolerance for 1 Hz input
0.80
UIpp
1-3,6,10 -15,22-23,25-27,29
2
Jitter tolerance for 5 Hz input
0.70
UIpp
1-3,6,10 -15,22-23,25-27,29
3
Jitter tolerance for 20 Hz input
0.60
UIpp
1-3,6,10 -15,22-23,25-27,29
4
Jitter tolerance for 300 Hz input
0.20
UIpp
1-3,6,10 -15,22-23,25-27,29
5
Jitter tolerance for 400 Hz input
0.15
UIpp
1-3,6,10 -15,22-23,25-27,29
6
Jitter tolerance for 700 Hz input
0.08
UIpp
1-3,6,10 -15,22-23,25-27,29
7
Jitter tolerance for 2400 Hz input
0.02
UIpp
1-3,6,10 -15,22-23,25-27,29
8
Jitter tolerance for 3600 Hz input
0.01
UIpp
1-3,6,10 -15,22-23,25-27,29
† See “Notes” following AC Electrical Characteristics tables.
AC Electrical Characteristics - 1.544 MHz Input Jitter Tolerance
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Jitter tolerance for 1 Hz input
150
UIpp
1-3,7,10 -15,22-23,25-27,30
2
Jitter tolerance for 5 Hz input
140
UIpp
1-3,7,10 -15,22-23,25-27,30
3
Jitter tolerance for 20 Hz input
130
UIpp
1-3,7,10 -15,22-23,25-27,30
4
Jitter tolerance for 300 Hz input
35
UIpp
1-3,7,10 -15,22-23,25-27,30
5
Jitter tolerance for 400 Hz input
25
UIpp
1-3,7,10 -15,22-23,25-27,30
6
Jitter tolerance for 700 Hz input
15
UIpp
1-3,7,10 -15,22-23,25-27,30
7
Jitter tolerance for 2400 Hz input
4
UIpp
1-3,7,10 -15,22-23,25-27,30
8
Jitter tolerance for 10 kHz input
1
UIpp
1-3,7,10 -15,22-23,25-27,30
9
Jitter tolerance for 100 kHz input
0.5
UIpp
1-3,7,10 -15,22-23,25-27,30
† See “Notes” following AC Electrical Characteristics tables.
AC Electrical Characteristics - 2.048 MHz Input Jitter Tolerance
Characteristics
Sym.
Min.
Max.
Units
Conditions/Notes†
1
Jitter tolerance for 1 Hz input
150
UIpp
1-3,8,10 -15,22-23,25-27,31
2
Jitter tolerance for 5 Hz input
140
UIpp
1-3,8,10 -15,22-23,25-27,31
3
Jitter tolerance for 20 Hz input
130
UIpp
1-3,8,10 -15,22-23,25-27,31
4
Jitter tolerance for 300 Hz input
50
UIpp
1-3,8,10 -15,22-23,25-27,31
5
Jitter tolerance for 400 Hz input
40
UIpp
1-3,8,10 -15,22-23,25-27,31
6
Jitter tolerance for 700 Hz input
20
UIpp
1-3,8,10 -15,22-23,25-27,31
7
Jitter tolerance for 2400 Hz input
5
UIpp
1-3,8,10 -15,22-23,25-27,31
8
Jitter tolerance for 10 kHz input
1
UIpp
1-3,8,10 -15,22-23,25-27,31
9
Jitter tolerance for 100 kHz input
1
UIpp
1-3,8,10 -15,22-23,25-27,31
† See “Notes” following AC Electrical Characteristics tables.
31
Zarlink Semiconductor Inc.
MT9046
Data Sheet
AC Electrical Characteristics - OSCi 20 MHz Master Clock Input
Characteristics
Min.
Max.
Units
-0
+0
ppm
16,19
2
-32
+32
ppm
17,20
3
-100
+100
ppm
18,21
40
60
%
1
Sym.
Tolerance
4
Duty cycle
5
Rise time
10
ns
6
Fall time
10
ns
Conditions/Notes†
† See “Notes” following AC Electrical Characteristics tables.
† Notes:
Voltages are with respect to ground (V SS) unless otherwise stated.
Supply voltage and operating temperature are as per Recommended Operating Conditions.
Timing parameters are as per AC Electrical Characteristics - Timing Parameter Measurement Voltage Levels
1. PRI reference input selected.
2. SEC reference input selected.
3. Normal Mode selected.
4. Holdover Mode selected.
5. Freerun Mode selected.
6. 8kHz Frequency Mode selected.
7. 1.544 MHz Frequency Mode selected.
8. 2.048 MHz Frequency Mode selected.
9. 19.44 MHz Frequency Mode selected.
10. Master clock input OSCi at 20 MHz ±0 ppm.
11. Master clock input OSCi at 20 MHz ±32 ppm.
12. Master clock input OSCi at 20 MHz ±100 ppm.
13. Selected reference input at ±0 ppm.
14. Selected reference input at ±32 ppm.
15. Selected reference input at ±100 ppm.
16. For Freerun Mode of ±0 ppm.
17. For Freerun Mode of ±32 ppm.
18. For Freerun Mode of ±100 ppm.
19. For capture range of ±230 ppm.
20. For capture range of ±198 ppm.
21. For capture range of ±130 ppm.
22. 25 pF capacitive load.
23. OSCi Master Clock jitter is less than 2 nspp, or 0.04 UIpp where1 UIpp=1/20 MHz.
24. Jitter on reference input is less than 7 nspp.
25. Applied jitter is sinusoidal.
26. Minimum applied input jitter magnitude to regain synchronization.
27. Loss of synchronization is obtained at slightly higher input jitter amplitudes.
28. Within 10 ms of the state, reference or input change.
29. 1 UIpp = 125 us for 8 kHz signals.
30. 1 UIpp = 648 ns for 1.544 MHz signals.
31. 1 UIpp = 488 ns for 2.048 MHz signals.
32. 1 UIpp = 323 ns for 3.088 MHz signals.
33. 1 UIpp = 244 ns for 4.096 MHz signals.
34. 1 UIpp = 122 ns for 8.192 MHz signals.
35. 1 UIpp = 61 ns for 16.384 MHz signals.
36. 1 UIpp = 51.44 ns for 19.44 MHz signals.
37. No filter.
38. 40 Hz to 100 kHz bandpass filter.
39. With respect to reference input signal frequency.
40. After a RST or TCLR.
41. Master clock duty cycle 40% to 60%.
42. Prior to Holdover Mode, device was in Normal Mode and phase locked.
32
Zarlink Semiconductor Inc.
Package Code
c Zarlink Semiconductor 2003 All rights reserved.
ISSUE
ACN
DATE
APPRD.
Previous package codes
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