This is a short form datasheet and is intended to provide an overview only. Additional details are available from IDT. Contact information may be found on
the last page.
HIGHLIGHTS
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DPLL1 and DPLL2 can be used on line cards to manage the genera-
tion of synchronous port clocks and IEEE 1588 synchronization sig-
nals based on multiple system backplane references
DPLL3 can be used on line cards to select incoming line clocks for
use on system backplanes; it can also be used for general purpose
timing applications
APLL1 and APLL2 generate clocks with jitter < 1 ps RMS (12 kHz to
20 MHz) for: 1000BASE-T and 1000BASE-X ports and to generate
IEEE 1588 time stamp clocks and 1 pulse per second (PPS) signals
Fractional-N input dividers support a wide range of reference frequen-
cies
The device can be configured from an external EEPROM after reset
FEATURES
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Differential reference inputs (IN1 to IN4) accept clock frequencies
between 2 kHz and 650 MHz
Single ended inputs (IN5 to IN6) accept reference clock frequencies
between 2 kHz and 162.5 MHz
Loss of Signal (LOS) pins (LOS0 to LOS3) can be assigned to any
clock reference input
Reference monitors qualify/disqualify references depending on activ-
ity, frequency and LOS pins
Automatic reference selection state machines select the active refer-
ence for each DPLL based on the reference monitors, priority tables,
revertive and non-revertive settings and other programmable settings
Fractional-N input dividers enable the DPLLs to lock to a wide range
of reference clock frequencies including: 10/100/1000 Ethernet, 10G
Ethernet, OTN, SONET/SDH, PDH, TDM, GSM and GNSS frequen-
cies
Any reference inputs (IN1 to IN6) can be designated as external sync
pulse inputs (1 PPS, 2 kHz, 4 kHz or 8 kHz) associated with a select-
able reference clock input
FRSYNC_8K_1PPS and MFRSYNC_2K_1PPS output sync pulses
that are aligned with the selected external input sync pulse input and
frequency locked to the associated reference clock input
DPLL1 and DPLL2 can be configured with bandwidths between 18 Hz
and 567 Hz
DPLL1 and DPLL2 lock to input references with frequencies between
2 kHz and 650 MHz
DPLL3 locks to input references with frequencies between 8 kHz and
650 MHz
DPLL1 and DPLL2 generate clocks with PDH, TDM, GSM, CPRI/
OBSAI, 10/100/1000 Ethernet and GNSS frequencies; these clocks
are directly available on OUT1 and OUT8
DPLL3 generates N x 8 kHz clocks up to 100 MHz that are output on
OUT9 and OUT10
APLL1 and APLL2 can be connected to DPLL1 and DPLL2
APLL1 and APLL2 generate 10/100/1000 Ethernet, 10G Ethernet, or
SONET/SDH frequencies
Any of eight common XO frequencies can be used for the System
The 82P33724 Port Synchronizer for IEEE 1588 and Synchronous Ethernet provides tools to manage timing references, clock conversion and tim-
ing paths for IEEE 1588 and Synchronous Ethernet (SyncE). The device supports up to three independent timing paths for: IEEE 1588 clock genera-
tion; SyncE clock generation; and general purpose frequency translation. The device outputs low-jitter clocks that can directly synchronize Ethernet
interfaces; as well as SONET/SDH and PDH interfaces and IEEE 1588 Time Stamp Units (TSUs).
The 82P33724 accepts four differential reference inputs and two single ended reference inputs that can operate at common Ethernet, SONET/
SDH and PDH frequencies that range from 2 kHz to 650 MHz. The references are continually monitored for loss of signal and for frequency offset per
user programmed thresholds. All of the references are available to all three Digital PLLs (DPLLs). The active reference for each DPLL is determined
by forced selection or by automatic selection based on user programmed priorities, locking allowances, reference monitors, and LOS inputs.
The 82P33724 can accept a clock reference and an associated phase locked sync signal as a pair. DPLL1/DPLL2 can lock to the clock reference
and align the frame sync and multi-frame sync outputs with the paired sync input. The device allows any of the differential or single ended reference
inputs to be configured as sync inputs that can be associated with any of the other differential or single ended reference inputs. The input sync signals
can have a frequency of 1 PPS, 2 kHz, 4kHz or 8 kHz. This feature enables DPLL1/DPLL2 to phase align its frame sync and multi-frame sync outputs
with a sync input without the need use a low bandwidth setting to lock directly to the sync input.
The DPLLs support three primary operating modes: Free-Run, Locked and Holdover. In Free-Run mode the DPLLs synthesize clocks based on
the system clock alone. In Locked mode the DPLLs filter reference clock jitter with the selected bandwidth. In Locked mode, the long-term output fre-
quency accuracy is the same as the long term frequency accuracy of the selected input reference. In Holdover mode, the DPLL uses frequency data
acquired while in Locked mode to generate accurate frequencies when input references are not available.
The 82P33724 requires a system clock for its reference monitors and other digital circuitry. The frequency accuracy of the system clock deter-
mines the frequency accuracy of the DPLLs in Free-Run mode. The frequency stability of the system clock determines the frequency stability of the
DPLLs in Free-Run mode and in Holdover mode; and it affects the wander generation of the DPLLs in Locked mode.
DPLL1 and DPLL2 can be configured with a range of selectable filtering bandwidths from 18 Hz to 567 Hz. DPLL3 is a wideband (BW > 25Hz) fre-
quency translator that can be used, for example, to convert a recovered SyncE clock to a 25MHz backplane clock.
Clocks generated by DPLL1 and DPLL2 can be passed through APLL1 or APLL2 which are LC based jitter attenuating Analog PLLs (APLLs). The
output clocks generated by APLL1 and APLL2 are suitable for serial GbE and lower rate interfaces, and for IEEE 1588 time stamps clocks and 1 PPS
signals.
All 82P33724 control and status registers are accessed through an I2C slave, SPI or the UART microprocessor interface. For configuring the
DPLLs, APLL1 and APLL2, the I2C master interface can automatically load a configuration from an external EEPROM after reset.
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