DS21610
3.3V/5V Clock Rate Adapter
www.maxim-ic.com
GENERAL DESCRIPTION
The DS21610 is a multirate, low-jitter clock adapter
that converts E-carrier and T-carrier clocks to
multiple PDH carrier clock rates. Two clock outputs
are available that are frequency-locked to the input
clock. The clock outputs along with an 8kHz frame-
sync output can be phase-aligned to a frame-sync
input. The device is backward compatible with the
LXP610 and operates from either a 3.3V or 5V
supply. All modes of operation include a standard
8kHz output.
FEATURES
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Direct Replacement for LXP610SE
Converts E-Carrier Clock Rates to T-Carrier
Clock Rates
Converts T-Carrier Clock Rates to E-Carrier
Clock Rates
3.3V or 5V Supply
Low Jitter Output
Multiple Output Clocks Synchronized to Input
Clock
8kHz Frequency-Locked Output for all Operation
Modes
No External Components Required
16-Pin SO and 28-Pin PLCC
Industrial Temperature Range: -40ºC to +85ºC
PIN CONFIGURATION
TOP VIEW
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ORDERING INFORMATION
Dallas
Semiconductor
DS21610
PART
DS21610SN
DS21610QN
TEMP RANGE
-40ºC to +85ºC
-40ºC to +85ºC
PIN-PACKAGE
16 SO
29 PLCC
SO
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
www.maxim-ic.com/errata.
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REV: 113004
DS21610 3.3V/5V Clock Rate Adapter
TABLE OF CONTENTS
1.
1.1
PIN DESCRIPTION ......................................................................................................................3
C
OMPATIBILITY WITH
LXP610.........................................................................................................................3
2.
3.
3.1
FUNCTIONAL DESCRIPTION......................................................................................................5
OUTPUT JITTER ..........................................................................................................................6
J
ITTER
T
RANSFER
..........................................................................................................................................6
4.
5.
6.
OPERATING PARAMETERS .......................................................................................................8
PACKAGE INFORMATION ........................................................................................................13
REVISION HISTORY ..................................................................................................................15
LIST OF FIGURES
Figure 1-1. Block Diagram ....................................................................................................................4
Figure 3-1. Nominal Jitter Transfer (1.544MHz CLKIN to 2.048MHz CLKOUT1) ..................................6
Figure 3-2. Nominal Jitter Transfer (2.048MHz CLKIN to 1.544MHz CLKOUT1) ..................................7
Figure 4-1. SYNCIN/CLKIN to CLKOUT1/SYNCOUT and CLKOUT2 ................................................ 10
Figure 4-2. Output Frame-Sync Alignment When CLKOIT2 = 2 x CLKOUT1 ..................................... 11
Figure 4-3. Output Frame-Sync Alignment When CLKOUT2 = 3 x CLKOUT1.................................... 11
Figure 4-4. Output Frame-Sync Alignment When CLKOIT2 = 4 x CLKOUT1 ..................................... 12
Figure 4-5. Output Frame-Sync Alignment When CLKOUT2 = 5 x CLKOUT1.................................... 12
LIST OF TABLES
Table 1-A. Pin Description ....................................................................................................................3
Table 1-B. Pin Name Cross-Reference to LXP610 ...............................................................................3
Table 2-A. Program Pin Functions (SEL = 0)........................................................................................5
Table 2-B. Program Pin Functions (SEL = 1)........................................................................................5
Table 3-A. Output Jitter Specifications, CLKOUT1 = 1.544MHz ...........................................................6
Table 3-B. Output Jitter Specifications, CLKOUT1 = 2.048MHz ...........................................................6
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DS21610 3.3V/5V Clock Rate Adapter
1. PIN DESCRIPTION
Table 1-A. Pin Description
PIN
PLCC
1
2
3–5, 7–9,
11, 12, 17–
19, 21, 23,
25, 26
6
10
13
14
15
16
20
22
24
27
28
SO
1
2
3, 6, 11
4
5
7
8
9
10
12
13
14
15
16
NAME
P3
SYNCOUT
N.C.
CLKOUT2
CLKIN
CLKOUT1
P1
V
SS
P2
SEL
FSP
SYNCIN
P4
V
DD
TYPE
Input
Output
—
Output
Input
Output
Input
Supply
Input
Input
Input
Input
Input
Supply
FUNCTION
Program Pin 3. Used to select the various combinations of
clock and sync outputs.
Synchronization Pulse Output. An 8kHz output that can be
synchronized to the clock outputs and SYNCIN (if present).
No Connect
Clock Output 2. T1 or E1 carrier clock output referenced to
CLKIN.
Clock Input. Reference Clock Input. CLKOUT1 and CLKOUT2
will be referenced to this clock.
Clock Output 1. T1 or E1 carrier clock output referenced to
CLKIN.
Program Pin 3. Used to select the various combinations of
clock and sync outputs.
Ground
Program Pin 2. Used to select the various combinations of
clock and sync outputs.
Clock Mode Select. T-carrier/E-carrier mode select.
Frame Synchronization Pulse Polarity. Used to change the
polarity of the SYNCOUT output.
Synchronization Pulse Input. Used to synchronize the clock
outputs and SYNCOUT to CLKIN and SYNCIN. SYNCIN
should be tied high or low when not in use.
Program Pin 4. Used to select the various combinations of
clock and sync outputs.
Positive Supply, 3.3V or 5V ±5%
1.1
Compatibility with LXP610
The DS21610 is pin compatible with the LXP610.
Table 1-B. Pin Name Cross-Reference to LXP610
DS21610
P3
SYNCOUT
CLKOUT2
CLKIN
CLKOUT1
P1
V
SS
P2
N.C.
LXP610
P3
FSO
HFO
CLKI
CLKO
P1
GND
P2
N.C.
FUNCTION
Program Pin 3
Synchronization Pulse Output
Clock 2 Output
Clock Input
Clock 1 Output
Program pin 1
Ground
Program Pin 2
No Connect
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DS21610 3.3V/5V Clock Rate Adapter
Figure 1-1. Block Diagram
CLKOUT2
CLKIN
ANALOG
PLL
FEEDBACK
CIRCUIT
Dallas Semiconductor
DS21610
OUTPUT
DIVIDER
CLKOUT1
SEL
SYNCIN
FRAME SYNC
GENERATOR
SYNCOUT
FSP
P1
P2
P3
P4
FREQUENCY
PLL
SELECT
LOGIC
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DS21610 3.3V/5V Clock Rate Adapter
2. FUNCTIONAL DESCRIPTION
A clock input at CLKIN is converted to various clocks available on CLKOUT1 and CLKOUT2. Additionally, an 8kHz
clock locked to CLKIN and SYNCIN (if present) is always available at the SYNCOUT pin. The pulse width of the
SYNCOUT is selectable. It can be one or one-half the clock period of CLKIN, centered on the rising edge of
CLKIN. Pins P1 to P4 are used to select the various clock rates and operational modes.
Table 2-A
and
Table 2-B
list the various operational modes of the DS21610.
CLKIN, CLKOUT1, and CLCKOUT2 are always frequency-locked. They can all be phase-locked to a system
frame-sync pulse. A frame-sync pulse applied to SYNCIN will cause CLKIN and CLKOUT1 and CLKOUT2 to be
phased-locked to that sync pulse. This causes the clocks to have a fixed alignment at the frame-sync boundaries.
The signal applied to SYNCIN can be 8kHz or some integer subrate such as 1kHz, 2kHz, or 4kHz. Phase
synchronization occurs within a maximum of 50ms when SYNCIN is 8kHz.
Table 2-A. Program Pin Functions (SEL = 0)
P4
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
P3
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
P2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
P1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
CLKIN
1.544
3.088
1.544
1.544
1.544
6.176
1.544
6.176
3.088
3.088
3.088
1.544
6.176
6.176
6.176
6.176
CLKOUT1
2.048
2.048
2.048
2.048
2.560
4.096
2.560
2.048
2.048
4.096
2.048
4.096
2.560
4.096
2.560
4.096
CLKOUT2
6.144
8.192
6.144
8.192
7.680
8.192
7.680
8.192
6.144
8.192
6.144
8.192
7.680
8.192
7.680
8.192
SYNCOUT
Long
Short
Long
Short
Long
Long
Long
Short
Long
Long
Long
Long
Long
Long
Long
Long
Table 2-B. Program Pin Functions (SEL = 1)
P4
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
P3
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
P2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
P1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
CLKIN
2.048
2.048
2.048
2.048
2.560
8.192
2.560
8.192
2.048
4.096
2.048
4.096
2.560
8.192
2.560
8.192
CLKOUT1
3.088
3.088
1.544
1.544
1.544
3.088
1.544
1.544
3.088
3.088
3.088
1.544
1.544
3.088
1.544
1.544
CLKOUT2
6.176
6.176
6.176
6.176
7.720
6.176
7.720
6.176
6.176
6.176
6.176
6.176
7.720
6.176
7.720
6.176
SYNCOUT
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
Long
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