IDT IDT5T940

IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
IDT5T940
PRECISION CLOCK GENERATOR
OC-192 APPLICATIONS
FEATURES:
DESCRIPTION:
• Input frequency:
- For SONET non-FEC: 19.44MHz, 38.88MHz, 77.76MHz, 155.52MHz,
311.04MHz, or 622.08MHz
- For SONET FEC: 20.83MHz, 41.66MHz, 83.31MHz, 166.63MHz,
333.26MHz, or 666.52MHz
- For 10GE copper: 19.53MHz, 39.06MHz, 78.125MHz, 156.25MHz,
312.5MHz, or 625MHz
- For 10GE optical: 20.14MHz, 40.28MHz, 80.56MHz, 161.13MHz,
322.26MHz, or 644.53MHz
• 3-level inputs for feedback divide ratio and output frequency range
selection
• 1x, 2x, 4x, 8x, 16x, and 32x outputs on QOUT
• Regenerated input clock or QOUT/4 on QREG
• Lock indicator
• Power-down mode
• LVPECL or LVDS outputs
• Three modes of output frequency range
- Mode 0: QOUT range 155.5 - 166.6MHz. QREG is a regenerated version
of the input clock.
- Mode 1: QOUT range 622 - 666.5MHz. QREG output 155.5-166.6MHz.
- Mode 2: QOUT range 622 - 666.5MHz. QREG is a regenerated version
of the input clock frequency.
• Selectable loop bandwidths
• Hitless switchover
• Differential LVPECL, LVDS, or single-ended LVTTL input interface
• 2.375 - 3.465V core and I/O
• Available in VFQFPN package
The IDT5T940 generates a high precision FEC (Forward Error Correction) or non-FEC source clock for SONET/SDH systems as well as a
source clock for Gigabit Ethernet systems. This device also has clock
regeneration capability: it creates a "clean" version of the clock input by
using the internal oscillator to square the input clock's rising and falling
edges and remove jitter. In the event that the main clock input fails, the
device automatically locks to a backup reference clock using a hitless
switchover mechanism.
This device detects loss of valid CLKIN and leaves the VCO of the PLL at
the last valid frequency while an alternate input REFIN is selected. If CLKIN
and REFIN are different frequencies, the multiplication factor will be adjusted to
retain the same output frequency.
The IDT5T940 can act as a translator from a differential LVPECL, LVDS, or
single-ended LVTTL input to LVPECL or LVDS outputs. The IDT5T940-10
has LVDS outputs and the IDT5T940-30 has LVPECL outputs.
The three modes of output frequency range are controlled by the SELmode,
which is a 3-level pin. When SELmode is high or low, the QOUT is a multiplied
version of the input clock while QREG is a regenerated version of the input clock.
When SELmode is mid, the QOUT is a multiplied version of the input clock while
QREG is QOUT/4.
The IDT5T940 features a selectable loop bandwidth.
APPLICATIONS:
•
•
•
•
•
Terabit routers
Gigabit ethernet systems
SONET / SDH systems
Digital cross connects
Optical transceiver modules
FUNCTIONAL BLOCK DIAGRAM
PLLBW1
CLKIN
CLKIN
PLLBW0
QREG
INPUT
MUX
DIVN
PLL
QREG
QOUT
DIVM
REFIN
REFIN
QOUT
CONTROL
LOGIC
LOCK,
FREQ.
DETECTOR
PD
SELMODE
LOCK
CLK/
REF0
CLK/
REF1
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
INDUSTRIAL TEMPERATURE RANGE
DECEMBER 2003
1
c
2003
Integrated Device Technology, Inc.
DSC 6195/23
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS(1)
PD
VDD
GND
QOUT
QOUT
GND
VDD
Symbol
28
27
26
25
24
23
22
GND
1
21
VDD
CLKIN
2
20
GND
CLKIN
3
19
QREG
GND
4
18
QREG
REFIN
5
17
GND
REFIN
6
16
VDD
GND
7
15
LOCK
GND
Max
Unit
VDD
Power Supply Voltage
–0.5 to +4.1
V
VI
Input Voltage
–0.5 to +4.1
V
VO
Output Voltage
–0.5 to VDD+0.5
V
TJ
Junction Temperature
150
°C
TSTG
Storage Temperature
–65 to +165
°C
NOTE:
1. Stresses beyond those listed under ABSOLUTE MAXIMUM RATINGS may cause
permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolutemaximum-rated conditions for extended periods may affect device reliability.
14
CAPACITANCE(TA = +25°C, f = 1MHz, VIN = 0V)
Parameter
PLLBW1
13
PLLBW0
12
VDD
11
SELMODE
10
CLK/REF0
9
CLK/REF1
VDD
8
Description
Typ.
Max.
Unit
CIN
Input Capacitance
Description
2.5
3
pF
COUT
Output Capacitance
—
—
pF
NOTE:
1. Capacitance applies to all inputs except CLK/REF[1:0] and SELmode.
VFQFPN
TOP VIEW
RECOMMENDED OPERATING RANGE
Symbol
Description
Min.
Typ.
Max.
Unit
TA
Ambient Operating Temperature
–40
+25
+85
°C
VDD
Power Supply Voltage
2.375
—
3.465
V
VT
Termination Voltage (LVPECL)
—
VDD – 2
—
V
Termination Voltage (LVDS)
—
1.2
—
2
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
PLL BANDWIDTH SELECTION
PLLBW[1:0]
Min.
Max.
Min. CLKIN/REFIN
OUTPUT FREQUENCY RANGE
SELmode
QOUT/QOUT
QREG/QREG
Unit
LL
65KHz
120KHz
19.44MHz
L
155.5 - 166.6
regenerated CLKIN/CLKIN
MHz
LH
250KHz
500KHz
19.44MHz
M
622 - 666.5
155.5 - 166.6
MHz
HL
1MHz
2MHz
38.88MHz
H
622 - 666.5
regenerated CLKIN/CLKIN
MHz
HH
4MHz
8MHz
155.52MHz
LOCK FREQUENCY DETECTOR
INPUT FREQUENCY RANGE
CLK/REF[1:0]
Input Frequency Range
HH
19.4MHz - 20.9MHz
HM
reserved
HL
38.8MHz - 41.7MHz
MH
77.7MHz - 83.4MHz
MM
Automatic Detection
ML
155.5MHz - 167MHz
LH
311MHz - 334MHz
LM
reserved
LL
622MHz - 667MHz
The 5T940 will lock to, and track, a valid CLKIN signal; LOCK will be low
when this has occurred. If CLKIN fails, the 5T940 PLL will smoothly switch
to lock to REFIN without generating any glitches on the output. The fact that
the PLL is locked to REFIN rather than CLKIN is indicated by a high state on
LOCK. When a valid input is then applied to CLKIN, the 5T940 will smoothly
switch back to locking on CLKIN, and LOCK will go low. LOCK will also switch
to high should the frequency of CLKIN drift close to the limits of the VCO tuning
range.
PIN DESCRIPTION
Pin Name
I/O
Type
CLKIN, CLKIN
I
Adjustable(1)
Differential or single-ended clock input signal. For differential, LVPECL or LVDS supported. If left open-circuited, inputs will float
to LVTTL threshold voltage so that either input may be used as a single-ended input. A capacitor to ground should be connected
on the floating input.
Description
REFIN, REFIN
I
Adjustable(1)
Differential reference clock input. The reference clock input is used as an input to the PLL when CLKIN/CLKIN fails. Differential
or single-ended clock input signal. For differential, LVPECL or LVDS supported. If left open-circuited, inputs will float to LVTTL
threshold voltage so that either input may be used as a single-ended input. A capacitor to ground should be connected on the
floating input.
CLK/REF[1:0]
I
3-level(2)
3 level inputs controlling PLL feedback divider ratio. Automatic detection is used if both inputs are MID.
SELmode
I
3-level(2)
3 level input to select output frequency range for QOUT/QOUT and QREG/QREG (see Output Frequency Range table)
PLLBW[1:0]
I
LVTTL
PLL Bandwidth Select Inputs (see PLL Bandwidth Selection table)
Power Down Control. Shuts off entire chip when LOW.
PD
I
LVTTL
QOUT, QOUT
0
Adjustable(3)
Differential clock output. LVPECL or LVDS outputs.
QREG, QREG
0
Adjustable
Regenerated clock output from CLKIN/CLKIN, LVPECL, or LVDS outputs.
LOCK
0
LVTTL
LOW when PLL is locked to CLKIN, HIGH in all other conditions
VDD
PWR
Power Supply
GND
PWR
Ground
(3)
NOTES:
1. Inputs are capable of translating the following interface standards:
Single-ended 3.3V LVTTL levels
Single-ended 2.5V LVTTL levels
Differential LVPECL levels
Differential LVDS levels
2. 3-level inputs are static inputs and must be tied to VDD or GND or left floating.
3. Outputs can be LVPECL or LVDS.
3
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
CLOCK INPUT/OUTPUT CONFIGURATION DESCRIPTION
Application
Non-FEC
REFIN (MHz)
19.44, 38.88, 77.76, 155.52, 311.04,
622.08
CKIN (MHz)
SELmode
19.44
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
38.88
77.76
155.52
311.04
622.08
FEC
20.83, 41.66, 83.31, 166.63, 333.26,
666.52
20.83
41.66
83.31
166.63
333.26
666.52
4
QREG (MHz)
QOUT (MHz)
19.44
155.52
19.44
38.88
155.52
38.88
77.76
155.52
77.76
155.52
155.52
155.52
311.04
155.52
311.04
622.08
155.52
622.08
20.83
166.63
20.83
41.66
166.63
41.66
83.31
166.63
83.31
166.63
166.63
166.63
333.26
166.63
333.26
666.52
166.63
666.52
155.52
622.08
622.08
155.52
622.08
622.08
155.52
622.08
622.08
155.52
622.08
622.08
155.52
622.08
622.08
155.52
622.08
622.08
166.63
666.52
666.52
166.63
666.52
666.52
166.63
666.52
666.52
166.63
666.52
666.52
166.63
666.52
666.52
166.63
666.52
666.52
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
CLOCK INPUT/OUTPUT CONFIGURATION DESCRIPTION (CONTINUED)
Application
REFIN (MHz)
10GE copper
19.53, 39.06, 78.12, 156.25, 312.5,
625
CKIN (MHz)
SEL mode
19.53
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
LOW
MID
HIGH
39.06
78.12
156.25
312.5
625
10GE optical
20.14, 40.28, 80.56, 161.13, 322.26,
644.53
20.14
40.28
80.56
161.13
322.26
644.53
5
QREG (MHz)
QOUT (MHz)
19.53
156.25
19.53
39.06
156.25
39.06
78.12
156.25
78.12
156.25
156.25
156.25
312.50
156.25
312.5
625
156.25
625
20.14
161.13
20.14
40.28
161.13
40.28
80.56
161.13
80.56
161.13
161.13
161.13
322.26
161.13
322.26
644.53
161.13
644.53
156.25
625
625
156.25
625
625
156.25
625
625
156.25
625
625
156.25
625
625
156.25
625
625
161.13
644.53
644.53
161.13
644.53
644.53
161.13
644.53
644.53
161.13
644.53
644.53
161.13
644.53
644.53
161.13
644.53
644.53
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
POWER SUPPLY CHARACTERISTICS(1,2)
Symbol
Typ.
Max
Unit
IDD_PD
Power Supply Current
Parameter
VDD = Max., PD = GND, All outputs unloaded
Test Conditions
—
50
µA
∆IDD
Power Supply Current per Input HIGH
VDD = Max., VIN = 2.375V
—
100
µA
VDD = Max., QOUT = 622MHz, All outputs unloaded
—
200
mA
(LVTTL inputs only)
ITOT
Total Power Supply Current
NOTES:
1. These power consumption characteristics are for all the valid input interfaces and cover the worst case input and output interface combinations.
2. As a general requirement, these parts must be capable of operating at the maximum frequency under a nominal load at a reasonable operating temperature. That means that
these parts must not burn up under extended use in a typical application.
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Symbol
VIHH
VIMM
VILL
I3
Parameter
Input HIGH Voltage Level(1)
Input MID Voltage Level(1)
Input LOW Voltage Level(1)
3-Level Input DC Current
Test Conditions
3-Level Inputs Only
3-Level Inputs Only
3-Level Inputs Only
VIN = VDD
VIN = VDD/2
VIN = GND
Min.
VDD – 0.4
VDD/2 – 0.2
—
—
–50
–200
HIGH Level
MID Level
LOW Level
Max
—
VDD/2 + 0.2
0.4
200
+50
—
Unit
V
V
V
µA
NOTE:
1. These inputs are normally wired to VDD, GND, or left floating. Internal termination resistors bias unconnected inputs to VDD/2. If these inputs are switched dynamically after powerup,
the function and timing of the outputs may be glitched, and the PLL may require additional tAQ time before all datasheet limits are achieved.
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE FOR LVTTL
Symbol
IIH
IIL
VIK
VIN
VIH
VIL
Parameter
Input HIGH Current
Input LOW Current
Clamp Diode Voltage
DC Input Voltage
DC Input HIGH
DC Input LOW
Test Conditions
VDD = 3.465V
VDD = 3.465V
VDD = 2.375V, IIN = -18mA
Min.
—
—
—
- 0.3
1.7
—
Typ.
—
—
- 0.7
—
—
—
Max
±1
±1
- 1.2
+3.465
—
0.7
Unit
µA
V
V
V
V
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE FOR LVPECL(1)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
VDD = 3.465V
-20
—
+20
µA
Input Characteristics
IIN
Input Current (CLKIN, REFIN)
VCMR
Common Mode Input Voltage
VDIF
Differential Voltage Required to Toggle Input
1
—
VDD - 0.3
V
100
—
—
mV
Output Characteristics
VOH
Output Voltage HIGH (terminated through 50Ω tied to VDD - 2V)(2)
VDD - 1.15
—
VDD - 0.9
V
VOL
Output Voltage LOW (terminated through 50Ω tied to VDD - 2V)(2)
VDD - 1.95
—
VDD - 1.61
V
0.55
—
0.93
V
VSWING
Peak-to-Peak Output Voltage Swing
NOTES:
1. VDD = 2.375 - 3.645V.
2. Not to exceed VDD - 0.05V.
6
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE FOR LVDS
Symbol
Parameter
Test Conditions
Min.
VDD = 3.465V
Typ.
Max.
Unit
Input Characteristics
-20
—
+20
µA
VCM
Common Mode Input Voltage Range(1)
0.9
—
VDD - 0.05
V
VDIF
Differential Voltage Required to Toggle Input
100
—
—
mV
IIN
Input Current (CLKIN, REFIN)
Output Characteristics
VOT(+)
Differential Output Voltage for the TRUE Binary State
247
—
454
mV
VOT(-)
Differential Output Voltage for the FALSE Binary State
-247
—
-454
mV
∆VOT
Change in VOT Between Complementary Output States
—
—
50
mV
VOS
Output Common Mode Voltage (Offset Voltage)
1.125
1.2
1.375
V
∆VOS
Change in VOS Between Complementary Output States
IOS
Outputs Short Circuit Current
IOSD
Differential Outputs Short Circuit Current
—
—
50
mV
VOUT(+) and VOUT(-) = 0V
—
9
24
mA
VOUT(+) = VOUT(-)
—
6
12
mA
Min.
Typ.
Max.
Unit
40
50
60
%
NOTE:
1. Not to exceed VDD - 0.05V.
INPUT TIMING REQUIREMENTS
Symbol
Parameter
REFH
Input Reference Clock Duty Cycle
FREF
Input Reference Clock Range
19.44
—
666.52
MHz
REFTOL
Input Reference Clock Frequency Tolerance
-100
—
100
ppm
FCLKIN
Clock in Frequency Range
CLKIN H
tAQ
LOCKTOL
tJIT(TOL)
19.44
—
666.52
MHz
Clock in Duty Cycle
40
50
60
%
Acquisition Time from Return of Valid CLKIN
—
60
150
us
Frequency Tolerance for LOCK
-600
±450
600
ppm
Tolerance to Input Jitter
GR-253 Sect. 5.6.2.2
AC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE (OC-192)
Symbol
QOUT
Parameter
Multiplied Clock Output Frequency
Min.
Typ.
Max.
SELmode = LOW
155.52
—
166.63
SELmode = MID
155.52
—
666.52
SELmode = HIGH
622.08
—
666.52
Unit
MHz
QREG
Regenerated Clock Output Frequency
19.44
—
666.52
MHz
CLKIN
Input Clock Frequency
19.44
—
667
MHz
LVPECL
—
150
—
ps
LVDS
—
100
—
LVPECL
—
150
—
tR
Output Rise Time
tF
Output Fall Time
—
100
—
tSK
Skew between QOUT and QREG
—
10
20
ps
PLLBW
PLL Bandwidth Setting
65
80
120
KHz
tP
Jitter Transfer Peaking
—
—
0.1
dB
tJ
Jitter Generation(1)
Output Frequency = 622MHz - 666.5MHz
—
0.3
0.65
ps (RMS)
(with 50KHz to 80MHz band pass filter)
Output Frequency = 155.5MHz - 166.6MHz
—
1
2
45
—
55
LVDS
tDUTY
Output Duty Cycle
NOTE:
1. All input frequencies and PLLBW[1:0] permitted by PLL Bandwidth Selection table.
7
ps
%
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
AC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE (OC-48)
Symbol
Parameter
SELmode = LOW
QOUT
Multiplied Clock Output Frequency
QREG
Regenerated Clock Output Frequency
CLKIN
Input Clock Frequency
tR
Output Rise Time
tF
Output Fall Time
tSK
Min.
Typ.
Max.
155.52
—
166.63
Unit
SELmode = MID
155.52
—
666.52
SELmode = HIGH
622.08
—
666.52
MHz
19.44
—
666.52
MHz
19.44
—
667
MHz
LVPECL
—
150
—
ps
LVDS
—
100
—
LVPECL
—
150
—
LVDS
—
100
—
ps
Skew between QOUT and QREG
—
10
20
ps
PLLBW
PLL Bandwidth Setting
65
80
120
KHz
250
305
500
tP
Jitter Transfer Peaking
—
0.05
0.1
Output frequency = 622MHz - 666.5MHz
—
0.1
0.3
Jitter Generation
Output frequency = 155.5MHz - 166.6MHz
—
0.4
1.5
(with 12KHz to 20MHz filter)(1)
Output frequency = 77.7MHz - 83.4MHz
—
0.5
1.7
45
—
55
tJ
tDUTY
Output Duty Cycle
dB
ps (RMS)
%
NOTE:
1. All input frequencies and PLLBW[1:0] permitted by PLL Bandwidth Selection table.
AC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE (OC-12)
Symbol
Parameter
SELmode = LOW
QOUT
Multiplied Clock Output Frequency
Min.
Typ.
Max.
155.52
—
166.63
SELmode = MID
155.52
—
666.52
SELmode = HIGH
622.08
—
666.52
Unit
MHz
QREG
Regenerated Clock Output Frequency
19.44
—
666.52
MHz
CLKIN
Input Clock Frequency
19.44
—
667
MHz
LVPECL
—
150
—
ps
LVDS
—
100
—
LVPECL
—
150
—
LVDS
—
100
—
—
10
20
65
80
120
tR
Output Rise Time
tF
Output Fall Time
tSK
Skew between QOUT and QREG
PLLBW
tP
tJ
PLL Bandwidth Setting
Jitter Transfer Peaking
Jitter Generation
(with 3KHz to 5MHz filter)
tDUTY
(1)
250
305
500
1000
1250
2000
—
0.05
0.1
Output frequency = 155.5MHz - 166.6MHz
—
0.3
1.1
Output frequency = 77.7MHz - 83.4MHz
—
0.4
1.3
Output frequency = 19.4MHz - 20.9MHz
—
0.5
1.6
45
—
55
Output Duty Cycle
NOTE:
1. All input frequencies and PLLBW[1:0] permitted by PLL Bandwidth Selection table.
8
ps
ps
KHz
dB
ps (RMS)
%
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
TEST CONDITIONS
A
LVDS
DRIVER
50Ω
VDIFF
VT TEST POINT
50Ω
B
Test Circuit for LVDS Output Characteristics
A
50Ω
VDIFF
VT
50Ω
B
Test Circuit for LVDS Input Characteristics
A
LVPECL
DRIVER
50Ω
VDIFF
VDD - 2V
50Ω
B
Test Circuit for LVPECL Output Characteristics
A
50Ω
VDIFF
VB
50Ω
B
VB = VDD - 2V
Test Circuit for LVPECL Input Characteristics
9
IDT5T940
PRECISION CLOCK GENERATOR OC-192 APPLICATIONS
INDUSTRIAL TEMPERATURE RANGE
ORDERING INFORMATION
IDT XXXXX
Device Type
XX
Package
X
Process
CORPORATE HEADQUARTERS
2975 Stender Way
Santa Clara, CA 95054
I
-40°C to +85°C (Industrial)
NL
Thermally Enhanced Plastic Very Fine
Pitch Quad Flat No Lead Package
5T940-10
5T940-30
Precision Clock Generator - LVDS Output
Precision Clock Generator - LVPECL Output
for SALES:
800-345-7015 or 408-727-6116
fax: 408-492-8674
www.idt.com
10
for Tech Support:
[email protected]
(408) 654-6459