• Phase-Lock Loop Clock Distribution for Applications ranging
from 10MHz to 133MHz operating frequency
• Distributes one clock input to two banks of four outputs
• Separate output enable for each output bank
• External feedback (FBK) pin is used to synchronize the outputs
to the clock input
• Output Skew <200 ps
• Low jitter <200 ps cycle-to-cycle
• 1x, 2x, 4x output options (see table):
– IDT2308-1 1x
– IDT2308-2 1x, 2x
– IDT2308-3 2x, 4x
– IDT2308-4 2x
– IDT2308-1H, -2H, and -5H for High Drive
• No external RC network required
• Operates at 3.3V VDD
• Available in SOIC and TSSOP packages
IDT2308
DESCRIPTION:
The IDT2308 is a high-speed phase-lock loop (PLL) clock multiplier. It is
designed to address high-speed clock distribution and multiplication applications. The zero delay is achieved by aligning the phase between the incoming
clock and the output clock, operable within the range of 10 to 133MHz.
The IDT2308 has two banks of four outputs each that are controlled via two
select addresses. By proper selection of input addresses, both banks can be
put in tri-state mode. In test mode, the PLL is turned off, and the input clock
directly drives the outputs for system testing purposes. In the absence of an
input clock, the IDT2308 enters power down, and the outputs are tri-stated. In
this mode, the device will draw less than 25µA.
The IDT2308 is available in six unique configurations for both prescaling and multiplication of the Input REF Clock. (See available options
table.)
The PLL is closed externally to provide more flexibility by allowing the user
to control the delay between the input clock and the outputs.
The IDT2308 is characterized for both Industrial and Commercial operation.
NOTE: For new designs, refer to AN-233.
FUNCTIONAL BLOCK DIAGRAM
(-3, -4)
16
FBK
REF
S2
S1
2
1
2
(-5)
8
9
PLL
Control
Logic
(-2, -3)
2
CLKA1
3
CLKA2
14
CLKA3
15
CLKA4
2
6
CLKB1
7
CLKB2
10
CLKB3
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
1Input Reference Clock, 5 Volt Tolerant Input
2Clock Output for Bank A
3Clock Output for Bank A
6Clock Output for Bank B
7Clock Output for Bank B
8Select Input, Bit 2
9Select Input, Bit 1
1 0Clock Output for Bank B
1 1Clock Output for Bank B
1 4Clock Output for Bank A
1 5Clock Output for Bank A
161
15
14
13
12
11
10
ABSOLUTE MAXIMUM RATINGS
SymbolRatingMax.Unit
VDDSupply Voltage Range–0.5 to +4.6V
(2)
FBK
VI
V
IInput Voltage Range–0.5 toV
CLKA4
CLKA3
DD
V
GND
CLKB4
CLKB3
9
S1
IIK (VI < 0)Input Clamp Current–5 0mA
IOKTerminal Voltage with Respect±50mA
(VO < 0 or VO > VDD) to GND (inputs VIH 2.5, VIL 2.5)
I
OContinuous Output Current±50mA
(VO = 0 to VDD)
VDD or GNDContinuous Current±100mA
TA = 55°CMaximum Power Dissipation0.7W
(in still air)
TSTGStorage Temperature Range–65 to +150°C
OperatingCommercial Temperature0 to +70°C
TemperatureRange
OperatingIndustrial Temperature-40 to +85°C
TemperatureRange
NOTES:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may
2. The input and output negative-voltage ratings may be exceeded if the input and output
3. The maximum package power dissipation is calculated using a junction temperature
(3)
cause permanent damage to the device. This is a stress rating 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 absolute maximum
rating conditions for extended periods may affect reliability.
DeviceFeedback FromBank A FrequencyBank B Frequency
IDT2308-1Bank A or Bank BReference Reference
IDT2308-1HBank A or Bank BReference Reference
IDT2308-2Bank AReference Reference/2
IDT2308-2Bank B2 x Reference Reference
IDT2308-2HBank AReference Reference/2
IDT2308-2HBank B2 x Reference Reference
IDT2308-3Bank A2 x Reference Reference or Reference
IDT2308-3Bank B4 x Reference 2 x Reference
IDT2308-4Bank A or Bank B2 x Reference 2 x Reference
IDT2308-5HBank A or Bank BReference/2 Reference/2
NOTE:
1. Output phase is indeterminant (0° or 180° from input clock).
(1)
3
IDT2308
3.3V ZERO DELAY CLOCK MULTIPLIER
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
ZERO DELA Y AND SKEW CONTROL
To close the feedback loop of the IDT2308, the FBK pin can be driven from any of the eight available output pins. The output driving the FBK pin will
be driving a total load of 7pF plus any additional load that it drives. The relative loading of this output (with respect to the remaining outputs) can adjust
the input-output delay.
For applications requiring zero input-output delay, all outputs including the one providing feedback should be equally loaded. If input-output delay
adjustments are required, use the Output Load Difference Chart to calculate loading differences between the feedback output and remaining outputs.
Ensure the outputs are loaded equally, for zero output-output skew.
REF TO CLKA/CLKB DELAY vs. OUTPUT LOAD DIFFERENCE BETWEEN FBK PIN AND CLKA/CLKB PINS
1500
1000
500
0
-30-25-20
-500
REF to CLKA/CLKB Delay (ps)
-1000
-1500
OUTPUT LOAD DIFFERENCE BETWEEN FBK PIN AND CLKA/CLKB PINS ( pF)
-15
-10
-5
05
10152025
30
4
IDT2308
3.3V ZERO DELAY CLOCK MULTIPLIER
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
OPERATING CONDITIONS- COMMERCIAL
SymbolParameterTest ConditionsMin.Max.Unit
VDDSupply Voltage33.6V
TAOperating Temperature (Ambient Temperature)07 0°C
CLLoad Capacitance below 100MHz—3 0pF
Load Capacitance from 100MHz to 133MHz—1 5pF
C
INInput Capacitance
NOTE:
1. Applies to both REF and FBK.
(1)
—7pF
DC ELECTRICAL CHARACTERISTICS - COMMERCIAL
SymbolParameterConditionsMin.Typ.
VILInput LOW Voltage Level——0.8V
VIHInput HIGH Voltage Level2——V
(-1, -2, -3, -4, -1H, -2H, -5H)15pF Load
t3Rise Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 30pF Load——2.2ns
t3Rise Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 15pF Load——1.5ns
t3Rise Time (-1H, -2H, -5H)Measured between 0.8V and 2V, 30pF Load——1.5ns
t4Fall Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 30pF Load——2. 2ns
t4Fall Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 15pF Load——1. 5ns
t4Fall Time (-1H, -5H)Measured between 0.8V and 2V, 30pF Load——1.25ns
t5Output to Output Skew on same BankAll outputs equally loaded——20 0ps
(-1, -2, -3, -4, -1H, -2H, -5H)15pF Load
t3Rise Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 30pF Load2.2ns
t3Rise Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 15pF Load1.5ns
t3Rise Time (-1H, -2H, -5H)Measured between 0.8V and 2V, 30pF Load1.5ns
t4Fall Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 30pF Load2.5ns
t4Fall Time (-1, -2, -3, -4)Measured between 0.8V and 2V, 15pF Load1.5ns
t4Fall Time (-1H, -5H)Measured between 0.8V and 2V, 30pF Load1.25ns
t5Output to Output Skew on same BankAll outputs equally loaded200ps
(-1, -2, -3, -4)
Output to Output Skew (-1H, -2H, -5H)All outputs equally loaded200ps
Output Bank A to Output Bank B (-1, -4, -2H, -5H)All outputs equally loaded200ps
Output Bank A to Output Bank B Skew (-2, -3)All outputs equally loaded400ps
t6Delay, REF Rising Edge to FBK Rising EdgeMeasured at VDD/20±250ps
t7Device to Device SkewMeasured at VDD/2 on the FBK pins of devices0700ps
t8Output Slew RateMeasured between 0.8V and 2V on -1H, -2H, -5H1V/ns
device using Test Circuit 2
tJCycle to Cycle JitterMeasured at 66.67 MHz, loaded outputs, 15pF Load200
Measured at 133.3 MHz, loaded outputs, 15pF Load100
tJCycle to Cycle JitterMeasured at 66.67 MHz, loaded outputs, 30pF Load400ps
(-2, -2H, -3)Measured at 66.67 MHz, loaded outputs, 15pF Load400
tLOCKPLL Lock TimeStable Power Supply, valid clocks presented1ms
on REF and FBK pins
NOTE:
1. IDT2308-5H has maximum input frequency of 133.33 MHz and maximum output of 66.67MHz.
(1)
10133.3MHz
8
IDT2308
3.3V ZERO DELAY CLOCK MULTIPLIER
SWITCHING WAVEFORMS
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
t1
t2
Output
1.4V
0.8V
t3
Output
Output
1.4V
Duty Cycle Timing
2V
2V
0.8V
t4
All Outputs Rise/Fall Time
1.4V
1.4V
t5
1.4V
3.3V
0V
Input
FBK
Input to Output Propagation Delay
FBK, Device 1
FBK, Device 2
Output to Output Skew
V
DD/2
t6
DD/2
V
t7
Device to Device Skew
V
V
DD/2
DD/2
9
IDT2308
3.3V ZERO DELAY CLOCK MULTIPLIER
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
TYPICAL DUTY CY CLE
(for 30pf loads over frequency - 3.3V, 25C)
Duty Cycle vs V
60
58
56
)
54
%
(
e
52
l
c
y
C
50
y
t
u
D
48
46
44
42
40
3
3.1
3.2
Duty Cycle vs Frequency
(for 30pf loads over te m perature - 3. 3V)
60
58
56
)
54
%
(
e
l
c
52
y
C
y
50
t
u
D
48
46
44
42
40
20
40
60
Frequency(MHz)
I
DD vs Number of Loaded Outputs
140
(for 30pf loads over frequenc y - 3.3V, 25C)
DD
3.4
3.3
VDD (V)
80100120140
(1)
AND IDD TRENDS
33MHz
66MHz
100MHz
3.53.6
-40C
0C
25C
70C
85C
(2)
FOR IDT2308-1, 2, 3, AND 4
Duty Cycle vs V
DD
(for 15pF loads over frequency - 3.3V, 25C)
60
58
56
)
54
%
(
e
52
l
c
y
C
50
y
t
u
D
48
46
44
42
40
3
3.1
3.2
3.3
3.4
VDD (V)
Duty Cycle vs Frequency
(for 15pF loads over temperature - 3.3V)
60
58
56
)
54
%
(
e
l
c
52
y
C
y
50
t
u
D
48
46
44
42
40
20
40
80100120140
60
Frequency(MHz)
I
DD vs Number of Loaded Outputs
140
(for 15pF loads over frequency - 3.3V, 25C)
3.53.6
33MHz
66MHz
100MHz
133MHz
-40C
0C
25C
70C
85C
120
100
80
)
A
m
(
D
60
D
I
40
20
0
02
Number of Loaded Outputs
33MHz
66MHz
100MHz
4
6
8
120
100
80
)
A
m
(
D
60
D
I
40
20
0
02
Number of Loaded Outputs
33MHz
66MHz
100MHz
4
6
8
NOTES:
1. Duty Cycle is taken from typical chip measured at 1.4V.
2. IDD data is calculated from IDD = ICORE + nCVf, where ICORE is the Unloaded Current (n = Number of Outputs; C = Capacitance Load per Output (F); V = Voltage Supply(V);
f = Frequency (Hz).
10
IDT2308
3.3V ZERO DELAY CLOCK MULTIPLIER
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
TYPICAL DUTY CY CLE
(for 30pf loads over fr equency - 3.3V, 25C)
Duty Cycle vs V
60
58
56
)
54
%
(
e
52
l
c
y
C
50
y
t
u
D
48
46
44
42
40
3
3.1
3.2
Duty Cycle vs Frequency
(for 30pf loads over temp erature - 3.3V)
60
58
56
)
54
%
(
e
l
c
52
y
C
y
50
t
u
D
48
46
44
42
40
20
40
60
Frequency(MHz)
I
DD vs Number of Loaded Outputs
(for 30pf loads over fr equency - 3.3V, 25C)
160
140
120
DD
3.4
3.3
VDD (V)
80100120140
(1)
AND IDD TRENDS
33MHz
66MHz
100MHz
3.53.6
-40C
0C
25C
70C
85C
(2)
FOR IDT2308-1H, -2H, AND -5H
Duty Cycle vs V
DD
(for 15pF loads over frequency - 3.3V, 25C)
60
58
56
)
54
%
(
e
52
l
c
y
C
50
y
t
u
D
48
46
44
42
40
3
3.1
3.2
3.3
3.4
3.53.6
VDD (V )
Duty Cycle vs Frequency
(for 15pF loads over tem perature - 3.3V)
60
58
56
)
54
%
(
e
l
c
52
y
C
y
50
t
u
D
48
46
44
42
40
20
40
80100120140
60
Frequency(MHz)
DD vs Number of Loaded Outputs
I
(for 15pF loads over frequency - 3.3V, 25C)
160
140
120
33MHz
66MHz
100MHz
133MHz
-40C
0C
25C
70C
85C
100
80
)
A
m
(
D
60
D
I
40
20
NOTES:
0
02
Number of Loaded Outputs
33MHz
66MHz
100MHz
4
6
8
100
80
)
A
m
(
D
60
D
I
40
20
0
02
Number of Loaded Outputs
33MHz
66MHz
100MHz
4
6
8
1. Duty Cycle is taken from typical chip measured at 1.4V.
2. IDD data is calculated from IDD = ICORE + nCVf, where ICORE is the Unloaded Current (n = Number of Outputs; C = Capacitance Load per Output (F); V = Voltage Supply(V);
f = Frequency (Hz).
11
IDT2308
3.3V ZERO DELAY CLOCK MULTIPLIER
TEST CIRCUITS
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
0.1µF
0.1µF
TEST CIRCUIT 1
VDD
DD
V
OUTPUTS
CLK
OUT
C
LOAD
GNDGND
Test Circuit for all Parameters Except t8
TEST CIRCUIT 1
0.1µF
VDD
OUTPUTS
1KΩ
CLK
1KΩ
DD
V
0.1µF
GND
GND
Test Circuit for t8, Output Slew Rate On -1H, -2H, and -5H Device