8725AY-01LFT [IDT]
PLL Based Clock Driver, 8725 Series, 5 True Output(s), 0 Inverted Output(s), PQFP32, 7 X 7 MM, 1.40 MM HEIGHT, ROHS COMPLIANT, MS-026, LQFP-32;
| 型号： | 8725AY-01LFT |
| 厂家： | 
INTEGRATED DEVICE TECHNOLOGY |
| 描述： | PLL Based Clock Driver, 8725 Series, 5 True Output(s), 0 Inverted Output(s), PQFP32, 7 X 7 MM, 1.40 MM HEIGHT, ROHS COMPLIANT, MS-026, LQFP-32 |
| 文件： | 总16页 (文件大小：229K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
GENERAL DESCRIPTION
FEATURES
The ICS8725-01 is a highly versatile 1:5 Dif- • Five differential HSTL outputs
ICS
HiPerClockS™
ferential-to-HSTL clock generator and a
• Selectable differential CLKx, nCLKx input pairs
member of the HiPerClockS™ family of High
Performance Clock Solutions from ICS. The
ICS8725-01 has a fully integrated PLL and can
• CLKx, nCLKx pairs can accept the following differential
input levels: LVPECL, LVDS, HSTL, SSTL, HCSL
be configured as zero delay buffer, multiplier or divider,
and has an output frequency range of 31.25MHz to
700MHz. The reference divider, feedback divider and out-
put divider are each programmable, thereby allowing for
the following output-to-input frequency ratios: 8:1, 4:1, 2:1,
1:1, 1:2, 1:4, 1:8. The external feedback allows the device
to achieve “zero delay” between the input clock and the
output clocks. The PLL_SEL pin can be used to bypass the
PLL for system test and debug purposes. In bypass mode,
the reference clock is routed around the PLL and into the
internal output dividers.
• Output frequency range: 31.25MHz to 700MHz
• Input frequency range: 31.25MHz to 700MHz
• VCO range: 250MHz to 700MHz
• External feedback for “zero delay” clock regeneration
with configurable frequencies
• Programmable dividers allow for the following output-to-input
frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8
• Static phase offset: 100ps
• Cycle-to-cycle jitter: 25ps
• Output skew: 25ps
• 3.3V core, 1.8V output operating supply
• 0°C to 70°C ambient operating temperature
• Available in both standard and lead-free RoHS-compliant
packages
BLOCK DIAGRAM
PIN ASSIGNMENT
PLL_SEL
Q0
nQ0
Q1
nQ1
÷1, ÷2, ÷4, ÷8,
÷16, ÷32,÷64
32 31 30 29 28 27 26 25
0
1
CLK0
nCLK0
Q2
nQ2
0
1
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
SEL0
SEL1
VDDO
Q3
CLK1
nCLK1
Q3
nQ3
CLK0
nQ3
Q2
PLL
nCLK0
CLK1
Q4
nQ4
ICS8725-01
10 11 12 13 14 15 16
32-Lead LQFP
CLK_SEL
nQ2
Q1
8:1, 4:1, 2:1, 1:1,
1:2, 1:4, 1:8
nCLK1
CLK_SEL
FB_IN
nFB_IN
nQ1
VDDO
MR
9
SEL0
SEL1
SEL2
SEL3
MR
7mm x 7mm x 1.4mm package body
Y Package
TopView
8725AY-01
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REV.B NOVEMBER 15, 2005
1
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
TABLE 1. PIN DESCRIPTIONS
Number
Name
Type
Description
1, 2,
12, 29
SEL0, SEL1,
SEL2, SEL3
Determines output divider values in Table 3.
LVCMOS/LVTTL interface levels.
Input Pulldown
3
4
5
6
CLK0
nCLK0
CLK1
Input Pulldown Non-inverting differential clock input.
Input Pullup Inverting differential clock input.
Input Pulldown Non-inverting differential clock input.
nCLK1
Input
Pullup Inverting differential clock input.
Clock select input. When HIGH, selects CLK1, nCLK1.
7
CLK_SEL
MR
Input Pulldown
When LOW, selects CLK0, nCLK0. LVCMOS/LVTTL interface levels.
Active HIGH Master Reset. When logic HIGH, the internal dividers are reset
causing the true outputs Qx to go low and the inverted outputs nQx to go
high. When logic LOW, the internal dividers and the outputs are enabled.
LVCMOS/LVTTL interface levels.
8
Input Pulldown
Power
9, 32
10
VDD
Core supply pins.
nFB_IN
FB_IN
GND
Input
Pullup
Feedback input to phase detector for regenerating clocks with "zero delay".
11
Input Pulldown Feedback input to phase detector for regenerating clocks with "zero delay".
13, 28
14, 15
Power
Output
Power supply ground.
nQ0, Q0
Differential output pair. HSTL interface levels.
16, 17,
24, 25
VDDO
Power
Output supply pins.
18, 19
20, 21
22, 23
26, 27
30
nQ1, Q1
nQ2, Q2
nQ3, Q3
nQ4, Q4
VDDA
Output
Output
Output
Output
Power
Differential output pair. HSTL interface levels.
Differential output pair. HSTL interface levels.
Differential output pair. HSTL interface levels.
Differential output pair. HSTL interface levels.
Analog supply pin.
Selects between the PLL and reference clock as the input to the dividers.
When LOW, selects reference clock. When HIGH, selects PLL.
LVCMOS/LVTTL interface levels.
31
PLL_SEL
Input
Pullup
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
TABLE 2. PIN CHARACTERISTICS
Symbol
CIN
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
pF
Input Capacitance
Input Pullup Resistor
4
RPULLUP
51
51
kΩ
RPULLDOWN Input Pulldown Resistor
kΩ
8725AY-01
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REV.B NOVEMBER 15, 2005
2
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
TABLE 3A. CONTROL INPUT FUNCTION TABLE
Outputs
Inputs
SEL0
PLL_SEL = 1
PLL Enable Mode
Q0:Q4, nQ0:nQ4
SEL3
SEL2
SEL1
Reference Frequency Range (MHz)*
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
250 - 700
125 - 350
62.5 - 175
31.25 - 87.5
250 - 700
125 - 350
62.5 - 175
250 - 700
125 - 350
250 - 700
125 - 350
62.5 - 175
31.25 - 87.5
62.5 - 175
31.25 - 87.5
31.25 - 87.5
÷ 1
÷ 1
÷ 1
÷ 1
÷ 2
÷ 2
÷ 2
÷ 4
÷ 4
÷ 8
x 2
x 2
x 2
x 4
x 4
x 8
*NOTE: VCO frequency range for all configurations above is 250MHz to 700MHz.
TABLE 3B. PLL BYPASS FUNCTION TABLE
Inputs
Outputs
PLL_SEL = 0
PLL Bypass Mode
SEL3
SEL2
SEL1
SEL0
Q0:Q4, nQ0:nQ4
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
÷ 4
÷ 4
÷ 4
÷ 8
÷ 8
÷ 8
÷ 16
÷ 16
÷ 32
÷ 64
÷ 2
÷ 2
÷ 4
÷ 1
÷ 2
÷ 1
8725AY-01
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REV.B NOVEMBER 15, 2005
3
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
ABSOLUTE MAXIMUM RATINGS
SupplyVoltage, V
4.6V
NOTE: Stresses beyond those listed under Absolute
Maximum Ratings may cause permanent damage to the
device.These ratings are stress specifications only.Functional
operation of product at these conditions or any conditions be-
yond those listed in the DC Characteristics or AC Character-
istics is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect product reliability.
DD
Inputs, V
-0.5V to VDD + 0.5 V
-0.5V to VDDO + 0.5V
47.9°C/W (0 lfpm)
-65°C to 150°C
I
Outputs, VO
PackageThermal Impedance, θ
JA
StorageTemperature, T
STG
TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDA = 3.3V 5ꢀ, VDDO = 1.8V 0.2V, TA = 0°C TO 70°C
Symbol Parameter
Test Conditions
Minimum Typical Maximum Units
VDD
VDDA
VDDO
IDD
Core Supply Voltage
3.135
3.135
1.6
3.3
3.3
1.8
3.465
3.465
2.0
V
V
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
V
120
15
mA
mA
mA
IDDA
IDDO
No Load
0
TABLE 4B. LVCMOS/LVTTL DC CHARACTERISTICS, VDD = VDDA = 3.3V 5ꢀ, VDDO = 1.8V 0.2V, TA = 0°C TO 70°C
Symbol Parameter
Test Conditions
Minimum Typical Maximum Units
VIH
VIL
Input High Voltage
2
VDD + 0.3
0.8
V
V
Input Low Voltage
-0.3
CLK_SEL, MR, SEL0,
SEL1, SEL2, SEL3
VDD = VIN = 3.465V
150
5
µA
µA
µA
µA
V
DDO = 2V
IIH
Input High Current
VDD = VIN = 3.465V
VDDO = 2V
PLL_SEL
CLK_SEL, MR, SEL0,
SEL1, SEL2, SEL3
VDD = 3.465V,
= 2V, VIN = 0V
-5
V
DDO
IIL
Input Low Current
VDD = 3.465V,
PLL_SEL
-150
VDDO = 2V, VIN = 0V
TABLE 4C. DIFFERENTIAL DC CHARACTERISTICS, VDD = VDDA = 3.3V 5ꢀ, VDDO = 1.8V 0.2V, TA = 0°C TO 70°C
Symbol Parameter
Test Conditions
VDD = VIN = 3.465V
VDD = VIN = 3.465V
VDD = 3.465V, VIN = 0V
VDD = 3.465V, VIN = 0V
Minimum Typical Maximum Units
CLK0, CLK1, FB_IN
nCLK0, nCLK1, nFB_IN
CLK0, CLK1, FB_IN
nCLK0, nCLK1, nFB_IN
150
5
µA
µA
µA
µA
V
Input
IIH
High Current
-5
Input
IIL
Low Current
-150
0.15
0.5
VPP
Peak-to-Peak Input Voltage
1.3
VCMR
Common Mode Input Voltage; NOTE 1, 2
VDD - 0.85
V
NOTE 1: For single ended applications, the maximum input voltage for CLKx, nCLKx is VDD + 0.3V.
NOTE 2: Common mode voltage is defined as VIH.
8725AY-01
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REV.B NOVEMBER 15, 2005
4
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
TABLE 4D. HSTL DC CHARACTERISTICS, VDD = VDDA = 3.3V 5ꢀ, VDDO = 1.8V 0.2V, TA = 0°C TO 70°C
Symbol Parameter Test Conditions Minimum Typical Maximum Units
VOH
VOL
VOX
Output High Voltage; NOTE 1
1
0
1.4
0.4
60
V
V
Output Low Voltage; NOTE 1
Output Crossover Voltage; NOTE 2
Peak-to-Peak Output Voltage Swing
40
ꢀ
VSWING
0.6
1.1
V
NOTE 1: Outputs terminated with 50Ω to ground.
NOTE 2: Defined with respect to output voltage swing at a given condition.
TABLE 5. INPUT FREQUENCY CHARACTERISTICS, VDD = VDDA = 3.3V 5ꢀ, VDDO = 1.8V 0.2V, TA = 0°C TO 70°C
Symbol Parameter
fIN Input Frequency
Test Conditions
PLL_SEL = 1
PLL_SEL = 0
Minimum Typical Maximum Units
31.25
700
700
MHz
MHz
CLK0, nCLK0,
CLK1, nCLK1
TABLE 6. AC CHARACTERISTICS, VDD = VDDA = 3.3V 5ꢀ, VDDO = 1.8V 0.2V, TA = 0°C TO 70°C
Symbol Parameter
fMAX Output Frequency
tPD
Test Conditions
Minimum
Typical
Maximum
Units
700
MHz
PLL_SEL = 0V
IJ 700MHz
Propagation Delay; NOTE 1
3.4
3.9
4.4
ns
t(Ø)
tsk(o)
tjit(cc)
tjit(Ø)
tL
Static Phase Offset; NOTE 2, 5
Output Skew; NOTE 3, 5
Cycle-to-Cycle Jitter; NOTE 5, 6
Phase Jitter; NOTE 4, 5, 6
PLL Lock Time
PLL_SEL = 3.3V
-100
100
25
25
50
1
ps
ps
ps
ps
ms
ps
ps
tR / tF
tPW
Output Rise/Fall Time
20ꢀ to 80ꢀ @ 50MHz
300
700
Output Pulse Width
tcycle/2 - 85 tcycle/2 tcycle/2 + 85
All parameters measured at fMAX unless noted otherwise.
NOTE 1: Measured from the differential input crossing point to the differential output crossing point.
NOTE 2: Defined as the time difference between the input reference clock and the averaged feedback input signal
across alll conditions, when the PLL is locked and the input reference frequency is stable.
NOTE 3: Defined as skew between outputs at the same supply voltage and with equal load conditions.
Measured at output differential cross points.
NOTE 4: Phase jitter is dependent on the input source used.
NOTE 5: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 6: Characterized at VCO frequency of 622MHz.
8725AY-01
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REV.B NOVEMBER 15, 2005
5
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
PARAMETER MEASUREMENT INFORMATION
3.3V 5ꢀ
1.8V 0.2V
VDD
SCOPE
,
VDD
VDDA
Qx
nCLK0,
nCLK1
VDDO
VPP
VCMR
Cross Points
HSTL
CLK0,
CLK1
GND
nQx
GND
0V
3.3V CORE/1.8V OUTPUT LOAD AC TEST CIRCUIT
DIFFERENTIAL INPUT LEVEL
nQ0:nQ4
Q0:Q4
nQx
nQ
➤
➤
➤
tcycle n
tcycle n+1
➤
nQy
Qy
tjit(cc) = tcycle n –tcycle n+1
tsk(o)
1000 Cycles
CYCLE-TO-CYCLE JITTER
OUTPUT SKEW
nCLK0,
VOH
VOL
nCLK1
CLK0,
CLK1
80ꢀ
tF
80ꢀ
tR
VOH
VOL
nFB_IN
VOD
Clock
Outputs
20ꢀ
20ꢀ
FB_IN
➤
t(Ø)
➤
tjit(Ø) = t(Ø) — t(Ø) mean = Phase Jitter
t(Ø) mean = Static Phase Offset
(where t(Ø) is any random sample, and t(Ø) mean is the average
of the sampled cycles measured on controlled edges)
OUTPUT RISE/FALL TIME
PHASE JITTER AND STATIC PHASE OFFSET
nCLK0,
nCLK1
nQ0:nQ4
Q0:Q4
CLK0,
CLK1
tPW
tPERIOD
nQ0:nQ4
Q0:Q4
tPW
odc =
x 100ꢀ
tPD
tPERIOD
PROPAGATION DELAY
OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
8725AY-01
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REV.B NOVEMBER 15, 2005
6
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
APPLICATION INFORMATION
POWER SUPPLY FILTERING TECHNIQUES
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS8725-01 provides
separate power supplies to isolate any high switching
noise from the outputs to the internal PLL.VDD, VDDA, and VDDO
should be individually connected to the power supply
plane through vias, and bypass capacitors should be
used for each pin. To achieve optimum jitter performance,
power supply isolation is required. Figure 1 illustrates how
a 10Ω resistor along with a 10μF and a .01μF bypass
capacitor should be connected to each VDDA pin.
3.3V
VDD
.01μF
.01μF
10Ω
VDDA
10 μF
FIGURE 1. POWER SUPPLY FILTERING
WIRING THE DIFFERENTIAL INPUT TO ACCEPT SINGLE ENDED LEVELS
Figure 2 shows how the differential input can be wired to accept
single ended levels. The reference voltage V_REF = VDD/2 is
generated by the bias resistors R1, R2 and C1.This bias circuit
should be located as close as possible to the input pin.The ratio
of R1 and R2 might need to be adjusted to position theV_REF in
the center of the input voltage swing. For example, if the input
clock swing is only 2.5V andVDD = 3.3V, V_REF should be 1.25V
and R2/R1 = 0.609.
VDD
R1
1K
Single Ended Clock Input
V_REF
CLKx
nCLKx
C1
0.1u
R2
1K
FIGURE 2. SINGLE ENDED SIGNAL DRIVING DIFFERENTIAL INPUT
8725AY-01
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REV.B NOVEMBER 15, 2005
7
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
DIFFERENTIAL CLOCK INPUT INTERFACE
The CLK /nCLK accepts LVDS, LVPECL, HSTL, SSTL, HCSL here are examples only. Please consult with the vendor of the
and other differential signals.BothVSWING and VOH must meet the driver component to confirm the driver termination requirements.
VPP and VCMR input requirements. Figures 3A to 3D show inter- For example in Figure 3A, the input termination applies for ICS
face examples for the HiPerClockS CLK/nCLK input driven by HiPerClockS HSTL drivers. If you are using an HSTL driver from
the most common driver types.The input interfaces suggested another vendor, use their termination recommendation.
3.3V
3.3V
3.3V
1.8V
Zo = 50 Ohm
CLK
Zo = 50 Ohm
CLK
Zo = 50 Ohm
nCLK
Zo = 50 Ohm
HiPerClockS
Input
LVPECL
nCLK
HiPerClockS
Input
LVHSTL
R1
50
R2
50
ICS
HiPerClockS
R1
50
R2
50
LVHSTL Driver
R3
50
FIGURE 3A. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
ICS HIPERCLOCKS LVHSTL DRIVER
FIGURE 3B. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER
3.3V
3.3V
3.3V
3.3V
Zo = 50 Ohm
3.3V
R3
125
R4
125
LVDS_Driver
Zo = 50 Ohm
Zo = 50 Ohm
CLK
CLK
R1
100
nCLK
Receiv er
nCLK
HiPerClockS
Input
Zo = 50 Ohm
LVPECL
R1
84
R2
84
FIGURE 3C. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
3.3V LVPECL DRIVER
FIGURE 3D. HIPERCLOCKS CLK/NCLK INPUT DRIVEN BY
3.3V LVDS DRIVER
RECOMMENDATIONS FOR UNUSED INPUT AND OUTPUT PINS
INPUTS:
OUTPUTS:
CLK/nCLK INPUT:
HSTL OUTPUT
For applications not requiring the use of the differential input, All unused HSTL outputs can be left floating. We recommend
both CLK and nCLK can be left floating. Though not required, that there is no trace attached. Both sides of the differential
but for additional protection, a 1kΩ resistor can be tied from output pair should either be left floating or terminated.
CLK to ground.
LVCMOS CONTROL PINS:
All control pins have internal pull-ups or pull-downs; additional
resistance is not required but can be added for additional
protection. A 1kΩ resistor can be used.
8725AY-01
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REV.B NOVEMBER 15, 2005
8
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
LAYOUT GUIDELINE
The schematic of the ICS8725-01 layout example is shown in depend on the selected component types, the density of the
Figure 4A. The ICS8725-01 recommended PCB board layout components, the density of the traces, and the stacking of the
for this example is shown in Figure 4B. This layout example is P.C.board.
used as a general guideline.The layout in the actual system will
VDD
SP = Space (i.e. not intstalled)
R7
VDD
VDDA
RU2
SP
RU3
1K
RU4
1K
RU5
SP
RU6
1K
RU7
SP
10
C11
0.01u
CLK_SEL
PLL_SEL
SEL0
C16
10u
SEL1
SEL2
SEL3
Zo = 50 Ohm
Zo = 50 Ohm
(155.5 MHz)
+
-
RD2
1K
RD3
SP
RD4
SP
RD5
1K
RD6
SP
RD7
1K
VDD
VDDO
LVHSTL_input
U1
3.3V
R4A
50
R4B
50
(155.5 MHz)
SEL0
SEL1
Zo = 50 Ohm
1
24
23
22
21
20
19
18
17
SEL0
SEL1
VDDO
2
3
4
5
6
7
8
Q3
nQ3
Q2
nQ2
Q1
nQ1
VDDO
CLK0
nCLK0
CLK1
nCLK1
CLK_SEL
MR
Zo = 50 Ohm
CLK_SEL
3.3V PECL Driver
VDD=3.3V
R8
50
R9
50
VDDO=1.8V
8725_01
SEL[3:0] = 0101,
Divide by 2
R10
50
SEL2
R2B
50
R2A
50
Bypass capacitors located near the power pins
VDD
VDDO
(U1-9)
(U1-32)
(U1-16)
(U1-17)
(U1-24)
(U1-25)
C1
0.1uF
C6
0.1uF
C2
0.1uF
C4
0.1uF
C5
0.1uF
C7
0.1uF
FIGURE 4A. ICS8725-01 HSTL ZERO DELAY BUFFER SCHEMATIC EXAMPLE
8725AY-01
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REV.B NOVEMBER 15, 2005
9
ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
The following component footprints are used in this layout
example:
trace delay might be restricted by the available space on the board
and the component location.While routing the traces, the clock
signal traces should be routed first and should be locked prior to
routing other signal traces.
All the resistors and capacitors are size 0603.
POWER AND GROUNDING
• The differential 50Ω output traces should have same
Place the decoupling capacitors C1, C6, C2, C4, and C5, as
close as possible to the power pins. If space allows, placement
of the decoupling capacitor on the component side is preferred.
This can reduce unwanted inductance between the decoupling
capacitor and the power pin caused by the via.
length.
• Avoid sharp angles on the clock trace.Sharp angle
turns cause the characteristic impedance to change on
the transmission lines.
• Keep the clock traces on the same layer.Whenever pos-
sible, avoid placing vias on the clock traces. Placement
of vias on the traces can affect the trace characteristic
impedance and hence degrade signal integrity.
Maximize the power and ground pad sizes and number of vias
capacitors.This can reduce the inductance between the power
and ground planes and the component power and ground pins.
• To prevent cross talk, avoid routing other signal traces in
parallel with the clock traces. If running parallel traces is
unavoidable, allow a separation of at least three trace
widths between the differential clock trace and the other
signal trace.
The RC filter consisting of R7, C11, and C16 should be placed
as close to the VDDA pin as possible.
CLOCK TRACES AND TERMINATION
Poor signal integrity can degrade the system performance or
cause system failure. In synchronous high-speed digital systems,
the clock signal is less tolerant to poor signal integrity than other
signals. Any ringing on the rising or falling edge or excessive ring
back can cause system failure. The shape of the trace and the
• Make sure no other signal traces are routed between the
clock trace pair.
• The matching termination resistors should be located as
close to the receiver input pins as possible.
GND
R7
C16
C11
C7
VDDO
C6
C5
VDD
U1
Pin 1
VDDA
VIA
50 Ohm
Traces
C4
C1
C2
FIGURE 4B. PCB BOARD LAYOUT FOR ICS8725-01
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ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS8725-01.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS8725-01 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VDD = 3.3V + 5% = 3.465V, which gives worst case results.
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
•
•
Power (core)MAX = VDD_MAX * (IDD_MAX + IDDA_MAX) = 3.465V * (120mA + 15mA) = 468mW
Power (outputs)MAX = 32.8mW/Loaded Output pair
If all outputs are loaded, the total power is 5 * 32.8mW = 164mW
Total Power_MAX (3.465V, with all outputs switching) = 468mW + 164mW = 632mW
2. JunctionTemperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad and directly affects the reliability of the
device.The maximum recommended junction temperature for HiPerClockSTM devices is 125°C.
The equation for Tj is as follows: Tj = θJA * Pd_total + TA
Tj = JunctionTemperature
θJA = Junction-to-AmbientThermal Resistance
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
TA = Ambient Temperature
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θJA must be used. Assuming a
moderate air flow of 200 linear feet per minute and a multi-layer board, the appropriate value is 42.1°C/W per Table 7 below.
Therefore, Tj for an ambient temperature of 70°C with all outputs switching is:
70°C + 0.632W * 42.1°C/W = 96.6°C. This is well below the limit of 125°C.
This calculation is only an example.Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow,
and the type of board (single layer or multi-layer).
Table 7. Thermal Resistance θJA for 32-pin LQFP, Forced Convection
θJA byVelocity (Linear Feet per Minute)
0
200
500
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
67.8°C/W
55.9°C/W
50.1°C/W
47.9°C/W
42.1°C/W
39.4°C/W
NOTE: Most modern PCB designs use multi-layered boards.The data in the second row pertains to most designs.
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ICS8725-01
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ZERO DELAY CLOCK GENERATOR
Integrated
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3. Calculations and Equations.
The purpose of this section is to derive the power dissipated into the load.
HSTL output driver circuit and termination are shown in Figure 5.
VDDO
Q1
VOUT
RL
50Ω
FIGURE 5. HSTL DRIVER CIRCUIT AND TERMINATION
To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load.
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = (V
Pd_L = (V
/R ) * (V
- V
)
OH_MIN
L
DDO_MAX
DDO_MAX
OH_MIN
/R ) * (V
- V
)
OL_MAX
L
OL_MAX
Pd_H = (1V/50Ω) * (2V - 1V) = 20mW
Pd_L = (0.4V/50Ω) * (2V - 0.4V) = 12.8mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 32.8mW
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ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
RELIABILITY INFORMATION
TABLE 8. θJAVS. AIR FLOW TABLE FOR 32 LEAD LQFP
θJA byVelocity (Linear Feet per Minute)
0
200
55.9°C/W
42.1°C/W
500
50.1°C/W
39.4°C/W
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
67.8°C/W
47.9°C/W
NOTE: Most modern PCB designs use multi-layered boards.The data in the second row pertains to most designs.
TRANSISTOR COUNT
The transistor count for ICS8725-01 is: 2969
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REV.B NOVEMBER 15, 2005
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ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
PACKAGE OUTLINE - Y SUFFIX FOR 32 LEAD LQFP
TABLE 9. PACKAGE DIMENSIONS
JEDEC VARIATION
ALL DIMENSIONS IN MILLIMETERS
BBA
SYMBOL
MINIMUM
NOMINAL
MAXIMUM
N
A
32
--
--
--
1.60
0.15
1.45
0.45
0.20
A1
A2
b
0.05
1.35
0.30
0.09
1.40
0.37
c
--
D
9.00 BASIC
7.00 BASIC
5.60 Ref.
9.00 BASIC
7.00 BASIC
5.60 Ref.
0.80 BASIC
0.60
D1
D2
E
E1
E2
e
L
0.45
0.75
θ
--
0°
7°
ccc
--
--
0.10
Reference Document: JEDEC Publication 95, MS-026
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ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
TABLE 10. ORDERING INFORMATION
Part/Order Number
ICS8725AY-01
Marking
Package
Shipping Packaging
tray
Temperature
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
ICS8725AY-01
ICS8725AY-01
ICS8725AY01L
ICS8725AY01L
32 Lead LQFP
ICS8725AY-01T
ICS8725AY-01LF
ICS8725AY-01LFT
32 Lead LQFP
1000 tape & reel
tray
32 Lead "Lead-Free" LQFP
32 Lead "Lead-Free" LQFP
1000 tape & reel
NOTE: Parts that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.
The aforementioned trademark, HiPerClockS™ is a trademark of Integrated Circuit Systems, Inc. or its subsidiaries in the United States and/or other countries.
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems, Incorporated (ICS) assumes no responsibility for either its use or
for infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal
commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not
recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for
use in life support devices or critical medical instruments.
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ICS8725-01
1:5 DIFFERENTIAL-TO-HSTL
ZERO DELAY CLOCK GENERATOR
Integrated
Circuit
Systems, Inc.
REVISION HISTORY SHEET
Description of Change
Rev
Table
Page
Date
1
5
3
5
2
Updated Block Diagram.
Changed PLL Reference Zero Delay to Static Phase Offset.
Added note at bottom of the table.
Added Note 6.
A
11/2/01
6
3A
6
A
A
11/20/01
8/22/02
1
Pin Description Table - revised MR description.
8
Updated Output Rise/Fall Time Diagram.
Format changes.
Changed LVHSTL to HSTL throughout data sheet to conform with JEDEC
terminology.
Pin Description table - revised MR and VDD descriptions.
Pin Characteristics table - changed CIN 4pF max. to 4pF typical.
Absolute Maximum Ratings - updated Inputs ratings.
Added Power Supply Filtering Techniques section.
Added Differential Input Interface section.
2
2
4
7
8
T1
T2
A
9/26/03
Updated format throughout data sheet.
5
HSTL table - changed VOX minimum to 40ꢀ and maximum to 60ꢀ; added
NOTE 2.
Features Section - add Lead-Free bullet.
Ordering Information Table - added Lead-Free package and note.
Added Recommendations for Unused Input and Output Pins.
B
B
B
T4D
T10
11/11/04
6/9/05
1
15
8
11/15/05
11-12
Corrected Power Considerations, Power Dissipation calculation.
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REV.B NOVEMBER 15, 2005
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