ICST ICS8432I-101 700mhz, differential-to-3.3v lvpecl frequency synthesizer Datasheet

ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
FEATURES
The ICS8432I-101 is a general purpose, dual output Differential-to-3.3V LVPECL high frequency
HiPerClockS™
synthesizer and a member of the HiPerClockS™
family of High Performance Clock Solutions from
ICS. The ICS8432I-101 has a selectable
TEST_CLK or CLK, nCLK inputs. The TEST_CLK input accepts
LVCMOS or LVTTL input levels and translates them to 3.3V
LVPECL levels. The CLK, nCLK pair can accept most standard
differential input levels. The VCO operates at a frequency range
of 250MHz to 700MHz. The VCO frequency is programmed in
steps equal to the value of the input differential or single ended
reference frequency. The VCO and output frequency can be
programmed using the serial or parallel interfaces to the
configuration logic. The low phase noise characteristics of the
ICS8432I-101 makes it an ideal clock source for Gigabit
Ethernet and SONET applications.
• Dual differential 3.3V LVPECL outputs
ICS
• Selectable CLK, nCLK or LVCMOS/LVTTL TEST_CLK
• TEST_CLK can accept the following input levels:
LVCMOS or LVTTL
• CLK, nCLK pair can accept the following differential
input levels: LVPECL, LVDS, LVHSTL, SSTL, HCSL
• CLK, nCLK or TEST_CLK maximum input frequency: 40MHz
• Output frequency range: 25MHz to 700MHz
• VCO range: 250MHz to 700MHz
• Accepts any single-ended input signal on CLK input
with resistor bias on nCLK input
• Parallel interface for programming counter
and output dividers
• RMS period jitter: 5ps (maximum)
• Cycle-to-cycle jitter: 25ps (maximum)
• 3.3V supply voltage
• -40°C to 85°C ambient operating temperature
• Lead-Free package fully RoHS compliant
BLOCK DIAGRAM
PIN ASSIGNMENT
nCLK
nP_LOAD
M0
1
M1
CLK
nCLK
M2
0
M3
M4
CLK_SEL
TEST_CLK
VCO_SEL
VCO_SEL
32 31 30 29 28 27 26 25
PLL
PHASE DETECTOR
MR
VCO
÷M
1
3
22
CLK_SEL
M8
4
21
VCCA
N0
5
20
S_LOAD
N1
6
19
S_DATA
nc
7
18
S_CLOCK
VEE
8
17
MR
ICS8432I-101
9 10 11 12 13 14 15 16
VEE
nFOUT0
FOUT0
VCCO
TEST
32-Lead LQFP
7mm x 7mm x 1.4mm package body
Y Package
Top View
M0:M8
N0:N1
8432DYI-101
TEST_CLK
M7
nFOUT1
CONFIGURATION
INTERFACE
LOGIC
CLK
23
FOUT1
FOUT0
nFOUT0
FOUT1
nFOUT1
24
2
VCC
÷1
÷2
÷4
÷8
1
M6
TEST
S_LOAD
S_DATA
S_CLOCK
nP_LOAD
0
M5
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1
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
FUNCTIONAL DESCRIPTION
rial event occurs. As a result, the M and N bits can be hardwired
to set the M divider and N output divider to a specific default
state that will automatically occur during power-up. The TEST
output is LOW when operating in the parallel input mode. The
relationship between the VCO frequency, the input frequency
and the M divider is defined as follows: fVCO = fIN x M
NOTE: The functional description that follows describes operation using a 25MHz clock input. Valid PLL loop divider values for different input frequencies are defined in the Input Frequency Characteristics, Table 5, NOTE 1.
The ICS8432I-101 features a fully integrated PLL and therefore requires no external components for setting the loop bandwidth. A differential clock input is used as the input to the
ICS8432-101. This input is fed into the phase detector. A
25MHz clock input provides a 25MHz phase detector reference frequency. The VCO of the PLL operates over a range
of 250MHz to 700MHz. The output of the M divider is also
applied to the phase detector.
The M value and the required values of M0 through M8 are
shown in Table 3B, Programmable VCO Frequency Function
Table. Valid M values for which the PLL will achieve lock for a
25MHz reference are defined as 8 ≤ M ≤ 28. The frequency
out is defined as follows: fOUT = fVCO = fIN x M
N
N
Serial operation occurs when nP_LOAD is HIGH and S_LOAD is
LOW. The shift register is loaded by sampling the S_DATA
bits with the rising edge of S_CLOCK. The contents of the shift
register are loaded into the M divider and N output divider when
S_LOAD transitions from LOW-to-HIGH. The M divide and N output divide values are latched on the HIGH-to-LOW transition of
S_LOAD. If S_LOAD is held HIGH, data at the S_DATA input is
passed directly to the M divider and N output divider on each rising
edge of S_CLOCK. The serial mode can be used to
program the M and N bits and test bits T1 and T0. The internal registers T0 and T1 determine the state of the TEST output as follows:
The phase detector and the M divider force the VCO output
frequency to be M times the reference frequency by adjusting the VCO control voltage. Note, that for some values of M
(either too high or too low), the PLL will not achieve lock. The
output of the VCO is scaled by a divider prior to being sent to
each of the LVPECL output buffers. The divider provides a
50% output duty cycle.
The programmable features of the ICS8432I-101 support two
input modes to program the PLL M divider and N output divider.
The two input operational modes are parallel and serial. Figure1
shows the timing diagram for each mode. In parallel mode, the
nP_LOAD input is initially LOW. The data on inputs M0 through
M8 and N0 and N1 is passed directly to the M divider and
N output divider. On the LOW-to-HIGH transition of the
nP_LOAD input, the data is latched and the M divider remains
loaded until the next LOW transition on nP_LOAD or until a se-
T1
T0
TEST Output
0
0
LOW
0
1
S_Data, Shift Register Input
1
0
Output of M divider
1
1
CMOS Fout
SERIAL LOADING
S_CLOCK
T1
S_DATA
t
S_LOAD
S
t
T0
* NULL
N1
N0
M8
M7
M6
M5
M4
M3
M2
M1
M0
H
nP_LOAD
t
S
PARALLEL LOADING
M, N
M0:M8, N0:N1
nP_LOAD
t
S
t
H
S_LOAD
Time
FIGURE 1. PARALLEL & SERIAL LOAD OPERATIONS
*NOTE:
8432DYI-101
The NULL timing slot must be observed.
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2
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
TABLE 1. PIN DESCRIPTIONS
Number
Name
1
2, 3, 4
28, 29
30, 31, 32
M5
M6, M7, M8,
M0, M1,
M2, M3, M4
5, 6
Type
Input
Description
Pullup
Input
M divider inputs. Data latched on LOW-to-HIGH transistion
Pulldown of nP_LOAD input. LVCMOS / LVTTL interface levels.
N0, N1
Input
Pulldown
7
nc
Unused
8, 16
VEE
Power
9
TEST
Output
Determines output divider value as defined in Table 3C,
Function Table. LVCMOS / LVTTL interface levels.
No connect.
10
VCC
Power
Negative supply pins.
Test output which is ACTIVE in the serial mode of operation. Output
driven LOW in parallel mode. LVCMOS / LVTTL interface levels.
Core supply pin.
11, 12
FOUT1, nFOUT1
Output
Differential output for the synthesizer. 3.3V LVPECL interface levels.
13
VCCO
Power
Output supply pin.
14, 15
FOUT0, nFOUT0
Output
Differential output for the synthesizer. 3.3V LVPECL interface levels.
23
TEST_CLK
Input
Pulldown
Active High Master Reset. When logic HIGH, the internal dividers
are reset causing the true outputs FOUTx to go low and the inver ted
outputs nFOUTx to go high. When logic LOW, the internal dividers
and the outputs are enabled. Asser tion of MR does not affect loaded
M, N, and T values. LVCMOS / LVTTL interface levels.
Clocks in serial data present at S_DATA input into the shift register
on the rising edge of S_CLOCK. LVCMOS / LVTTL interface levels.
Shift register serial input. Data sampled on the rising edge
of S_CLOCK. LVCMOS / LVTTL interface levels.
Controls transition of data from shift register into the dividers.
LVCMOS / LVTTL interface levels.
Analog supply pin.
Clock select input. Selects between differential clock input or
TEST_CLK input as the PLL reference source. When HIGH,
selects CLK, nCLK inputs. When LOW, selects TEST_CLK input.
LVCMOS / LVTTL interface levels.
Test clock input. LVCMOS / LVTTL interface levels.
24
CLK
Input
Pulldown
Non-inver ting differential clock input.
25
nCLK
Input
Pullup
26
nP_LOAD
Input
27
VCO_SEL
Input
17
MR
Input
Pulldown
18
S_CLOCK
Input
Pulldown
19
S_DATA
Input
Pulldown
20
S_LOAD
Input
Pulldown
21
VCCA
Power
22
CLK_SEL
Input
Pullup
Inver ting differential clock input.
Parallel load input. Determines when data present at M8:M0 is
Pulldown loaded into M divider, and when data present at N1:N0 sets the
N output divider value. LVCMOS / LVTTL interface levels.
Determines whether synthesizer is in PLL or bypass mode.
Pullup
LVCMOS / LVTTL interface levels.
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characterisitics, for typical values.
TABLE 2. PIN CHARACTERISTICS
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
CIN
Input Capacitance
4
pF
RPULLUP
Input Pullup Resistor
51
kΩ
RPULLDOWN
Input Pulldown Resistor
51
kΩ
8432DYI-101
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3
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
TABLE 3A. PARALLEL
AND
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
SERIAL MODE FUNCTION TABLE
Inputs
Conditions
MR
nP_LOAD
M
N
S_LOAD
S_CLOCK
S_DATA
H
X
X
X
X
X
X
L
L
Data
Data
X
X
X
L
↑
Data
Data
L
X
X
L
H
X
X
L
↑
Data
L
H
X
X
↑
L
Data
L
H
X
X
↓
L
Data
M divider and N output divider values are latched.
L
H
X
X
L
X
X
Parallel or serial inputs do not affect shift registers.
H
↑
Data
L
H
X
X
NOTE: L = LOW
H = HIGH
X = Don't care
↑ = Rising edge transition
↓ = Falling edge transition
Reset. Forces outputs LOW.
Data on M and N inputs passed directly to the
M divider and N output divider. TEST output
forced LOW.
Data is latched into input registers and remains loaded
until next LOW transition or until a serial event occurs.
Serial input mode. Shift register is loaded with data on
S_DATA on each rising edge of S_CLOCK.
Contents of the shift register are passed to the
M divider and N output divider.
S_DATA passed directly to M divider as it is clocked.
TABLE 3B. PROGRAMMABLE VCO FREQUENCY FUNCTION TABLE
256
128
64
32
16
8
4
2
1
M8
M7
M6
M5
M4
M3
M2
M1
M0
10
0
0
0
0
0
1
0
1
0
275
11
0
0
0
0
0
1
0
1
1
•
•
•
•
•
•
•
•
•
•
•
VCO Frequency
(MHz)
M Divide
250
•
•
•
•
•
•
•
•
•
•
•
650
26
0
0
0
0
1
1
0
1
0
675
27
0
0
0
0
1
1
0
1
1
700
28
0
0
0
0
1
1
1
0
0
NOTE 1: These M divide values and the resulting frequencies correspond to differential input or TEST_CLK input frequency
of 25MHz.
TABLE 3C. PROGRAMMABLE OUTPUT DIVIDER FUNCTION TABLE
Inputs
N1
N0
N Divider Value
Output Frequency (MHz)
Minimum
Maximum
0
0
1
250
700
0
1
2
125
350
1
0
4
62.5
175
1
1
8
31.25
87.5
8432DYI-101
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4
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC
4.6V
Inputs, VI
-0.5V to VCC + 0.5 V
Outputs, IO
Continuous Current
Surge Current
50mA
100mA
Package Thermal Impedance, θJA
47.9°C/W (0 lfpm)
Storage Temperature, TSTG
-65°C to 150°C
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 beyond those listed in the DC Characteristics or AC Characteristics is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect product reliability.
TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = -40°C TO 85°C
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
3.135
3. 3
3.465
V
VCCA
Analog Supply Voltage
3.135
3. 3
3.465
V
VCCO
Output Supply Voltage
3.135
3.3
3.465
V
IEE
Power Supply Current
120
mA
ICCA
Analog Supply Current
15
mA
Maximum
Units
2
VCC + 0.3
V
2
VCC + 0.3
V
-0.3
0.8
V
-0.3
1.3
V
VCC = VIN = 3.465V
150
µA
VCC = VIN = 3.465V
5
µA
TABLE 4B. LVCMOS / LVTTL DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = -40°C TO 85°C
Symbol
VIH
VIL
IIH
IIL
Parameter
Input
High Voltage
Input
Low Voltage
Input
High Current
Input
Low Current
Test Conditions
VCO_SEL, CLK_SEL, MR,
S_LOAD, S_DATA,
S_CLOCK, nP_LOAD,
M0:M8, N0:N1
TEST_CLK
VCO_SEL, CLK_SEL, MR,
S_LOAD, S_DATA,
S_CLOCK, nP_LOAD,
M0:M8, N0:N1
TEST_CLK
M0-M4, M6-M8, N0, N1, MR,
S_CLOCK, TEST_CLK,
S_DATA, S_LOAD, nP_LOAD
M5, CLK_SEL, VCO_SEL
M0-M4, M6-M8, N0, N1, MR,
S_CLOCK, TEST_CLK,
S_DATA, S_LOAD, nP_LOAD
Typical
VCC = 3.465V,
VIN = 0V
-5
µA
M5, CLK_SEL, VCO_SEL
VCC = 3.465V,
VIN = 0V
-150
µA
2.6
V
VOH
Output
High Voltage
TEST
VCC = 3.135V,
IOH = -36mA
VOL
Output
Low Voltage
TEST
VCC = 3.135V,
IOL = 36mA
8432DYI-101
Minimum
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5
0.5
V
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
TABLE 4C. DIFFERENTIAL DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = -40°C TO 85°C
Symbol
Parameter
Test Conditions
IIH
Input High Current
IIL
Input Low Current
VPP
Peak-to-Peak Input Voltage
Minimum
Typical
Maximum
Units
CLK
VCC = VIN = 3.465V
150
µA
nCLK
VCC = VIN = 3.465V
5
µA
CLK
VCC = 3.465V, VIN = 0V
-5
nCLK
VCC = 3.465V, VIN = 0V
-150
µA
µA
0.15
VCMR
Common Mode Input Voltage
VEE + 0.5
NOTE 1: For single ended applications, the maximum input voltage for CLK, nCLK is VCC + 0.3V.
NOTE 2: Common mode voltage is defined as VIH.
1.3
V
VCC - 0.85
V
TABLE 4D. LVPECL DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = -40°C TO 85°C
Symbol
Parameter
Test Conditions
VOH
Output High Voltage; NOTE 1
VOL
Output Low Voltage; NOTE 1
Minimum
Maximum
Units
VCCO - 1.4
VCCO - 0.9
V
VCCO - 2.0
VCCO - 1.7
V
0.6
1. 0
V
Maximum
Units
Peak-to-Peak Output Voltage Swing
VSWING
NOTE 1: Outputs terminated with 50 Ω to VCCO - 2V.
Typical
TABLE 5. INPUT FREQUENCY CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = -40°C TO 85°C
Symbol
Parameter
Test Conditions
fIN
Input Frequency
Minimum
Typical
TEST_CLK; NOTE 1
14
25
MHz
CLK, nCLK; NOTE 1
14
25
MHz
S_CLOCK
25
MHz
NOTE 1: For the differential input and TEST_CLK frequency range, the M value must be set for the VCO to operate within
the 250MHz to 700MHz range. Using the minimum input frequency of 14MHz, valid values of M are 18 ≤ M ≤ 50.
Using the maximum frequency of 25MHz, valid values of M are 10 ≤ M ≤ 28.
TABLE 6. AC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = -40°C TO 85°C
Symbol Parameter
Test Conditions
FOUT
Output Frequency
tjit(cc)
Cycle-to-Cycle Jitter ; NOTE 1, 3
fVCO > 350MHz
tjit(per)
Period Jitter, RMS; NOTE 1
fOUT > 100MHz
tsk(o)
Output Skew; NOTE 2, 3
t R / tF
Output Rise/Fall Time
tS
Setup Time
tH
Hold Time
Minimum
Typical
31.25
20% to 80%
200
Maximum
Units
700
MHz
25
ps
5
ps
15
ps
700
ps
M, N to nP_LOAD
5
ns
S_DATA to S_CLOCK
5
ns
S_CLOCK to S_LOAD
5
ns
M, N to nP_LOAD
5
ns
S_DATA to S_CLOCK
5
ns
S_CLOCK to S_LOAD
5
ns
odc
Output Duty Cycle
N>1
47
53
%
tPW
Output Pulse Width
N=1
tPERIOD/2 - 150
tPERIOD/2 + 150
ps
PLL Lock Time
tLOCK
See Parameter Measurement Information section.
NOTE 1: Jitter performance using XTAL inputs.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions.
Measured at the output differential cross points.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
8432DYI-101
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6
1
ms
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
PARAMETER MEASUREMENT INFORMATION
2V
VCC,
VCCA,
VCCO
Qx
VCC
SCOPE
nCLK
LVPECL
V
V
Cross Points
PP
CMR
CLK
nQx
VEE
V EE
-1.3V ± 0.165V
3.3V OUTPUT LOAD AC TEST CIRCUIT
DIFFERENTIAL INPUT LEVEL
VOH
nFOUTx
VREF
FOUTx
➤
tcycle n+1
➤
➤
1000 Cycles
Mean Period
(Trigger Edge)
n
t jit(cc) = tcycle n –tcycle n+1
Histogram
Reference Point
tcycle
➤
VOL
1σ contains 68.26% of all measurements
2σ contains 95.4% of all measurements
3σ contains 99.73% of all measurements
4σ contains 99.99366% of all measurements
6σ contains (100-1.973x10-7)% of all measurements
(First edge after trigger)
PERIOD JITTER
CYCLE-TO-CYCLE JITTER
nFOUTx
80%
80%
FOUTx
VSW I N G
Clock
Outputs
nFOUTy
20%
20%
tR
tF
FOUTy
tsk(o)
OUTPUT SKEW
OUTPUT RISE/FALL TIME
nFOUTx
FOUTx
t PW
t
odc =
PERIOD
t PW
x 100%
t PERIOD
OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
8432DYI-101
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7
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
APPLICATION INFORMATION
STORAGE AREA NETWORKS
A variety of technologies are used for interconnection of the
elements within a SAN. The tables below list the common appli-
cation frequencies as well as the ICS8432I-101 configurations
used to generate the appropriate frequency.
Table 7. Common SANs Application Frequencies
Clock Rate
Reference Frequency to SERDES
(MHz)
Crystal Frequency
(MHz)
1.25 GHz
125, 250, 156.25
25, 19.53125
FC1 1.0625 GHz
FC2 2.1250 GHz
106.25, 53.125, 132.8125
16.6015625, 25
2.5 GHz
125, 250
25
Interconnect Technology
Gigabit Ethernet
Fibre Channel
Infiniband
Table 8. Configuration Details for SANs Applications
Interconnect
Technology
CLK, nCLK Input
(MHz)
ICS8432I-101
Output Frequency
to SERDES
(MHz)
25
125
0
0
0
0
1
0
1
0
25
250
0
0
0
0
1
0
1
25
156.25
0
0
0
0
1
1
19.53125
156.25
0
0
0
1
0
25
53.125
0
0
0
0
25
106.25
0
0
0
16.6015625
132.8125
0
0
25
125
0
25
250
0
ICS8432I-101
M & N Settings
M8 M7 M6 M5 M4 M3 M2
M1 M0
N1
N0
0
1
0
0
0
0
1
0
0
1
1
0
0
0
0
0
1
0
1
0
0
0
1
1
1
0
1
0
0
0
1
1
0
0
1
0
0
0
0
0
1
0
0
0
0
1
0
1
0
0
1
0
0
0
0
1
0
1
0
0
0
1
Gigabit Ethernet
Fiber Channel 1
Fiber Channel 2
Infiniband
POWER SUPPLY FILTERING TECHNIQUES
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS8432I-101 provides
separate power supplies to isolate any high switching
noise from the outputs to the internal PLL. VCC, VCCA, and VCCO
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 2 illustrates how
a 10Ω resistor along with a 10μF and a .01μF bypass
capacitor should be connected to each VCCA pin.
8432DYI-101
3.3V
VCC
.01μF
10Ω
V CCA
.01μF
10μF
FIGURE 2. POWER SUPPLY FILTERING
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8
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
WIRING THE DIFFERENTIAL INPUT TO ACCEPT SINGLE ENDED LEVELS
of R1 and R2 might need to be adjusted to position the V_REF in
the center of the input voltage swing. For example, if the input
clock swing is only 2.5V and VCC = 3.3V, V_REF should be 1.25V
and R2/R1 = 0.609.
Figure 3 shows how the differential input can be wired to accept
single ended levels. The reference voltage V_REF = VCC/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
VCC
R1
1K
Single Ended Clock Input
CLK
V_REF
nCLK
C1
0.1u
R2
1K
FIGURE 3. SINGLE ENDED SIGNAL DRIVING DIFFERENTIAL INPUT
TERMINATION FOR LVPECL OUTPUTS
designed to drive 50Ω transmission lines. Matched impedance
techniques should be used to maximize operating frequency
and minimize signal distortion. Figures 4A and 4B show two
different layouts which are recommended only as guidelines.
Other suitable clock layouts may exist and it would be recommended that the board designers simulate to guarantee
compatibility across all printed circuit and clock component
process variations.
The clock layout topology shown below is a typical termination for LVPECL outputs. The two different layouts mentioned
are recommended only as guidelines.
FOUT and nFOUT are low impedance follower outputs that
generate ECL/LVPECL compatible outputs. Therefore, terminating resistors (DC current path to ground) or current
sources must be used for functionality. These outputs are
3.3V
Zo = 50Ω
125Ω
FOUT
FIN
Zo = 50Ω
Zo = 50Ω
FOUT
50Ω
1
RTT =
Z
((VOH + VOL) / (VCC – 2)) – 2 o
FIN
50Ω
Zo = 50Ω
VCC - 2V
RTT
84Ω
FIGURE 4A. LVPECL OUTPUT TERMINATION
8432DYI-101
125Ω
84Ω
FIGURE 4B. LVPECL OUTPUT TERMINATION
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9
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
DIFFERENTIAL CLOCK INPUT INTERFACE
The CLK /nCLK accepts LVDS, LVPECL, LVHSTL, SSTL, HCSL
and other differential signals. Both VSWING and VOH must meet the
VPP and VCMR input requirements. Figures 5A to 5D show interface examples for the HiPerClockS CLK/nCLK input driven by
the most common driver types. The input interfaces suggested
here are examples only. Please consult with the vendor of the
driver component to confirm the driver termination requirements.
For example in Figure 5A, the input termination applies for ICS
HiPerClockS LVHSTL drivers. If you are using an LVHSTL driver
from 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
LVPECL
nCLK
HiPerClockS
Input
LVHSTL
ICS
HiPerClockS
LVHSTL Driver
R1
50
R1
50
HiPerClockS
Input
R2
50
R2
50
R3
50
FIGURE 5A. HIPERCLOCKS CLK/NCLK INPUT DRIVEN
ICS HIPERCLOCKS LVHSTL DRIVER
FIGURE 5B. HIPERCLOCKS CLK/NCLK INPUT DRIVEN
3.3V LVPECL DRIVER
BY
3.3V
3.3V
3.3V
3.3V
3.3V
R3
125
BY
R4
125
Zo = 50 Ohm
LVDS_Driv er
Zo = 50 Ohm
CLK
CLK
R1
100
Zo = 50 Ohm
nCLK
LVPECL
R1
84
HiPerClockS
Input
Receiv er
R2
84
FIGURE 5C. HIPERCLOCKS CLK/NCLK INPUT DRIVEN
3.3V LVPECL DRIVER
8432DYI-101
nCLK
Zo = 50 Ohm
FIGURE 5D. HIPERCLOCKS CLK/NCLK INPUT DRIVEN
3.3V LVDS DRIVER
BY
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10
BY
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
LAYOUT GUIDELINE
The schematic of the ICS8432I-101 layout example used in
this layout guideline is shown in Figure 6A. The ICS8432I-101
recommended PCB board layout for this example is shown in
Figure 6B. This layout example is used as a general guideline.
The layout in the actual system will depend on the selected component types, the density of the components, the density of the
traces, and the stack up of the P.C. board.
nCLK
CLK
32
31
30
29
28
27
26
25
CLK
REF_IN
nCLK_SEL
VDDA
S_LOAD
S_DATA
S_CLOCK
MR
10
24
23
22
21
20
19
18
17
C11
0.01u
C16
10u
XTAL_SEL
VCCA
S_LOAD
S_DATA
S_CLOCK
MR
Termination A
VCC
VCC
FOUT
FOUTN
VCC
TEST
8432-101
M4
M3
M2
M1
M0
VCO_SEL
nP_LOAD
nCLK
M5
M6
M7
M8
N0
N1
nc
VEE
VCC
TEST
VDD
FOUT1/2
nFOUT1/2
VCCO
FOUT
nFOUT
VEE
1
2
3
4
5
6
7
8
R7
9
10
11
12
13
14
15
16
U1
R1
125
R3
125
Termination B
(not shown in
the layout)
IN+
Zo = 50 Ohm
IN+
IN-
TL1
R2
50
Zo = 50 Ohm
C14
0.1u
INC15
0.1u
TL2
R2
84
FIGURE 6A. SCHEMATIC
8432DYI-101
R1
50
OF
R3
50
RECOMMENDED LAYOUT
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11
R4
84
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
The following component footprints are used in this layout
example: All the resistors and capacitors are size 0603.
POWER
AND
system failure. The trace shape and the 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.
GROUNDING
Place the decoupling capacitors C14 and C15 as close as possible to the power pins. If space allows, placing the decoupling
capacitor at the component side is preferred. This can reduce
unwanted inductance between the decoupling capacitor and the
power pin generated by the via.
• The traces with 50Ω transmission lines TL1 and TL2 at
FOUT and nFOUT should have equal delay and run adjacent to each other. Avoid sharp angles on the clock trace.
Sharp angle turns cause the characteristic impedance to
change on the transmission lines.
Maximize the pad size of the power (ground) at the decoupling
capacitor. Maximize the number of vias between power (ground)
and the pads. This can reduce the inductance between the power
(ground) plane and the component power (ground) pins.
• Keep the clock trace on same layer. Whenever possible,
avoid any vias on the clock traces. Any via on the trace
can affect the trace characteristic impedance and hence
degrade signal quality.
• To prevent cross talk, avoid routing other signal traces in
parallel with the clock traces. If running parallel traces is
unavoidable, allow more space between the clock trace
and the other signal trace.
If VCCA shares the same power supply with VCC, insert the RC
filter R7, C11, and C16 in between. Place this RC filter as close
to the VCCA as possible.
CLOCK TRACES
AND
TERMINATION
• Make sure no other signal trace is routed between the
clock trace pair.
The component placements, locations and orientations should be
arranged to achieve the best clock signal quality. Poor clock signal
quality can degrade the system performance or cause system failure. In the synchronous high-speed digital system, the clock signal
is less tolerable to poor signal quality than other signals. Any ringing on the rising or falling edge or excessive ring back can cause
The matching termination resistors R1, R2, R3 and R4 should
be located as close to the receiver input pins as possible. Other
termination schemes can also be used but are not shown in this
example.
GND
U1
VCC
PIN 1
C11
VIA
C16
VCCA
R7
Close to the input
pins of the
receiver
R4
R3
TL1N
TL1N
C15
C14
TL1
TL1
R2
TL1, TL2 are 50 Ohm traces and
equal length
FIGURE 6B. PCB BOARD LAYOUT
8432DYI-101
FOR
ICS8432I-101
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12
R1
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS8432I-101.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS8432I-101 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VCC = 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 = VCC_MAX * IEE_MAX = 3.465V * 120mA = 416mW
Power (outputs)MAX = 30mW/Loaded Output pair
If all outputs are loaded, the total power is 2 * 30mW = 60mW
Total Power_MAX (3.465V, with all outputs switching) = 416mW + 60mW = 476mW
2. Junction Temperature.
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 = Junction Temperature
θJA = Junction-to-Ambient Thermal 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 9 below.
Therefore, Tj for an ambient temperature of 85°C with all outputs switching is:
85°C + 0.476W * 42.1°C/W = 105°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 9. THERMAL RESISTANCE θJA
FOR
32-PIN LQFP, FORCED CONVECTION
θ JA by Velocity (Linear Feet per Minute)
0
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
67.8°C/W
47.9°C/W
200
55.9°C/W
42.1°C/W
500
50.1°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.
8432DYI-101
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13
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
3. Calculations and Equations.
The purpose of this section is to derive the power dissipated into the load.
LVPECL output driver circuit and termination are shown in Figure 7.
VCCO
Q1
VOUT
RL
50
VCCO - 2V
FIGURE 7. LVPECL DRIVER CIRCUIT
TERMINATION
AND
To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination
voltage of V - 2V.
CCO
•
For logic high, VOUT = V
OH_MAX
(V
CCO_MAX
•
-V
OH_MAX
=V
OL_MAX
CCO_MAX
-V
OL_MAX
CCO_MAX
– 0.9V
) = 0.9V
For logic low, VOUT = V
(V
=V
CCO_MAX
– 1.7V
) = 1.7V
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = [(V
OH_MAX
– (V
CCO_MAX
- 2V))/R ] * (V
Ω] * 0.9V = 19.8mW
[(2V - 0.9V)/50Ω
Pd_L = [(V
OL_MAX
– (V
CCO_MAX
CCO_MAX
L
- 2V))/R ] * (V
Ω] * 1.7V = 10.2mW
[(2V - 1.7V)/50Ω
L
CCO_MAX
-V
OH_MAX
-V
OL_MAX
) = [(2V - (V
CCO_MAX
) = [(2V - (V
CCO_MAX
-V
))/R ] * (V
OH_MAX
-V
OL_MAX
CCO_MAX
L
))/R ] * (V
L
CCO_MAX
-V
OH_MAX
-V
OL_MAX
)=
)=
Total Power Dissipation per output pair = Pd_H + Pd_L = 30mW
8432DYI-101
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14
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
RELIABILITY INFORMATION
TABLE 10. θJAVS. AIR FLOW TABLE
FOR
32 LEAD LQFP
θ JA by Velocity (Linear Feet per Minute)
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
0
200
500
67.8°C/W
47.9°C/W
55.9°C/W
42.1°C/W
50.1°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.
TRANSISTOR COUNT
The transistor count for ICS8432I-101 is: 3712
8432DYI-101
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15
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
PACKAGE OUTLINE - Y SUFFIX
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
FOR
32 LEAD LQFP
TABLE 11. PACKAGE DIMENSIONS
JEDEC VARIATION
ALL DIMENSIONS IN MILLIMETERS
BBA
SYMBOL
MINIMUM
NOMINAL
32
N
1.60
A
A1
MAXIMUM
0.05
0.15
A2
1.35
1.40
1.45
b
0.30
0.37
0.45
c
0.09
0.20
D
9.00 BASIC
D1
7.00 BASIC
D2
5.60
E
9.00 BASIC
E1
7.00 BASIC
E2
5.60
0.80 BASIC
e
L
0.45
θ
0°
0.60
0.75
7°
0.10
ccc
Reference Document: JEDEC Publication 95, MS-026
8432DYI-101
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16
REV. A MAY 23, 2005
ICS8432I-101
Integrated
Circuit
Systems, Inc.
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
TABLE 12. ORDERING INFORMATION
Part/Order Number
Marking
Package
Shipping Packaging
Temperature
ICS8432DYI-101
ICS8432DI-101
32 Lead LQFP
250
-40°C to 85°C
ICS8432DYI-101T
ICS8432DI-101
32 Lead LQFP
1000 tape & reel
-40°C to 85°C
ICS8432DYI-101LF
ICS432DI101L
32 Lead "Lead-Free" LQFP
250
-40°C to 85°C
ICS8432DYI-101LFT
ICS432DI101L
32 Lead "Lead-Free" LQFP
1000 tape & reel
-40°C to 85°C
NOTE: Par ts that are ordered with an "LF" suffix to the par t 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 and industrial applications. Any other applications such as those requiring 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.
8432DYI-101
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17
REV. A MAY 23, 2005
Integrated
Circuit
Systems, Inc.
ICS8432I-101
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
REVISION HISTORY SHEET
Rev
A
8432DYI-101
Table
T 12
Page
1
17
Description of Change
Features Section - added Lead-Free bullet.
Ordering Information Table - add Lead-Free par ts.
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18
Date
5/23/05
REV. A MAY 23, 2005