levels. The high gain differential amplifier accepts peak-topeak input voltages as small as 150mV as long as the common mode voltage is within the specified minimum and maximum range.
Guaranteed output and part-to-part skew characteristics
make the ICS8530-01 ideal for those clock distribution applications demanding well defined performance and repeatability.
The ICS8530-01 is a low skew, 1-to-16 Dif ferential-to-3.3V LVPECL Fanout Buffer and a member of the HiPerClockS™ family of High Performance Clock Solutions from ICS. The CLK, nCLK
pair can accept most standard differential input
FEATURES
• 16 differential 3.3V L VPECL outputs
• CLK, nCLK input pair
• CLK, nCLK pair can accept the following differential input
levels: L VDS, L VPECL, L VHSTL, SSTL, HCSL
• Maximum output frequency up to 500MHz
• Translates any single-ended input signal to 3.3V L VPECL
levels with a resistor bias on nCLK input
• Output skew: 75ps (maximum)
• Part-to-part skew: 250ps (maximum)
• 3.3V output operating supply
• 0°C to 70°C ambient operating temperature
• Industrial temperature information available upon request
BLOCK DIAGRAMPIN ASSIGNMENT
nQ13
nQ12
CLK
nCLK
Q0
nQ0
Q1
nQ1
Q2
nQ2
Q3
nQ3
Q4
nQ4
Q5
nQ5
Q6
nQ6
Q7
nQ7
Q15
nQ15
Q14
nQ14
Q13
nQ13
Q12
nQ12
Q11
nQ11
Q10
nQ10
Q9
nQ9
Q8
nQ8
VCCO
Q11
nQ11
Q10
nQ10
V
nQ9
nQ8
V
CCO
VCC
V
Q12
CCO
48 47 46 45 44 43 42 41 40 39 38 37
1
2
3
4
5
6
Q9
Q8
EE
7
8
9
10
11
12
ICS8530-01
13 14 15 16 17 18 19 20 21 22 23 24
nQ7
Q7
V
VCC
CCO
48-Pin LQFP
7mm x 7mm x 1.4mm package body
nQ14
Q14
Q13
V
EE
Q5
VEEnQ6
Q6
Y Package
Top View
nQ15
nQ5
Q15
Q4
V
CCO
nQ4
nCLK
36
35
34
33
32
31
30
29
28
27
26
25
VCCO
CLK
VCCO
nQ0
Q0
nQ1
Q1
V
EE
nQ2
Q2
nQ3
Q3
Vcco
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
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
ods may affect product reliability.
4.6V
-0.5V to VCC + 0.5V
-0.5V to V
CCO
+ 0.5V
47.9°C/W
-65°C to 150°C
is not implied. Exposure to absolute maximum rating conditions for extended peri-
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
4
Page 5
Integrated
Circuit
Systems, Inc.
PARAMETER MEASUREMENT INFORMATION
V
CC
LVPECL
VCC = 2V ± 5%
V
CCO
V
CCO
= 2V ± 5%
VEE = -1.3V ± 0.135V
ICS8530-01
LOW SKEW, 1-TO-16
D
IFFERENTIAL-TO-3.3V L VPECL FANOUT BUFFER
SCOPE
Qx
nQx
Qx
nQx
V
CLK
nCLK
V
FIGURE 1 - OUTPUT LOAD TEST CIRCUIT
CC
V
VPP
EE
Cross Points
CMR
FIGURE 2 - DIFFERENTIAL INPUT LEVEL
Qy
nQy
tsk(o)
FIGURE 3 - OUTPUT SKEW
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
5
Page 6
Integrated
Circuit
Systems, Inc.
Qx
PART 1
nQx
Qy
PART 2
nQy
D
IFFERENTIAL-TO-3.3V L VPECL FANOUT BUFFER
tsk(pp)
FIGURE 4 - PART-TO-PART SKEW
ICS8530-01
LOW SKEW, 1-TO-16
Clock Inputs
and Outputs
CLK
nCLK
Q0 - Q15
nQ0 - nQ15
80%
20%
t
R
t
F
FIGURE 5 - INPUTAND OUTPUT RISEAND FALL TIME
t
PD
FIGURE 6 - PROPAGATION DELAY
80%
20%
V
SWING
CLK, Qx
nCLK, nQx
Pulse Width
t
PERIOD
t
odc =
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
PW
t
PERIOD
FIGURE 7 - odc & t
6
PERIOD
Page 7
Integrated
Circuit
Systems, Inc.
D
IFFERENTIAL-TO-3.3V L VPECL FANOUT BUFFER
APPLICA TION INFORMATION
WIRINGTHE DIFFERENTIAL INPUTTO ACCEPT SINGLE ENDED LEVELS
ICS8530-01
LOW SKEW, 1-TO-16
Figure 8
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 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.
shows how the differential input can be wired to accept single ended levels. The reference voltage V_REF ~ VCC/2 is
CLK_IN
C1
0.1uF
FIGURE 8 - SINGLE ENDED SIGNAL DRIVING DIFFERENTIAL INPUT
R1
1K
V_REF
R2
1K
VCC
+
-
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
7
Page 8
Integrated
Circuit
Systems, Inc.
D
IFFERENTIAL-TO-3.3V L VPECL FANOUT BUFFER
ICS8530-01
LOW SKEW, 1-TO-16
POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS8530-01.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS8530-01 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for V
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
= 3.3V + 5% = 3.465V , which gives worst case results.
CC
•Power (core)
•Power (outputs)
If all outputs are loaded, the total power is 16 * 30.2mW = 483.2mW
T otal Power
2. Junction T emperature.
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 HiPerClockS
The equation for Tj is as follows: Tj = θ
Tj = Junction T emperature
θJA = junction-to-ambient thermal resistance
Pd_total = T otal device power dissipation (example calculation is in section 1 above)
T
= Ambient T emperature
A
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θ
moderate air flow of 200 linear feet per minute and a multi-layer board, the appropriate value is 47.9°C/W per T able 6 below .
Therefore, Tj for an ambient temperature of 70°C with all outputs switching is:
70°C + 0.899W * 47.9°C/W = 1 13.1°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).
MAX
= V
MAX
_MAX
* I
CC_MAX
= 30.2mW/Loaded Output pair
= 3.465V * 120mA = 415.8mW
EE_MAX
(3.465V , with all outputs switching) = 415.8mW + 483.2mW = 899mW
TM
devices is 125°C.
* Pd_total + T
JA
A
JA
must be used . Assuming a
Table 6. Thermal Resistance qJA for 48-pin LQFP, Forced Convection
q
by Velocity (Linear Feet per Minute)
JA
0200500
Single-Layer PCB, JEDEC Standard Test Boards67.8°C/W55.9°C/W50.1°C/W
Multi-Layer PCB, JEDEC Standard Test Boards47.9°C/W42.1°C/W39.4°C/W
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
8
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Integrated
Circuit
Systems, Inc.
D
IFFERENTIAL-TO-3.3V L VPECL FANOUT BUFFER
3. Calculations and Equations.
The purpose of this section is to derive the power dissipated into the load.
ICS8530-01
LOW SKEW, 1-TO-16
LVPECL output driver circuit and termination are shown in
Figure 9.
V
CCO
Q1
V
OUT
RL
50
V
- 2V
CCO
FIGURE 9 - LVPECL DRIVER CIRCUITAND TERMINATION
To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination
voltage of VCC- 2V .
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low .
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.
ICS8530DY-01www.icst.com/products/hiperclocks.htmlREV. B AUGUST 8, 2001
12
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