AK8181D

AK8181D
Preliminary
3.3V LVPECL 1:4
Clock Fanout Buffer
AK8181D
Features
Description
The AK8181D is a member of AKM’s LVPECL
clock fanout buffer family designed for telecom,
networking and computer applications, requiring a
range of clocks with high performance and low
skew. The AK8181D distributes 4 buffered clocks.
Four differential 3.3V LVPECL outputs
Selectable differential PCLK0p/n or LVPECL
clock inputs
PCLK0p/n pair can accept the following
differential input levels; LVDS, LVPECL,
LVHSTL, SSTL, HCSL
PCLK1p/n supports the following input types;
LVPECL, CML, SSTL
Clock output frequency up to 650MHz
Translates any single-ended input signal to
3.3V LVPECL levels with resistor bias on
PCLK0n input
Output skew : 30ps (maximum)
Part-to-part skew : 150ps (maximum)
Propagation delay : 1.5ns (maximum)
Additive phase jitter(RMS) : 0.040ps (typical)
Operating Temperature Range: -40 to +85℃
Package: 20-pin TSSOP (Pb free)
Pin compatible with ICS8533I-01
AK8181D are derived from AKM’s long-termexperienced clock device technology, and enable
clock output to perform low skew. The AK8181D is
available in a 20-pin TSSOP package.
Block Diagram
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AK8181D
Pin Descriptions
Package: 20-Pin TSSOP(Top View)
Pin No.
1
2
3
Pin Name
VSS
CLK_EN
CLK_SEL
Pin
Type
Pullup
down
PWR
---
IN
IN
Pull up
Pull down
Description
Negative power supply
Synchronizing clock output enable (LVCMOS/LVTTL)
Pin is connected to VDD by internal resistor. (typ. 51kΩ
High (Open): clock outputs follow clock input.
Low: Q outputs are forced low, Qn outputs are forced high.
CLK Select Input (LVCMOS/LVTTL)
Pin is connected to VSS by internal resistor. (typ. 51kΩ
High: selects PCLK1p/n inputs
Low (Open): selects PCLK0p/n inputs
Non-inverting differential clock input
4
PCLK0p
IN
Pull down
Pin is connected to VSS by internal resistor. (typ. 51kΩ
*When using PCLK1 input (CLK_SEL=High), it should be
connected to VSS or opened.
Inverting differential clock input
5
PCLK0n
IN
Pull up
Pin is connected to VDD by internal resistor. (typ. 51kΩ
*When using PCLK1 input (CLK_SEL=High), it should be
connected to VDD or opened.
Non-inverting differential LVPECL clock input
6
PCLK1p
IN
Pull down
Pin is connected to VSS by internal resistor. (typ. 51kΩ
*When using PCLK0 input (CLK_SEL=Low), it should be
connected to VSS or opened.
Inverting differential LVPECL clock input
Pin is connected to VDD by internal resistor. (typ. 51kΩ
7
PCLK1n
IN
Pull up
8
NC
--
---
No connect
*When using PCLK0 input (CLK_SEL=Low), it should be
connected to VDD or opened.
9
NC
--
---
No connect
10
VDD
PWR
---
Positive power supply
11, 12
Q3n, Q3
OUT
---
Differential clock output (LVPECL)
13
VDD
PWR
---
Positive power supply
14, 15
Q2n, Q2
OUT
---
Differential clock output (LVPECL)
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AK8181D
Pin No.
Pin Name
Pin
Type
Pullup
down
16, 17
Q1n, Q1
OUT
---
Differential clock output (LVPECL)
18
VDD
PWR
---
Positive power supply
19, 20
Q0n, Q0
OUT
---
Differential clock output (LVPECL)
Description
Ordering Information
Part Number
Marking
Shipping
Packaging
Package
Temperature
Range
AK8181D
AK8181D
Tape and Reel
20-pin TSSOP
-40 to 85 °C
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AK8181D
Absolute Maximum Rating
Over operating free-air temperature range unless otherwise noted
Items
Supply voltage
Symbol
Ratings
Unit
VDD
-0.3 to 4.6
V
Vin
VSS-0.5 to VDD+0.5
V
IIN
±10
mA
Tstg
-55 to 150
C
Input voltage
Input current (any pins except supplies)
Storage temperature
(1)
Note
(1) Stress beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
These are stress ratings only. Functional operation of the device at these or any other conditions beyond those
indicated under “Recommended Operating Conditions” is not implied. Exposure to absolute-maximum-rating
conditions for extended periods may affect device reliability. Electrical parameters are guaranteed only over the
recommended operating temperature range.
(2) VSS=0V
ESD Sensitive Device
This device is manufactured on a CMOS process, therefore, generically susceptible to
damage by excessive static voltage. Failure to observe proper handling and
installation procedures can cause damage. AKM recommends that this device is handled with
appropriate precautions.
Recommended Operation Conditions
Parameter
Operating temperature
Supply voltage
(1)
Symbol
Conditions
Ta
VDD
Min
Typ
-40
VDD5%
3.135
(1) Power of 3.3V requires to be supplied from a single source.
be located close to each VDD pin.
3.3
Max
Unit
85
C
3.465
V
A decoupling capacitor of 0.1F for power supply line should
Pin Characteristics
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
Input Capacitance
CIN
4
pF
Input Pullup Resistor
RPU
51
kΩ
Input Pulldown Resistor
RPD
51
kΩ
Power Supply Characteristics
Parameter
Symbol
Conditions
PCLK0p/n = input 650MHz
Power Supply Current
IDD
PCLK1p/n = open
PCLK0p/n = open
PCLK1p/n = input 650MHz
Dec-2012
Min
Typ
Max
Unit
45
mA
40
mA
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AK8181D
DC Characteristics (LVCMOS/LVTTL)
All specifications at VDD=3.3V5%, VSS=0V, Ta: -40 to +85℃, unless otherwise noted
Parameter
Symbol
Input High Voltage
Conditions
VIH
Input Low Voltage
Input High Current
CLK_EN
IH
Input Low Current
-0.3
IL
CLK_EN
MAX
Unit
VDD+0.3
V
0.8
V
Vin=VDD=3.465V
150
μA
Vin=VDD=3.465V
5
μA
Vin=VSS,
CLK_SEL
TYP
2.0
VIL
CLK_SEL
MIN
VDD=3.465V
Vin=VSS,
VDD=3.465V
-5
μA
-150
μA
DC Characteristics (Differential)
All specifications at VDD=3.3V5%, VSS=0V, Ta: -40 to +85℃, unless otherwise noted
Parameter
Symbol
PCLK0p
Input High Current
PCLK0n
IH
IL
PCLK0n
Peak-to-Peak Input Voltage
Common Mode Input Voltage
(1)
(2)
(1) (2)
MAX
Unit
Vin=VDD=3.465V
150
μA
Vin=VDD=3.465V
5
μA
Vin=VSS,
PCLK0p
Input Low Current
Conditions
VDD=3.465V
Vin=VSS,
VDD=3.465V
MIN
TYP
-5
μA
-150
μA
VPP
0.15
1.3
V
VCMR
VSS+0.5
VDD-0.85
V
MAX
Unit
Vin=VDD=3.465V
150
μA
Vin=VDD=3.465V
5
μA
For single ended applications, the maximum input voltage for PCLK0p and PCLK0n is VDD+0.3V.
Common mode voltage is defined as VIH.
DC Characteristics (LVPECL)
All specifications at VDD=3.3V5%, VSS=0V, Ta: -40 to +85℃, unless otherwise noted
Parameter
Symbol
PCLK1p
Input High Current
PCLK1n
IH
Vin=VSS,
PCLK1p
Input Low Current
IL
PCLK1n
Peak-to-Peak Input Voltage
Common Mode Input Voltage
Output High Voltage
Output Low Voltage
(1) (2)
(3)
(3)
Peak-to-Peak Output Voltage Swing
(1)
(2)
(3)
Conditions
VDD=3.465V
Vin=VSS,
VDD=3.465V
MIN
TYP
-5
μA
-150
μA
VPP
0.3
1.0
V
VCMR
VSS+1.5
VDD
V
VOH
VDD-1.4
VDD-0.9
V
VOL
VDD-2.0
VDD-1.7
V
VSWING
0.6
1.0
V
For single ended applications, the maximum input voltage for PCLK1p and PCLK1n is VDD+0.3V.
Common mode voltage is defined as VIH.
Outputs terminated with 50Ω to VDD-2V.
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AK8181D
AC Characteristics
All specifications at VDD=3.3V5%, VSS=0V, Ta: -40 to +85℃, unless otherwise noted
Parameter
Symbol
Output Frequency
(1)
Unit
650
MHz
0.43
1.5
ns
0.43
1.3
ns
tsk(O)
30
ps
tskPP
150
ps
(3) (4)
Output Rise/Fall Time
MAX
PCLK1p, PCLK1n tPD1
Buffer Additive Jitter, RMS
Output Duty Cycle
TYP
PCLK0p, PCLK0n tPD0
(2) (3)
Part-to-Part Skew
MIN
fOUT
Propagation Delay
Output Skew
Conditions
(5)
(5)
tjit
156.25MHz (12kHz – 20MHz)
tr , tf
20% to 80%
DCOUT
0.04
200
47
50
ps
600
ps
53
%
All parameters measured at f ≤ 650MHz unless noted otherwise.
The cycle to cycle jitter on the input will equal the jitter on the output. The part does not add jitter.
(1) Measured from the differential input crossing point to the differential output crossing point.
(2) Defined as skew between outputs at the same supply voltage and with equal load conditions.
(3) This parameter is defined in accordance with JEDEC Standard 65.
(4) Defined as skew between outputs on different devices operating at the same supply voltages and with equal load
conditions. Using the same type of inputs on each device, the outputs are measured at the differential cross points.
(5) Design value.
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AK8181D
Figure 1 3.3V Output Load Test Circuit
Figure 2 Differential Input Level
Qxn
80%
Clock
Outputs
Qx
Qyn
80%
VSWING
20%
20%
tR
tF
Qy
tsk(o)
Figure 3 Output Skew
Figure 4 Output Rise/Fall Time
Figure 5 Propagation Delay
Figure 6 Output Duty/ Pulse Width/ Period
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AK8181D
Function Table
The following table shows the inputs/outputs clock state configured through the control pins.
Table 1: Control Input Function Table
Inputs
Outputs
CLK_EN
CLK_SEL
Selected Source
Q0:Q3
Q0n:Q3n
0
0 (Open)
PCLK0p/n
Disabled: Low
Disabled: High
0
1
PCLK1p/n
Disabled: Low
Disabled: High
1 (Open)
0 (Open)
PCLK0p/n
Enabled
Enabled
1 (Open)
1
PCLK1p/n
Enabled
Enabled
After CLK_EN switches, the clock outputs are disabled or enabled following a rising and falling input clock edge
as shown in Figure 7. In the active mode, the state of the outputs are a function of the PCLK0p/n and PCLK1p/n
as described in Table 2.
Figure 7 CLK_EN Timing Diagram
Table 2 Clock Input Function Table
Inputs
Outputs
Input to Output
Polarity
High
Differential to Differential
Non Inverting
PCLK0/1p
PCLK0/1n
Q0:Q3
Q0n:Q3n
0
1
Low
1
0
0
1
High
Low
Differential to Differential
Non Inverting
Biased
(1)
Low
High
Single Ended to Differential
Non Inverting
Biased
(1)
High
Low
Single Ended to Differential
Non Inverting
Biased
(1)
0
High
Low
Single Ended to Differential
Inverting
Biased
(1)
1
Low
High
Single Ended to Differential
Inverting
(1) Please refer to the application Information section, “Wiring the Differential Input to Accept Single Ended
Levels”.
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AK8181D
Application Information
Wiring the Differential Input to Accept Single Ended Levels
Figure.8 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
the V_REF in the center of the input voltage swing. For example, if the input clock swing is only 2.5V and
VDD = 3.3V, V_REF should be 1.25V and R2/R1 = 0.609.
Figure 8 Single Ended Signal Driving Differential Input
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AK8181D
Package Information
 Mechanical data : 20pin TSSOP
6.50±0.10
0.15±0.05
11
1
6.40±0.10
4.40±0.10
0.6±0.10
20
10
0.25±0.05
0.65
0°~8°
S
S
1.10 MAX
0.10
0.10±0.05
0.90±0.05
 Marking
20
11
b
AK8181D
XXXXXXX
c
a:
b:
c:
#1 Pin Index
Part number
Date code ( 7 digits)
a
10
1
 RoHS Compliance
All integrated circuits form Asahi Kasei Microdevices Corporation (AKM)
assembled in “lead-free” packages* are fully compliant with RoHS.
(*) RoHS compliant products from AKM are identified with “Pb free” letter indication on
product label posted on the anti-shield bag and boxes.
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AK8181D
IMPORTANT NOTICE
 These products and their specifications are subject to change without notice.
When you consider any use or application of these products, please make inquiries the sales office of Asahi Kasei
Microdevices Corporation (AKM) or authorized distributors as to current status of the products.
 Descriptions of external circuits, application circuits, software and other related information contained in this
document are provided only to illustrate the operation and application examples of the semiconductor products. You
are fully responsible for the incorporation of these external circuits, application circuits, software and other related
information in the design of your equipments. AKM assumes no responsibility for any losses incurred by you or third
parties arising from the use of these information herein. AKM assumes no liability for infringement of any patent,
intellectual property, or other rights in the application or use of such information contained herein.
 Any export of these products, or devices or systems containing them, may require an export license or other official
approval under the law and regulations of the country of export pertaining to customs and tariffs, currency exchange,
or strategic materials.
 AKM products are neither intended nor authorized for use as critical components Note1) in any safety, life support, or
other hazard related device or systemNote2), and AKM assumes no responsibility for such use, except for the use
approved with the express written consent by Representative Director of AKM. As used here:
Note1) A critical component is one whose failure to function or perform may reasonably be expected to result,
whether directly or indirectly, in the loss of the safety or effectiveness of the device or system containing it,
and which must therefore meet very high standards of performance and reliability.
Note2) A hazard related device or system is one designed or intended for life support or maintenance of safety
or for applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to function or
perform may reasonably be expected to result in loss of life or in significant injury or damage to person or
property.
 It is the responsibility of the buyer or distributor of AKM products, who distributes, disposes of, or otherwise places
the product with a third party, to notify such third party in advance of the above content and conditions, and the buyer
or distributor agrees to assume any and all responsibility and liability for and hold AKM harmless from any and all
claims arising from the use of said product in the absence of such notification.
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