AK8138C

AK8138C
Low power
Multiclock Generator with VCXO
AK8138C
Features
Description
The AK8138C is a member of AKM’s low power
multi clock generator family designed for a feature
rich DTV or STB, requiring a range of system
clocks with high performance. The AK8138C
generates different frequency clocks from a 27MHz
crystal oscillator and provides them to up to four
outputs configured by pin-setting. The on-chip
VCXO accepts a voltage control input to allow the
output clocks to vary by ±110 ppm for
synchronizing to the external clock system. Both
circuitries of VCXO and PLL in AK8138C are
derived from AKM’s long-term-experienced clock
device technology, and enable clock output to
perform low jitter and to operate with very low
current consumption. The AK8138C is available
in a 16-pin SSOP package.
27MHz Crystal Input
Four Frequency-Selectable Clock Outputs
One 27MHz-Reference Output
Selectable Clock out Frequencies:
- 74.1758, 74.250MHz
- 25.000MHz
- 4.9152, 12.000, 24.000,24.576MHz
- 33.333MHz
Built-in VCXO
- Pull Range: ±110ppm (Min.)
Low Jitter Performance
- Period Jitter:
150 psec (Typ.) at CLK1-4
- Long Term Jitter :
0.85ns (Typ.) 74.1758MHz
160 psec (Typ.) at REFOUT
Low Current Consumption:
16.5mA (Typ.) at 3.3V
Supply Voltage:
3.0 – 3.6V
Operating Temperature Range:
-20 to +85℃
Package:
16-pin SSOP (Lead free)
Applications
Digital TV Sets
Personal Video Recorders
Set-Top-Boxes
Multi Media Receivers
Block Diagram
VDD
X1
X2
VIN
Voltage
Controlled
Crystal
Oscillator
PLL1
PLL1
PLL2
Divide
Logic
and
Output
Control
PLL3
CLK1
CLK2
CLK3
CLK4
S0
S1
REFOUT
S2
GND
AK8138C Multi Clock Generator
MS1137-E-02
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AK8138C
Pin Descriptions
Package: 16-Pin SSOP(Top View)
X1
1
16
X2
S0
2
15
VDD3
S1
3
14
S2
VIN
4
13
VDD2
VDD1
5
12
GND2
GND1
6
11
CLK4
CLK1
7
10
CLK3
CLK2
8
9
Pin
No.
Pin
Name
REFOUT
Pin
Type
Description
Crystal connection, Connect to 27.000MHz crystal
1
X1
XO
2
S0
IN
Clock Out Frequency Select 0, See Table 1 for the selection
(1)
3
S1
IN
Clock Out Frequency select 1, See Table 1 for the selection
(1)
4
VIN
IN
VCXO Control Voltage Input
5
VDD1
--
Power Supply 1
6
GND1
--
Ground 1
7
CLK1
OUT
Clock output 1, See Table 1 for its selectable frequency
8
CLK2
OUT
Clock output 2, See Table 1 for its selectable frequency
9
REF
OUT
OUT
Reference Clock Output of VCXO based on 27.000MHz Crystal
10
CLK3
OUT
Clock output 3, See Table 1 for its selectable frequency
11
CLK4
OUT
Clock output 4, See Table 1 for its selectable frequency
12
GND2
--
Ground 2
13
VDD2
--
Power Supply 2
14
S2
IN
Clock Out Frequency select 1, See Table 1 for the selection
15
VDD3
--
Power Supply 3
Please open when an external clock input is used
(2)
(1)
Crystal connection, Connect to 27.000MHz crystal
16
X2
XI
Or external clock input (minimum 1Vpp input).
(1) Internal pull up 360k
(2) Internal pull down 510k
Ordering Information
Part Number
Marking
Shipping
Packaging
Package
Temperature
Range
AK8138C
8138C
Tape and Reel
16-pin SSOP
-20 to 85 ℃
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AK8138C
Absolute Maximum Rating
Over operating free-air temperature range unless otherwise noted
Items
(1)
Symbol
Ratings
Unit
VDD
-0.3 to 4.6
V
Vin
VSS-0.3 to VDD+0.3
V
IIN
±10
mA
Tstg
-55 to 130
C
Supply voltage
Input voltage
Input current (any pins except supplies)
Storage temperature
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.
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)
Output Load Capacitance
Symbol
Conditions
Min
Ta
-20
VDD
3.0
Typ
Max
Unit
85
C
3.3
3.6
V
Cp1
Pin: CLK1-4
15
pF
Cp2
Pin: REFOUT
25
pF
Note:
(1) Power to VDD1, VDD2 and VDD3 requires to be supplied from a single source.
0.1F for power supply line should be installed close to each VDD pin.
MS1137-E-02
A decoupling capacitor of
Dec-2013
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AK8138C
DC Characteristics
All specifications at VDD: over 3.0 to 3.6V, Ta:
Parameter
-20 to +85℃, 27MHz Crystal, unless otherwise noted
Symbol
Conditions
High Level Input Voltage
VIH
Pin: S0,S1,S2
Low Level Input Voltage
VIL
Pin: S0,S1,S2
Input Current 1
IL 1
Pin: S0,S1,S2
Input Current 2
IL 2
PIN: VIN
High Level Output
Voltage
VOH
Low level Output
Voltage
VOL
Current Consumption
IDD
MIN
TYP
MAX
Unit
0.7VDD
Pin: CLK1-4, REFOUT
V
0.3VDD
V
-20
+10
μA
-3
+3
μA
0.8VDD
IOH=-4mA
V
Pin: CLK1-4, REFOUT
0.2VDD
IOL=+4mA
V
No load
Clock out selection by note
Ta=25℃
(1)
16.5
mA
(1) Pin setting for output clock selection: [S2:S0] = HLH
AC Characteristics
All specifications at VDD: over 3.0 to 3.6V, Ta: over -20 to +85℃, 27MHz Crystal, unless otherwise noted
Parameter
Symbol
Conditions
MIN
Crystal Clock Frequency
VCXO Pullable Range
(3)
VCXO Gain
Period Jitter
GVCXO
Long Term Jitter
VIN range at 1.5V±1.0V
150
ppm/
V
CLK1-4
150
ps
0.85
ns
160
ps
Pin: CLK1-4
Output Clock Duty
Cycle
(1)
Pin: REFOUT
Pin: CLK1-4
Output Clock Rise Time
trise
Pin: CLK1-4
Pin: REFOUT
Output Transition Time
Pin: CLK1-4
(6)
(2 )
(1)
tfall
Power-up Time
(2)
(1)
Pin: REFOUT
Output Clock Fall Time
Unit
MHz
±110
CLK1 at 74.1758MHz
1000 cycle delay
REFOUT at 27.000MHz
1000 cycle delay
(5)
MAX
27.0000
VIN at over 0 to VDD V
(4)
TYP
(2 )
(1)
Pin: CLK1 at
74.25 or 74.175MHz
ppm
45
50
55
%
40
50
60
%
1.5
4
ns
2.5
4
ns
1.5
4
ns
2.5
4
ns
1
2
ms
90
140
s
(1) Measured with load capacitance of 15pF
(2) Measured with load capacitance of 25pF
(3) Pullable range depends on crystal characteristics, on-chip load capacitance, and stray capacity of PCB.
Min. ±110ppm is applied to AKM’s authorized test condition.
(4) ±3 in 10000 sampling or more
(5) ±3 in 5000 sampling or more
(6) Time to settle output into ±20ppm of specified frequency
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AK8138C
Output clock frequency selection
The AK8138C generates a range of low-jitter and hi-accuracy clock frequencies with three built-in PLLs
and provides to up to four assigned outputs. A frequency selection at assigned output pin is configured by
pin-setting of S0 (Pin2), S1 (Pin3), and S2 (Pin14).
The selectable frequency is shown in Table 1..
Table 1: Clock output Frequency
Selection Pin
S2
(Pin 14)
L
L
L
L
H
H
H
H
S1
(Pin 3)
L
L
H
H
L
L
H
H
Clock Output Frequency (MHz)
S0
(Pin 2)
L
H
L
H
L
H
L
H
CLK1
(Pin 7)
74.250
74.250
74.1758
74.1758
74.250
74.250
74.1758
74.1758
CLK2
(Pin 8)
25.000
25.000
25.000
25.000
25.000
OFF
25.000
25.000
CLK3
(Pin 10)
24.000
12.000
24.000
12.000
24.576
24.000
24.576
4.9152
CLK4
(Pin 11)
33.333
33.333
33.333
33.333
33.333
33.333
33.333
33.333
Voltage Control Crystal Oscillator (VCXO)
The AK8138C has a voltage control crystal oscillator (VCXO), featuring fine frequency tuning for 27MHz of
primary clock frequency by external DC voltage control. This tuning enables output clock frequency to
synchronize the external clock system. VIN (Pin 4) accepts DC voltage control from a processor or a
system controller, and pulls the primary frequency of crystal to higher or lower. This pulling range is
determined by crystal characteristic, on-chip load capacitor, and stray capacitance of PCB. The AK8138C
is designed to range ±110ppm of primary frequency in AKM’s authorized condition, and the typical pulling
profile is shown in Figure 1. For details about the condition and other specific crystal application case,
refer the AK8138 Family application note.
27.0[MHz] VCXO Characteristics
NDK : NX5032GA <CL=7.5[pF]> (Cext1=10[pF], Cext2=1[pF])
200.0
150.0
D f [ppm]
100.0
50.0
0.0
-50.0
0
0.5
1
1.5
2
2.5
3
3.5
-100.0
-150.0
-200.0
VIN [V]
Figure 1: Typical VCXO Pulling Profile
MS1137-E-02
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AK8138C
Typical Connection Diagram
+3.3V typ.
27.0MHz AT Cut Crystal
MPEG-TS
DECODER
Cext2
Cext1
AK8138C
CTL OUT2
1:X1
X2:16
CTL OUT0
2:S0
VDD3:15
CTL OUT1
3:S1
S2:14
DC Voltage
CTL OUT
(PWM)
R11
C11
C1
REF CLK IN
GND
C3
C2
IEEE1394
4:VIN
VDD2:13
5:VDD1
GND2:12
6:GND1
CLK4:11
USB I/F
7:CLK1
CLK3:10
12.0/24.0MHz
8:CLK2
REFOUT:9
24.576MHz
1
Ethernet I/F
2
25.0MHz
3
HD Display I/F
4
74.25/74.1758MHz
5
6
7
Figure 2: Typical
Connection Diagram
8
C1, C2, C3: 0.1F
Cext1, Cext2: Depends on crystal characteristics. Refer the specification of the crystal.
R11, C11: In case of interface by PWM. For right configuration, refer the specification of the
applied processor.
PCB Layout Consideration
The AK8138C is a high-accuracy and low-jitter multi clock generator. For proper performances specified
in this datasheet, careful PCB layout should be taken. The followings are layout guidelines based on the
typical connection diagram shown in Figure 2
Power supply line – AK8138C has three power supply pins (VDD1-3) which deliver power to internal
circuitry segments. A 0.1F decoupling capacitor should be placed as close to each VDD pin as possible.
Ground pin connection – AK8138C has two ground pins (GND1-2). These pin require connecting to
plane ground which will eliminate any common impedance with other critical switching signal return.
0.1F decoupling capacitors placed at VDD1, VDD2, and VDD3 should be grounded at close to the
GND1pin, the GND2 pin, and the GND2, respectively.
Crystal connection – Proper oscillation performance and pullable range are susceptible to stray or
parasitic capacitors around crystal. The wiring traces to a crystal form X1 (Pin 1) and X2 (Pin 14) have
equal lengths with no via and as short in length as possible. These traces should be also located away
from any traces with switching signal.
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AK8138C
Package Information
 Mechanical data
16pin SSOP (Unit: mm)
5.00TYP
16
9
A
6.40.3
4.4TYP
1
8
0.220.1
0.65
0.150.1
1.25 TYP
0.10.1
Detail A
0.50.2
0.1
0-10
 Marking
1
9
6
b
c
8138C
XXXXX
AKM
d
a
1
a:
#1 Pin Index
b:
Part number
c:
Date code (5 digits)
d
Product Family Logo
(1)
8
 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.
MS1137-E-02
Dec-2013
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AK8138C
IMPORTANT NOTICE
0. Asahi Kasei Microdevices Corporation (“AKM”) reserves the right to make changes to the
information contained in this document without notice. When you consider any use or application of
AKM product stipulated in this document (“Product”), please make inquiries the sales office of AKM
or authorized distributors as to current status of the Products.
1. All information included in this document are provided only to illustrate the operation and application
examples of AKM Products. AKM neither makes warranties or representations with respect to the
accuracy or completeness of the information contained in this document nor grants any license to any
intellectual property rights or any other rights of AKM or any third party with respect to the
information in this document. You are fully responsible for use of such information contained in this
document in your product design or applications. AKM ASSUMES NO LIABILITY FOR ANY
LOSSES INCURRED BY YOU OR THIRD PARTIES ARISING FROM THE USE OF SUCH
INFORMATION IN YOUR PRODUCT DESIGN OR APPLICATIONS.
2. The Product is neither intended nor warranted for use in equipment or systems that require
extraordinarily high levels of quality and/or reliability and/or a malfunction or failure of which may
cause loss of human life, bodily injury, serious property damage or serious public impact, including
but not limited to, equipment used in nuclear facilities, equipment used in the aerospace industry,
medical equipment, equipment used for automobiles, trains, ships and other transportation, traffic
signaling equipment, equipment used to control combustions or explosions, safety devices, elevators
and escalators, devices related to electric power, and equipment used in finance-related fields. Do not
use Product for the above use unless specifically agreed by AKM in writing.
3. Though AKM works continually to improve the Product’s quality and reliability, you are responsible
for complying with safety standards and for providing adequate designs and safeguards for your
hardware, software and systems which minimize risk and avoid situations in which a malfunction or
failure of the Product could cause loss of human life, bodily injury or damage to property, including
data loss or corruption.
4. Do not use or otherwise make available the Product or related technology or any information
contained in this document for any military purposes, including without limitation, for the design,
development, use, stockpiling or manufacturing of nuclear, chemical, or biological weapons or missile
technology products (mass destruction weapons). When exporting the Products or related technology
or any information contained in this document, you should comply with the applicable export control
laws and regulations and follow the procedures required by such laws and regulations. The Products
and related technology may not be used for or incorporated into any products or systems whose
manufacture, use, or sale is prohibited under any applicable domestic or foreign laws or regulations.
5. Please contact AKM sales representative for details as to environmental matters such as the RoHS
compatibility of the Product. Please use the Product in compliance with all applicable laws and
regulations that regulate the inclusion or use of controlled substances, including without limitation, the
EU RoHS Directive. AKM assumes no liability for damages or losses occurring as a result of
noncompliance with applicable laws and regulations.
6. Resale of the Product with provisions different from the statement and/or technical features set forth in
this document shall immediately void any warranty granted by AKM for the Product and shall not
create or extend in any manner whatsoever, any liability of AKM.
7. This document may not be reproduced or duplicated, in any form, in whole or in part, without prior
written consent of AKM.
Dec-2013
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