MB88155
Spread Spectrum Clock Generator
MB88155 is a clock generator for EMI (Electro Magnetic Interference) reduction. The peak of unnecessary radiation noise (EMI) can
be attenuated by making the oscillation frequency slightly modulate periodically with the internal modulator. For modulation, the
MB88155 supports both center-spreading and down-spreading. It has a non-modulated clock output pin (REFOUT) as well as a
modulated clock output pin (CKOUT) .
Features
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■
■
■
■
Input frequency : 12.5 MHz to 50 MHz (Multiplied by 1)
12.5 MHz to 20 MHz (Multiplied by 4)
Output frequency : CKOUT
REFOUT
Modulation rate :
12.5 MHz to 80 MHz
The same as input frequency (not multiplied)
0.5,
1.0 (center spread) ,
1.0,
2.0 (Down spread)
Equipped with oscillation circuit : range of oscillation 12.5 MHz to 40 MHz (Fundamental oscillation)
40 MHz to 48 MHz (3rd overtone)
Modulation clock output Duty : 40 to 60
Modulation clock cycle
cycle jitter : MB88155-1xx
MB88155-1xx
MB88155-4xx
Power supply voltage : 3.3 V
0.3 V
Operating temperature :
12.5 MHz to 20 MHz
20 MHz to 50 MHz
less than 150 ps
less than 100 ps
less than 200 ps
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■
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Low current consumption by CMOS process : 5 mA (24 MHz : Typ-sample, no load)
40 °C to
85 °C
Package : 8-pin plastic TSSOP
Cypress Semiconductor Corporation
Document Number: 002-08298 Rev. *A
•
198 Champion Court
•
San Jose
,
CA 95134-1709
•
408-943-2600
Revised December 21, 2016
MB88155
Contents
Product Lineup ................................................................. 3
Pin Assignment ................................................................ 4
Pin Description ................................................................. 4
I/O Circuit Type ................................................................. 5
Handling Devices .............................................................. 7
Preventing Latch-up .................................................... 7
Handling unused pins .................................................. 7
The attention when the external clock is used ............ 7
Power supply pins ....................................................... 7
Oscillation circuit ......................................................... 7
Block Diagram .................................................................. 8
Pin Setting ......................................................................... 9
Absolute Maximum Ratings .......................................... 11
Recommended Operating Conditions .......................... 12
Electrical Characteristics ............................................... 13
Output Clock Duty Cycle (tdcc, tdcr
½
tb/ta) ............... 15
Input Frequency (fin
½
1/tin) ......................................... 15
Output Slew Rate (SRc, SRr) ........................................ 15
Cycle-Cycle Jitter (tjc
½
|tn
tn
1| ) ......................... 16
Modulation Waveform .................................................... 17
Lock-Up Time .................................................................. 18
Oscillation Circuit ........................................................... 20
Interconnection Circuit Example .................................. 21
Spectrum Example Characteristics .............................. 22
Ordering Information ...................................................... 23
Package Dimensions ...................................................... 25
Document History ........................................................... 26
Sales, Solutions, and Legal Information .......................27
Document Number: 002-08298 Rev. *A
Page 2 of 27
MB88155
1. Product Lineup
The MB88155 is available in different models : 2 models different in multiplier (× 1 and × 4) , 2 in modulation type (center-spreading
and down-spreading) , 2 in input frequency range at a multiplier of 1 (12.5 MHz to 25 MHz and 25 MHz to 50 MHz) , and 1 in input
frequency range at a multiplier of 4 (12.5 MHz to 20 MHz) .
The MB88155 is also available in two versions : modulation-on/off selectable version (with ENS pin) and power-down function built-
in version (with XPD pin) .
MB88155-M T F
Input frequency range,
With/without ENS/XPD
Multiplied
0 : 12.5 MHz to 25.0 MHz, With ENS, Without XPD
by 1
1 : 25.0 MHz to 50.0 MHz, With ENS, Without XPD
2 : 12.5 MHz to 25.0 MHz, Without ENS, With XPD
3 : 25.0 MHz to 50.0 MHz, Without ENS, With XPD
Multiplied
0 : 12.5 MHz to 20.0 MHz, With ENS, Without XPD
by 4
2 : 12.5 MHz to 20.0 MHz, Without ENS, With XPD
→
0 : Down spread, 1 : Center spread
→
1 : Multiplied by 1, 4 : Multiplied by 4
→
Spread type
Multiplication rate setting
Line-up of MB88155
Product
MB88155-100
MB88155-101
MB88155-102
MB88155-103
MB88155-110
MB88155-111
MB88155-112
MB88155-113
MB88155-400
MB88155-402
MB88155-410
MB88155-412
Input frequency
12.5 MHz to 25 MHz
25 MHz to 50 MHz
12.5 MHz to 25 MHz
25 MHz to 50 MHz
12.5 MHz to 25 MHz
25 MHz to 50 MHz
12.5 MHz to 25 MHz
25 MHz to 50 MHz
12.5 MHz to 20 MHz
Multiplication
rate
Output
frequency
Modulation
type
Down
spread
Modulation
enable pin
Yes
No
Yes
No
Power down
pin
No
Yes
No
Yes
No
Yes
No
Yes
Multiplied by 1
The same as
input frequency
Center
spread
Multiplied by 4
50 MHz to
80 MHz
Down
spread
Center
spread
Yes
No
Yes
No
Document Number: 002-08298 Rev. *A
Page 3 of 27
MB88155
2. Pin Assignment
XIN 1
XOUT 2
ENS 3
SEL 4
8 V
DD
XIN 1
XOUT 2
XPD 3
SEL 4
8 V
DD
MB88155
-xx0
-xx1
7 CKOUT
6 V
SS
5 REFOUT
MB88155
-xx2
-xx3
7 CKOUT
6 V
SS
5 REFOUT
FPT-8P-M07
3. Pin Description
Pin name
XIN
XOUT
ENS/XPD
SEL
I/O
I
O
I
I
Pin no.
1
2
3
4
Connection pin of resonator
Modulation enable pin/power down pin
Modulation rate setting pin
Down spread, SEL
½
“L” : Modulation rate
1.0
Down spread, SEL
½
“H” : Modulation rate
2.0
Down spread, SEL
½
“L” : Modulation rate
0.5
Down spread, SEL
½
“H” : Modulation rate
1.0
Non-modulated clock output pin
This pin becomes to“L” at power-down.
GND Pin
Modulated clock output pin
This pin becomes to“L” at power-down.
Power supply voltage pin
Description
Connection pin of resonator/clock input pin
REFOUT
V
SS
CKOUT
V
DD
O
O
5
6
7
8
Document Number: 002-08298 Rev. *A
Page 4 of 27
MB88155
4. I/O Circuit Type
Pin
SEL,
XPD
Circuit type
Remarks
CMOS hysteresis input
ENS
CMOS hysteresis input with pull-up
resistor of 50 k (Typ)
50 kΩ
REFOUT
■
■
■
CMOS output
I
OL
½
3 mA
“L” output at power-down
(Continued)
Document Number: 002-08298 Rev. *A
Page 5 of 27
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