FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-29125-2E
Spread Spectrum Clock Generator
MB88152A
MB88152A-100/101/102/110/111/112
■
DESCRIPTION
MB88152A 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. It corresponds to both of the center spread which modulates input frequency as Middle
Centered and down spread which modulates so as not to exceed input frequency.
■
FEATURES
•
•
•
•
•
•
•
•
•
•
Input frequency : 16.6 MHz to 134 MHz
Output frequency : 16.6 MHz to 134 MHz
Modulation rate :
±
0.5%,
±
1.5% (Center spread),
−
1.0%,
−
3.0% (Down spread)
Equipped with oscillation circuit: Range of oscillation 16.6 MHz to 48 MHz
Modulation clock output Duty : 40% to 60%
Modulation clock Cycle-Cycle Jitter : Less than 100 ps
Low current consumption by CMOS process : 5.0 mA (24 MHz : Typ-sample, no load)
Power supply voltage : 3.3 V
±
0.3 V
Operating temperature :
−
40
°C
to
+85 °C
Package : SOP 8-pin
Copyright©2006-2007 FUJITSU LIMITED All rights reserved
MB88152A
■
PRODUCT LINE-UP
MB88152A has three kinds of input frequency, and two kinds of modulation type (center/down spread), total six line-
ups.
Product
Input/Output Frequency
Modulation type
Modulation enable pin
MB88152A-100
MB88152A-101
MB88152A-102
MB88152A-110
MB88152A-111
MB88152A-112
16.6 MHz to 134 MHz
16.6 MHz to 67 MHz
40 MHz to 134 MHz
16.6 MHz to 134 MHz
16.6 MHz to 67 MHz
40 MHz to 134 MHz
Center spread
Down spread
No
Yes
No
Yes
■
PIN ASSIGNMENT
TOP VIEW
XIN 1
XOUT 2
V
SS
8
XENS
XIN 1
XOUT 2
MB88152A-100
V
SS
3
SEL
4
8
FREQ1
7 FREQ0
6 V
DD
5 CKOUT
MB88152A-101
MB88152A-102
7 FREQ
MB88152A-111
3
6 V
DD
MB88152A-112
5 CKOUT
MB88152A-110
SEL
4
FPT-8P-M02
FPT-8P-M02
■
PIN DESCRIPTION
Pin name
XIN
XOUT
V
SS
SEL
CKOUT
V
DD
FREQ/FREQ0
XENS/FREQ1
I/O
I
O
⎯
I
O
⎯
I
I
Pin no.
1
2
3
4
5
6
7
8
Description
Crystal resonator connection pin/clock input pin
Crystal resonator connection pin
GND pin
Modulation rate setting pin
Modulated clock output pin
Power supply voltage pin
Frequency setting pin
Modulation enable setting pin/frequency setting pin
2
MB88152A
■
I/O CIRCUIT TYPE
Pin
Circuit type
Remarks
CMOS hysteresis input
SEL
FREQ
FREQ0
FREQ1
XENS
• CMOS output
• I
OL
=
4 mA
CKOUT
Note : For XIN and XOUT pins, refer to “■OSCILLATION CIRCUIT”.
3
MB88152A
■
HANDLING DEVICES
Preventing Latch-up
A latch-up can occur if, on this device, (a) a voltage higher than V
DD
or a voltage lower than V
SS
is applied to an
input or output pin or (b) a voltage higher than the rating is applied between V
DD
and V
SS
pins. The latch-up, if it
occurs, significantly increases the power supply current and may cause thermal destruction of an element. When
you use this device, be very careful not to exceed the maximum rating.
Handling unused pins
Do not leave an unused input pin open, since it may cause a malfunction. Handle by, using a pull-up or
pull-down resistor.
Unused output pin should be opened.
The attention when the external clock is used
Input the clock to XIN pin, and XOUT pin should be opened when you use the external clock.
Please pay attention so that an overshoot and an undershoot do not occur to an input clock of XIN pin.
Power supply pins
Please design connecting the power supply pin of this device by as low impedance as possible from the current
supply source.
We recommend connecting electrolytic capacitor (about 10
µF)
and the ceramic capacitor (about 0.01
µF)
in
parallel between V
SS
and V
DD
pins near the device, as a bypass capacitor.
Oscillation Circuit
Noise near the XIN and XOUT pins may cause the device to malfunction. Design printed circuit boards so that
electric wiring of XIN or XOUT pin and resonator (or ceramic oscillator) do not intersect other wiring.
Design the printed circuit board that surrounds the XIN and XOUT pins with ground.
4
MB88152A
■
BLOCK DIAGRAM
V
DD
SEL
Modulation rate setting
Frequency setting
FREQ/FREQ0
XENS/FREQ1
Modulation enable /
Frequency setting
PLL block
Clock output
CKOUT
XOUT
Reference clock
XIN
R
f
=
1 MΩ
V
SS
1
−
M
Phase
compare
Charge
pump
V/I
conversion
IDAC
ICO
Reference
clock
1
−
N
Loop filter
Modulation
clock
output
1
−
L
Modulation logic
MB88152A PLL block
Modulation
rate setting/
Modulation
enable setting
A glitchless IDAC (current output D/A converter) provides precise modulation, thereby
dramatically reducing EMI.
5
京公网安备 11010802033920号
EEWORLD
