ETC IMISG501XB

IMISG501
SYSTEM CLOCK CHIP
PATENT PENDING
March 1996
REDUCED EMI CLOCK GENERATOR
PRODUCT FEATURES
þ
PRODUCT DESCRIPTION
Generates CPU Clock Signals for Microprocessor
Systems
þ
Reduces Measured EMI by 10 db nominal
þ
4V to 7V Operating Supply Range
þ
Supports 80286-, 80386-, 80486-, Pentium- and
29000-based designs
þ
Wide range of selectable output frequencies
including 50, 25, 20 and 10 Mhz
þ
single, low
frequency
þ
Glitch-free switching
þ
50% duty cycle
þ
Power down mode for low power consumption
þ
TTL or CMOS compatible outputs with 6mA drive
capability
cost
crystal
used
as
reference
þ
Low, short- and long-term jitter
þ
16 PDIP and 16 Pin SOIC (300 mil body) package
options
BLOCK DIAGRAM
The IMISG501 is a spectrum spread clock generator
specially designed for personal computers, laser
printers and other digital systems. IMISG501 uses a
patent pending concept to generate popular clock
frequencies that are intentionally broadbanded to
reduce electromagnetic interference. IMISG501
attenuates the radiated emission amplitudes from
products associated with either the clock harmonics or
any signals derived from the clock signals nominally 10
db and could significantly reduce the cost of complying
with the regulatory requirements.
PRCLK is the broadbanded output and can be
programmed to generate 50, 25, 20 and 10 Mhz with
S0 and S1 pins. A single, low cost external crystal is
required as reference frequency for the synthesizer.
Output modulation function can be turned off with the
SSON pin. Several power down modes add the
flexibility to operate the device in a completely static
mode to reduce standby currents and simplify system
board tests.
PDIP/SOIC CONNECTION DIAGRAM
VDD
OSCin
OSCout
VSS
MPSEL
AVDD
S0
S1
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
TEST
VDD
MPCLK
VSS
PRCLK
AVSS
LF1
SSON
3
44.2 MHz
MPSEL
LF
S0
S1
TEST
SSON
2
REF
/4 OR /12
14
MPCLK
5
APPLICATIONS
10
7
8
16
SPECTRUM
SPREAD
CLOCK GEN
/2
12
PRCLK
9
IMISG501 eliminates the need for multiple oscillators
and generates the CPU clock signals for personal
computers, laser printers and other digital systems.
Supports 8086-, 80286-, 80386-, 80486-, Pentiumand 29000-based designs. IMISG501 can be used with
laptop or notebook computers to save power by
running the system slower than normal CPU speeds or
completely disabling the clocks in standby mode.
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 1of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
PIN DESCRIPTION
OSCin, OSCout - These pins form an on-chip
reference oscillator when connected to terminals of an
external 44.2 Mhz third overtone parallel resonant
crystal. OSCin may also serve as an input for an
externally generated CMOS level or AC coupled
reference signal.
S0, and S1 - Frequency select inputs. These inputs
control the PRCLK frequency selection. S0-S1 inputs
control the CPU clock frequencies. All these inputs
have internal pull-downs.
MPCLK - This is a nonmodulated output. This output
can be programmed to be 3.7 Mhz or 11.06 mHz. The
selection of these frequencies are controlled by the
MPSEL pin shown in Table 1.
PRCLK - Output from the spectrum spread clock
generator. Frequency selection is shown on Table 1.
When the SSON pin is high, outputs are not
modulated. When SSON is low, sprectrum spread
function is enabled.
Table 1 shows the output freuqncy selection conditions.
VSS - Circuit ground
TEST - Controls power down and Test Mode selection.
When high, S0-S1 and MPSEL controls the mode
selection as shown on Table 1 and Table 2. When low,
device operates in normal mode. This pin has an
internal pull-down.
VDD - Positive power supply
MPSEL - Controls MPCLK output frequency selections.
Table 2 shows the selected frequencies for MPCLK.
This input has an internal pull-up.
SSON - This pin controls the sprectrum spread
function. When low, PRCLK is modulated. When high,
spreading is turned off. This pin has an internal pull-up.
LF1 - This is the control output for the clock generator.
It is a single-ended, tri-state output. Component
connections are shown in Figure 1.
PRCLK FREQUENCY SELECTION
Inputs
Output
TEST
S1
S0
PRCLK
0
0
0
9.96 Mhz
0
0
1
19.92 Mhz
0
1
0
24.9 Mhz
0
1
1
49.80 Mhz
1
0
0
0; Power Down
1
0
1
1; Power Down
1
1
0
TEST
1
1
1
Hi-Z
TABLE 1: When Power Down address is slected, the
VCO is turned off and the device goes to standby
mode. Phase detector is in tri-state mode.
AVSS - Analog circuit ground
AVDD - Analog positive power supply
2k
R2
2200 pf
330 pf
C1
C2
Figure 1
MPCLK FREQUENCY SELECTION
Inputs
Output
TEST MPSEL
S1
S0
PRCLK
0
0
X
X
3.7 Mhz
0
1
X
X
11.06 MHz
1
X
0
0
0; Power Down
1
X
0
1
1; Power Down
1
X
1
0
TEST
1
X
1
1
Hi-Z
TABLE 2: When Power Down address is selected, the
VCO is turned off and the device goes to standby
mode. Phase detector is in tri-state mode.
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 2 of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
MAXIMUM RATINGS
This device contains circuitry to protect the inputs
against damage due to high static voltages or electric
field; however, precautions should be taken to avoid
application of any voltage higher than the maximum
rated voltages to this circuit. For proper operation, Vin
and Vout should be constrained to the range:
Voltage Relative to VSS:
-0.3V to 7V
Voltage Relative to VDD:
0.3V
Storage Temperature:
-65°C to 150°C
Ambient Temperature:
-0°C to 70°C
Recommend Operating Range:
4.5-5.5V
VSS< (Vin or Vout) < VDD
All inputs are tied high or low internally.
ELECTRICAL CHARACTERISTICS
Characteristic
Symbol
Min
Typ
Max
Units
Input Low Voltage
VIL
-
-
0.8
Vdc
Input High Voltage
VIH
2.0
-
-
Vdc
Input Low Current with Pull-up/ Pull-down
IIL/IIH
-
-
10/100
µA
Output Low Voltage IOL = 6mA
VOL
-
-
0.4
Vdc
Output High Voltage IOH=6mA
VOH
2.5
-
-
Vdc
Tri-State leakage Current
IOZ
-
-
10
µA
Static Supply Current
IDD
-
-
250
µA
Dynamic Supply Current
ICC
-
25
30
mA
Short Circuit Current
ISC
25
-
-
mA
VDD = 5V + 10%, TA = 0°°C to 70°°C
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 3 of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
SWITCHING CHARACTERISTICS
Characteristic
Symbol
Min
Typ
Max
Output Rise and Fall Time Measured at 10% - 90% of
VDD
Units
tTLH, tTHL
-
-
5
ns
Output Rise and Fall Time Measured at 0.8V - 2.0V
tTLH, tTHL
-
-
3
ns
Output Duty Cycles
TsymF1
-
-
45/55
%
Jitter One Sigma
tj1s
-
-
2
% of Fout
Cycle-to-Cycle Jitter with Normal Crystal
tjcc
-
-
50
ps
VDD = 5 + 10%, TA = 0°°C to 70°°C, CL = 15 pF
OSCILLATOR CHARACTERISTICS
Characteristic
Symbol
Min
Typ
Max
Units
Conditions
Transconductance
gm
20
80
180
Millimho
s
@ 44.2 Mhz
Output Impedance
Zo
-
200
800
ohms
@ 44.2 Mhz
Input Capacitance
Ci
8
13
18
pf
-
Output Capacitance
Co
3
6
9
pf
-
DC Bias Voltage
Vb
1.5
VDD/2
3.5
Volt
-
Start-up Time
ts
-
-
2
ms
@ VDD = 4.5V
TsymF1
-
-
45/55
%
-
ICLKr
-
-
20
ns
-
Duty Cycle
Input Rise Time OSCin
VCO CHARACTERISTICS
Characteristic
Symbol
Min
Typ
Max
Units
Conditions
VCO Gain
Ko
35
55
65
MHz/Volt
∆F/∆V Measured with VCO Control at
2V - 3V
Phase Detector Gain
Kd
100
145
200
µA/rad
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 4 of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
CHARTS
FREQUENCY SELECTION
SCALING FACTOR
S0
S1
PRCLK
REFERENCE
0
0
.225
0
1
.450
1
0
.562
1
1
1.25
Reference Range:
Output Range:
35 Mhz MIN to 55 MHZMAX
8 MHzMIN to 60 MHzMAX
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 5 of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
EXTERNAL CONNECTIONS
VCC
L1
DIGITAL POWER PLANE
DIGITAL GND PLANE
DVDD
C11
10uf
ANALOG GND PLANE
ANALOG POWER PLANE
1.5 uH
R1
AVDD
C10 10 Ohms
22uf
DVDD
C3
10pf
XTAL
44.2 MHz
C5
C4
10pf
.033uF
L2
1.2 uH
C7
10 pf
SG501
1
2
3
4
5
6
7
8
VDD
XIN
XOUT
VSS
MPSEL
AVDD
S0
S1
TEST
VDD
MPCLK
VSS
PRCLK
AVSS
LF1
SSON
16
15
14
13
12
11
10
9
C9
.1uF
MPSEL
S0
S1
C2
2200pf
JP5
1
2
HEADER
R2
2K
JP1
DVDD
C8
.1uF
AVDD
C1
330 pf
JP2
JP3
TEST JP4
DVDD
NOTE1: KEEP C3, C4, C5, C6 CLOSE TO THEIR PINS (4, 11, 13, 10, 9 RESPECTIVELY).
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 6 of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
PACKAGE DRAWING AND DIMENSIONS
16 PIN SOIC OUTLINE DIMENSIONS
INCHES
C
L
H
E
D
a
A2
A
e
B
SYMBOL
MIN
NOM
MAX
MIN
NOM
MAX
A
0.097
0.101
0.104
2.46
2.56
2.64
A1
0.0020
0.009
0.0015
0.060
0.22
0.38
A2
0.090
0.092
0.111
2.29
2.34
2.39
B
0.014
0.016
0.019
0.35
0.41
0.48
C
0.0091
0.010
0.0125
0.23
0.25
0.32
D
.399
.407
.412
10.13
10.34
10.46
E
0.285
0.296
0.299
7.24
7.52
7.59
0.050 BSC
e
A1
MILLIMETERS
1.27 BSC
H
0.400
0.406
0.410
10.16
10.31
10.41
a
0°
5°
10°
0°
5°
10°
L
0.024
0.032
0.040
0.61
0.81
1.02
16-PIN PLASTIC DIP DIMENSIONS
INCHES
MILLIMETERS
C
SYMBOL
E2
a
E
E1
D
B2
Q2
Q
A1
A
MIN
NOM
MAX
S
e1
L
B
NOM
MAX
4.318
A
0.150
0.160
0.170
3.81
4.06
A1
0.015
-
-
0.381
-
-
B
0.016
0.018
0.020
0.40
0.45
0.50
B1
0.056
0.059
0.062
1.47
1.52
1.57
B2
0.046
0.049
0.052
1.17
1.24
1.32
C
0.008
0.010
0.012
0.20
0.25
0.30
D
0.748
0.750
0.752
19.00
19.05
19.10
E
0.300
0.312
0.325
7.62
7.924
8.255
E1
0.240
0.252
0.260
6.096
6.49
6.604
E2
0.335
0.345
0.355
8.51
8.76
9.01
0.100 BSC
e1
B1
MIN
2.54 BSC
L
0.25
0.230
0.135
3.175
3.30
a
0°
7°
15°
0°
7°
3.429
15°
Q1
0.059
0.060
0.061
1.50
1.53
1.55
Q2
0.128
0.130
0.132
3.25
3.30
3.35
S
0.073
0.075
0.077
1.85
1.90
1.95
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 7 of 8
IMISG501
SYSTEM CLOCK CHIP
March 1996
REDUCED EMI CLOCK GENERATOR
ORDERING INFORMATION
Part Number
Package Type
Production Flow
IMISG501xPB
16 Pin Plastic Dip
Commercial, 0°C to + 70°C
IMISG501xXB
16 Pin SOIC
Commercial, 0°C to + 70C°
Note:
The “x” following the IMI Device Number denotes the device revision. The ordering part number is formed
by a combination of device number, device revision, package style, and screening as shown below.
Marking:
Example:
IMI
SG501xPB
Date Code, Lot #
IMISG501xPB
Flow
B = Commercial, 0°C to + 70°C
Package
P = Plastic Dip
X = Small Outline
Revision
IMI Device Number
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: 408-263-6300 FAX 408-263-6571
Page 8 of 8