TI CDC925DL 133-mhz clock synthesizer/driver for pc motherboards with 3-state output Datasheet

CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
D
D
D
D
D
D
D
D
D
Supports Pentium III Class Motherboards
Uses a 14.318-MHz Crystal Input to
Generate Multiple Output Frequencies
Includes Spread Spectrum Clocking (SSC),
0.34% Downspread for Reduced EMI
Performance
Power Management Control Terminals
Low Output Skew and Jitter for Clock
Distribution
2.5-V and 3.3-V Supplies
Generates the Following Clocks:
– 4 CPU (2.5 V, 100/133 MHz)
– 7 PCI (3.3 V, 33.3 MHz)
– 1 PCI_F (Free Running, 3.3 V, 33.3 MHz)
– 2 CPU/2 (2.5 V, 50/66 MHz)
– 3 APIC (2.5 V, 16.67 MHz)
– 4 3V66 (3.3 V, 66 MHz)
– 2 REF (3.3 V, 14.318 MHz)
– 1 48MHz (3.3 V, 48 MHz)
Packaged in 56-Pin SSOP Package
Designed for Use with TI’s Direct Rambus
Clock Generators (CDCR81, CDCR82,
CDCR83)
description
The CDC925 is a clock synthesizer/driver that
generates system clocks necessary to support
Intel Pentium III systems on CPU, CPU_DIV2,
3V66, PCI, APIC, 48MHz, and REF clock signals.
DL PACKAGE
(TOP VIEW)
GND
REF0
REF1
VDD3.3V
XIN
XOUT
GND
PCI_F
PCI1
VDD3.3V
PCI2
PCI3
GND
PCI4
PCI5
VDD3.3V
PCI6
PCI7
GND
GND
3V66(0)
3V66(1)
VDD3.3V
GND
3V66(2)
3V66(3)
VDD3.3V
SEL133/100
1
56
2
55
3
54
4
53
5
52
6
51
7
50
8
49
9
48
10
47
11
46
12
45
13
44
14
43
15
42
16
41
17
40
18
39
19
38
20
37
21
36
22
35
23
34
24
33
25
32
26
31
27
30
28
29
VDD2.5V
APIC2
APIC1
APIC0
GND
VDD2.5V
CPU_DIV2(1)
CPU_DIV2(0)
GND
VDD2.5V
CPU3
CPU2
GND
VDD2.5V
CPU1
CPU0
GND
VDD3.3V
GND
PCI_STOP
CPU_STOP
PWR_DWN
SPREAD
SEL1
SEL0
VDD3.3V
48MHz
GND
All output frequencies are generated from a
14.318-MHz crystal input. A reference clock input instead of a crystal can be provided at the XIN input. Two
phase-locked loops (PLLs) are used, one to generate the host frequencies and the other to generate the 48-MHz
clock frequency. On-chip loop filters and internal feedback loops eliminate the need for external components.
The host and PCI clock outputs provide low-skew and low-jitter clock signals for reliable clock operation. All
outputs have 3-state capability, which can be selected via control inputs SEL0, SEL1, and SEL133/100.
The outputs are either 3.3-V or 2.5-V single-ended CMOS buffers. With a logic high-level on the PWR_DWN
terminal, the device operates normally, but when a logical low-level input is applied, the device powers down
completely, with the outputs in a low-level output state. When a high-level is applied to the PCI_STOP or
CPU_STOP, the outputs operate normally. With a low-level applied to the PCI_STOP or CPU_STOP terminals,
the PCI or CPU and 3V66 outputs, respectively, are held in a low-level state.
The CPU bus can operate at 100 MHz or 133 MHz. Output frequency selection is done with corresponding
setting for SEL133/100 control input. The PCI bus frequency is fixed to 33MHz.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Intel and Pentium III are trademarks of Intel Corporation.
Direct Rambus and Rambus are trademarks of Rambus Inc.
Copyright  1999, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
1
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
description (continued)
Since the CDC925 is based on PLL circuitry, it requires a stabilization time to achieve phase lock of the PLL.
This stabilization time is required after power up or after changes to the SEL inputs are made. With use of an
external reference clock, this signal must be fixed-frequency and fixed-phase before the stabilization time starts.
function tables
SELECT FUNCTIONS
INPUTS
SEL133/
100
SEL1
L
L
OUTPUTS
FUNCTION
SEL0
CPU
CPU_DIV2
3V66
PCI,
PCI_F
48MHz
REF
APIC
L
L
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
3-state
L
H
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Reserved
L
H
L
100 MHz
50 MHz
66 MHz
33 MHz
Hi-Z
14.318 MHz
16.67 MHz
48-MHz PLL off
L
H
H
100 MHz
50 MHz
66 MHz
33 MHz
48 MHz
14.318 MHz
16.67 MHz
48-MHz PLL on
H
L
L
TCLK/2
TCLK/4
TCLK/4
TCLK/8
TCLK/2
TCLK
TCLK/16
Test
H
L
H
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Reserved
H
H
L
133 MHz
66 MHz
66 MHz
33 MHz
Hi-Z
14.318 MHz
16.67 MHz
48-MHz PLL off
H
H
H
133 MHz
66 MHz
66 MHz
33 MHz
48 MHz
14.318 MHz
16.67 MHz
48-MHz PLL on
ENABLE FUNCTIONS
OUTPUTS
INPUTS
INTERNAL
CPU_STOP
PWR_DWN
PCI_STOP
CPU
CPU_DIV2
APIC
3V66
PCI
PCI_F
REF,
48MHz
X
L
X
L
L
L
L
L
L
L
L
H
L
L
On
On
L
L
On
On
On
On
L
H
H
L
On
On
L
On
On
On
On
On
H
H
L
On
On
On
On
L
On
On
On
On
H
H
H
On
On
On
On
On
On
On
On
On
OUTPUT BUFFER SPECIFICATIONS
2
BUFFER NAME
VDD RANGE
(V)
IMPEDANCE
(Ω)
BUFFER TYPE
CPU, CPU_DIV2, APIC
2.375 – 2.625
13.5 – 45
TYPE 1
48MHz, REF
3.135 – 3.465
20 – 60
TYPE 3
PCI, PCI_F, 3V66
3.135 – 3.465
12 – 55
TYPE 5
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
Crystal
VCOs
Off
Off
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
Terminal Functions
TERMINAL
NAME
3V66 [0–3]
48MHz
NO.
I/O
DESCRIPTION
21, 22, 25, 26
O
3.3 V, Type 5, 66-MHz clock outputs
30
O
3.3 V, Type 3, 48-MHz clock output
APIC [0–2]
53, 54, 55
O
2.5 V, Type 1, APIC clock outputs
CPU [0–3]
41, 42, 45, 46
O
2.5 V, Type 1, CPU clock outputs
49, 50
O
2.5 V, Type 1, CPU_DIV2 clock outputs
36
I
Disables CPU clock to low state
CPU_DIV2 [0–1]
CPU_STOP
GND
PCI [1–7]
1, 7, 13, 19,
20, 24, 29, 38,
40, 44, 48, 52
9, 11, 12, 14,
Ground
O
3.3 V, Type 5, 33-MHz PCI clock outputs
15, 17, 18
PCI_F
8
O
Free-running 3.3-V, Type 5, 33-MHz PCI clock output
PCI_STOP
37
I
Disables PCI clock to low state
PWR_DWN
35
I
Power down for complete device with outputs forced low
REF0, REF1
2, 3
O
3.3 V, Type 3, 14.318-MHz reference clock output
SEL0, SEL1
32, 33
I
LVTTL level logic select terminals for function selection
SEL133/100
28
I
LVTTL level logic select pins for enabling 100/133 MHz
SPREAD
34
I
Disables SSC function
VDD3.3V
4, 10, 16, 23,
27, 31, 39
VDD2.5V
XIN
43, 47, 51, 56
XOUT
Power for the 3V66, 48MHz, PCI, REF outputs and CORE logic
Power for CPU and APIC outputs
5
I
Crystal input – 14.318 MHz
6
O
Crystal output – 14.318 MHz
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
3
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
spread spectrum clock (SSC) implementation for CDC925
Simultaneously switching at fixed frequency generates a significant power peak at the selected frequency,
which in turn will cause EMI disturbance to the environment. The purpose of the internal frequency modulation
of the CPU–PLL allows to distribute the energy to many different frequencies which reduces the power peak.
A typical characteristic for a single frequency spectrum and a frequency modulated spectrum is shown in
Figure 1.
Highest Peak
∆
Non-SSC
SSC
δ of fnom
fnom
Figure 1. Frequency Power Spectrum With and Without the Use of SSC
The modulated spectrum has its distribution left hand to the single frequency spectrum which indicates a
“down-spread modulation”.
The peak reduction depends on the modulation scheme and modulation profile. System performance and timing
requirements are the limiting factors for actual design implementations. The implementation was driven to keep
the average clock frequency closed to its upper specification limit. The modulation amount was set to
approximately –0.34% (compared to – 0.5% on the CDC924).
Period of Output Frequency – ns
In order to allow a downstream PLL to follow the frequency modulated signal, the bandwidth of the modulation
signal is limited in order to minimize SSC induced tracking skew jitter. The ideal modulation profile used for
CDC925 is shown in Figure 2.
10.03
10.02
10.01
10
9.99
9.98
9.97
5
10
15
20
25
30
35
Period of Modulation Signal – µs
Figure 2. SSC Modulation Profile
4
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• DALLAS, TEXAS 75265
40
45
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
functional block diagram
SEL133/100
28
SEL0
32
SEL1
33
3–State
Control
Logic
48–MHz Inactive
Test
SEL133/100
2*REF
14.318 MHz
(2,3)
XIN
XOUT
5
6
1*48MHz
48 MHz
(30)
48 MHz
PLL
Xtal
Oscillator
STOP
/4
CPU_STOP
36
STOP
SPREAD
34
Spread
Logic
CPU
PLL
/2
/2
Sync Logic & Power Down Logic
/3
4*AGP (3V66)
66 MHz
(21,22,25,26)
4*CPU
100/133 MHz
(41,42,45,46)
2*CPU_DIV2
50/66 MHz
(49,50)
3*APIC
16.67 MHz
(53, 54, 55)
/2
/3
1*PCI_F
33 MHz
(8)
/4
STOP
PCI_STOP
PWR_DOWN
37
7*PCI
33 MHz
(9,11,12,14,
15,17,18)
35
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
5
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage range, VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 4.6 V
Input voltage range, VI (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 4.6 V
Voltage range applied to any output in the high-impedance state or power-off state,
VO (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to VDD + 0.5 V
Current into any output in the low state, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 × IOL
Input clamp current, IIK (VI < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 18 mA
Output clamp current, IOK (VO < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 50 mA
Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0°C to 85°C
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
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-rated conditions for extended periods may affect device reliability.
NOTE 1: The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.
DISSIPATION RATING TABLE
PACKAGE
TA ≤ 25°C
POWER RATNG
DERATING FACTOR†
ABOVE TA = 25°C
TA = 70°C
POWER RATING
TA = 85°C
POWER RATING
DL
1558.6 mW
12.468 mW/°C
997.5 mW
810.52 mW
† This is the inverse of the traditional junction-to-case thermal resistance (RθJA) and uses a board-mounted device
at 80.2°C/W.
recommended operating conditions (see Note 2)
MIN
Supply voltage
voltage, VDD
NOM†
3.465
2.5 V
2.375
2.625
2
VDD +
0.3 V
V
GND –
0.3 V
0.8
V
VDD
–12
V
Low-level input voltage, VIL
Input voltage, VI
0
CPUx, CPU_DIV2x
Low level output current
Low-level
current, IOL
APICx
–12
48MHz, REFx
–14
PCIx, PCI_F, 3V66x
–18
CPUx, CPU_DIV2x
12
APICx
12
48MHz, REFx
9
PCIx, PCI_F, 3V66x
Reference frequency, f(XIN)‡
Crystal frequency, f(XTAL)§
UNIT
3.135
High-level input voltage, VIH
High level output current,
High-level
current IOH
MAX
3.3 V
Normal mode
mA
mA
12
Test mode
Operating free-air temperature, TA
V
130
13.8
0
14.318
MHz
14.8
85
MHz
°C
NOTE 2: Unused inputs must be held high or low to prevent them from floating.
† All nominal values are measured at their respective nominal VDD values.
‡ Reference frequency is a test clock driven on the XIN input during the device test mode and normal mode. In test mode, XIN can be driven
externally up to f(XIN) = 130 MHz. If XIN is driven externally, XOUT is floating.
§ This is a series fundamental crystal with fO = 14.31818 MHz.
6
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VIK
RI
IIH
TEST CONDITIONS
Input clamp voltage
Input resistance
High-level input current
XIN-XOUT
VDD = 3.135 V,
VDD = 3.465 V,
II = –18 mA
VI = VDD –0.5 V
XOUT
VDD = 3.135 V,
VI = VDD –0.5 V
SEL0, SEL1,
CPU_STOP,
PCI_STOP,
SPREAD
VDD = 3.465 V,
SEL133/100
Low-level input current
kΩ
VI = VDD
<10
10
µA
VDD = 3.465 V,
VDD = 3.465 V,
VI = VDD
VI = VDD
<10
10
µA
<10
10
µA
XOUT
VDD = 3.135 V,
VO = 0 V
–2
–5
mA
SEL0, SEL1,
CPU_STOP,
PCI_STOP,
SPREAD
VDD = 3.465 V,
VI = GND
<10
–10
µA
VDD = 3.465 V,
VDD = 3.465 V,
VI = GND
VI = GND
<10
–10
µA
<10
–10
µA
|VDD| = max,
VO = VDD or GND
PWR_DWN = low,
±10
µA
High-impedance-state output current
Supplyy current
IDD(Z) High-impedance-state
High impedance state supply current
Dynamic supply current
CI
Input capacitance
V
mA
VDD = 2.625 V,
All outputs = low
IDD
UNIT
–1.2
50
SEL133/100
VDD = 2.625 V,
All outputs = high
VDDx = 2.5 V,
VDD = 3.465 V,
All outputs = low
PWR_DWN = low,
VDD = 3.465 V,
VDD = 2.625 V
All outputs = high
80
MAX
350
PWR_DWN
IOZ
TYP†
20
PWR_DWN
IIL
MIN
<20
100
<20
100
<50
200
12
VDD = 3.465 V
28
CL = 20 pF,
CPU = 133 MHz
VDD = 3.465 V
VDD = 2.625 V
VDD = 3.3 V,
VDD = 3.3 V,
VI = VDD or GND
VI = 0.3 V
Crystal terminal capacitance
† All typical values are measured at their respective nominal VDD values.
POST OFFICE BOX 655303
35
1.4
• DALLAS, TEXAS 75265
114
146
52
70
3.3
18
18.5
µA
mA
mA
mA
5.8
pF
22.5
pF
7
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted) (continued)
CPUx, CPU_DIV2x, APICx (Type 1)
PARAMETER
VOH
g
g
High-level
output voltage
VOL
Low level output voltage
Low-level
IOH
High-level output current
IOL
Low-level output current
CO
Output capacitance
ZO
TEST CONDITIONS
Output impedance
High state
VDD = min to max,
IOH = – 1 mA
VDD = 2.375 V,
VDD = min to max,
IOH = –12 mA
IOL = 1 mA
VDD = 2.375 V,
VDD = 2.375 V,
IOL = 12 mA
VO = 1 V
VDD = 2.5 V,
VDD = 2.625 V,
VO = 1.25 V
VO = 2.375 V
VDD = 2.375 V,
VDD = 2.5 V,
VDD = 2.625 V,
VO = 1.2 V
VO = 1.25 V
VDD = 3.3 V,
VO = 0.5 VDD,
Low state
VO = 0.5 VDD,
† All typical values are measured at their respective nominal VDD values.
VO = 0.3 V
VO = VDD or GND
VO/IOH
VO/IOL
MIN
TYP†
MAX
VDD –
0.1 V
UNIT
V
2
0.1
0.18
–26
0.4
–42
mA
–46
–16
27
V
–27
57
mA
63
23
6
43
8.5
13.5
27
45
13.5
20
45
MIN
TYP†
MAX
pF
Ω
48MHz, REFx (Type 3)
PARAMETER
VOH
VOL
IOH
IOL
CO
ZO
TEST CONDITIONS
High-level
g
output voltage
g
Low level output voltage
Low-level
High-level output current
Low-level output current
Output capacitance
Output impedance
High state
VDD = min to max,
IOH = – 1 mA
VDD = 3.135 V,
VDD = min to max,
IOH = –14 mA
IOL = 1 mA
VDD = 3.135 V,
VDD = 3.135 V,
IOL = 9 mA
VO = 1 V
VDD = 3.3 V,
VDD = 3.465 V,
VO = 1.65 V
VO = 3.135 V
VDD = 3.135 V,
VDD = 3.3 V,
VDD = 3.465 V,
VO = 1.95 V
VO = 1.65 V
VDD = 3.3 V,
VO = 0.5 VDD,
VO = 0.5 VDD,
† All typical values are measured at their respective nominal VDD values.
8
Low state
POST OFFICE BOX 655303
VO = 0.4 V
VO = VDD or GND
VO/IOH
VO/IOL
• DALLAS, TEXAS 75265
VDD –
0.1 V
UNIT
V
2.4
0.1
0.18
–27
0.4
–41
mA
–41
–12
29
V
–23
50
mA
53
20
37
20
40
60
20
31
60
4.5
7
pF
Ω
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted) (continued)
PCIx, PCI_F, 3V66x (Type 5)
PARAMETER
VOH
g
g
High-level
output voltage
VOL
Low level output voltage
Low-level
IOH
High-level output current
IOL
Low-level output current
CO
Output capacitance
ZO
TEST CONDITIONS
Output impedance
High state
MIN
VDD = min to max,
IOH = – 1 mA
VDD = 3.135 V,
VDD = min to max,
IOH = –18 mA
IOL = 1 mA
VDD = 3.135 V,
VDD = 3.135 V,
IOL = 12 mA
VO = 1 V
VDD = 3.3 V,
VDD = 3.465 V,
VO = 1.65 V
VO = 3.135 V
VDD = 3.135 V,
VDD = 3.3 V,
VDD = 3.465 V,
VO = 1.95 V
VO = 1.65 V
VDD = 3.3 V,
VO = 0.5 VDD,
Low state
VO = 0.5 VDD,
† All typical values are measured at their respective nominal VDD values.
TYP†
MAX
VDD –
0.1 V
UNIT
V
2.4
0.1
0.15
–33
0.4
–53
mA
–53
–16
30
–33
67
mA
70
VO = 0.4 V
VO = VDD or GND
VO/IOH
VO/IOL
V
27
49
4.5
7.5
12
31
55
12
24
55
pF
Ω
switching characteristics, VDD = 3.135 V to 3.465 V, TA = 0°C to 85°C
PARAMETER
TEST CONDITIONS
Overshoot/undershoot
tdis3
Disable time, PWR_DWN to PCIx
Stabilization time, PWR_DWN to CPUx
tdis4
Disable time, PWR_DWN to CPUx
Stabilization time†
TYP
GND – 0.7 V
Ring back
Stabilization time, PWR_DWN to PCIx
MIN
VIL – 0.1 V
f(CPU) = 133 MHz
f(CPU) = 133 MHz
0.05
f(CPU) = 133 MHz
f(CPU) = 133 MHz
0.03
MAX
UNIT
VDD + 0.7 V
VIH + 0.1 V
V
3
ms
3
ms
50
V
ns
50
ns
After SEL1, SEL0
3
After power up
3
ms
† Stabilization time is the time required for the integrated PLL circuit to obtain phase lock of its feedback signal to its reference signal. In order for
phase lock to be obtained, a fixed-frequency, fixed-phase reference signal must be present at XIN. Until phase lock is obtained, the specifications
for propagation delay and skew parameters given in the switching characteristics tables are not applicable. Stabilization time is defined as the
time from when VDD achieves its nominal operating level until the output frequency is stable and operating within specification.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
9
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
switching characteristics, VDD = 2.375 V to 2.625 V, TA = 0°C to 85°C (continued)
CPUx
FROM
(INPUT)
PARAMETER
ten1
tdis1
tc
TO
(OUTPUT)
Output enable time
SEL133/100
CPUx
Output disable time
SEL133/100
CPUx
TEST CONDITIONS
Cycle to cycle jitter
f(CPU) = 100 or 133MHz
f(CPU) = 100 or 133MHz
Duty cycle
TYP
MAX
6
10
ns
8
10
ns
10
10.04
10.2
ns
7.5
7.53
f(CPU) = 100 or 133MHz
f(CPU) = 100 or 133MHz
f(CPU) = 100 MHz
f(CPU) = 133 MHz
CPU clock period†
MIN
45
f(CPU) = 100 or 133MHz
f(CPU) = 100 or 133MHz
7.7
ns
250
ps
55
%
175
ps
2.2
ns
tsk(o)
tsk(p)
CPU bus skew
CPUx
CPUx
CPU pulse skew
CPUn
CPUn
t(off)
t(off)
CPU clock to APIC clock offset, rising edge
1.5
2.8
4
ns
CPU clock to 3V66 clock offset, rising edge
0
0.75
1.5
ns
2.6
4.3
1.4
3.7
2.8
4.3
1.7
4
0.4
1.5
2.2
ns
0.4
1.4
2
ns
MIN
TYP
MAX
6
10
ns
8
10
ns
20
20.08
20.4
ns
15
15.06
15.3
ns
250
ps
tw1
1
Pulse duration width,
width high
f(CPU) = 100 MHz
f(CPU) = 133 MHz
tw2
2
Pulse duration width
width, low
f(CPU) = 100 MHz
f(CPU) = 133 MHz
tr
Rise time
VO = 0.4 V to 2.0 V
tf
Fall time
VO = 0.4 V to 2.0 V
† The average over any 1-µs period of time is greater than the minimum specified period.
50
UNIT
ns
ns
CPU_DIV2x
FROM
(INPUT)
TO
(OUTPUT)
Output enable time
SEL133/100
CPU_DIV2x
Output disable time
SEL133/100
CPU_DIV2x
PARAMETER
ten1
tdis1
tc
TEST CONDITIONS
f(CPU) = 100 or 133MHz
f(CPU) = 100 or 133MHz
f(CPU) = 100 MHz
f(CPU) = 133 MHz
CPU DIV2 clock period†
CPU_DIV2
Cycle to cycle jitter
f(CPU) = 100 or 133MHz
f(CPU) = 100 or 133MHz
Duty cycle
45
f(CPU) = 100 or 133MHz
f(CPU) = 100 or 133MHz
55
%
175
ps
1.6
ns
tsk(o)
tsk(p)
CPU_DIV2 bus skew
CPU_DIV2x
CPU_DIV2x
CPU_DIV2 pulse skew
CPU_DIV2n
CPU_DIV2n
tw1
1
Pulse duration width,
width high
f(CPU) = 100 MHz
f(CPU) = 133 MHz
7.1
tw2
2
Pulse duration width
width, low
f(CPU) = 100 MHz
f(CPU) = 133 MHz
7.3
8.9
5
6.6
0.4
1.4
2
ns
0.4
1.3
1.8
ns
tr
Rise time
VO = 0.4 V to 2.0 V
tf
Fall time
VO = 0.4 V to 2.0 V
† The average over any 1-µs period of time is greater than the minimum specified period.
10
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
50
UNIT
ns
4.7
ns
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
switching characteristics, VDD = 2.375 V to 2.625 V, TA = 0°C to 85°C (continued)
APIC
PARAMETER
ten1
tdis1
tc
FROM
(INPUT)
TO
(OUTPUT)
Output enable time
SEL133/100
APICx
Output disable time
APIC clock period†
SEL133/100
APICx
Cycle to cycle jitter
Duty cycle
tsk(o)
tsk(p)
t(off)
tw1
tw2
TEST CONDITIONS
f(APIC) = 16.67 MHz
f(APIC) = 16.67 MHz
f(APIC) = 16.67 MHz
f(CPU) = 100 or 133 MHz
60
45
APIC bus skew
APICx
APICx
f(APIC) = 16.67 MHz
f(APIC) = 16.67 MHz
APIC pulse skew
APICn
APICn
f(APIC) = 16.67 MHz
APIC clock to CPU clock offset,
rising edge
APICx
CPUx
Pulse duration width, high
TYP
MAX
6
10
ns
8
10
ns
60.24
60.6
ns
400
ps
55
%
100
ps
3
ns
–4
ns
30
–1.5
f(APIC) = 16.67 MHz
f(APIC) = 16.67 MHz
Pulse duration width, low
MIN
tr
Rise time
VO = 0.4 V to 2 V
tf
Fall time
VO = 0.4 V to 2 V
† The average over any 1-µs period of time is greater than the minimum specified period.
UNIT
25.5
28
ns
25.3
29.2
ns
0.4
1.6
2.1
ns
0.4
1.2
1.7
ns
MIN
TYP
MAX
6
10
ns
8
10
ns
15.06
15.3
ns
400
ps
switching characteristics, VDD = 3.135 V to 3.465 V, TA = 0°C to 85°C
3V66
PARAMETER
ten1
tdis1
tc
FROM
(INPUT)
TO
(OUTPUT)
Output enable time
SEL133/100
3V66x
Output disable time
3V66 clock period†
SEL133/100
3V66x
Cycle to cycle jitter
Duty cycle
TEST CONDITIONS
f(3V66) = 66 MHz
f(3V66) = 66 MHz
f(3V66) = 66 MHz
f(CPU) = 100 or 133 MHz
15
45
tsk(o)
tsk(p)
3V66 bus skew
3V66x
3V66x
f(3V66) = 66 MHz
f(3V66) = 66 MHz
3V66 pulse skew
3V66n
3V66n
f(3V66) = 66 MHz
t(off)
t(off)
3V66 clock to CPU clock offset
3V66x
CPUx
tw1
tw2
Pulse duration width, high
3V66 clock to PCI clock offset, rising edge
UNIT
55
%
50
150
ps
2.6
ns
0
–0.75
–1.5
ns
1.2
2.1
3
ns
f(3V66) = 66 MHz
f(3V66) = 66 MHz
5.2
tr
Rise time
VO = 0.4 V to 2 V
tf
Fall time
VO = 0.4 V to 2 V
† The average over any 1-µs period of time is greater than the minimum specified period.
0.5
1.5
2
ns
0.5
1.5
2
ns
Pulse duration width, low
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
ns
5
ns
11
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
switching characteristics, VDD = 3.135 V to 3.465 V, TA = 0°C to 85°C (continued)
48MHz
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
ten1
tdis1
Output enable time
SEL133/100
48MHz
Output disable time
SEL133/100
48MHz
tc
48MHz clock period†
Duty cycle
48MHz pulse skew
tw2
tr
Pulse duration width, low
48MHz
48MHz
Pulse duration width, high
MIN
f(48MHz) = 48 MHz
f(48MHz) = 48 MHz
f(48MHz) = 48 MHz
f(CPU) = 100 or 133 MHz
Cycle to cycle jitter
tsk(p)
tw1
TEST CONDITIONS
20.5
TYP
MAX
UNIT
6
10
ns
8
10
ns
20.83
21.1
ns
500
ps
55
%
3
ns
f(48MHz) = 48 MHz
f(48MHz) = 48 MHz
45
f(48MHz) = 48 MHz
f(48MHz) = 48 MHz
7.8
ns
7.8
ns
Rise time
VO = 0.4 V to 2 V
tf
Fall time
VO = 0.4 V to 2 V
† The average over any 1-µs period of time is greater than the minimum specified period.
1
2.1
2.8
ns
1
1.9
2.8
ns
MIN
TYP
MAX
6
10
ns
8
10
ns
REF
PARAMETER
ten1
tdis1
tc
FROM
(INPUT)
TO
(OUTPUT)
Output enable time
SEL133/100
REFx
Output disable time
REF clock period†
SEL133/100
REFx
TEST CONDITIONS
f(REF) = 14.318 MHz
f(REF) = 14.318 MHz
f(REF) = 14.318 MHz
f(CPU) = 100 or 133 MHz
Cycle to cycle jitter
Duty cycle
tsk(o)
tsk(p)
REF bus skew
REFx
REFx
REF pulse skew
REFn
REFn
tw1
tw2
Pulse duration width, high
f(REF) = 14.318 MHz
f(REF) = 14.318 MHz
f(REF) = 14.318 MHz
f(REF) = 14.318 MHz
Pulse duration width, low
f(REF) = 14.318 MHz
tr
Rise time
VO = 0.4 V to 2 V
tf
Fall time
VO = 0.4 V to 2 V
† The average over any 1-µs period of time is greater than the minimum specified period.
12
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
69.84
ns
700
45
150
UNIT
ps
55
%
250
ps
2
ns
26.2
32.7
ns
26.2
31.2
1
2
2.8
ns
1
1.9
2.8
ns
ns
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
switching characteristics, VDD = 3.135 V to 3.465 V, TA = 0°C to 85°C (continued)
PCI, PCI_F
PARAMETER
ten1
tdis1
tc
FROM
(INPUT)
TO
(OUTPUT)
Output enable time
SEL133/100
PCIx
Output disable time
PCIx clock period†
SEL133/100
PCIx
Cycle to cycle jitter
Duty cycle
TEST CONDITIONS
MIN
f(PCI) = 33 MHz
f(PCI) = 33 MHz
f(PCI) = 33 MHz
f(CPU) = 100 or 133 MHz
30
45
tsk(o)
tsk(p)
PCIx bus skew
PCIx
PCIx
f(PCI) = 33 MHz
f(PCI) = 33 MHz
PCIx pulse skew
PCIn
PCIn
f(PCI) = 33 MHz
t(off)
tw1
PCIx clock to 3V66 clock offset
tw2
tr
Pulse duration width, low
TYP
MAX
6
10
ns
8
10
ns
30.12
30.5
ns
300
ps
55
%
300
ps
4
ns
–3
ns
70
–1.2
Pulse duration width, high
Rise time
f(PCI) = 33 MHz
f(PCI) = 33 MHz
12
VO = 0.4 V to 2 V
VO = 0.4 V to 2 V
0.5
1.6
2
ns
0.5
1.5
2
ns
tf
Fall time
† The average over any 1-µs period of time is greater than the minimum specified period.
POST OFFICE BOX 655303
UNIT
• DALLAS, TEXAS 75265
ns
12
ns
13
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
PARAMETER MEASUREMENT INFORMATION
RL = 500 Ω
From Output
Under Test
CL
(see Note A)
VO_REF
OPEN
GND
S1
RL = 500 Ω
TEST
S1
tPLH/tPHL
tPLZ/tPZL
tPHZ/tPZH
Open
VO_REF
GND
LOAD CIRCUIT for tpd and tsk
ÎÎ
tw
From Output
Under Test
Test
Point
3V
VIH_REF
VT_REF
0V
VIL_REF
Input
CL
(see Note A)
VOLTAGE WAVEFORMS
LOAD CIRCUIT FOR tr and tf
3V
Input
VT_REF
VT_REF
0V
tPLH
Output
Enable
(high-level
enabling)
VDD
VT_REF
0V
tPZL
tPHL
tPLZ
VOH
VIH_REF
Output VT_REF
VIL_REF
VOL
tf
tr
VT_REF
≈3 V
Output
Waveform 1
S1 at 6 V
(see Note B)
VT_REF
tPZH
tw_low
VOL
tPHZ
Output
Waveform 2
S1 at GND
(see Note B)
tw_high
VOL + 0.3 V
VOH – 0.3 V
VOH
VT_REF
≈0 V
VOLTAGE WAVEFORMS
VOLTAGE WAVEFORMS
NOTES: A. CL includes probe and jig capacitance. CL = 20 pF (CPUx, APICx, 48MHz, REF), CL = 30 pF (PCIx, 3V66)
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. All input pulses are supplied by generators having the following characteristics: PRR
14.318 MHz, ZO = 50 Ω, tr ≤ 2.5 ns,
tf ≤ 2.5 ns.
D. The outputs are measured one at a time with one transition per measurement.
v
PARAMETER
3.3-V INTERFACE
2.5-V INTERFACE
UNIT
VIH_REF
High-level reference voltage
2.4
2
V
VIL_REF
Low-level reference voltage
0.4
0.4
V
VT_REF
Input Threshold reference voltage
1.5
1.25
V
VO_REF
Off-state reference voltage
6
4.6
V
Figure 3. Load Circuit and Voltage Waveforms
14
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
PARAMETER MEASUREMENT INFORMATION
VT_REF
CPUx or PCIx Clock
tc
VT_REF
CPUx or PCIx Clock
tsk(o)
t
sk(p)
+
Ť
t
–t
t(low)
Ť
t(high)
Duty Cycle
PLH PHL
+
t
(low or high)
tc
100
3V66 or CPUx
VT_REF
VT_REF
3V66, PCIx, or APICx
t(off) [3V66 to PCIx]
t(off) [CPUx to APICx]
t(off) [CPUx to 3V66]
Figure 4. Waveforms for Calculation of Skew, Offset, and Jitter
CPU
(internal)
PCI
(internal)
CPU_STOP
PCI_STOP
PWR_DOWN
PCI_F
(external)
CPU
(external)
3V66
(external)
Figure 5. CPU_STOP Timing
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
15
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
PARAMETER MEASUREMENT INFORMATION
CPU
(internal)
PCI
(internal)
CPU_STOP
PCI_STOP
PWR_DOWN
PCI_F
(external)
PCI
(external)
Figure 6. PCI_STOP Timing
CPU
(internal)
PCI
(internal)
PWR_DOWN
CPU
(external)
PCI
(external)
VCO
CRYSTAL
ÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
NOTE A: Shaded sections on the VCO and Crystal waveforms indicate that the VCO and crystal oscillators are active and there is a valid clock.
Figure 7. Power-Down Timing
16
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
CDC925
133-MHz CLOCK SYNTHESIZER/DRIVER FOR PC MOTHERBOARDS
WITH 3-STATE OUTPUTS
SCAS633 – JULY 28, 1999
MECHANICAL DATA
DL (R-PDSO-G**)
PLASTIC SMALL-OUTLINE PACKAGE
48-PIN SHOWN
0.025 (0,635)
0.012 (0,305)
0.008 (0,203)
48
0.005 (0,13) M
25
0.006 (0,15) NOM
0.299 (7,59)
0.291 (7,39)
0.420 (10,67)
0.395 (10,03)
Gage Plane
0.010 (0,25)
1
0°– 8°
24
0.040 (1,02)
A
0.020 (0,51)
Seating Plane
0.110 (2,79) MAX
0.004 (0,10)
0.008 (0,20) MIN
PINS **
28
48
56
A MAX
0.380
(9,65)
0.630
(16,00)
0.730
(18,54)
A MIN
0.370
(9,40)
0.620
(15,75)
0.720
(18,29)
DIM
4040048 / D 08/97
NOTES: B.
C.
D.
E.
All linear dimensions are in inches (millimeters).
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion not to exceed 0.006 (0,15).
Falls within JEDEC MO-118
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
17
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