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Integrated Circuit Systems, Inc.
ICS9248-55
Pentium/Pro/IITM System Clock Chip
General Description
The ICS9248-55 is a Clock Synthesizer chip for Pentium and PentiumPro CPU based Desktop/Notebook systems that will provide all necessary clock timing. Features include four CPU and eight PCI clocks. Three reference outputs are available equal to the crystal frequency. Additionally, the device meets the Pentium power-up stabilization requirement, assuring that CPU and PCI clocks are stable within 2ms after power-up. PD# pin enables low power mode by stopping crystal OSC and PLL stages. Other power management features include CPU_STOP#, which stops CPU (0:3) clocks, and PCI_STOP#, which stops PCICLK (0:6) clocks. High drive CPUCLK outputs typically provide greater than 1 V/ns slew rate into 20pF loads. PCICLK outputs typically provide better than 1V/ns slew rate into 30pF loads while maintaining 505% duty cycle. The REF clock outputs typically provide better than 0.5V/ns slew rates. The ICS9248-55 accepts a 14.318MHz reference crystal or clock as its input and runs on a 3.3V core supply.
Features
Generates system clocks for CPU, IOAPIC, PCI, plus 14.314 MHz REF (0:2), USB, and Super I/O Supports single or dual processor systems Supports Spread Spectrum modulation for CPU & PCI clocks, down spread -0.5% Skew from CPU (earlier) to PCI clock (rising edges for 100/33.3MHz) 1.5 to 4ns Two fixed outputs at 48MHz. Separate 2.5V and 3.3V supply pins 2.5V or 3.3V output: CPU, IOAPIC 3.3V outputs: PCI, REF, 48MHz No power supply sequence requirements Uses external 14.318MHz crystal, no external load cap required for CL=18pF crystal 48 pin 300 mil SSOP
Block Diagram
Pin Configuration
48-Pin SSOP
Power Groups
VDD = Supply for PLL core VDD1 = REF (0:2), X1, X2 VDD2 = PCICLK_F, PCICLK (0:6) VDD3 = 48MHz0, 48MHz1 VDDL1 = IOAPIC (0:1) VDDL2 = CPUCLK (0:3)
9248-55 Rev B 12/04/98
Ground Groups
* Internal Pull-down Resistor of 240K to GND. on indicated inputs
GND = Ground for PLL core GND1 = REF (0:2), X1, X2 GND2 = PCICLK_F, PCICLK (0:6) GND3 = 48MHz0, 48MHz1 GNDL1 = IOAPIC (0:1) GNDL2 = CPUCLK (0:3)
Pentium is a trademark on Intel Corporation.
ICS reserves the right to make changes in the device data identified in this publication without further notice. ICS advises its customers to obtain the latest version of all device data to verify that any information being relied upon by the customer is current and accurate.
ICS9248-55
Pin Descriptions
PIN NUMBER 1, 2 3 4 5 6, 12, 18 7 8, 10, 11, 13, 14, 16, 17 9, 15 19, 33 20, 32 21 22, 23 24 25, 26, 27 28 29 30 31 37, 41 34, 38 35, 36, 39, 40 42 43 44, 45 46 47 48 PIN NAME REF0, REF1 GND1 X1 X2 GND2 PCICLK_F PCICLK (0:6) VDD2 VDD GND VDD3 48MHz (0:1) GND3 FS (0:2) SPREAD# PD# CPU_STOP# PCI_STOP# VDDL2 GNDL2 CPUCLK (3:0) N/C GNDL1 IOAPIC (0:1) VDDL1 SS_SEL REF2 VDD1 TYPE OUT PWR IN OUT PWR OUT OUT PWR PWR PWR PWR OUT PWR IN IN IN IN IN PWR PWR OUT PWR OUT PWR IN OUT PWR DESCRIPTION 14.318MHz clock output Ground for REF outputs XTAL_IN 14.318MHz Crystal input, has internal 33pF load cap and feed back resistor from X2 XTAL_OUT Crystal output, has internal load cap 33pF Ground for PCI outputs Free Running PCI output PCI clock outputs. TTL compatible 3.3V Power for PCICLK outputs, nominally 3.3V Isolated power for core, nominally 3.3V Isolated ground for core Power for 48MHz outputs, nominally 3.3V 48MHz outputs Ground for 48MHz outputs Frequency Select pins Enables Spread Spectrum feature when LOW Powers down chip, active low Halts CPU clocks at logic "0" level when low Halts PCI Bus at logic "0" level when low Power for CPU outputs, nominally 2.5V Ground for CPU outputs. CPU and Host clock outputs @ 2.5V Not internally connected Ground for IOAPIC outputs IOAPIC outputs (14.318MHz) @ 2.5V Power for IOAPIC outputs, nominally 2.5V .25% Spread Spectrum Selector at power up. Logic 0 for Downspread Logic 1 for Centerspread 14.318MHz clock output Supply for REF (0:2), X1, X2, nominal 3.3V
Select Functions
Functionality Tristate Testmode Spread Spectrum CPU HI - Z TCLK/2
1 2
PCI, PCI_F HI - Z TCLK/6
1 2
REF HI - Z TCLK
1
IOAPIC HI - Z TCLK
1
48 MHz Selection HI - Z TCLK/21 48.0MHz
Modulated
Modulated
14.318MHz
14.318MHz
FS2 0 0 0 0 1 1 1 1
FS1 0 0 1 1 0 0 1 1
FS0 0 1 0 1 0 1 0 1
CPU MHz 133 83.3 75 66.6 124 133 112 100
PCI MHz 33.25 41.65 37.5 33.3 41.33 44.3 37.3 33.3
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ICS9248-55
Power Management
Clock Enable Configuration
Other Clocks, REF, IOAPICs, 48 MHz 0 48 MHz 1 Stopped Running Running Running Running
CPU_STOP#
PCI_STOP#
PWR_DWN#
CPUCLK
PCICLK
Crystal
VCOs
X 0 0 1 1
X 0 1 0 1
0 1 1 1 1
Low Low Low Running Running
Low Low Running Low Running
Off Running Running Running Running
Off Running Running Running Running
Full clock cycle timing is guaranteed at all times after the system has initially powered up except where noted. During power up and power down operations using the PD# select pin will not cause clocks of a shorter or longer pulse than that of the running clock. The first clock pulse coming out of a stopped clock condition may be slightly distorted due to clock network charging circuitry. Board routing and signal loading may have a large impact on the initial clock distortion also.
ICS9248-55 Power Management Requirements
SIGNAL SIGNAL STATE Latency No. of rising edges of free running PCICLK 1 1 1 1 3ms 2max
CPU_ STOP# PCI_STOP# PD#
0 (Disabled) 2 1 (Enabled) 1 0 (Disabled) 2 1 (Enabled) 1 1 (Normal Operation) 3 0 (Power Down) 4
Notes. 1. Clock on latency is defined from when the clock enable goes active to when the first valid clock comes out of the device. 2. Clock off latency is defined from when the clock enable goes inactive to when the last clock is driven low out of the device. 3. Power up latency is when PD# goes inactive (high) to when the first valid clocks are output by the device. 4. Power down has controlled clock counts applicable to CPUCLK, PCICLK only. The REF and IOAPIC will be stopped independent of these.
3
ICS9248-55
CPU_STOP# Timing Diagram
CPUSTOP# is an asychronous input to the clock synthesizer. It is used to turn off the CPUCLKs for low power operation. CPU_STOP# is synchronized by the ICS9248-55. The minimum that the CPUCLK is enabled (CPU_STOP# high pulse) is 100 CPUCLKs. All other clocks will continue to run while the CPUCLKs are disabled. The CPUCLKs will always be stopped in a low state and start in such a manner that guarantees the high pulse width is a full pulse. CPUCLK on latency is less than 4 CPUCLKs and CPUCLK off latency is less than 4 CPUCLKs.
Notes: 1. All timing is referenced to the internal CPUCLK. 2. CPU_STOP# is an asynchronous input and metastable conditions may exist. This signal is synchronized to the CPUCLKs inside the ICS9248-55. 3. All other clocks continue to run undisturbed. 4. PD# and PCI_STOP# are shown in a high (true) state.
PCI_STOP# Timing Diagram
PCI_STOP# is an asynchronous input to the ICS9248-55. It is used to turn off the PCICLK (0:6) clocks for low power operation. PCI_STOP# is synchronized by the ICS9248-55 internally. The minimum that the PCICLK (0:6) clocks are enabled (PCI_STOP# high pulse) is at least 10 PCICLK (0:6) clocks. PCICLK (0:6) clocks are stopped in a low state and started with a full high pulse width guaranteed. PCICLK (0:6) clock on latency cycles are only one rising PCICLK. Clock off latency is one PCICLK clock.
Notes: 1. All timing is referenced to the Internal CPUCLK (defined as inside the ICS9248 device.) 2. PCI_STOP# is an asynchronous input, and metastable conditions may exist. This signal is required to be synchronized inside the ICS9248-55. 3. All other clocks continue to run undisturbed. 4. PD# and CPU_STOP# are shown in a high (true) state.
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ICS9248-55
PD# Timing Diagram
The power down selection is used to put the part into a very low power state without turning off the power to the part. PD# is an asynchronous active low input. This signal is synchronized internally by the ICS9248-55 prior to its control action of powering down the clock synthesizer. Internal clocks will not be running after the device is put in power down state. When PD# is active (low) all clocks are driven to a low state and held prior to turning off the VCOs and the Crystal oscillator. The power on latency is guaranteed to be less than 3ms. The power down latency is less than three CPUCLK cycles. PCI_STOP# and CPU_STOP# are dont care signals during the power down operations.
Notes: 1. All timing is referenced to the Internal CPUCLK (defined as inside the ICS9248 device). 2. PD# is an asynchronous input and metastable conditions may exist. This signal is synchronized inside the ICS9248. 3. The shaded sections on the VCO and the Crystal signals indicate an active clock is being generated.
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ICS9248-55
Absolute Maximum Ratings
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 V Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND 0.5 V to VDD +0.5 V Ambient Operating Temperature . . . . . . . . . . . . 0C to +70C Storage Temperature . . . . . . . . . . . . . . . . . . . . . 65C to +150C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings are stress specifications only and functional operation of the device at these or any other conditions above those listed in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability.
Electrical Characteristics - Input/Supply/Common Output Parameters
TA = 0 - 70C; Supply Voltage VDD = VDDL = 3.3 V +/-5% (unless otherwise stated) PARAMETER Input High Voltage Input Low Voltage Input High Current Input Low Current Input Low Current Operating Supply Current Power Down Supply Current Input frequency Input Capacitance1 Transition Time1 Settling Time1 Clk Stabilization 1 Skew1
1
SYMBOL VIH VIL IIH IIL1 IIL2 IDD3.3OP66 IDD3.3OP100 IDD3.3PD Fi CIN C INX Ttrans Ts TSTAB TCPU-PCI1
CONDITIONS
MIN 2 VSS-0.3 -5 -200
TYP
VIN = VDD VIN = 0 V; Inputs with no pull-up resistors VIN = 0 V; Inputs with pull-up resistors C L = 0 pF; Select @ 66MHz C L = 0 pF; Select @ 100MHz C L = 0 pF; With input address to Vdd or GND VDD = 3.3 V; Logic Inputs X1 & X2 pins To 1st crossing of target Freq. From 1st crossing to 1% target Freq. From VDD = 3.3 V to 1% target Freq. VT = 1.5 V;
0.1 2.0 -100 60 66 70
MAX UNITS VDD+0.3 V 0.8 V 5 A A A 170 mA 170 mA 600 16 5 45 3 3 4 A MHz pF pF ms ms ms ns
11 27
14.318 36 5
1.5
3
Guaranteed by design, not 100% tested in production.
Electrical Characteristics - Input/Supply/Common Output Parameters
TA = 0 - 70C; Supply Voltage VDD = 3.3 V +/-5%, VDDL = 2.5 V +/-5% (unless otherwise stated) PARAMETER Operating Supply Current Skew1
1
SYMBOL IDD2.5OP66 IDD2.5OP100 tCPU-PCI2
CONDITIONS CL = 0 pF; Select @ 66.8 MHz CL = 0 pF; Select @ 100 MHz VT = 1.5 V; VTL = 1.25 V
MIN
TYP 16 23 3
MAX 72 100 4
UNITS mA mA ns
1.5
Guaranteed by design, not 100% tested in production.
6
ICS9248-55
Electrical Characteristics - CPUCLK
TA = 0 - 70C; VDD = 3.3 V +/-5%, VDDL = 2.5 V +/-5%; CL = 10 - 20 pF (unless otherwise stated) PARAMETER Output High Voltage Output Low Voltage Output High Current Output Low Current Rise Time Fall Time Duty Cycle Skew Jitter, Cycle-to-cycle Jitter, One Sigma Jitter, Absolute
1
SYMBOL VOH2B VOL2B IOH2B IOL2B tr2B
1
CONDITIONS IOH = -12.0 mA IOL = 12 mA VOH = 1.7 V VOL = 0.7 V VOL = 0.4 V, VOH = 2.0 V VOH = 2.0 V, VOL = 0.4 V VT = 1.25 V VT = 1.25 V VT = 1.25 V VT = 1.25 V VT = 1.25 V
MIN 2
19
TYP 2.3 0.2 -41 37 1.25 1
MAX UNITS V 0.4 V -19 mA mA 1.6 1.6 55 175 200 150 +250 ns ns % ps ps ps ps
tf2B1 d t2B1 tsk2B1 tjcyc-cyc2B1 tj1s2B1 tjabs2B1
45
48 30 150 40
-250
140
Guaranteed by design, not 100% tested in production.
Electrical Characteristics - IOAPIC
TA = 0 - 70C; VDD = 3.3 V +/-5%, VDDL = 2.5 V +/-5%; CL = 20 pF PARAMETER Output High Voltage Output Low Voltage Output High Current Output Low Current Rise Time1 Fall Time1 Duty Cycle1 Skew1 Jitter, One Sigma Jitter, Absolute1
1 1
SYMBOL VOH4B VOL4B IOH4B IOL4B Tr4B Tf4B Dt4B tsk4B1 Tj1s4B Tjabs4B
CONDITIONS IOH = -18 mA IOL = 18 mA VOH = 1.7 V VOL = 0.7 V VOL = 0.4 V, VOH = 2.0 V VOH = 2.0 V, VOL = 0.4 V VT = 1.25 V VT = 1.25 V VT = 1.25 V VT = 1.25 V
MIN 2
29
TYP 2.2 0.33 -41 37 1.5 1.3
MAX UNITS V 0.4 V -28 mA mA 2 2 55 250 3 5 ns ns % ps % %
45
54 60 1
-5
Guaranteed by design, not 100% tested in production.
7
ICS9248-55
Electrical Characteristics - PCICLK
TA = 0 - 70C; VDD = VDDL = 3.3 V +/-5%; CL = 30 pF PARAMETER Output High Voltage Output Low Voltage Output High Current Output Low Current Rise Time1 Fall Time Skew
1 1 1
SYMBOL VOH1 VOL1 IOH1 IOL1 tr1 tf1 dt1 tsk1 tj1s1 tjabs1
CONDITIONS IOH = -11 mA IOL = 9.4 mA VOH = 2.0 V VOL = 0.8 V VOL = 0.4 V, VOH = 2.4 V VOH = 2.4 V, VOL = 0.4 V VT = 1.5 V VT = 1.5 V VT = 1.5 V VT = 1.5 V
MIN 2.4
16
TYP 3.1 0.1 -62 57 1.5 1.1
MAX UNITS V 0.4 V -22 mA mA 2 2 55 500 150 500 ns ns % ps ps ps
Duty Cycle
45
50 140 17
Jitter, One Sigma1 Jitter, Absolute1
1
-500
70
Guaranteed by design, not 100% tested in production.
Electrical Characteristics - REF
TA = 0 - 70C; VDD = VDDL = 3.3 V +/-5%; CL = 10 - 20 pF (unless otherwise stated) PARAMETER Output High Voltage Output Low Voltage Output High Current Output Low Current Rise Time1 Fall Time1 Duty Cycle1 Jitter, One Sigma Jitter, Absolute1
1 1
SYMBOL VOH5 VOL5 IOH5 IOL5 tr5 tf5 dt5 tj1s5 tjabs5
CONDITIONS IOH = -12 mA IOL = 9 mA VOH = 2.0 V VOL = 0.8 V VOL = 0.4 V, VOH = 2.4 V VOH = 2.4 V, VOL = 0.4 V VT = 1.5 V VT = 1.5 V VT = 1.5 V
MIN 2.6
29
TYP 3.1 0.17 -44 42 1.4 1.1
MAX UNITS V 0.4 V -22 mA mA 2 2 55 3 5 ns ns % % %
45
53 1 3
Guaranteed by design, not 100% tested in production.
8
ICS9248-55
Electrical Characteristics - 48 MHz
TA = 0 - 70C; VDD = VDDL = 3.3 V +/-5%; CL = 10 - 20 pF (unless otherwise stated) PARAMETER Frequency Accuracy1 Output High Voltage Output Low Voltage Output High Current Output Low Current Rise Time1 Fall Time1 Duty Cycle
1 1
SYMBOL FACC48m VOH5 VOL5 IOH5 IOL5 tr5 tf5 dt5 tj1s5 tjabs5 IOH = -12 mA IOL = 9 mA VOH = 2.0 V VOL = 0.8 V
CONDITIONS
MIN 2.6
TYP 3 0.14 -44 42 1.2 1.2
MAX UNITS 167 0.4 -22 4 4 55 3 5 ppm V V mA mA ns ns % % %
16
VOL = 0.4 V, VOH = 2.4 V VOH = 2.4 V, VOL = 0.4 V VT = 1.5 V VT = 1.5 V VT = 1.5 V 45
52 1 3
Jitter, One Sigma Jitter, Absolute1
1
Guaranteed by design, not 100% tested in production.
9
ICS9248-55
SSOP Package
SYMBOL A A1 A2 B C D E e H h L N
X
COMMON DIMENSIONS MIN. NOM. MAX. .095 .101 .110 .008 .012 .016 .088 .090 .092 .008 .010 .0135 .005 .006 .0085 See Variations .292 .296 .299 0.025 BSC .400 .406 .410 .010 .013 .016 .024 .032 .040 See Variations 0 5 8 .085 .093 .100
VARIATIONS AC AD MIN. .620 .720
D NOM. .625 .725
N MAX. .630 .730 48 56
This table in inches
Ordering Information
ICS9248BF-55
Example:
ICS XXXX F - PPP
Pattern Number (2 or 3 digit number for parts with ROM code patterns) Package Type F=SSOP Device Type (consists of 3 or 4 digit numbers) Prefix ICS, AV = Standard Device
ICS reserves the right to make changes in the device data identified in this publication without further notice. ICS advises its customers to obtain the latest version of all device data to verify that any information being relied upon by the customer is current and accurate.
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