Integrated
Circuit
Systems, Inc.
ICS932S421C
PCIe Gen 2 and QPI Clock for Intel-based Servers
Recommended Application:
PCIe Gen 2 & QPI compliant CK410B+ clock for Intel-based
servers
Output Features:
•
4 - 0.7V current-mode differential CPU pairs
•
5 - 0.7V current-mode differential SRC pair
•
4 - PCI (33MHz)
•
3 - PCICLK_F, (33MHz) free-running
•
1 - 48MHz
•
2 - REF, 14.318MHz
Features/Benefits:
•
Supports spread spectrum modulation, 0 to -0.5%
down spread
•
•
•
•
Uses external 14.318MHz crystal and external load
capacitors for low ppm synthesis error
CPU clocks independent of SRC/PCI clocks
D2/D3 SMBus address
Increased CPU amplitude at higher speeds compared
to 932S421B
Key Specifications:
•
PCIe Gen 2 compliant SRC outputs
•
QPI & FBD 2 compliant CPU clocks
•
CPU cycle-cycle jitter: < 50ps
•
SRC cycle-cycle jitter: < 125ps
•
PCI cycle-cycle jitter: < 500ps
•
CPU output skew: < 50ps
•
SRC output skew: < 250ps
•
± 100ppm frequency accuracy on all outputs
Functionality
FS_C
0
0
0
0
1
1
1
1
1
FS_B
0
0
1
1
0
0
1
1
1
FS_A
0
1
0
1
0
1
0
1
2
CPU
SRC
MHz
MHz
266.67
133.33
200.00
166.67
100.00
333.33
100.00
400.00
Reserved
PCI
MHz
REF
MHz
U
SB
MHz
33.33
14.32
48.00
1. FS_B and FS_C are three-level inputs. Please see V
IL_FS
and V
IH_FS
specifications in
the Input/Supply/Common Output Parameters Table for correct values.
Also refer to the Test Clarification Table.
2. FS_A is a low-threshold input. Please see the V
IL_FS
and V
IH_FS
specifications in the Input/Supply/Common Output Parameters Table for correct values.
Pin Configuration
VDDPCI
GNDPCI
PCICLK0
PCICLK1
PCICLK2
PCICLK3
GNDPCI
VDDPCI
PCICLK_F0
PCICLK_F1
PCICLK_F2
VDD48
48MHz
GND48
VDDSRC
SRCCLKT0
SRCCLKC0
SRCCLKC1
SRCCLKT1
GNDSRC
SRCCLKT2
SRCCLKC2
SRCCLKC3
SRCCLKT3
VDDSRC
SRCCLKT4
SRCCLKC4
VDDSRC
1460E—08/25/09
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
FS_C/TEST_SEL
REF0
REF1
VDDREF
X1
X2
GNDREF
FS_B/TEST_MODE
FS_A
VDDCPU
CPUCLKT0
CPUCLKC0
VDDCPU
CPUCLKT1
CPUCLKC1
GNDCPU
CPUCLKT2
CPUCLKC2
VDDCPU
CPUCLKT3
CPUCLKC3
VDDA
GNDA
IREF
NC
Vtt_PwrGd#/PD
SDATA
SCLK
56-pin SSOP & TSSOP
ICS932S421
Integrated
Circuit
Systems, Inc.
ICS932S421C
Pin Description
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
PIN NAME
VDDPCI
GNDPCI
PCICLK0
PCICLK1
PCICLK2
PCICLK3
GNDPCI
VDDPCI
PCICLK_F0
PCICLK_F1
PCICLK_F2
VDD48
48MHz
GND48
VDDSRC
SRCCLKT0
SRCCLKC0
SRCCLKC1
SRCCLKT1
GNDSRC
SRCCLKT2
SRCCLKC2
SRCCLKC3
SRCCLKT3
VDDSRC
SRCCLKT4
SRCCLKC4
VDDSRC
PIN TYPE
PWR
PWR
OUT
OUT
OUT
OUT
PWR
PWR
OUT
OUT
OUT
PWR
OUT
PWR
PWR
OUT
OUT
OUT
OUT
PWR
OUT
OUT
OUT
OUT
PWR
OUT
OUT
PWR
DESCRIPTION
Power supply for PCI clocks, nominal 3.3V
Ground pin for the PCI outputs
PCI clock output.
PCI clock output.
PCI clock output.
PCI clock output.
Ground pin for the PCI outputs
Power supply for PCI clocks, nominal 3.3V
Free running PCI clock not affected by PCI_STOP# .
Free running PCI clock not affected by PCI_STOP# .
Free running PCI clock not affected by PCI_STOP# .
Power pin for the 48MHz output.3.3V
48MHz clock output.
Ground pin for the 48MHz outputs
Supply for SRC clocks, 3.3V nominal
True clock of differential SRC clock pair.
Complementary clock of differential SRC clock pair.
Complementary clock of differential push-pull SRC clock pair.
True clock of differential SRC clock pair.
Ground pin for the SRC outputs
True clock of differential SRC clock pair.
Complementary clock of differential SRC clock pair.
Complementary clock of differential SRC clock pair.
True clock of differential SRC clock pair.
Supply for SRC clocks, 3.3V nominal
True clock of differential SRC clock pair.
Complementary clock of differential SRC clock pair.
Supply for SRC clocks, 3.3V nominal
1460E—08/25/09
2
Integrated
Circuit
Systems, Inc.
ICS932S421C
Pin Description (Continued)
Pin #
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
PIN NAME
SCLK
SDATA
Vtt_PwrGd#/PD
NC
IREF
GNDA
VDDA
CPUCLKC3
CPUCLKT3
VDDCPU
CPUCLKC2
CPUCLKT2
GNDCPU
CPUCLKC1
CPUCLKT1
VDDCPU
CPUCLKC0
CPUCLKT0
VDDCPU
FS_A
Type
IN
I/O
IN
N/A
OUT
PWR
PWR
OUT
OUT
PWR
OUT
OUT
PWR
OUT
OUT
PWR
OUT
OUT
PWR
IN
Pin Description
Clock pin of SMBus circuitry, 5V tolerant.
Data pin for SMBus circuitry, 3.3V tolerant.
Vtt_PwrGd# is an active low input used to determine when latched inputs are ready to
be sampled. PD is an asynchronous active high input pin used to put the device into a
low power state. The internal clocks, PLLs and the crystal oscillator are stopped.
No Connection.
This pin establishes the reference current for the differential current-mode output pairs.
This pin requires a fixed precision resistor tied to ground in order to establish the
appropriate current. 475 ohms is the standard value.
Ground pin for the PLL core.
3.3V power for the PLL core.
Complementary clock of differential pair CPU outputs. These are current mode
outputs. External resistors are required for voltage bias.
True clock of differential pair CPU outputs. These are current mode outputs. External
resistors are required for voltage bias.
Supply for CPU clocks, 3.3V nominal
Complementary clock of differential pair CPU outputs. These are current mode
outputs. External resistors are required for voltage bias.
True clock of differential pair CPU outputs. These are current mode outputs. External
resistors are required for voltage bias.
Ground pin for the CPU outputs
Complementary clock of differential pair CPU outputs. These are current mode
outputs. External resistors are required for voltage bias.
True clock of differential pair CPU outputs. These are current mode outputs. External
resistors are required for voltage bias.
Supply for CPU clocks, 3.3V nominal
Complementary clock of differential pair CPU outputs. These are current mode
outputs. External resistors are required for voltage bias.
True clock of differential pair CPU outputs. These are current mode outputs. External
resistors are required for voltage bias.
Supply for CPU clocks, 3.3V nominal
3.3V tolerant input for CPU frequency selection. Refer to input electrical characteristics
for Vil_FS and Vih_FS values.
3.3V tolerant input for CPU frequency selection. Refer to input electrical characteristics
for Vil_FS and Vih_FS values. TEST_MODE is a real time input to select between Hi-Z
and REF/N divider mode while in test mode. Refer to Test Clarification Table.
Ground pin for the REF outputs.
Crystal output, Nominally 14.318MHz
Crystal input, Nominally 14.318MHz.
Ref, XTAL power supply, nominal 3.3V
14.318 MHz reference clock.
14.318 MHz reference clock.
3.3V tolerant input for CPU frequency selection. Low voltage threshold inputs, see
input electrical characteristics for Vil_FS and Vih_FS values.
TEST_Sel: 3-level latched input to enable test mode.
Refer to Test Clarification Table
49
50
51
52
53
54
55
56
FS_B/TEST_MODE
GNDREF
X2
X1
VDDREF
REF1
REF0
FS_C/TEST_SEL
IN
PWR
OUT
IN
PWR
OUT
OUT
IN
1460E—08/25/09
3
Integrated
Circuit
Systems, Inc.
ICS932S421C
General Description
The
ICS932S421C
is a main clock synthesizer for CK410B+ generation Intel server platforms. The
ICS932S421C
is driven
with a 14.318MHz crystal. It generates CPU outputs up to 400MHz and PCI-Express clocks at 100 or 200 MHz. The 48 MHz
USB clock is an exact 48.000 MHz clock.
Block Diagram
REF(1:0)
X1
X2
XTAL
OSC.
48MHz
FIXED PLL
DIVIDER
CPU PLL
DIVIDERS
CPUCLK(3:0)
SRC/PCI
PLL
SRCCLK(4:0)
DIVIDERS
PCICLK(3:0), PCICLK_F(2:0)
FS(C:A)
TEST_SEL
CONTROL
LOGIC
VTT_PWRGD#/PD
SDATA
SCLK
IREF
Power Groups
Pin Number
VDD
GND
53
50
1,8
2,7
15,25,28
20
35
34
12
14
47,44,38
41
1460E—08/25/09
Description
Xtal, Ref
PCICLK outputs
SRCCLK outputs
Master clock, CPU Analog
48MHz, PLL_48
CPUCLK clocks
4
Integrated
Circuit
Systems, Inc.
ICS932S421C
Single-ended Output Terminations
ICS932S421C
Zo
Rs
CL=5pF
SEPP Output Buffer
(Single Ended
Push Pull)
Test Load
Zo
Rs
CL=5pF
Zo
Rs
SEPP Output Buffer
(Single Ended
Push Pull)
CL=5pF
The singled-ended outputs of the ICS 932S421C default to a drive strength of 2
loads. The REF clocks can be turned down to 1-load strength via the SMBus.
Suggested termination resistors are as follows for transmission lines with Zo =
50 ohms:
Single-ended outputs at 2-load strength (Power up default
for all single-ended outputs)
Single-ended outputs at 1-load strength (REF clock only)
Driving 1 load, Rs = 33 ohms
Driving 2 loads, Rs = 7.5 ohms
Driving 1 load, Rs = 22 ohms
1460E—08/25/09
5
