8-output 1.5V PCIe Gen1-2-3 Clock Generator
w/Zo=100ohms
9FGU0841
DATASHEET
General Description
The 9FGU0841 is a member of IDT's 1.5V Ultra-Low-Power
PCIe clock family with integrated output terminations
providing Zo=100Ω. The device has 8 output enables for clock
management, 2 different spread spectrum levels in addition to
spread off and 2 selectable SMBus addresses.
Features/Benefits
•
Direct connection to 100ohm transmission lines; saves 32
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resistors compared to standard PCIe devices
50mW typical power consumption; reduced thermal
concerns
Outputs can optionally be supplied from any voltage
between 1.05 and 1.5V; maximum power savings
OE# pins; support DIF power management
Programmable Slew rate for each output; allows tuning for
various line length
Programmable output amplitude; allows tuning for various
application environments
DIF outputs blocked until PLL is locked; clean system
start-up
Selectable 0%, -0.25% or -0.5% spread on DIF outputs;
reduces EM
External 25MHz crystal; supports tight ppm with 0 ppm
synthesis error
Configuration can be accomplished with strapping pins;
SMBus interface not required for device control
Selectable SMBus addresses; multiple devices can easily
share an SMBus segment
3.3V tolerant SMBus interface works with legacy controllers
Space saving 48-pin 6x6 mm VFQFPN; minimal board
space
Recommended Application
•
1.5V PCIe Gen1-2-3 Clock Generator
Output Features
•
8 - 100MHz Low-Power (LP) HCSL DIF pairs
•
w/Zo=100ohms
1 - 1.5V LVCMOS REF output w/Wake-On-LAN (WOL)
support
Key Specification
•
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DIF cycle-to-cycle jitter <50ps
DIF output-to-output skew < 60ps
DIF phase jitter is PCIe Gen1-2-3 compliant
REF phase jitter is < 3.0ps RMS
Functional Block Diagram
vOE(7:0)#
REF1.5
XIN/CLKIN_25
X2
OSC
DIF7
DIF6
DIF5
SS Capable PLL
vSADR
vSS_EN_tri
^CKPWRGD_PD#
SDATA_3.3
SCLK_3.3
CONTROL
LOGIC
DIF4
DIF3
DIF2
DIF1
DIF0
9FGU0841 REVISION B 08/14/15
1
©2014 Integrated Device Technology, Inc.
9FGU0841 DATASHEET
Pin Configuration
^CKPWRGD_PD#
VDD1.5
VDDIO
VDDIO
vOE7#
vOE6#
48 47 46 45 44 43 42 41 40 39 38 37
vSS_EN_tri
GNDXTAL
XIN/CLKIN_25
X2
VDDXTAL1.5
VDDREF1.5
vSADR/REF1.5
GNDREF
GNDDIG
SCLK_3.3
SDATA_3.3
VDDDIG1.5
1
2
3
4
5
6
7
8
9
10
11
12
vOE0#
DIF0
VDDIO
36
35
34
33
32
31
30
29
28
27
26
25
GND
DIF2#
DIF2
DIF5#
DIF5
vOE4#
DIF4#
DIF4
VDDIO
VDDA1.5
GNDA
vOE3#
DIF3#
DIF3
vOE2#
9FGU0841
13 14 15 16 17 18 19 20 21 22 23 24
DIF0#
vOE1#
DIF1#
DIF1
VDD1.5
VDDIO
48-pin MLF, 6x6 mm, 0.4mm pitch
vv prefix indicates internal 60KOhm pull down resistor
v prefix indicates internal 120KOhm pull down resistor
^ prefix indicates internal 120KOhm pull up resistor
Power Management Table
SMBus
DIFx
REF
OEx#
True O/P
Comp. O/P
OE bit
0
X
X
Low
Low
Hi-Z
1
1
1
0
Running
Running Running
1
0
1
Low
Low
Low
1. REF is Hi-Z until the 1st assertion of CKPWRGD_PD# high. After this, when
CKPWRGD_PD# is low, REF is Low.
CKPWRGD_PD#
SMBus Address Selection Table
State of SADR on first application
of CKPWRGD_PD#
SADR
0
1
Address
1101000
1101010
+
Read/Write Bit
x
x
Power Connections
Pin Number
VDD
5
6
12
20,38
30
13,21,31,39,
47
VDDIO
GND
2
8
9
22,29,40
29
Description
XTAL OSC
REF Power
Digital (dirty)
Power
DIF outputs
PLL Analog
8-OUTPUT 1.5V PCIE GEN1-2-3 CLOCK GENERATOR W/ZO=100OHMS
2
vOE5#
DIF7#
DIF6#
GND
DIF7
DIF6
REVISION B 08/14/15
9FGU0841 DATASHEET
Pin Descriptions
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
29
30
31
32
33
34
35
36
37
38
39
PIN NAME
vSS_EN_tri
GNDXTAL
XIN/CLKIN_25
X2
VDDXTAL1.5
VDDREF1.5
vSADR/REF1.5
GNDREF
GNDDIG
SCLK_3.3
SDATA_3.3
VDDDIG1.5
VDDIO
vOE0#
DIF0
DIF0#
vOE1#
DIF1
DIF1#
VDD1.5
VDDIO
GND
DIF2
DIF2#
vOE2#
DIF3
DIF3#
vOE3#
GNDA
VDDA1.5
VDDIO
DIF4
DIF4#
vOE4#
DIF5
DIF5#
vOE5#
VDD1.5
VDDIO
TYPE
LATCHED
IN
GND
IN
OUT
PWR
PWR
LATCHED
I/O
GND
GND
IN
I/O
PWR
PWR
IN
OUT
OUT
IN
OUT
OUT
PWR
PWR
GND
OUT
OUT
IN
OUT
OUT
IN
GND
PWR
PWR
OUT
OUT
IN
OUT
OUT
IN
PWR
PWR
DESCRIPTION
Latched select input to select spread spectrum amount at initial power up :
1 = -0.5% spread, M = -0.25%, 0 = Spread Off
GND for XTAL
Crystal input or Reference Clock input. Nominally 25MHz.
Crystal output.
Power supply for XTAL, nominal 1.5V
VDD for REF output. nominal 1.5V.
Latch to select SMBus Address/1.5V LVCMOS copy of X1/REFIN pin
Ground pin for the REF outputs.
Ground pin for digital circuitry
Clock pin of SMBus circuitry, 3.3V tolerant.
Data pin for SMBus circuitry, 3.3V tolerant.
1.5V digital power (dirty power)
Power supply for differential outputs
Active low input for enabling DIF pair 0. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 1. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Differential true clock output
Differential Complementary clock output
Power supply, nominally 1.5V
Power supply for differential outputs
Ground pin.
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 2. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 3. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Ground pin for the PLL core.
1.5V power for the PLL core.
Power supply for differential outputs
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 4. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 5. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Power supply, nominally 1.5V
Power supply for differential outputs
REVISION B 08/14/15
3
8-OUTPUT 1.5V PCIE GEN1-2-3 CLOCK GENERATOR W/ZO=100OHMS
9FGU0841 DATASHEET
Pin Descriptions (cont.)
PIN #
PIN NAME
40 GND
41 DIF6
42 DIF6#
43
44
45
46
47
48
vOE6#
DIF7
DIF7#
vOE7#
VDDIO
^CKPWRGD_PD#
TYPE
GND
OUT
OUT
IN
OUT
OUT
IN
PWR
IN
DESCRIPTION
Ground pin.
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 6. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Differential true clock output
Differential Complementary clock output
Active low input for enabling DIF pair 7. This pin has an internal pull-down.
1 =disable outputs, 0 = enable outputs
Power supply for differential outputs
Input notifies device to sample latched inputs and start up on first high
assertion. Low enters Power Down Mode, subsequent high assertions exit
Power Down Mode. This pin has internal pull-up resistor.
8-OUTPUT 1.5V PCIE GEN1-2-3 CLOCK GENERATOR W/ZO=100OHMS
4
REVISION B 08/14/15
9FGU0841 DATASHEET
Test Loads
Low-Power HCSL Differential Output Test Load
5 inches
Rs
Zo=100ohm
2pF
2pF
Rs
Device
REF Output Test Load
Zo = 50 ohms
33
5pF
Device
Alternate Terminations
3.3V
Driving LVDS
Cc
R7a
R7b
Rs
Zo
Cc
Rs
Device
R8a
R8b
LVDS Clock
input
Driving LVDS inputs
Value
Receiver has Receiver does not
termination
have termination Note
10K ohm
140 ohm
5.6K ohm
75 ohm
0.1 uF
0.1 uF
1.2 volts
1.2 volts
Component
R7a, R7b
R8a, R8b
Cc
Vcm
REVISION B 08/14/15
5
8-OUTPUT 1.5V PCIE GEN1-2-3 CLOCK GENERATOR W/ZO=100OHMS
