Synchronous Ethernet Frequency Translator
ICS840272I
DATA SHEET
General Description
The ICS840272I is a PLL-based Frequency Translator intended for use in Synchronous Ethernet applications. This high performance device is optimized to generate 25MHz and 8kHz LVCMOS clock outputs. The ICS840272I accepts the following differential or single-ended input signals: 161.1328125MHz (10GbE Mode), 156.25MHz (1GbE Mode), or 125MHz (Recovered clock from 10/100/1000BaseT Ethernet PHY). The extended temperature range supports telecommunication and networking end equipment requirements.
Features
• • • • • • • • • •
Two single-ended outputs (LVCMOS or LVTTL levels), output impedance: 17Ω Single-ended lock detect output (LVCMOS or LVTTL levels) Two selectable differential clock inputs Differential input pair (CLKx, nCLKx) accepts LVPECL, LVDS, LVHSTL, SSTL, HCSL input levels Internal resistor bias on nCLK pin allows the user to drive CLK input with external single-ended (LVCMOS/ LVTTL) input levels Selectable input frequencies: 161.1328MHz, 156.25MHz or 125MHz Output frequency: 25MHz, 8kHz Full 3.3V supply voltage -40°C to 85°C ambient operating temperature Available in lead-free (RoHS 6) package
Pin Assignment
VDD LOCK_DT REF_SEL SEL0 SEL1 OE VDDA GND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VDDO QA QB GND CLK0 nCLK0 CLK1 nCLK1
ICS840272I 16 Lead TSSOP 4.40mm x 5.0mm x 0.925mm package body G Package Top View
Block Diagram
LOCK_DT CLK0
Pulldown
0 0
nCLK0 Pullup/Pulldown CLK1 Pulldown
Pullup/Pulldown
N P PLL
1
QA 25MHz
1
÷3125
QB 8kHz
nCLK1 REF_SEL Pulldown
M
Input Control
SEL[1:0] Pulldown:Pullup
00 = PLL Bypass, 25MHz Input 01 = 161.1328125MHz (default) 10 = 156.25MHz 11 = 125MHz
OE Pulldown
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Table 1. Pin Descriptions
Number 1 2 3 4 5 6 7 8, 13 9 10 11 12 14 15 16 Name VDD LOCK_DT REF_SEL SEL0 SEL1 OE VDDA GND nCLK1 CLK1 nCLK0 CLK0 QB QA VDDO Power Output Input Input Input Input Power Power Input Input Input Input Output Output Power Pullup/ Pulldown Pulldown Pullup/ Pulldown Pulldown Pulldown Pullup Pulldown Pulldown Type Description Core supply pin. Lock detect. Logic HIGH when PLL is locked. Selects the input reference clock. When LOW, selects CLK0, nCLK0. When HIGH, selects CLK1, nCLK1. LVCMOS/LVTTL interface levels. Selects the input reference frequency and the PLL bypass mode. See Table 3A. LVCMOS/LVTTL interface levels. Selects the input reference frequency and the PLL bypass mode. See Table 3A. LVCMOS/LVTTL interface levels. 8kHz output enable pin. When LOW, QB is disabled. When HIGH, QB is enabled. LVCMOS/LVTTL interface levels. See Table 3B. Analog supply pin. Power supply ground. Inverting differential clock input. Internal resistor bias to VDD/2. Non-inverting differential clock input. Inverting differential clock input. Internal resistor bias to VDD/2. Non-inverting differential clock input. Single-ended clock output. LVCMOS/LVTTL interface levels. Single-ended clock output. LVCMOS/LVTTL interface levels. Output supply pin.
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Table 2. Pin Characteristics
Symbol CIN RPULLUP RPULLDOWN ROUT Parameter Input Capacitance Input Pullup Resistor Input Pulldown Resistor Output Impedance VDDO = 3.465V Test Conditions Minimum Typical 4 51 51 17 Maximum Units pF kΩ kΩ
Ω
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Function Tables
Table 3A. SEL[1:0] Function Table
Inputs SEL1 0 0 (default) 1 1 SEL0 0 1 (default) 0 1 CLKx, nCLKx (MHz) 25 161.1328125 156.25 125 Function Mode PLL Bypass PLL Enabled PLL Enabled PLL Enabled Output (MHz) QA 25 25 25 25
Table 3B. OE Function Table
Control Input OE 0 (default) 1 Function QB Output Disabled (High impedance) Enabled
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Absolute Maximum Ratings
NOTE: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings are stress specifications only. Functional operation of product at these conditions or any conditions beyond those listed in the DC Characteristics or AC Characteristics is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability. Item Supply Voltage, VDD Inputs, VI Outputs, IO (LVCMOS) Package Thermal Impedance, θJA Storage Temperature, TSTG Rating 4.6V -0.5V to VDD + 0.5V -0.5V to VDDO + 0.5V 81.2°C/W (0 mps) -65°C to 150°C
DC Electrical Characteristics
Table 4A. Power Supply DC Characteristics, VDD = VDDO = 3.3V±5%, TA = -40°C to 85°C
Symbol VDD VDDA VDDO IDD IDDA IDDO Parameter Core Supply Voltage Analog Supply Voltage Output Supply Voltage Power Supply Current Analog Supply Current Output Supply Current Test Conditions Minimum 3.135 VDD – 0.11 3.135 Typical 3.3 3.3 3.3 Maximum 3.465 VDD 3.465 57 11 5 Units V V V mA mA mA
Table 4B. LVCMOS/LVTTL DC Characteristics, VDD = VDDO = 3.3V±5%, TA = -40°C to 85°C
Symbol VIH VIL IIH Parameter Input High Voltage Input Low Voltage OE, SEL1, REF_SEL SEL0 OE, SEL1, REF_SEL SEL0 VOH VOL Output High Voltage Output Low Voltage Test Conditions VDD = 3.465V VDD = 3.465V VDD = VIN = 3.465V VDD = VIN = 3.465V VDD = 3.465V, VIN = 0V VDD = 3.465V, VIN = 0V IOH = -12mA IOL = 12mA -5 -150 2.6 0.5 Minimum 2 -0.3 Typical Maximum VDD + 0.3 0.8 150 5 Units V V µA µA µA µA V V
Input High Current
IIL
Input Low Current
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Table 4C. Differential DC Characteristics, VDD = VDDO = 3.3V±5%, TA = -40°C to 85°C
Symbol IIH IIL VPP VCMR Parameter Input High Current CLK[0:1], nCLK[0:1] CLK[0:1] Input Low Current nCLK[0:1] Peak-to-Peak Voltage; NOTE 1 Common Mode Input Voltage; NOTE 1, 2 Test Conditions VDD = VIN = 3.465V VDD = 3.465V, VIN = 0V VDD = 3.465V, VIN = 0V -5 -150 0.15 GND + 0.5 1.3 VDD – 0.85 Minimum Typical Maximum 150 Units µA µA µA V V
NOTE 1: VIL should not be less than -0.3V. NOTE 2: Common mode input voltage is defined as VIH.
AC Electrical Characteristics
Table 5. AC Characteristics, VDD = VDDO = 3.3V±5%, TA = -40°C to 85°C
Symbol fOUT tjit(Ø) tjit(cc) tR / t F odc Parameter Output Frequency RMS Phase Jitter (Random); NOTE 1 Cycle-to-Cycle Jitter Output Rise/Fall Time Output Duty Cycle QA QB QA QA QA QB QA QB 25MHz, Integration Range: 12kHz – 10MHz 25MHz 20% to 80% 20% to 80% 450 450 47 47 Test Conditions Minimum Typical 25 8 1.1 37 1100 1100 53 53 Maximum Units MHz kHz ps ps ps ps % %
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium has been reached under these conditions. NOTE 1: Refer to Phase Noise plot.
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Typical Phase Noise at 25MHz
Additive Phase Jitter @ 25MHz 12kHz to 10MHz = 1.1ps (typical)
Noise Power
dBc Hz
Offset Frequency (Hz)
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Parameter Measurement Information
1.65V±5% 1.65V±5%
VDD VDD, VDDO VDDA
SCOPE
nCLK[0:1]
LVCMOS
GND
Qx
CLK[0:1]
V
PP
Cross Points
V
CMR
GND
-1.65V±5%
LVCMOS Output Load AC Test Circuit
Differential Input Level
V
QA, QB
DDO
2
80% 20% tR
80% 20% tF
t PW
t
PERIOD
QA, QB
odc =
t PW t PERIOD
x 100%
Output Duty Cycle/Pulse Width/Period
Output Rise/Fall Time
Phase Noise Plot Noise Power
V
QA, QB
DDORx
V
DDORx
V
DDORx
2 t cycle n
2
2 t cycle n+1
➤
t jit(cc) = |t cycle n – t cycle n+1| 1000 Cycles f1 Offset Frequency f2
RMS Jitter = Area Under Curve Defined by the Offset Frequency Markers
RMS Phase Jitter
Cycle-to-Cycle Jitter
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➤
➤
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Applications Information
Power Supply Filtering Technique
As in any high speed analog circuitry, the power supply pins are vulnerable to random noise. To achieve optimum jitter performance, power supply isolation is required. The ICS840272I provides separate power supplies to isolate any high switching noise from the outputs to the internal PLL. VDD, VDDA and VDDO should be individually connected to the power supply plane through vias, and 0.01µF bypass capacitors should be used for each pin. Figure 1 illustrates this for a generic VDD pin and also shows that VDDA requires that an additional 10Ω resistor along with a 10µF bypass capacitor be connected to the VDDA pin.
3.3V VDD .01µF VDDA .01µF 10µF 10Ω
Figure 1. Power Supply Filtering
Recommendations for Unused Input and Output Pins Inputs:
LVCMOS Control Pins
All control pins have internal pullups or pulldowns; additional resistance is not required but can be added for additional protection. A 1kΩ resistor can be used. CLK/nCLK Inputs For applications not requiring the use of the differential input, both CLK and nCLK can be left floating. Though not required, but for additional protection, a 1kΩ resistor can be tied from CLK to ground.
Outputs:
LVCMOS Outputs
All unused LVCMOS output can be left floating. There should be no trace attached.
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Wiring the Differential Input to Accept Single-Ended Levels
Figure 2 shows how a differential input can be wired to accept single ended levels. The reference voltage VREF = VDD/2 is generated by the bias resistors R1 and R2. The bypass capacitor (C1) is used to help filter noise on the DC bias. This bias circuit should be located as close to the input pin as possible. The ratio of R1 and R2 might need to be adjusted to position the VREF in the center of the input voltage swing. For example, if the input clock swing is 2.5V and VDD = 3.3V, R1 and R2 value should be adjusted to set VREF at 1.25V. The values below are for when both the single ended swing and VDD are at the same voltage. This configuration requires that the sum of the output impedance of the driver (Ro) and the series resistance (Rs) equals the transmission line impedance. In addition, matched termination at the input will attenuate the signal in half. This can be done in one of two ways. First, R3 and R4 in parallel should equal the transmission line impedance. For most 50Ω applications, R3 and R4 can be 100Ω. The values of the resistors can be increased to reduce the loading for slower and weaker LVCMOS driver. When using single-ended signaling, the noise rejection benefits of differential signaling are reduced. Even though the differential input can handle full rail LVCMOS signaling, it is recommended that the amplitude be reduced. The datasheet specifies a lower differential amplitude, however this only applies to differential signals. For single-ended applications, the swing can be larger, however VIL cannot be less than -0.3V and VIH cannot be more than VDD + 0.3V. Though some of the recommended components might not be used, the pads should be placed in the layout. They can be utilized for debugging purposes. The datasheet specifications are characterized and guaranteed by using a differential signal.
Figure 2. Recommended Schematic for Wiring a Differential Input to Accept Single-ended Levels
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Differential Clock Input Interface
The CLK /nCLK accepts LVDS, LVPECL, LVHSTL, SSTL, HCSL and other differential signals. Both signals must meet the VPP and VCMR input requirements. Figures 3A to 3F show interface examples for the CLK/nCLK input driven by the most common driver types. The input interfaces suggested here are examples only. Please consult with the vendor of the driver component to confirm the driver termination requirements. For example, in Figure 3A, the input termination applies for IDT open emitter LVHSTL drivers. If you are using an LVHSTL driver from another vendor, use their termination recommendation.
3.3V 3.3V 1.8V Zo = 50Ω Zo = 50Ω CLK Zo = 50Ω nCLK Zo = 50Ω nCLK CLK 3.3V
LVPECL Differential Input
R1 50Ω R2 50Ω
Differential Input
LVHSTL IDT LVHSTL Driver
R1 50Ω R2 50Ω
R2 50Ω
Figure 3A. CLK/nCLK Input Driven by an IDT Open Emitter LVHSTL Driver
Figure 3B. CLK/nCLK Input Driven by a 3.3V LVPECL Driver
3.3V 3.3V 3.3V Zo = 50Ω CLK CLK Zo = 50Ω nCLK R1 100 R3 125Ω R4 125Ω 3.3V 3.3V Zo = 50Ω
LVPECL
R1 84Ω R2 84Ω
Differential Input
Zo = 50Ω
nCLK
LVDS
Receiver
Figure 3C. CLK/nCLK Input Driven by a 3.3V LVPECL Driver
Figure 3D. CLK/nCLK Input Driven by a 3.3V LVDS Driver
3.3V
2.5V 3.3V 3.3V 2.5V 33Ω Zo = 50Ω CLK Zo = 50Ω nCLK Zo = 60Ω nCLK Zo = 60Ω CLK R3 120Ω R4 120Ω
*R3
HCSL
*R4
33Ω R1 50Ω R2 50Ω
Differential Input
SSTL
R1 120Ω R2 120Ω
Differential Input
*Optional – R3 and R4 can be 0Ω
Figure 3E. CLK/nCLK Input Driven by a 3.3V HCSL Driver
Figure 3F. CLK/nCLK Input Driven by a 2.5V SSTL Driver
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Schematic Example
Figure 4 shows an example of ICS840272I applications schematic. In this example, the device is operated at VDD = 3.3V. The input is driven by either a 3.3V LVPECL or LVDS driver. Two examples of LVCMOS terminations are shown in this schematic. The decoupling capacitors should be located as close as possible to the power pin.
Logic Control Input Examples
VDD
Set Logic Input to '1'
RU1 1K
VDD
Set Logic Input to '0'
RU2 Not Install R8 35 VDD Zo = 50 Ohm
RD1 Not Install
To Logic Input pins
RD2 1K
To Logic Input pins
1 2 3 4 5 6 7 8
U1
LVCMOS 16 15 14 13 12 11 10 9 C4 0.1u Zo = 50 Ohm R10 100 LVCMOS
C3 0.1u VDD R1 10 VDDA C1 10uF C2 0.01u
VDD VDDO LOCK_DT QA REF_SEL QB SEL0 GND SEL1 CLK0 OE nCLK0 VDDA CLK1 GND nCLK1
VDD R9 100
LD1 LED R2 2.7K
VDD LVDS Zo = 50 Ohm R3 100 Zo = 50 Ohm
Optional Termination Unused output can be left floating. There should no trace attached to unused output. Device characterized with all outputs terminated.
R6 125
VDD VDD Zo = 50 Ohm R4 125
Zo = 50 Ohm LVPECL R5 84 R7 84
Figure 4. ICS840272I Schematic Example
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Power Considerations
This section provides information on power dissipation and junction temperature for the ICS840272I. Equations and example calculations are also provided. 1. Power Dissipation.
The total power dissipation for the ICS840272I is the sum of the core power plus the analog power plus the power dissipated in the load(s). The following is the power dissipation for VDD = 3.3V + 5% = 3.465V, which gives worst case results. • • Power (core)MAX = VDD_MAX * (IDD + IDDA+ IDDO) = 3.465V *(57mA + 11mA + 5mA) = 252.9mW Output Impedance ROUT Power Dissipation due to Loading 50Ω to VDD/2 Output Current IOUT = VDD_MAX / [2 * (50Ω + ROUT)] = 3.465V / [2 * (50Ω + 17Ω)] = 25.86mA Total Power Dissipation on the ROUT per LVCMOS output Power (ROUT) = ROUT * (IOUT)2 = 17Ω * (25.86mA)2 = 11.4mW per output Total Power (ROUT) = 11.4mW * 2 = 22.8mW
•
Total Power Dissipation • Total Power = Power (core)MAX + Total Power (ROUT) = 252.9mW + 22.8mW = 275.7mW
2. Junction Temperature. Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad directly affects the reliability of the device. The maximum recommended junction temperature is 125°C. Limiting the internal transistor junction temperature, Tj, to 125°C ensures that the bond wire and bond pad temperature remains below 125°C. The equation for Tj is as follows: Tj = θJA * Pd_total + TA Tj = Junction Temperature θJA = Junction-to-Ambient Thermal Resistance Pd_total = Total Device Power Dissipation (example calculation is in section 1 above) TA = Ambient Temperature In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θJA must be used. Assuming no air flow and a multi-layer board, the appropriate value is 81.2°C/W per Table 6 below. Therefore, Tj for an ambient temperature of 85°C with all outputs switching is: 85°C + 0.276W *81.2°C/W = 107.4°C. This is below the limit of 125°C. This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow and the type of board (multi-layer).
Table 6. Thermal Resistance θJA for 16 Lead TSSOP, Forced Convection
θJA by Velocity Meters per Second Multi-Layer PCB, JEDEC Standard Test Boards 0 81.2°C/W 1 73.9°C/W 2.5 70.2°C/W
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Reliability Information
Table 7. θJA vs. Air Flow Table for a 16 Lead TSSOP
θJA vs. Air Flow Meters per Second Multi-Layer PCB, JEDEC Standard Test Boards 0 81.2°C/W 1 73.9°C/W 2.5 70.2°C/W
Transistor Count
The transistor count for ICS840272I: 3326
Package Outline and Package Dimensions
Package Outline - G Suffix for 16 Lead TSSOP Table 8. Package Dimensions for 16 Lead TSSOP
All Dimensions in Millimeters Symbol Minimum Maximum N 16 A 1.20 A1 0.5 0.15 A2 0.80 1.05 b 0.19 0.30 c 0.09 0.20 D 4.90 5.10 E 6.40 Basic E1 4.30 4.50 e 0.65 Basic L 0.45 0.75 α 0° 8° aaa 0.10 Reference Document: JEDEC Publication 95, MO-153
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Ordering Information
Table 9. Ordering Information
Part/Order Number 840272AGILF 840272AGILFT Marking 40272AIL 40272AIL Package “Lead-Free” 16 Lead TSSOP “Lead-Free” 16 Lead TSSOP Shipping Packaging Tube 2500 Tape & Reel Temperature -40°C to 85°C -40°C to 85°C
NOTE: Parts that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.
While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology (IDT) assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial and industrial applications. Any other applications, such as those requiring high reliability or other extraordinary environmental requirements are not recommended without additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments.
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DISCLAIMER Integrated Device Technology, Inc. (IDT) and its subsidiaries reserve the right to modify the products and/or specifications described herein at any time and at IDT’s sole discretion. All information in this document, including descriptions of product features and performance, is subject to change without notice. Performance specifications and the operating parameters of the described products are determined in the independent state and are not guaranteed to perform the same way when installed in customer products. The information contained herein is provided without representation or warranty of any kind, whether express or implied, including, but not limited to, the suitability of IDT’s products for any particular purpose, an implied warranty of merchantability, or non-infringement of the intellectual property rights of others. This document is presented only as a guide and does not convey any license under intellectual property rights of IDT or any third parties. IDT’s products are not intended for use in life support systems or similar devices where the failure or malfunction of an IDT product can be reasonably expected to significantly affect the health or safety of users. Anyone using an IDT product in such a manner does so at their own risk, absent an express, written agreement by IDT. Integrated Device Technology, IDT and the IDT logo are registered trademarks of IDT. Other trademarks and service marks used herein, including protected names, logos and designs, are the property of IDT or their respective third party owners. Copyright 2010. All rights reserved.