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19-0977; Rev 0; 8/07
Low-Jitter, Precision Clock Generator with Four Outputs
General Description
The MAX3624 is a low-jitter precision clock generator optimized for network application. The device integrates a crystal oscillator and a phase-locked loop (PLL) clock multiplier to generate high-frequency clock outputs for Ethernet, Fibre Channel, SONET/SDH, and other networking applications. Maxim's proprietary PLL design features ultra-low jitter (0.36psRMS) and excellent power-supply noise rejection, minimizing design risk for network equipment. The MAX3624 has three LVPECL outputs and one LVCMOS output. Selectable output dividers and a selectable feedback divider allow a range of output frequencies. o CMOS Input: 19MHz to 40.5MHz o Output Frequencies Ethernet: 62.5MHz, 125MHz, 156.25MHz, 312.5MHz Fibre Channel: 106.25MHz, 159.375MHz, 212.5MHz, 318.5MHz SONET/SDH: 77.76MHz, 155.52MHz, 311.04MHz o Low Jitter 0.14psRMS (1.875MHz to 20MHz) 0.36psRMS (12kHz to 20MHz) o Excellent Power-Supply Noise Rejection o No External Loop Filter Capacitor Required
Features
o Crystal Oscillator Interface: 19.375MHz to 27MHz
MAX3624
Applications
Ethernet Networking Equipment Fibre Channel Storage Area Network SONET/SDH Network
Pin Configuration and Typical Application Circuit appear at end of data sheet.
Ordering Information
PART MAX3624UTJ+ TEMP RANGE PIN-PACKAGE 0C to +85C 32 TQFN-EP* PKG CODE T3255-3
+Denotes a lead-free package. *EP = Exposed pad.
Block Diagram
IN_SEL MR BYPASS SELA[1:0]
QAC_OE LVCMOS BUFFER RESET LOGIC/POR RESET DIVIDER NA LVPECL BUFFER
QA_C
SELA[1:0] SELB[1:0] FB_SEL[1:0] BYPASS
QA_OE QA QA
RESET LVCMOS REF_IN 27pF X_IN CRYSTAL OSCILLATOR X_OUT 33pF DIVIDERS: M = 16, 24, 25, 32 NA = 1, 2, 3, 4, 5, 6, 8, 10, 12 NB = 1, 2, 3, 4, 5, 6, 8, 10, 12 DIVIDER M DIVIDER NB 1 0 PFD FILTER RESET 620MHz TO 648MHz VCO 1 RESET 0
QB1_OE LVPECL BUFFER QB1 QB1 QB0_OE LVPECL BUFFER QB0 QB0
MAX3624
FB_SEL[1:0]
SELB[1:0]
________________________________________________________________ Maxim Integrated Products
1
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Low-Jitter, Precision Clock Generator with Four Outputs MAX3624
ABSOLUTE MAXIMUM RATINGS
Supply Voltage Range VCC, VCCA, VDDO_A, VCCO_A, VCCO_B ................................-0.3V to +4.0V Voltage Range at REF_IN, IN_SEL, FB_SEL[1:0], SELA[1:0], SELB[1:0], QAC_OE, QA_OE, QB0_OE, QB1_OE, MR, BYPASS ..........................................-0.3V to (VCC + 0.3V) Voltage Range at X_IN Pin ...................................-0.3V to +1.2V Voltage Range at GNDO_A...................................-0.3V to +0.3V Voltage Range at X_OUT Pin ......................-0.3V to (VCC - 0.6V) Current into QA_C ...........................................................50mA Current into QA, QA, QB0, QB0, QB1, QB1 .....................-56mA Continuous Power Dissipation (TA = +70C) 32-Pin TQFN (derate 34.5mW/C above +70C) .......2759mW Operating Junction Temperature Range ...........-55C to +150C Storage Temperature Range .............................-65C to +160C
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 in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, TA = 0C to +85C, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25C, unless otherwise noted.) (Notes 1, 2, and 3)
PARAMETER Power-Supply Current SYMBOL ICC (Note 4) CONDITIONS MIN TYP 77 MAX 100 UNITS mA
CONTROL INPUT CHARACTERISTICS (SELA[1:0], SELB[1:0], FB_SEL[1:0], IN_SEL, QAC_OE, QA_OE, QB1_OE, QB0_OE, MR, BYPASS Pins) Input Capacitance Input Pulldown Resistor Input Logic Bias Resistor Input Pullup Resistor CIN RPULLDOWN Pins MR, FB_SEL[1:0] RBIAS RPULLUP Pins SELA[1:0], SELB[1:0], QB0_OE Pins QAC_OE, QA_OE, QB1_OE, IN_SEL, BYPASS 2 75 50 75 pF k k k
LVPECL OUTPUTS (QA, QA, QB0, QB0, QB1, QB1 PINS) Output High Voltage Output Low Voltage Peak-to-Peak Output-Voltage Swing (Single-Ended) Clock Output Rise/Fall Time Output Duty-Cycle Distortion VOH VOL (Note 2) 20% to 80% (Note 2) PLL enabled PLL bypassed (Note 5) VCC 1.13 VCC 1.85 0.6 200 48 40 VCC 0.98 VCC 1.7 0.72 350 50 50 VCC 0.83 VCC 1.55 0.9 600 52 60 V V VP-P ps %
LVCMOS/LVTTL INPUTS (SELA[1:0], SELB[1:0], FB_SEL[1:0], IN_SEL, QAC_OE, QA_OE, QB1_OE, QB0_OE, MR, BYPASS Pins) Input-Voltage High Input-Voltage Low Input High Current Input Low Current VIH VIL IIH IIL VIN = VCC VIN = 0V -80 2.0 0.8 80 V V A A
2
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Low-Jitter, Precision Clock Generator with Four Outputs
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, TA = 0C to +85C, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25C, unless otherwise noted.) (Notes 1, 2, and 3)
PARAMETER SYMBOL PLL enabled PLL bypassed VIH VIL IIH IIL VIN = VCC VIN = 0V PLL enabled -240 30 2.5 VOH VOL QA_C sourcing 12mA QA_C sinking 12mA (Notes 3 and 6) PLL enabled PLL bypassed (Note 5) 250 42 40 14 620 RJRMS 12kHz to 20MHz 1.875MHz to 20MHz LVPECL output LVCMOS output 0.36 0.14 14 psP-P 25 0.9 LVPECL output, LVCMOS output 9 LVPECL output LVCMOS output -57 -47 -70 psP-P dBc dBc psRMS 648 1.0 500 50 2.6 0.4 1000 58 60 70 2.0 0.8 240 CONDITIONS MIN TYP MAX 40.5 320 UNITS
MAX3624
REF_IN SPECIFICATIONS (Input DC- or AC-Coupled) Reference Clock Frequency Input-Voltage High Input-Voltage Low Input High Current Input Low Current Reference Clock Duty Cycle Input Capacitance QA_C SPECIFICATIONS Output High Voltage Output Low Voltage Output Rise/Fall Time Output Duty Cycle Distortion Output Impedance CLOCK OUTPUT AC SPECIFICATIONS VCO Frequency Range Random Jitter (Note 7) Total Time Interval Error (TIE) with Supply Noise (Notes 7, 8, and 9) Total Time Interval Error (TIE) Without Supply Noise (Notes 7, 8) Spurs Induced by Power-Supply Noise (Notes 7, 9, 10) Nonharmonic and Subharmonic Spurs MHz psRMS V V ps % MHz V V A A % pF
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Low-Jitter, Precision Clock Generator with Four Outputs MAX3624
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, TA = 0C to +85C, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25C unless otherwise noted.) (Notes 1, 2, and 3)
PARAMETER Output Skew SYMBOL CONDITIONS Between QB0 and QB1 Between QA and QB0 or QB1, PECL outputs f = 1kHz f = 10kHz Clock Output SSB Phase Noise at 125MHz (Note 11) f = 100kHz f = 1MHz f > 10MHz MIN TYP 15 20 -124 -125 -130 -145 -153 dBc/Hz ps MAX UNITS
A series resistor of up to 10.5 is allowed between VCC and VCCA for filtering supply noise when system power-supply tolerance is VCC = 3.3V 5%. See Figure 3. Note 2: Guaranteed up to 320MHz for LVPECL output. Note 3: Guaranteed up to 160MHz for LVCMOS output. Note 4: All outputs enabled and unloaded. IN_SEL set high. Note 5: Measured with crystal or AC-coupled, 50% duty-cycle signal on REF_IN. Note 6: Measured using setup shown in Figure 1 with VCC = 3.3V 5%. Note 7: Measured with crystal source. Note 8: Total TIE including random and deterministic jitter. Measured with Agilent DSO81304A 40GS/s real-time oscilloscope using 2M sample record length. Note 9: Measured with 40mVP-P, 100kHz sinusoidal signal on the supply. Note 10: Measured at 156.25MHz output. Note 11: Measured with 25MHz crystal or 25MHz reference clock at LVCMOS input with a slew rate of 0.5V/ns or greater. Note 1:
MAX3624
QA_C
36
499 4.7pF
0.1F Z0 = 50
OSCILLOSCOPE
50
Figure 1. LVCMOS Output Measurement Setup
4
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Low-Jitter, Precision Clock Generator with Four Outputs
Typical Operating Characteristics
(Typical values are at VCC = +3.3V, TA = +25C, crystal frequency = 25MHz.)
MAX3624
SUPPLY CURRENT vs. TEMPERATURE
MAX3624 toc01
DIFFERENTIAL OUTPUT WAVEFORM AT 156.25MHz (LVPECL OUTPUT)
MAX3624 toc02
OUTPUT WAVEFORM AT 125MHz (LVCMOS OUTPUT)
MAX3624 toc03
250 225 200 SUPPLY CURRENT (mA) 175 150 125 100 75 50 25 0 0 10 20 30 40 50 60 70 80 ALL OUTPUTS ACTIVE AND UNTERMINATED ALL OUTPUTS ACTIVE AND TERMINATED
MEASURED USING 50 OSCILLOSCOPE INPUT THROUGH NETWORK SHOWN IN FIGURE 1 AMPLITUDE (200mv/div) AMPLITUDE (50mV/div) 1ns/div
90
1ns/div
AMBIENT TEMPERATURE (C)
PHASE NOISE AT 312.5MHz CLOCK FREQUENCY
MAX3624 toc04
PHASE NOISE AT 125MHz CLOCK FREQUENCY
MAX3624 toc05
PHASE NOISE AT 212.5MHz CLOCK FREQUENCY (26.5625MHz CRYSTAL)
-90 AMPLITUDE (dBc/Hz) -100 -110 -120 -130 -140 -150 -160
MAX3624 toc06
-80 -90 AMPLITUDE (dBc/Hz) -100 -110 -120 -130 -140 -150 -160 0.1 1 10 100
-80 -90 AMPLITUDE (dBc/Hz) -100 -110 -120 -130 -140 -150 -160
-80
1000 10,000 100,000
0.1
1
10
100
1000 10,000 100,000
0.1
1
10
100
1000 10,000 100,000
OFFSET FREQUENCY (kHz)
OFFSET FREQUENCY (kHz)
OFFSET FREQUENCY (kHz)
JITTER HISTOGRAM (312.5MHz OUTPUT, 40mVP-P SUPPLY NOISE AT 100kHz)
MAX3624 toc07
SPURS INDUCED BY POWER-SUPPLY NOISE vs. NOISE FREQUENCY
-10 fC = 312.5MHz NOISE AMPLITUDE = 40mVP-P
MAX3624 toc08
0
DJ = 5.6psP-P
SPUR AMPLITUDE (dBc)
-20 -30 -40 -50 -60 -70
DJ + RJ = 14psP-P 5ps/div
-80 -90 10 100 1000 10,000 NOISE FREQUENCY (kHz)
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Low-Jitter, Precision Clock Generator with Four Outputs MAX3624
Pin Description
PIN 1 2, 19, 24 3 4, 5 6 7 8 9 10 11 12 13 14 NAME VCCO_B GND QB0_OE SELB1, SELB0 QAC_OE MR GNDO_A QA_C VDDO_A VCCO_A QA QA BYPASS FB_SEL1, FB_SEL0 VCCA VCC QA_OE SELA0, SELA1 QB1_OE X_OUT X_IN REF_IN IN_SEL QB1 QB1 QB0 QB0 EP Supply Ground LVCMOS/LVTTL Input. Enables/disables QB0 clock output. Connect pin high or leave open to enable LVPECL clock output QB0. Connect low to set QB0 to a logic 0. Has internal 50k input impedance. LVCMOS/LVTTL Input. Controls NB divider setting. Has 50k more information. input impedance. See Table 2 for FUNCTION Power Supply for QB0 and QB1 Clock Outputs. Connect to +3.3V.
LVCMOS/LVTTL Input. Enables/disables QA_C clock output. Connect pin high or leave open to enable QA_C. Connect low to set QA_C to a high-impedance state. Has internal 75k pullup to VCC. LVCMOS/LVTTL Input. Master reset input. Pulse high for > 1s to reset all dividers. Has internal 75k pulldown to GND. Not required for normal operation. Ground for QA_C Output. Connect to supply ground. LVCMOS Clock Output Power Supply for QA_C Clock Output. Connect to +3.3V. Power Supply for QA Clock Output. Connect to +3.3V. Noninverting Clock Output, LVPECL Inverting Clock Output, LVPECL LVCMOS/LVTTL Input (Active Low). Connect low to bypass the internal PLL. Connect high or leave open for normal operation. When in bypass mode the output dividers are set to divide by 1. Has internal 75k pullup to VCC. LVCMOS/LVTTL Input. Controls M divider setting. See Table 3 for more information. Has internal 75k pulldown to GND. Analog Power Supply for the VCO. Connect to +3.3V. For additional power-supply noise filtering, this pin can connect to VCC through 10.5 as shown in Figure 2 (requires VCC = +3.3V 5%). Core Power Supply. Connect to +3.3V. LVCMOS/LVTTL Input. Enables/disables the QA clock output. Connect this pin high or leave open to enable the LVPECL clock output QA. Connect low to set QA to a logic 0. Has internal 75k pullup to VCC. LVCMOS/LVTTL Input. Controls NA divider setting. See Table 2 for more information. Has 50k input impedance. LVCMOS/LVTTL Input. Enables/disables QB1 clock output. Connect pin high or leave open to enable LVPECL clock output QB1. Connect low to set QB1 to a logic 0. Has internal 50k input impedance. Crystal Oscillator Output Crystal Oscillator Input LVCMOS Reference Clock Input. Self-biased to allow AC- or DC-coupling. LVCMOS/LVTTL Input. Connect high or leave open to use a crystal. Connect low to use REF_IN. Has internal 75k pullup to VCC. LVPECL, Inverting Clock Output LVPECL, Noninverting Clock Output LVPECL, Inverting Clock Output LVPECL, Noninverting Clock Output Exposed Pad. Connect to supply ground for proper electrical and thermal performance.
15, 16 17 18 20 21, 22 23 25 26 27 28 29 30 31 32 --
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Low-Jitter, Precision Clock Generator with Four Outputs
Detailed Description
The MAX3624 is a low-jitter clock generator designed to operate at Ethernet, Fibre Channel, and SONET/SDH frequencies. It consists of an on-chip crystal oscillator, PLL, programmable dividers, LVCMOS output buffer, and LVPECL output buffers. Using a low-frequency clock (crystal or CMOS input) as a reference, the internal PLL generates a high-frequency output clock with excellent jitter performance.
LVPECL Drivers
The high-frequency outputs--QA, QB0, and QB1--are differential PECL buffers designed to drive transmission lines terminated with 50 to VCC - 2.0V. The maximum operating frequency is specified up to 320MHz. Each output can be individually disabled, if not used. The outputs go to a logic 0 when disabled.
MAX3624
LVCMOS Driver
QA_C, the LVCMOS output, is designed to drive a single-ended high-impedance load. The maximum operating frequency is specified up to 160MHz. This output can be disabled by the QAC_OE pin if not used and goes to a high impedance when disabled.
Crystal Oscillator
An integrated oscillator provides the low-frequency reference clock for the PLL. This oscillator requires an external crystal connected between X_IN and X_OUT. Crystal frequency is 19.375MHz to 27MHz.
Reset Logic/POR
During power-on, the power-on reset (POR) signal is generated to synchronize all dividers. An external master reset (MR) signal is not required.
REF_IN Buffer
An LVCMOS-compatible clock source can be connected to REF_IN to serve as the reference clock. The LVCMOS REF_IN buffer is internally biased to allow AC- or DC-coupling. It is designed to operate up to 320MHz.
Applications Information
Power-Supply Filtering
The MAX3624 is a mixed analog/digital IC. The PLL contains analog circuitry susceptible to random noise. In addition to excellent on-chip power-supply noise rejection, the MAX3624 provides a separate powersupply pin, VCCA, for the VCO circuitry. Figure 2 illustrates the recommended power-supply filter network for V CCA . The purpose of this design technique is to ensure clean input power supply to the VCO circuitry and to improve the overall immunity to power-supply noise. This network requires that the power supply is +3.3V 5%. Decoupling capacitors should be used on all other supply pins for best performance.
PLL
The PLL takes the signal from the crystal oscillator or reference clock input and synthesizes a low-jitter, highfrequency clock. The PLL contains a phase-frequency detector (PFD), a lowpass filter, and a voltage-controlled oscillator (VCO) with a 620MHz to 648MHz operating range. The VCO output is connected to the PFD input through a feedback divider. See Table 3 for divider values. The PFD compares the reference frequency to the divided-down VCO output (fVCO/M) and generates a control signal that keeps the VCO locked to the reference clock. The high-frequency VCO output clock is sent to the output dividers. To minimize noiseinduced jitter, the VCO supply (VCCA) is isolated from the core logic and output buffer supplies.
+3.3V 5% VCC 0.1F 10.5 VCCA 0.1F 10F
Output Dividers
The output divider is programmable to allow a range of output frequencies. See Table 2 for the divider input settings. The output dividers are automatically set to divide by 1 when the MAX3624 is in bypass mode (BYPASS = 0).
Figure 2. Analog Supply Filtering
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Low-Jitter, Precision Clock Generator with Four Outputs MAX3624
Table 1. Output Frequency Determination Chart
XO OR CMOS INPUT FREQUENCY (MHz) FEEDBACK DIVIDER, M VCO FREQUENCY (MHz) OUTPUT DIVIDER, NA AND NB 2 4 25 25 625 5 8 10 25.78125 25 644.53125 4 2 4 26.04166 24 625 5 8 10 2 3 26.5625 24 637.5 4 6 12 2 19.44 32 622.08 4 8 2 38.88 (CMOS input) 16 622.08 4 8 OUTPUT FREQUENCY (MHz) 312.5 156.25 125 78.125 62.5 161.132812 312.5 156.25 125 78.125 62.5 318.75 212.5 159.375 106.25 53.125 311.04 155.52 77.76 311.04 155.52 77.76 SONET/SDH SONET/SDH Fibre Channel Ethernet 10Gbps Ethernet Ethernet APPLICATIONS
Output Divider Configuration
Table 2 shows the input settings required to set the output dividers. Leakage in the OPEN case must be less than 1A. Note that when the MAX3624 is in bypass mode (BYPASS set low), the output dividers are automatically set to divide by 1.
Table 2. Output Divider Configuration Chart
INPUT SELA1/SELB1 0 0 1 1 1 OPEN 0 OPEN OPEN SELA0/SELB0 0 1 0 1 OPEN 1 OPEN 0 OPEN NA/NB DIVIDER / 2* / 3* /4 /5 /6 /8 / 10 / 12 / 1*
*Maximum guaranteed output frequency is 160MHz for CMOS and 320MHz for LVPECL output.
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Low-Jitter, Precision Clock Generator with Four Outputs
PLL Divider Configuration
Table 3 shows the input settings required to set PLL feedback divider.
Crystal Input Layout and Frequency Stability
The crystal, trace, and two external capacitors should be placed on the board as close as possible to the MAX3624's X_IN and X_OUT pins to reduce crosstalk of active signals into the oscillator. The layout shown in Figure 3 gives approximately 3pF of trace plus footprint capacitors per side of the crystal (Y1). The dielectric material is FR-4 and dielectric thickness of the reference board is 15 mils. Using a 25MHz crystal and the capacitor values of C22 = 27pF and C23 = 33pF, the measured output frequency accuracy is -14ppm at +25C ambient temperature.
MAX3624
Crystal Selection
The crystal oscillator is designed to drive a fundamental mode, AT-cut crystal resonator. See Table 4 for recommended crystal specifications. See Figure 4 for external capacitance connection.
Table 3. PLL Divider Configuration Chart
INPUT FB_SEL1 0 0 1 1 FB_SEL0 0 1 0 1 M DIVIDER / 25 / 24 / 32 / 16
Table 4. Crystal Selection Parameters
PARAMETER Crystal Oscillation Frequency Shunt Capacitance Load Capacitance Equivalent Series Resistance (ESR) Maximum Crystal Drive Level SYMBOL fOSC CO CL RS MIN 19.375 2.0 18 50 300 TYP MAX 27 7.0 UNITS MHz pF pF W
27pF X_IN CRYSTAL (CL = 18pF) X_OUT 33pF
Figure 4. Crystal, Capacitors Connection
Figure 3. Crystal Layout
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Low-Jitter, Precision Clock Generator with Four Outputs MAX3624
Interfacing with LVPECL Outputs
The equivalent LVPECL output circuit is given in Figure 8. These outputs are designed to drive a pair of 50 transmission lines terminated with 50 to VTT = VCC 2V. If a separate termination voltage (VTT) is not available, other terminations methods can be used such as shown in Figure 5 and Figure 6. Unused outputs should be disabled and may be left open. For more information on LVPECL terminations and how to interface with other logic families, refer to Maxim Application Note HFAN01.0: Introduction to LVDS, PECL, and CML.
Interface Models
Figure 7, Figure 8, and Figure 9 show examples of interface models.
VCC VB = 1.4V
VCC
VB
14.5k REF_IN +3.3V VB
130
130 HIGH IMPEDANCE 82 ESD STRUCTURES
MAX3624 Qx
Qx
Z0 = 50 Z0 = 50 82
Figure 7. Simplified REF_IN Pin Circuit Schematic
VCC
Figure 5. Thevenin Equivalent of Standard PECL Termination
0.1F Qx Z0 = 50 100 0.1F Qx 150 150 Z0 = 50 HIGH IMPEDANCE Qx Qx
MAX3624
NOTE: AC-COUPLING IS OPTIONAL.
ESD STRUCTURES
Figure 6. AC-Coupled PECL Termination Figure 8. Simplified LVPECL Output Circuit Schematic
10
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Low-Jitter, Precision Clock Generator with Four Outputs
Exposed-Pad Package
VDDO_A
MAX3624
DISABLE
10 IN 10 QAC
The exposed pad on the 32-pin TQFN package provides a very low inductance path for return current traveling to the PCB ground plane. The pad is also electrical ground on the MAX3624 and must be soldered to the circuit board ground for proper electrical performance.
Pin Configuration
IN_SEL REF_IN QB1 X_IN 26 QB0 QB0 QB1
TOP VIEW
ESD STRUCTURES VCCO_B GND 1 2 3 4 5 6 7 8
32
31
30
29
28
27
25 24 GND QB1_OE SELA1 SELA0 QA_OE GND VCC VCCA
+
X_OUT 23 22 21 20 19 18 17 16 FB_SEL0
Figure 9. Simplified LVCMOS Output Circuit Schematic
QB0_OE
Layout Considerations
The inputs and outputs are critical paths for the MAX3624, and care should be taken to minimize discontinuities on these transmission line. Here are some suggestions for maximizing the MAX3624's performance: * An uninterrupted ground plane should be positioned beneath the clock I/Os. * Ground pin vias should be placed close to the IC and the input/output interfaces to allow a return current path to the MAX3624 and the receive devices. * Supply decoupling capacitors should be placed close to the MAX3624 supply pins. * Maintain 100 differential (or 50 single-ended) transmission line impedance out of the MAX3624. * Use good high-frequency layout techniques and multilayer boards with an uninterrupted ground plane to minimize EMI and crosstalk. Refer to the MAX3624 Evaluation Kit for more information.
SELB1 SELB0 QAC_OE MR GNDO_A
MAX3624
*EP
9 QA_C
10 VDDO_A
11 VCCO_A
12 QA
13 QA
14 BYPASS
15 FB_SEL1
THIN QFN-EP (5mm x 5mm)
*EXPOSED PAD CONNECTED TO GROUND.
Chip Information
TRANSISTOR COUNT: 10,780 PROCESS: BiCMOS
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11
Low-Jitter, Precision Clock Generator with Four Outputs MAX3624
Typical Application Circuit
+3.3V 5% 10.5 0.01F 0.1F
10F
VCC VCCA 0.1F MR REF_IN IN_SEL QAC_OE QA_OE QB0_OE VCC QB1_OE BYPASS SELA1 SELA0 SELB1 SELB0 FB_SEL1 FB_SEL0 X_OUT
VCCO_A
VCCO_B
VDDO_A QA_C 125MHz QA QA 125MHz
36 Z0 = 50 ASIC
Z0 = 50 Z0 = 50 50 50
ASIC
(VCC - 2V)
MAX3624
QB0 QB0 312.5MHz
Z0 = 50 Z0 = 50 50 50
ASIC
(VCC - 2V) QB1 QB1 X_IN GND GNDO_A 312.5MHz 50 50 (VCC - 2V) Z0 = 50 Z0 = 50 ASIC
25MHz (CL = 18pF) 33pF 27pF
Package Information
For the latest package outline information, go to www.maxim-ic.com/packages.
PACKAGE TYPE 32 TQFN-EP DOCUMENT NO. 21-0140
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

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