19-4910; Rev 0; 10/09 TION KIT EVALUA BLE IL AVA A Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs The MAX3638 is a highly flexible, precision phaselocked loop (PLL) clock generator optimized for the next generation of network equipment that demands low-jitter clock generation and distribution for robust high-speed data transmission. The device features subpicosecond jitter generation, excellent power-supply noise rejection, and pin-programmable LVDS/LVPECL output interfaces. The MAX3638 provides nine differential outputs and one LVCMOS output, divided into three banks. The frequency and output interface of each output bank can be individually programmed, making this device an ideal replacement for multiple crystal oscillators and clock distribution ICs on a system board, saving cost and space. This 3.3V IC is available in a 7mm x 7mm, 48-pin TQFN package and operates from -40°C to +85°C. Applications Ethernet Switch/Router S Outputs LVCMOS Output: Up to 160MHz LVPECL/LVDS Outputs: Up to 800MHz S Three Individual Output Banks Pin-Programmable Dividers Pin-Programmable Output Interface S Wide VCO Tuning Range (3.83GHz to 4.025GHz) S Low Phase Jitter 0.34psRMS (12kHz to 20MHz) 0.14psRMS (1.875MHz to 20MHz) S Excellent Power-Supply Noise Rejection S -40NC to +85NC Operating Temperature Range S +3.3V Supply Ordering Information PCIeM, Network Processors Wireless Base Station Features S Inputs Crystal Interface: 18MHz to 33.5MHz LVCMOS Input: 15MHz to 160MHz Differential Input: 15MHz to 350MHz DDR/QDR Memory Typical Application Circuits and Pin Configuration appear at end of data sheet. PART TEMP RANGE PIN-PACKAGE MAX3638ETM+ -40NC to +85NC 48 TQFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Functional Diagram LVPECL/LVDS QA0 QA0 LVPECL/LVDS MAX3638 QA1 QA1 LVPECL/LVDS QA2 QA2 XOUT LVPECL/LVDS XO QA3 XIN LVPECL/LVDS LVCMOS CIN QA3 QA4 PLL, DIVIDERS, MUXES VCO QA4 LVPECL/LVDS QB0 QB0 LVPECL/LVDS DIN DIN QB1 QB1 LVPECL/LVDS QB2 QB2 LVPECL/LVDS QC QC LVCMOS QCC PCIe is a registered trademark of PCI-SIG Corp. ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX3638 General Description MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs ABSOLUTE MAXIMUM RATINGS Supply Voltage Range (VCC, VCCA, VCCQA, VCCQB, VCCQC, VCCQCC).................................-0.3V to +4.0V Voltage Range at CIN, IN_SEL, DM, DF[1:0], DP, PLL_BP, DA[1:0], DB[1:0], DC[1:0], QA_CTRL1, QA_CTRL2, QB_CTRL, QC_CTRL, QCC, RES............................ -0.3V to (VCC + 0.3V) Voltage Range at DIN, DIN......... (VCC - 2.35V) to (VCC - 0.35V) Voltage Range at QA[4:0], QA[4:0], QB[2:0], QB[2:0], QC, QC when LVDS Output.... -0.3V to (VCC + 0.3V) Current into QA[4:0], QA[4:0], QB[2:0], QB[2:0], QC, QC when LVPECL Output...................................... -56mA Current into QCC.............................................................. Q50mA Voltage Range at XIN............................................-0.3V to +1.2V Voltage Range at XOUT..............................-0.3V to (VCC - 0.6V) Continuous Power Dissipation (TA = +70NC) 48-Pin TQFN (derate 40mW/NC above +70NC)...........3200mW Operating Junction Temperature Range.......... -55NC to +150NC Storage Temperature Range............................. -65NC to +160NC 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 = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. Signal applied to CIN or DIN/DIN only when selected as the reference clock.) (Note 1) PARAMETER Supply Current with PLL Enabled (Note 2) SYMBOL ICC Supply Current with PLL Bypassed (Note 2) CONDITIONS MIN TYP MAX Configured with LVPECL outputs 170 215 Configured with LVDS outputs 290 365 Configured with LVPECL outputs 110 Configured with LVDS outputs 230 UNITS mA mA LVCMOS/LVTTL CONTROL INPUTS (IN_SEL, DM, DF[1:0], DA[1:0], DB[1:0], DC[1:0], PLL_BP, DP, QA_CTRL1, QA_CTRL2, QB_CTRL, QC_CTRL) Input High Voltage VIH Input Low Voltage VIL 2.0 Input High Current IIH VIN = VCC Input Low Current IIL VIN = 0V V 0.8 V 80 FA -80 FA LVCMOS/LVTTL CLOCK INPUT (CIN) Reference Clock Input Frequency fREF Input Amplitude Range Internally AC-coupled (Note 3) Input High Current IIH VIN = VCC Input Low Current IIL VIN = 0V Reference Clock Input DutyCycle Distortion 15 160 MHz 1.2 3.6 VP-P 80 FA -80 40 Input Capacitance Input Differential Voltage Swing VCMI 15 VCC 1.8 % pF 350 VCC 1.3 MHz V 150 1800 mVP-P Single-Ended Voltage Range VCC 2.0 VCC 0.7 V Input Differential Impedance 80 Differential Input Capacitance 2 60 1.5 DIFFERENTIAL CLOCK INPUT (DIN, DIN) (Note 4) Differential Input Frequency fREF Input Bias Voltage FA 100 1.5 120 I pF Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs (VCC = +3.0V to +3.6V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. Signal applied to CIN or DIN/DIN only when selected as the reference clock.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP LVDS OUTPUTS (QA[4:0], QA[4:0], QB[2:0], QB[2:0], QC, QC) (Note 5) Output Frequency Output High Voltage VOH Output Low Voltage VOL 0.925 Differential Output Voltage |VOD| 250 Change in Magnitude of Differential Output for Complementary States Output Offset Voltage Change in Magnitude of Output Offset Voltage for Complementary States 1.125 D|VOS| Differential Output Impedance 80 Output Current Output Current When Disabled 3 Short to ground 6 PLL enabled Output Duty-Cycle Distortion 100 Short together 800 MHz 1.475 V 400 mV 25 mV 1.3 V 25 mV 140 I mA 10 VQ__ = VQ__ = 0V to VCC 20% to 80% Output Rise/Fall Time UNITS V D|VOD| VOS MAX 48 PLL bypassed (Note 6) FA 160 240 50 52 50 LVPECL OUTPUTS (QA[4:0], QA[4:0], QB[2:0], QB[2:0], QC, QC) (Note 7) Output Frequency ps % 800 MHz Output High Voltage VOH VCC 1.13 VCC 0.98 VCC 0.83 V Output Low Voltage VOL VCC 1.85 VCC 1.70 VCC 1.55 V 0.5 0.7 0.9 VP-P Output-Voltage Swing (Single-Ended) Output Current When Disabled VO = 0V to VCC 10 Output Rise/Fall Time 20% to 80%, differential load = 100I 140 240 50 52 Output Duty-Cycle Distortion PLL enabled 48 PLL bypassed (Note 6) FA 50 ps % LVCMOS/LVTTL OUTPUT (QCC) Output Frequency 160 MHz V IOH = -12mA Output Low Voltage IOL = 12mA 0.4 V Output Rise/Fall Time 20% to 80% (Note 8) 150 400 850 ps PLL enabled 42 50 58 Output Duty-Cycle Distortion Output Impedance PLL bypassed (Note 6) 2.6 VCC Output High Voltage 50 15 % I 3 MAX3638 ELECTRICAL CHARACTERISTICS (continued) MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.0V to +3.6V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. Signal applied to CIN or DIN/DIN only when selected as the reference clock.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 3932 4025 MHz 42 MHz PLL SPECIFICATIONS VCO Frequency Range fVCO 3830 Phase-Frequency Detector Compare Frequency fPFD 15 PLL Jitter Transfer Bandwidth Integrated Phase Jitter RJ 12kHz to 20MHz 0.34 1.875MHz to 20MHz 0.14 kHz 1.0 psRMS 25MHz LVCMOS or differential input (Notes 9, 10) 0.34 Supply-Noise Induced Phase Spur at LVPECL/LVDS Output (Note 11) -74 dBc Supply-Noise Induced Phase Spur at LVCMOS Output (Note 11) -49 dBc Determinisitic Jitter Induced by Power-Supply Noise LVPECL or LVDS (Note 11) 1 psP-P Nonharmonic and Subharmonic Spurs (Note 12) -70 dBc fOFFSET = 1kHz -111 fOFFSET = 10kHz -113 fOFFSET = 100kHz -119 fOFFSET = 1MHz -136 fOFFSET R 10MHz -147 fOFFSET = 1kHz -117 fOFFSET = 10kHz -119 fOFFSET = 100kHz -125 fOFFSET = 1MHz -142 fOFFSET R 10MHz -151 fOFFSET = 1kHz -124 fOFFSET = 10kHz -125 fOFFSET = 100kHz -131 fOFFSET = 1MHz -147 fOFFSET R 10MHz -153 fOFFSET = 1kHz -126 fOFFSET = 10kHz -127 fOFFSET = 100kHz -133 fOFFSET = 1MHz -148 fOFFSET R 10MHz -152 SSB Phase Noise at 491.52MHz SSB Phase Noise at 245.76MHz SSB Phase Noise at 125MHz SSB Phase Noise at 100MHz 4 130 25MHz crystal input (Note 9) dBc/ Hz dBc/ Hz dBc/ Hz dBc/ Hz Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs (VCC = +3.0V to +3.6V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. Signal applied to CIN or DIN/DIN only when selected as the reference clock.) (Note 1) PARAMETER SYMBOL SSB Phase Noise at 66.67MHz CONDITIONS MIN TYP fOFFSET = 1kHz -130 fOFFSET = 10kHz -131 fOFFSET = 100kHz -137 fOFFSET = 1MHz -152 fOFFSET R 10MHz -156 MAX UNITS dBc/ Hz Note 1: A series resistor of up to 10.5I is allowed between VCC and VCCA for filtering supply noise when system power-supply tolerance is VCC = 3.3V Q5%. See Figure 3. Note 2: Measured with all outputs enabled and unloaded. Note 3: CIN can be AC- or DC-coupled. See Figure 8. Input high voltage must be ≤ VCC + 0.3V. Note 4: DIN can be AC- or DC-coupled. See Figure 10. Note 5: Measured with 100I differential load. Note 6: Measured with crystal input, or with 50% duty cycle LVCMOS or differential input. Note 7: Measured with output termination of 50I to VCC - 2V or Thevenin equivalent. Note 8: Measured with a series resistor of 33I to a load capacitance of 3.0pF. See Figure 1. Note 9: Measured at 125MHz output. Note 10: Measured using LVCMOS/LVTTL input with slew rate R 1.0V/ns, or differential input with slew rate R 0.5V/ns. Note 11: Measured at 125MHz output with 200kHz, 50mVP-P sinusoidal signal on the supply using the crystal input and the power-supply filter shown in Figure 3. See the Typical Operating Characteristics for other supply noise frequencies. Deterministic jitter is calculated from the measured power-supply-induced spurs. For more information, refer to Application Note 4461: HFAN-04.5.5: Characterizing Power-Supply Noise Rejection in PLL Clock Synthesizers. Note 12: Measured with all outputs enabled and all three banks at different frequencies. LVCMOS QCC 33Ω 499Ω Z = 50Ω OSCILLOSCOPE 0.1µF Z = 50Ω 3pF 50Ω MAX3638 Figure 1. LVCMOS Output Measurement Setup 5 MAX3638 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = 3.3V, TA = +25NC, unless otherwise noted.) PLL BYPASS, ALL OUTPUTS LOADED 250 PLL NORMAL, ALL OUTPUTS UNLOADED 200 150 400 PLL NORMAL 350 300 250 200 150 PLL BYPASS 400 300 150 100 50 10 35 60 0 85 QA[2:0] ENABLED 200 50 -15 QA[4:3] AND QA[2:0] ENABLED 250 50 -40 QA[4:3], QA[2:0], AND QB[2:0] ENABLED 350 100 PLL BYPASS, ALL OUTPUTS UNLOADED QA[4:3], QA[2:0], QB[2:0], QC, AND QCC ENABLED 450 100 0 ALL OUTPUTS DISABLED 0 -40 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) SUPPLY CURRENT vs. TEMPERATURE (LVDS OUTPUTS) DIFFERENTIAL OUTPUT AT 500MHz (LVPECL) DIFFERENTIAL OUTPUT AT 245.75MHz (LVPECL) QA[4:3], QA[2:0], QB[2:0], QC, AND QCC ENABLED 300 250 QA[4:3], QA[2:0], AND QB[2:0] ENABLED 200 QA[4:3] AND QA[2:0] ENABLED 150 QA[2:0] ENABLED 100 MAX3638 toc06 MAX3638 toc04 MAX3638 toc05 350 SUPPLY CURRENT (mA) 500 SUPPLY CURRENT (mA) 350 300 450 SUPPLY CURRENT (mA) 400 SUPPLY CURRENT vs. TEMPERATURE (LVPECL OUTPUTS, ALL LOADED) MAX3638 toc02 PLL NORMAL, ALL OUTPUTS LOADED 450 500 MAX3638 toc01 500 SUPPLY CURRENT vs. TEMPERATURE (LVDS OUTPUTS, ALL ENABLED) MAX3638 toc03 SUPPLY CURRENT vs. TEMPERATURE (LVPECL OUTPUTS, ALL ENABLED) SUPPLY CURRENT (mA) MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs 200mV/div 200mV/div ALL OUTPUTS DISABLED 50 0 -40 -15 10 35 60 85 300ps/div 600ps/div DIFFERENTIAL OUTPUT AT 125MHz (LVDS) QCC OUTPUT AT 66.67MHz (LVCMOS) TEMPERATURE (°C) DIFFERENTIAL OUTPUT AT 125MHz (LVPECL) MAX3638 toc07 200mV/div 100mV/div 1.2ns/div 6 MAX3638 toc08 MAX3638 toc09 500mV/div 1.2ns/div 2ns/div Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs DIFFERENTIAL OUTPUT SWING vs. TEMPERATURE LVDS 1000 500 LVCMOS 2000 LVPECL 1500 LVDS 1000 LVPECL 0 -40 1000 -15 OUTPUT FREQUENCY (MHz) -60 MAX3638 toc13 50.4 LVPECL/LVDS 50.2 50.0 49.8 49.6 -90 -100 -110 -120 -130 -140 -110 -120 -130 -140 -150 85 1k TEMPERATURE (°C) 100k 1M 10M 100M 1k -100 -110 -120 -130 -90 -100 -110 -120 -130 -90 -110 -120 -130 -150 -150 -150 -160 -160 -160 100k 1M 10M OUTPUT FREQUENCY (Hz) 100M 100M -100 -140 10k 10M -80 -140 1k 1M PHASE JITTER = 0.38psRMS INTEGRATED 12kHz TO 20MHz -70 PHASE NOISE (dBc/Hz) -90 100k PHASE NOISE AT 66.67MHz -60 MAX3638 toc17 -80 PHASE NOISE (dBc/Hz) -80 PHASE JITTER = 0.36psRMS INTEGRATED 12kHz TO 20MHz -70 10k OUTPUT FREQUENCY (Hz) PHASE NOISE AT 100MHz -60 MAX3638 toc16 PHASE JITTER = 0.33psRMS INTEGRATED 12kHz TO 20MHz -70 10k OUTPUT FREQUENCY (Hz) PHASE NOISE AT 125MHz -60 85 -90 -160 60 60 -100 -160 35 35 -80 49.0 10 10 PHASE JITTER = 0.28psRMS INTEGRATED 12kHz TO 20MHz -70 -150 -15 -15 PHASE NOISE AT 245.76MHz -60 49.2 -40 PHASE NOISE (dBc/Hz) -40 TEMPERATURE (°C) -80 LVCMOS 49.4 85 PHASE NOISE (dBc/Hz) 50.6 60 PHASE JITTER = 0.28psRMS INTEGRATED 12kHz TO 20MHz -70 PHASE NOISE (dBc/Hz) DUTY-CYCLE DISTORTION (%) 50.8 35 PHASE NOISE AT 491.52MHz DUTY-CYCLE DISTORTION vs. TEMPERATURE 51.0 10 TEMPERATURE (°C) MAX3638 toc14 100 10 LVDS 200 100 500 0 0 300 MAX3638 toc15 1500 2500 LVCMOS 400 MAX3638 toc18 LVPECL 2000 3000 RISE/FALL TIME (ps) LVCMOS 2500 500 MAX3638 toc11 3000 3500 DIFFERENTIAL OUTPUT SWING (mVP-P) MAX3638 toc10 DIFFERNETIAL OUTPUT SWING (mVP-P) 3500 RISE/FALL TIME vs. TEMPERATURE (20% TO 80%) MAX3638 toc12 DIFFERENTIAL OUTPUT SWING vs. OUTPUT FREQUENCY -140 1k 10k 100k 1M 10M OUTPUT FREQUENCY (Hz) 100M 1k 10k 100k 1M 10M 100M OUTPUT FREQUENCY (Hz) 7 MAX3638 Typical Operating Characteristics (continued) (VCC = 3.3V, TA = +25NC, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = 3.3V, TA = +25NC, unless otherwise noted.) INTEGRATED PHASE JITTER (12kHz TO 20MHz) vs. TEMPERATURE LVCMOS 0.40 0.35 0.30 LVPECL 0.25 0 -5 JITTER TRANSFER (dB) 0.50 -10 -15 -20 -25 -30 -35 -40 LVDS -45 0.20 -50 -40 -15 10 35 60 85 1k 10k 100k 1M 10M SPURS INDUCED BY POWER-SUPPLY NOISE vs. NOISE FREQUENCY DETERMINISTIC JITTER INDUCED BY POWERSUPPLY NOISE vs. NOISE FREQUENCY fC = 125MHz, NOISE = 50mVP-P -20 -30 LVCMOS -40 -50 LVDS -60 -70 40 fC = 125MHz, NOISE = 50mVP-P 35 DETERMINISTIC JITTER (psP-P) 0 MAX3638 toc22 JITTER FREQUENCY (Hz) MAX3638 toc21 TEMPERATURE (°C) -10 30 LVCMOS 25 20 15 10 LVPECL/LVDS 5 -80 LVPECL -90 10 100 NOISE FREQUENCY (kHz) 8 MAX3638 toc20 OUTPUT FREQUENCY = 125MHz 0.55 0.45 JITTER TRANSFER 5 MAX3638 toc19 INTEGRATED PHASE JITTER (psRMS) 0.60 SPUR AMPLITUDE (dBc) MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs 0 1000 10 100 NOISE FREQUENCY (kHz) 1000 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs PIN NAME MAX3638 Pin Description FUNCTION 1 DM LVCMOS/LVTTL Input. Three-level control for input divider M. See Table 3. 2 XIN Crystal Oscillator Input 3 XOUT 4 VCC Crystal Oscillator Output Core Power Supply. Connect to +3.3V. 5 IN_SEL LVCMOS/LVTTL Input. Three-level control for input mux. See Table 1. 6 PLL_BP LVCMOS/LVTTL Input. Three-level control for PLL bypass mode. See Table 2. 7, 8 DF1, DF0 LVCMOS/LVTTL Inputs. Three-level controls for feedback divider F. See Table 4. 9 QC_CTRL LVCMOS/LVTTL Input. Three-level control input for C-bank output interface. See Table 10. 10 VCCA Power Supply for Internal Voltage-Controlled Oscillators (VCOs). See Figure 3. 11 RES Reserved. Connect to GND for normal operation. 12 DP LVCMOS/LVTTL Input. Three-level control for prescale divider P. See Table 7. 13, 14 DB1, DB0 LVCMOS/LVTTL Inputs. Three-level controls for output divider B. See Table 5. 15, 16 DA1, DA0 LVCMOS/LVTTL Inputs. Three-level controls for output divider A. See Table 5. 17, 18 DC1, DC0 LVCMOS/LVTTL Inputs. Three-level controls for output divider C. See Table 6. 19 QA_CTRL2 LVCMOS/LVTTL Input. Three-level control for QA[4:3] output interface. See Table 8. 20 VCCQCC 21 QCC 22, 23 QC, QC VCCQC C-Bank Differential Output. Configured as LVPECL or LVDS with the QC_CTRL pin. 24 25, 36 VCCQA Power Supply for A-Bank Differential Outputs. Connect to +3.3V. 26, 27 QA4, QA4 A-Bank Differential Output. Configured as LVPECL or LVDS with the QA_CTRL2 pin. 28, 29 QA3, QA3 A-Bank Differential Output. Configured as LVPECL or LVDS with the QA_CTRL2 pin. 30, 31 QA2, QA2 A-Bank Differential Output. Configured as LVPECL or LVDS with the QA_CTRL1 pin. 32, 33 QA1, QA1 A-Bank Differential Output. Configured as LVPECL or LVDS with the QA_CTRL1 pin. 34, 35 A-Bank Differential Output. Configured as LVPECL or LVDS with the QA_CTRL1 pin. 37 QA0, QA0 VCCQB 38, 39 QB0, QB0 B-Bank Differential Output. Configured as LVPECL or LVDS with the QB_CTRL pin. 40, 41 QB1, QB1 B-Bank Differential Output. Configured as LVPECL or LVDS with the QB_CTRL pin. 42, 43 B-Bank Differential Output. Configured as LVPECL or LVDS with the QB_CTRL pin. 44 QB2, QB2 QA_CTRL1 45 QB_CTRL LVCMOS/LVTTL Input. Three-level control for B-bank output interface. See Table 9. 46, 47 DIN, DIN Differential Clock Input. Operates up to 350MHz. This input can accept DC-coupled LVPECL signals, and is internally biased to accept AC-coupled LVDS, CML, and LVPECL signals. 48 CIN LVCMOS Clock Input. Operates up to 160MHz. — EP Exposed Pad. Connect to supply ground for proper electrical and thermal performance. Power Supply for QCC Output. Connect to +3.3V. C-Bank LVCMOS Clock Output Power Supply for C-Bank Differential Output. Connect to +3.3V. Power Supply for B-Bank Differential Outputs. Connect to +3.3V. LVCMOS/LVTTL Input. Three-level control for QA[2:0] output interface. See Table 8. 9 MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs Detailed Description banks of clock outputs. See Figure 2. The output banks include nine pin-programmable LVDS/LVPECL output buffers and one LVCMOS output buffer. The frequency, enabling, and output interface of each output bank can be individually programmed. In addition the A-bank is split into two banks with programmable enabling and The MAX3638 is a low-jitter clock generator designed to operate over a wide range of frequencies. It consists of a selectable reference clock (on-chip crystal oscillator, LVCMOS input, or differential input), PLL with on-chip VCO, pin-programmable dividers and muxes, and three IN_SEL VCC DM DP VCCA DA[1:0] PLL_BP VCCQA QA_CTRL1 2 QA0 QA0 XOUT CRYSTAL OSCILLATOR QA1 1 0 XIN fREF LVCMOS CIN NC ÷ ÷M PFD VCO CP fVCO ÷P ÷A fQA QA1 QA2 0/NC QA2 fPFD 15MHz TO 42MHz 3830MHz TO 4025MHz QA3 QA3 LVPECL DIN DIN QA4 ÷F QA4 1 QA_CTRL2 VCCQB QB_CTRL QB0 MAX3638 QB0 QB1 1 ÷B fQB QB1 QB2 0/NC QB2 DIVIDER A: 2, 3, 4, 5, 6, 8, 10, 12, 15 DIVIDER B: 2, 3, 4, 5, 6, 8, 10, 12, 15 DIVIDER C: 3, 5, 6, 8, 10, 12, 15, 20, 30 DIVIDER F: 16, 20, 24, 25, 28, 30, 32, 40, 48 DIVIDER M: 1, 2, 4 DIVIDER P: 4, 5, 6 QC_CTRL QC 1/NC ÷C 2 EP Figure 2. Detailed Functional Diagram 10 DF[1:0] 2 DB[1:0] fQC QC 0 QCC 2 DC[1:0] VCCQC VCCQCC Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs Crystal Oscillator The on-chip crystal oscillator provides the low-frequency reference clock for the PLL. This oscillator requires an external crystal connected between XIN and XOUT. See the Crystal Selection and Layout section for more information. The XIN and XOUT pins can be left open if not used. LVCMOS Clock Input An LVCMOS-compatible clock source can be connected to CIN to serve as the PLL reference clock. The input is internally biased to allow AC- or DC-coupling (see the Applications Information section). It is designed to operate from 15MHz to 160MHz. No signal should be applied to CIN if not used. Differential Clock Input A differential clock source can be connected to DIN to serve as the PLL reference clock. This input operates from 15MHz to 350MHz and contains an internal 100ω differential termination. This input can accept DC-coupled LVPECL signals, and is internally biased to accept AC-coupled LVDS, CML, and LVPECL signals (see the Applications Information section). No signal should be applied to DIN if not used. Phase-Locked Loop (PLL) The PLL takes the signal from the crystal oscillator, LVCMOS clock input, or differential clock input and synthesizes a low-jitter, high-frequency clock. The PLL contains a phase-frequency detector (PFD), a charge pump (CP), and a low phase noise VCO with a wide 3.83GHz to 4.025GHz frequency range. The high-frequency VCO output is divided by prescale divider P and then is connected to the PFD input through a feedback divider. The PFD compares the reference frequency to the divided-down VCO output and generates a control signal that keeps the VCO locked to the reference clock. The high-frequency VCO/P output clock is sent to the output dividers. To minimize noise-induced jitter, the VCO supply (VCCA) is isolated from the core logic and output buffer supplies. Dividers and Muxes The dividers and muxes are set with three-level control inputs. Divider settings and routing information are given in Tables 1 to 7. See Table 11 for example divider configurations used in various applications. Table 1. PLL Input IN_SEL INPUT 0 Crystal Input. XO circuit is disabled when not selected. 1 Differential Input. No signal should be applied to DIN if not selected. NC LVCMOS Input. No signal should be applied to CIN if not selected. Table 2. PLL Bypass PLL_BP PLL OPERATION 0 PLL Enabled for Normal Operation. All outputs from the A, B, and C banks are derived from the VCO. 1 PLL Bypassed. Selected input passes directly to the outputs. The VCO is disabled to minimize power consumption and intermodulation spurs. Used for system testing or clock distribution. NC The outputs from A-bank and B-bank are derived from the VCO, but the C-bank outputs are directly driven from the input signal for purposes of daisy chaining. 11 MAX3638 output interface. A PLL bypass mode is also available for system testing or clock distribution. MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs Table 3. Input Divider M Table 7. Prescale Divider P DM M DIVIDER RATIO DP P DIVIDER RATIO 0 ÷1 0 ÷4 1 ÷2 1 ÷5 NC ÷4 NC ÷6 Note: When the on-chip XO is selected (IN_SEL = 0), the setting DM = 0 is required. Table 4. PLL Feedback Divider F QA_CTRL1 QA[2:0] OUTPUT 0 QA[2:0] = LVDS DF1 DF0 F DIVIDER RATIO 1 QA[2:0] = LVPECL 0 0 ÷25 NC QA[2:0] disabled to high impedance 0 1 ÷20 QA_CTRL2 QA[4:3] OUTPUT 1 0 ÷16 0 QA[4:3] = LVDS 1 1 ÷32 1 QA[4:3] = LVPECL NC QA[4:3] disabled to high impedance 1 NC ÷24 NC 1 ÷30 0 NC ÷40 NC 0 ÷48 NC NC ÷28 Table 5. Output Divider A, B DA1/DB1 DA0/DB0 A, B DIVIDER RATIO 0 0 ÷2 0 1 ÷3 1 0 ÷4 1 1 ÷5 1 NC ÷6 NC 1 ÷8 0 NC ÷10 NC 0 ÷12 NC NC ÷15 Table 6. Output Divider C 12 Table 8. A-Bank Output Interface DC1 DC0 C DIVIDER RATIO 0 0 ÷5 0 1 ÷6 1 0 ÷8 1 1 ÷10 1 NC ÷12 NC 1 ÷15 0 NC ÷20 NC 0 ÷30 NC NC ÷3 Table 9. B-Bank Output Interface QB_CTRL QB[2:0] OUTPUT 0 QB[2:0] = LVDS 1 QB[2:0] = LVPECL NC QB[2:0] disabled to high impedance Table 10. C-Bank Output Interface QC_CTRL QC AND QCC OUTPUT 0 QC = LVDS, QCC = LVCMOS 1 QC = LVPECL, QCC = LVCMOS NC QC and QCC disabled to high impedance LVDS/LVPECL Clock Outputs The differential clock outputs (QA[4:0], QB[2:0], QC) operate up to 800MHz and have a pin-programmable LVDS/LVPECL output interface. See Tables 8 to 10. When configured as LVDS, the buffers are designed to drive transmission lines with a 100ω differential termination. When configured as LVPECL, the buffers are designed to drive transmission lines terminated with 50ω to VCC - 2V. Unused output banks can be disabled to high impedance and unused outputs can be left open. LVCMOS Clock Output The LVCMOS clock output operates up to 160MHz and is designed to drive a single-ended high-impedance load. If unused, this output can be left open or the C-bank can be disabled to high impedance. Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs The prescale divider P is set by DP as given in Table 7. In addition, the reference clock frequency and input divider M must also be selected so the PFD compare frequency (fPFD) falls within the specified range of 15MHz to 42MHz. If applicable, the higher fPFD should be selected for optimal jitter performance. Applications Information Output Frequency Configuration The MAX3638 output frequencies (fQA, fQB, fQC) are functions of the reference frequency (fREF) and the pinprogrammable dividers (A, B, C, F, M). The relationships can be expressed as: f F fQA = REF × M A (1) f F fQB = REF × M B (2) f F fQC = REF × M C (3) The frequency ranges for the selected reference clocks are 18MHz to 33.5MHz for the crystal oscillator input, 15MHz to 160MHz for the LVCMOS input, and 15MHz to 350MHz for the differential input. The available dividers are given in Tables 3 to 6. For a given reference frequency fREF, the input divider M, the PLL feedback divider F, and VCO prescale divider P must be configured so the VCO frequency (fVCO) falls within the specified ranges. Invalid PLL configuration leads to VCO frequencies beyond the specified ranges and can result in loss of lock. An expression for the VCO frequency along with the specified ranges is given by: f fVCO = REF × F × P M (4) 3830MHz ≤ fVCO ≤ 4025MHz (5) f f fPFD = REF = VCO M P ×F (6) 15MHz ≤ fPFD ≤ 42MHz (7) Note that the reference clock frequency is not limited by the fPFD range when the PLL is in bypass mode. Example Frequency Configuration The following is an example of how to find divider ratios for a valid PLL configuration, given a requirement of input and output frequencies. 1) S elect input and output frequencies for system clocking. fREF = 25MHz fQA = 125MHz fQB = 100MHz fQC = 66.67MHz 2) F ind the input divider M for a valid PFD compare frequency. Using Table 3 and equations (6) and (7), it is determined that M = ÷1 is the only valid option. 3) F ind the feedback divider F and prescale divider P for a valid fVCO. Using Tables 4 and 7 along with equations (4) and (5), it is determined that F = ÷40 and P = ÷4 results in fVCO = 4000MHz, which is within the valid range of the VCO. 4) F ind the output dividers A, B, C for the required output frequencies. Using Tables 5 and 6 and equations (1), (2), and (3), it is determined that A = ÷8 gives fQA = 125MHz, B = ÷10 gives fQB = 100MHz, and C = ÷15 gives fQC = 66.67MHz. Table 11 provides input and output frequencies along with valid divider ratios for a variety of applications. 13 MAX3638 Internal Reset During power-on, a power-on reset (POR) signal is generated to synchronize all dividers. A reset signal is also generated if any control pin is changed. Outputs within a bank are phase aligned, but outputs bank-to-bank may not be phase aligned. MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs Table 11. Reference Frequencies and Divider Ratios for Various Applications fREF (MHz) INPUT DIVIDER (M) PLL FEEDBACK DIVIDER (F) VCO PRESCALE DIVIDER (P) OUTPUT DIVIDER (A, B, C) OUTPUT FREQUENCY (MHz) 30.72 1 32 4 2 491.52 61.44 2 32 4 4 245.76 122.88 4 32 4 8 122.88 33.3/66.7/ 133.3 1/2/4 24 5 2 400 5 3 266.67 5 4 200 5 6 133.333 5 8 100 5 12 66.67 VCO FREQUENCY (MHz) 3932.16 4000 25/50/100 1/2/4 32 33.3/66.7/ 133.3 1/2/4 30 4 2 500 25/50/100 1/2/4 40 4 3 333.33 4 4 250 4 5 200 4 6 166.67 4 8 125 4 10 100 4 15 66.67 4 20 50 4 30 33.33 5 6 131.04 5 12 65.52 6 2 333.257 6 4 166.6285 4000 31.25/ 62.5/125 32.76 20.82857 41.6571 1/2/4 1 1 32 24 32 16 3931.2 3999.084 APPLICATIONS Wireless Base Station: WCDMA, cdma2000®, LTE, TD_SCDMA Server, Network Processor, DDR/ QDR Memory, PCIe, SATA Server, FB-DIMM, Network Processor, DDR/ QDR Memory, PCIe, SATA Microwave Radio Link OTU1, 10Gbps SONET with FEC 10Gbps Ethernet with FEC 25.78125 1 25 3867.1875 6 4 161.132812 27.392578 1 24 3944.53125 6 4 164.355 10Gbps FC 20.916 1 32 6 2 334.66 41.8329 1 16 6 4 167.33 OTU2, 10Gbps SONET with Digital Wrapper 4015.95949 cdma2000 is a registered trademark of the Telecommunications Industry Association. 14 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs +3.3V ±5% VCC 0.1µF 10.5Ω MAX3638 VCCA 0.1µF 10µF Figure 3. Power-Supply Filter Ground Connection The 48-pin TQFN package features an exposed pad (EP), which provides a low resistance thermal path for heat removal from the IC and also the electrical ground. For proper operation, the EP must be connected to the circuit board ground plane with multiple vias. Crystal Selection and Layout The MAX3638 features an integrated on-chip crystal oscillator to minimize system implementation cost. The crystal oscillator is designed to drive a fundamental mode, AT-cut crystal resonator. See Table 12 for recommended crystal specifications. See Figure 4 for the crystal equivalent circuit and Figure 5 for the recommended external capacitor connections. The crystal, trace, and two external capacitors should be placed on the board as close as possible to the XIN and XOUT pins to reduce crosstalk of active signals into the oscillator. The total load capacitance for the crystal is a combination of external and on-chip capacitance. The layout shown in Figure 6 gives approximately 1.7pF of trace plus footprint capacitance per side of the crystal. Note the ground plane is removed under the crystal to minimize capacitance. There is approximately 2.5pF of on-chip capacitance between XIN and XOUT. With an external 27pF capacitor connected to XIN and a 33pF external capacitor connected to XOUT, the total load capacitance for the crystal is approximately 18pF. The XIN and XOUT pins can be left open if not used. Table 12. Crystal Selection Parameters PARAMETER Crystal Oscillation Frequency SYMBOL MIN fOSC 18 TYP MAX UNITS 25 33.5 MHz Shunt Capacitance C0 2.0 7.0 pF Load Capacitance CL 18 Equivalent Series Resistance (ESR) RS 10 pF Maximum Crystal Drive Level XTAL 50 I 200 FW 27pF XIN CRYSTAL (CL = 18pF) C0 RS LS Figure 4. Crystal Equivalent Circuit CS MAX3638 XOUT 33pF Figure 5. Crystal, Capacitor Connections 15 MAX3638 Power-Supply Filtering The MAX3638 is a mixed analog/digital IC. The PLL contains analog circuitry susceptible to random noise. To take full advantage of on-board filtering and noise attenuation, in addition to excellent on-chip power-supply rejection, this part provides a separate power-supply pin, VCCA, for the VCO circuitry. Figure 3 illustrates the recommended power-supply filter network for VCCA. 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. All supply connections should be driven from the same source. Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs MAX3638 Interfacing with LVCMOS Input The equivalent LVCMOS input circuit for CIN is given in Figure 7. This input is internally biased to allow AC- or DC-coupling, and has 180kI input impedance. See Figure 8 for the interface circuit. No signal should be applied to CIN if not used. Interfacing with Differential Input The equivalent input circuit for DIN is given in Figure 9. This input operates up to 350MHz and contains an internal 100I differential termination as well as a 35I common-mode termination. The common-mode termination ensures good signal integrity when connected to a source with large common-mode signals. The input can accept DC-coupled LVPECL signals, and is internally biased to accept AC-coupled LVDS, CML, and LVPECL signals (Figure 10). No signal should be applied to DIN if not used. Figure 6. Crystal Layout 1.4V VCC VBIAS VCC 180kΩ CIN VCC ESD STRUCTURES ESD STRUCTURES DIN Figure 7. Equivalent CIN Circuit 50Ω 20kΩ 10Ω VCC VCC - 1.3V 16pF 50Ω DC-COUPLED MAX3638 DIN CIN XO ESD STRUCTURES Figure 9. Equivalent DIN Circuit AC-COUPLED MAX3638 0.1µF XO Figure 8. Interface to CIN 16 CIN 20kΩ Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs MAX3638 150Ω +3.3V +3.3V DIN Z = 50Ω LVPECL 100Ω LVPECL DIN Z = 50Ω The equivalent LVPECL output circuit is given in Figure 11. These outputs are designed to drive a pair of 50ω transmission lines terminated with 50ω to VTT = VCC - 2V. If a separate termination voltage (VTT) is not available, other terminations methods can be used, as shown in Figure 12. For more information on LVPECL terminations and how to interface with other logic families, refer to Application Note 291: HFAN-01.0: Introduction to LVDS, PECL, and CML. 150Ω VCC_ _ LVPECL SOURCE DRIVING MAX3638 DIFFERENTIAL INPUT AC-COUPLED +3.3V MAX3638 150Ω 0.1µF Z = 50Ω LVPECL 0.1µF Z = 50Ω +3.3V DIN 100Ω Q_ _ LVPECL Q_ _ DIN 150Ω ESD STRUCTURES LVDS OR CML SOURCE DRIVING MAX3638 DIFFERENTIAL INPUT AC-COUPLED Figure 11. Equivalent LVPECL Output Circuit MAX3638 VDD 0.1µF Z = 50Ω LVDS OR CML 0.1µF Z = 50Ω +3.3V DIN 100Ω LVPECL DIN Figure 10. Interfacing to DIN 17 MAX3638 Interfacing with LVPECL Outputs LVPECL SOURCE DRIVING MAX3638 DIFFERENTIAL INPUT DC-COUPLED MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs DC-COUPLED LVPECL DRIVING THEVENIN EQUIVALENT TERMINATION +3.3V +3.3V +3.3V 130Ω MAX3638 Q_ _ +3.3V 130Ω HIGH IMPEDANCE WITH/WITHOUT DC BIAS Z = 50Ω LVPECL LVPECL Q_ _ Z = 50Ω 82Ω 82Ω AC-COUPLED LVPECL DRIVING INTERNAL 100Ω DIFFERENTIAL TERMINATION +3.3V VDD 150Ω MAX3638 Q_ _ ON-CHIP TERMINATION WITH DC BIAS 0.1µF Z = 50Ω LVPECL 100Ω 0.1µF Q_ _ LVPECL Z = 50Ω 150Ω AC-COUPLED LVPECL DRIVING EXTERNAL 50Ω WITH COMMON-MODE TERMINATION +3.3V VDD 150Ω MAX3638 Q_ _ 0.1µF HIGH IMPEDANCE WITH DC BIAS Z = 50Ω LVPECL LVPECL 0.1µF Q_ _ Z = 50Ω 150Ω 50Ω 0.1µF Figure 12. Interface to LVPECL Outputs 18 50Ω Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs Interfacing with LVDS Outputs VCC_ _ 50Ω Q_ _ The equivalent LVDS output circuit is given in Figure 13. These outputs provide 100ω differential output impedance designed to drive a 100ω differential transmission line terminated with a 100ω differential load. Example interface circuits are shown in Figure 14. For more information on LVDS terminations and how to interface with other logic families, refer to Application Note 291: HFAN01.0: Introduction to LVDS, PECL, and CML. 50Ω Q_ _ ESD STRUCTURES Interfacing with LVCMOS Output The equivalent LVCMOS output circuit is given in Figure 15. This output provides 15ω output impedance and is designed to drive a high-impedance load. A series resistor of 33ω is recommended at the LVCMOS output before the transmission line. An example interface circuit is shown in Figure 16. Figure 13. Equivalent LVDS Output Circuit VCCQCC DC-COUPLED LVDS OUTPUT DRIVING LVDS INPUT +3.3V +3.3V 10Ω MAX3638 Q_ _ Z = 50Ω LVDS QCC LVDS* Q_ _ 10Ω Z = 50Ω ESD STRUCTURES AC-COUPLED LVDS OUTPUT DRIVING LVDS INPUT +3.3V MAX3638 Figure 15. Equivalent LVCMOS Output Circuit VDD Q_ _ LVDS Q_ _ 0.1µF Z = 50Ω LVDS* 0.1µF LVCMOS QCC 33Ω Z = 50Ω HIGH IMPEDANCE Z = 50Ω MAX3638 *100Ω DIFFERENTIAL INPUT IMPEDANCE ASSUMED. Figure 16. Interface to LVCMOS Output Figure 14. Interface to LVDS Outputs 19 MAX3638 VREG Layout Considerations • T he crystal, trace, and two external capacitors should be placed on the board as close as possible to the XIN and XOUT pins to reduce crosstalk of active signals into the oscillator. The inputs and outputs are the most critical paths for the MAX3638; great care should be taken to minimize discontinuities on the transmission lines. Here are some suggestions for maximizing the performance of the MAX3638: • M aintain 100ω differential (or 50ω single-ended) transmission line impedance into and out of the part. • A n uninterrupted ground plane should be positioned beneath the clock outputs. The ground plane under the crystal should be removed to minimize capacitance. • P rovide space between differential output pairs to reduce crosstalk, especially if the outputs are operating at different frequencies. • U se multilayer boards with an uninterrupted ground plane to minimize EMI and crosstalk. • S upply decoupling capacitors should be placed close to the supply pins, preferably on the same side of the board as the MAX3638. Refer to the MAX3638 evaluation kit for more information. Chip Information • T ake care to isolate input traces from the MAX3638 outputs. PROCESS: BiCMOS QA0 QA1 QA1 QA2 QA2 QA3 QA3 QA4 QA4 VCCQA 36 QA0 TOP VIEW VCCQA Pin Configuration 35 34 33 32 31 30 29 28 27 26 25 VCCQB 37 24 VCCQC QB0 38 23 QC QB0 39 22 QC QB1 40 21 QCC QB1 41 20 VCCQCC QB2 42 19 QA_CTRL2 DC0 MAX3638 QB2 43 18 QA_CTRL1 44 17 DC1 QB_CTRL 45 16 DA0 DIN 46 15 DA1 14 DB0 13 DB1 4 5 6 7 8 9 10 11 12 DF1 DF0 QC_CTRL VCCA RES DP 3 PLL_BP 2 VCC 1 IN_SEL 48 XOUT 47 CIN XIN DIN *EP + DM MAX3638 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs THIN QFN (7mm × 7mm × 0.8mm) *THE EXPOSED PAD OF THE QFN PACKAGE MUST BE SOLDERED TO GROUND FOR PROPER THERMAL AND ELECTRICAL OPERATION. 20 Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs +3.3V 10.5Ω 10µF 0.1µF 0.1µF VCCA 27pF VCC 0.1µF VCCQA VCCQB XIN 0.1µF VCCQC 0.1µF 0.1µF VCCQCC 150Ω 125MHz LVPECL Z = 50Ω QA[4:0] 0.1µF 25MHz XOUT NC CIN NC DIN NC DIN 100Ω 0.1µF Z = 50Ω QA[4:0] 33pF ASIC WITH LVPECL TERMINATION 150Ω 100MHz LVDS Z = 50Ω IN_SEL MAX3638 PLL_BP QB[2:0] ASIC WITH LVDS TERMINATION 100Ω DM +3.3V NC DF0 NC DA1 Z = 50Ω QB[2:0] DF1 DA0 66.67MHz LVDS Z = 50Ω QC DB1 NC DB0 NC DC1 ASIC WITH LVDS TERMINATION 100Ω Z = 50Ω QC DC0 DP RES 33Ω QA_CTRL1 QCC QA_CTRL2 66.67MHz LVCMOS Z = 50Ω ASIC WITH LVCMOS TERMINATION HIGH IMPEDANCE QB_CTRL QC_CTRL EP 21 MAX3638 Typical Application Circuits Low-Jitter, Wide Frequency Range, Programmable Clock Generator with 10 Outputs MAX3638 Typical Application Circuits (continued) CLOCK GENERATOR FOR ETHERNET AND SYSTEM CLOCKING XIN QA[4:0] 312.5MHz LVPECL OR LVDS BACKPLANE TRANSCEIVER QB[2:0] 156.25MHz LVPECL OR LVDS 10GbE PHY 25MHz LVCMOS ASIC QA[4:0] 125MHz LVPECL OR LVDS 1GbE PHY QB[2:0] 100MHz LVPECL OR LVDS PCIe QC 66.67MHz LVPECL OR LVDS NETWORK PROCESSOR QCC 66.67MHz LVCMOS FPGA 25MHz XOUT QCC MAX3637 QC 25MHz LVPECL DIN MAX3638 FREQUENCY TRANSLATOR FOR BASE STATION 30.72MHz QA[4:0] 245.76MHz LVPECL OR LVDS ASIC QB[2:0] 122.88MHz LVPECL OR LVDS CPRI SerDes QC 30.72MHz LVPECL OR LVDS FPGA QCC 30.72MHz LVCMOS FPGA DIN MAX3638 Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 48 TQFN-EP T4877+4 21-0144 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. 22 © 2009 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.