CTSLV351SG

CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 FEATURES BLOCK DIAGRAM LVPECL Outputs Optimized for Very Low Phase Noise (-165dBc/Hz)  Up to 800MHz Bandwidth  Selectable ÷1, ÷2 Output  Selectable Enable Logic  3.0V to 3.6V Operation  RoHS Compliant Pb Free Packages  DESCRIPTION The CTSLV351 is a sine wave/CMOS to LVPECL buffer & translator optimized for very low phase noise (-165dBc/Hz). It is particularly useful in converting crystal or SAW based oscillators into LVPECL outputs for up 800MHz of bandwidth. The CTSLV351 is one of a family of parts that provide options of fixed ÷1, fixed ÷2 and selectable ÷1, ÷2 modes as well as active high enable or active low enable to oscillator designers. Refer to Table 1 for the comparison of parts within the CTSLV35x and CTSLV363 family. ENGINEERING NOTES Functionality Table 1 details the differences between the parts to assist designers in selecting the optimal part for their design. Table 2 lists the specific CTSLV351 functional operation. Figure 1 plots the S-parameters of the D input. Table 1 Part Number EN Pull-Up / Pull-Down Bandwidth active HIGH Pull-up > 800MHz selectable selectable > 800MHz selectable selectable ≥ 1GHz Divide Ratio EN Logic CTSLV351 ÷1 CTSLV353 Selectable ÷1 or ÷2 CTSLV363 Selectable ÷1 or ÷2 North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 1 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 Table 2 - CTSLV351 Functional Operation, ÷1 mode Inputs Part Number CTSLV351 EN_SEL High, NC Low Outputs D Q `Q Low Low High High High Low X Z Z Figure 1 - S11, Parameters, D Input North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 2 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 Input Termination The D input bias is VDD/2 fed through an internal 10k resistor. For clock applications, an input signal of at least 750mVPP ensures the CTSLV351 meets AC specifications. The input should also be AC coupled to maintain a 50% duty cycle on the outputs. The input can be driven to any voltage between 0V and VDD without damage or waveform degradation. Figure 2 - Input Termination Output Termination Techniques The LVPECL compatible output stage of the CTSLV351 uses a current drive topology to maximize switching speed as illustrated below in Figure 3. Two current source PMOS transistors (M1-M2) feed the output pins. M5 is an NMOS current source which is switched by M3 and M4. When M4 is on, M5 takes current from M2. This produces an output current of 5.1mA (low output state). M3 is off, and the entire 21.1mA flows through the output pin. The associated output voltage swings match LVPECL levels when external 50 resistors terminate the outputs. Both Q and Q ¯ should always be terminated identically to avoid waveform distortion and circulating current caused by unsymmetrical loads. This rule should be followed even if only one output is in use. VDD (+3.3 V) Output Stage Vbp External Circuitry M2 M1 21.1mA 21.1mA Q Q M4 M3 D Vbn M5 16mA 21.1mA - High 5.1mA - Low 50Ω 50Ω VTT = VDD - 2.0V Figure 3 - Typical Output Termination North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 3 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 Dual Supply LVPECL Output Termination The standard LVPECL loads are a pair of 50 resistors connected between the outputs and VDD-2.0V (Figure 3). The resistors provide both the DC and the AC loads, assuming 50 interconnect. If an additional supply is available within the application, a four resistor termination configuration is possible (Figure 4). Figure 4 - Dual Supply Output Termination Three Resistor Termination Another termination variant eliminates the need for the additional supply (Figure 5). Alternately three resistors and one capacitor accomplish the same termination and reduce power consumption. Figure 5 - Three Resistor Termination North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 4 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 Evaluation Board (EBP53) CTS’s evaluation board, EBP53, provides the most convenient way to test and prototype CTSLV351 series circuits. Built for the CTSLV353QG 1.5x1.0mm package, it is designed to support both dual and single supply operation. Dual supply operation (VDD=+2.0V, VSS=-1.3V) enables direct coupling to 50 time domain test equipment (Figure 6). Figure 6 - Split Supply LVPECL Output Termination AC Termination Clock applications or phase noise/frequency domain testing scenarios typically require AC coupling. Figure 7 below shows the AC coupling technique. The 200 resistors form the required DC loads, and the 50 resistors provide the AC termination. The parallel combination of the 200 and 50 resistors results in a net 40 AC load termination. In many cases this will work well. If necessary, the 50 resistors can be increased to about 56. Alternately, bias tees combined with current setting resistors will eliminate the lowered AC load impedance. The 50 resistors are typically connected to ground but can be connected to the bias level needed by the succeeding stage. Figure 7 - AC Termination North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 5 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 ELECTRICAL SPECIFICATIONS Absolute Maximum Ratings Absolute Maximum Ratings are those values beyond which device life may be impaired. Symbol Characteristic Rating Unit VDD Power Supply 0 to +5.5 V VI Input Voltage -0.5 to VDD + 0.5 V TA Operating Temperature Range -40 to +85 °C TSTG Storage Temperature Range -65 to +150 °C ESDHBM Human Body Model 2500 V ESDMM Machine Model 200 V ESDCDM Charged Device Model 2500 V DC Characteristics DC Characteristics (VDD = 3.0V to 3.6V unless otherwise specified, TA = -40°C to +85°C) Symbol Characteristic Conditions -40°C VOH VOL Output HIGH Voltage Output LOW Voltage Min Typ Max 2.05 2.415 2.05 2.48 +85°C 2.05 2.54 -40°C 1.365 1.615 1.43 1.68 1.49 1.74 10 +25°C +25°C VDD = 3.3V VDD = 3.3V +85°C Unit V V IZ Output Leakage Current, Tri-state EN=Disable -10 VIH High Level Input Voltage EN 2 VIL Low Level Input Voltage EN IPD Pull-down Current EN -2.2 μA RBIAS Bias Resistor D Input to Internal VDD/2 Reference 10k Ω IDD Power Supply Current IDDZ V 0.8 22 Power Supply Current D Input ≤ VIL Outputs Tri-state EN=Disable μA V 35 mA 8 mA North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 6 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 AC Characteristics AC Characteristics (VDD = 3.0V to 3.6V, TA = -40°C to +85°C) AC Specifications guaranteed by design Symbol tR / tF Characteristic Output Rise/Fall Min Typ Max Unit 250 ps 1, 2 (20% - 80%) 80 fMAX Maximum Input Frequency - Sine wave2 800 MHz VINMAX Maximum Recommended Input Signal VDD VPP VINMIN Minimum Recommended Input Signal 0.2 tPLH Propagation Delay 938 1614 ps tPHL Propagation Delay RMS Jitter: 12kHz - 20MHz, 155MHz Center Freq Phase Noise1, 2 - 1MHz offset 938 1614 ps jRMS nP VPP 36 fs -165 dBc/Hz North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 7 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 Pin Description and Configuration Pin Assignments Pin Name Type Function 1 VDD Power Positive Supply 2 GND Power Negative Supply 3 D Input Sine or CMOS Input 4 EN Input Enable 5 Q Input Sine or CMOS Input 6 Q Output LVPECL Output VDD 1 6 Q GND 2 5 Q D 3 4 EN PART ORDERING INFORMATION Part Number Package Marking CTSLV351SG SC70-6 D1 YW North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 8 Rev B0215 CTSLV351 Low Phase Noise LVPECL Buffer & Translator SC70-6 PACKAGE DIMENSIONS North Americas: +1-800-757-6686 • International: +1-508-435-6831 • Asia: +65-655-17551 • www.ctscorp.com/semiconductors Specifications are subject to change without notice. 9 Rev B0215