19-1913; Rev 0; 1/01 L MANUA ION KIT HEET T A U L EVA TA S WS DA FOLLO 2.4GHz Monolithic Voltage-Controlled Oscillator with Differential Outputs The MAX2753 is a self-contained voltage-controlled oscillator (VCO) intended for use in 2.4GHz radios that utilize a low-IF or zero-IF architecture. It combines a fully integrated oscillator and output buffer in a miniature 8-pin µMAX package. The inductor and varactor elements of the tank are integrated on-chip, greatly simplifying application of the part. The only required external components are a couple of supply bypass capacitors. The MAX2753 provides direct connection to the VCO tuning voltage input and the VCO buffer output. The tuning voltage input range is +0.4V to +2.4V, and the oscillator frequency tuning range is factory adjusted to provide guaranteed limits. The output signal is buffered by an amplifier stage (internally matched to 50Ω) to provide higher output power and isolate the device from load impedance variations. In addition, the MAX2753 provides differential outputs. The MAX2753 operates over a +2.7V to +5.5V supply voltage range. Internal regulation of the oscillator supply voltage eliminates the need for an external LDO regulator for the VCO. The MAX2753 also provides a digitally controlled shutdown mode to permit implementation of sophisticated power-supply management. In shutdown, the supply current is reduced to less than 1µA. Features ♦ Guaranteed Frequency Tuning Range: 2400MHz to 2500MHz ♦ Compatible with Low-IF or Zero-IF Radio Architectures ♦ Differential Outputs ♦ On-Chip Tank Circuit ♦ Internally Matched Output Buffer Amplifier ♦ 1µA Shutdown Mode ♦ +2.7V to +5.5V Supply Voltage Range ♦ Miniature 8-Pin µMAX Package Ordering Information PART MAX2753EUA TEMP. RANGE PIN-PACKAGE -40°C to +85°C 8 µMAX Pin Configuration TOP VIEW BYP 1 8 GND 7 OUTN 3 6 VCC SHDN 4 5 OUTP TUNE 2 MAX2753 ________________________Applications GND 802.11 FHSS WLAN Home RF 2.4GHz Bluetooth ISM Proprietary Radio µMAX Typical Operating Circuit BYP GND TUNE TUNE OSCILLATOR CORE OUT TO MIXER/ SYNTHESIZER OUTN GND VCC VCC MAX2753 SHDN SHDN OUTP BIAS OUT TO MIXER/ SYNTHESIZER ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX2753 General Description MAX2753 2.4GHz Monolithic Voltage-Controlled Oscillator with Differential Outputs ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V TUNE, SHDN, BYP, OUTP, OUTN to GND .................................-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70°C) 8-Pin µMAX (derate 5.7mW/°C above TA = +70°C).....457mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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. DC ELECTRICAL CHARACTERISTICS (VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN ≥ +2V, OUTP = OUTN = connected to 50Ω load, TA = -40°C to +85°C. Typical values are at VCC = +3.0V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS Supply Voltage Supply Current Shutdown Supply Current MIN TYP 2.7 TA = +25oC 8.6 TA = -40oC to +85oC MAX UNITS 5.5 V 13.0 13.5 V SHDN ≤ 0.6V 0.2 SHDN Input Voltage Low SHDN Input Voltage High mA 1 µA 0.6 V 2.0 V SHDN Input Current Low V SHDN ≤ 0.6V -1 1 µA SHDN Input Current High V SHDN ≥ 2.0V -2 2 µA TUNE Input Current 0.4V ≤ V TUNE ≤ 2.4V 0.02 nA AC ELECTRICAL CHARACTERISTICS (MAX2753 EV kit, VCC = +2.7V to +5.5V, VTUNE = +0.4V to +2.4V, V SHDN ≥ +2V, OUTP = OUTN = connected to 50Ω load, TA = +25°C. Typical values are at VCC = +3.0V, unless otherwise noted.) PARAMETER Oscillator Guaranteed Frequency Limits (Note1) CONDITIONS V TUNE = +0.4V to +2.4V, TA = -40oC to +85oC MIN TYP 2400 MAX UNITS 2500 MHz fOFFSET = 4MHz -130 dBc/Hz Noise floor -153 dBm/Hz fOSC = 2400MHz 150 fOSC = 2500MHz 110 -8 dBm Pins OUTP or OUTN 11 dB Harmonics Differential output -26 dBc Load Pulling VSWR = 2:1, all phases, pins OUTP or OUTN 3.4 MHzp-p Supply Pushing VCC stepped: +3.3V to +2.8V 1.1 MHz/V Oscillator Turn-On Time (Note 3) Exiting shutdown 10 µs Oscillator Turn-Off Time (Note 4) Entering shutdown 8 µs Phase Noise Tuning Gain (Note 2) Differential Output Power Return Loss Note 1: Note 2: Note 3: Note 4: 2 MHz/V Specifications are production tested at TA = +25°C. Limits over temperature are guaranteed by design and characterization. Tuning gain is measured at the oscillator’s guaranteed frequency limits. Turn-on time to within 3dB of final output power Turn-off time to output power of -15dBm. _______________________________________________________________________________________ 2.4GHz Monolithic Voltage-Controlled Oscillator with Differential Outputs 10 9 8 7 6 0.3 0.2 TA = -40°C 2600 0.1 MAX2753 toc03 0.4 FREQUENCY (MHz) 11 2700 MAX2753 toc02 MAX2753 toc01 0.5 TUNE INPUT CURRENT (nA) SUPPLY CURRENT (mA) 12 VCO TUNING CURVE TUNING CURRENT vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE 13 TA = +25°C 2500 2400 TA = +85°C 2300 2200 5 2100 0 4 -20 0 20 40 60 -40 80 -20 0 TEMPERATURE (°C) 40 60 0.0 80 0.5 -5.5 -90 -100 -110 -120 -130 3.0 OUTPUT POWER vs. TEMPERATURE OUTPUT POWER (dBm) -6.0 OUTPUT POWER (dBm) -80 2.5 -6.0 MAX2753 toc05 -5.0 MAX2753 toc04 -70 2.0 VTUNE (V) OUTPUT POWER vs. FREQUENCY PHASE NOISE 1.5 1.0 TEMPERATURE (°C) -60 -6.5 -7.0 -7.5 -8.0 -8.5 -7.0 -8.0 -9.0 -9.0 -140 -9.5 -150 -10.0 1 10 -10.0 2400 2420 OFFSET FREQUENCY (MHz) 2460 2480 2ƒO FREQUENCY -20 OUTPUT POWER (dBm) -30 -40 -50 -60 -70 3ƒO 60 80 8µs MAX2753 toc09 -20 40 0 MAX2753 toc08 MAX2753 toc09 ∆ = 27dBc -10 20 OSCILLATOR TURN-OFF TIME OSCILLATOR TURN-ON TIME 0 0 TEMPERATURE (°C) -10 -20 -30 -40 -50 -60 -70 7µs -80 -80 ƒO -40 2500 FREQUENCY (MHz) NORMALIZED HARMONIC OUTPUT SPECTRUM ∆ = 30dBc 2440 OUTPUT POWER (dBm) 0.1 OUTPUT POWER (dBm) PHASE NOISE (dBc/Hz) 20 MAX2753 toc06 -40 -90 -90 -100 -100 0 2 4 6 8 10 12 14 16 18 20 TIME (µs) 0 2 4 6 8 10 12 14 16 18 20 TIME (µs) _______________________________________________________________________________________ 3 MAX2753 Typical Operating Characteristics (MAX2753 EV kit, VCC = +3.0V, VTUNE = +0.4V to +2.4V, V SHDN ≥ +2V, TA = +25°C, unless otherwise noted.) 2.4GHz Monolithic Voltage-Controlled Oscillator with Differential Outputs MAX2753 Pin Description PIN NAME FUNCTION 1 BYP 2 TUNE Oscillator Frequency Tuning Voltage Input. High-impedance input with a voltage input range of +0.4V (low frequency) to +2.4V (high frequency). 3 GND Ground Connection for Oscillator and Biasing. Requires a low-inductance connection to the circuit board ground plane. 4 SHDN Shutdown Logic Input. A high-impedance input logic level low disables the device and reduces supply current to less than 1.0µA. A logic level high enables the device. 5 OUTP Positive Buffered Oscillator Output. Incorporates an internal DC blocking capacitor. OUTP is internally matched to 50Ω. 6 VCC 7 OUTN Negative Buffered Oscillator Output. Incorporates an internal DC blocking capacitor. OUTN is internally matched to 50Ω. 8 GND Ground Connection for Output Buffer. Requires a low-inductance connection to the circuit board ground plane. VCO Bypass. Bypass with a 0.1µF capacitor to GND. DC Supply Voltage Connection. Bypass with a 220pF capacitor to GND for best high frequency performance. Detailed Description Applications Information Oscillator Tune Input The MAX2753 VCO is implemented as an LC oscillator topology, integrating all of the tank components onchip. This fully monolithic approach provides an extremely easy-to-use VCO, equivalent to a VCO module. The frequency is controlled by a voltage applied to the TUNE pin, which is internally connected to the varactor. The VCO core uses a differential topology to provide a stable frequency versus supply voltage and improve the immunity to load variations. In addition, there is a differential buffer amplifier following the oscillator core to provide added isolation from load variations and to boost the output power. The tuning input is typically connected to the output of the PLL loop filter. The loop filter provides an appropriately low-impedance source. The input may incorporate an extra RC filter stage to reduce high-frequency noise and spurious signals. Any excess noise on the tuning input is directly translated into FM noise, which can degrade the phase-noise performance of the oscillator. Therefore, it is important to minimize the noise introduced on the tuning input. A simple RC filter with low corner frequency is needed during testing to filter the noise present on the voltage source driving the tuning line. Output Buffer Layout Issues The oscillator signal from the core drives a differential output buffer amplifier. Each of the two amplifier outputs is internally matched to 50Ω including an on-chip DC-blocking capacitor. No external DC-blocking capacitor is required, eliminating the need for any external components. The amplifier boosts the oscillator signal to a level suitable for driving most RF mixers. Always use controlled impedance lines (microstrip, coplanar waveguide, etc.) for high-frequency signals. Always place decoupling capacitors as close to the VCC pins as possible; for long VCC lines, it may be necessary to add additional decoupling capacitors located further from the device. Always provide a low-inductance path to ground, and keep GND vias as close to the device as possible. Thermal reliefs on GND pads are not recommended. 4 _______________________________________________________________________________________ 2.4GHz Monolithic Voltage-Controlled Oscillator with Differential Outputs MAX2753 BYP GND 0.1µF FROM SYNTHESIZER TUNE OSCILLATOR CORE OUTN OUT TO MIXER/ SYNTHESIZER LOOP FILTER GND VCC MAX2753 SHDN SHDN VCC 220pF OUTP BIAS OUT TO MIXER/ SYNTHESIZER Figure 1. Typical Application Circuit Chip Information TRANSISTOR COUNT: 176 PROCESS: BiPOLAR _______________________________________________________________________________________ 5 2.4GHz Monolithic Voltage-Controlled Oscillator with Differential Outputs 8LUMAXD.EPS MAX2753 Package Information 6 _______________________________________________________________________________________