19-2389; Rev 1; 8/03 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer Features ♦ Single Voltage Supply (2.7V to 3.6V) The device typically achieves 34dBc of carrier and sideband suppression at a -1dBm output level. The wideband, internally matched RF output can also be disabled while the synthesizer and 3-wire bus remain powered up for continuous programming. ♦ 34dBc Typical Sideband Suppression The device consumes 72mA from a single +3.0V supply and is packaged in an ultra-compact 28-pin QFN package (5mm ✕ 5mm) with an exposed pad. Applications Wireless Broadband ♦ 75MHz 3dB I/Q Input Bandwidth ♦ Wideband 50Ω RF Output: 700MHz to 2300MHz ♦ Ultra-Fine Frequency Resolution: 100mHz ♦ High Reference Frequency for Fast-Switching Applications ♦ Ultra-Low Phase Noise ♦ Low Spurious and Reference Emissions ♦ -1dBm RMS Output Power ♦ 60dB RF Muting Control ♦ 34dBc Typical Carrier Suppression ♦ Software- and Hardware-Controlled Shutdown Modes Ordering Information PART MAX2150ETI TEMP RANGE PIN-PACKAGE -40°C to +85°C 28 Thin QFN-EP* *EP = exposed pad. Satellite Uplink Pin Configuration/ Functional Diagram LMDS Wireless Base Station VCC_RF I+ I- Q+ Q- 28 27 26 25 24 BUFEN BUFOUT 23 22 TXEN 1 21 LO+ VCC_PA 2 20 LO- RFOUT 3 N.C. 4 N.C. 5 LOCK 6 VCC_SD 7 0 19 VCC_LO 90 18 VCC_D 1/N MAX2150 ∑ ∆ – MOD PFD 17 VCC_A CHP 16 CHP 1/R PROGRAMMING AND CONTROL 15 VCC_CHP 8 9 10 11 CLK DATA EN SHDN 12 13 14 SYNEN OSCIN VCC_XTAL QFN ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX2150 General Description The MAX2150 is a complete wideband direct upconversion quadrature modulator IC incorporating a 28-bit sigma-delta fractional-N synthesizer. The device is targeted for applications in the 700MHz to 2300MHz frequency range. The super-high-resolution sigma-delta fractional-N synthesizer is capable of better than 50mHz resolution when used with a 10MHz reference. Other features: fully differential I/Q modulation inputs, an internal LO buffer, and a 50Ω wideband output driver amplifier. A standard 3-wire interface is provided for synthesizer programming and overall device configuration. An onchip low-noise crystal oscillator amplifier is also included and can be configured as a buffer when an external reference oscillator is used. MAX2150 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V RF Signals: LO+, LO-, OSCIN ........................................+10dBm I+ to I-, Q+ to Q-.......................................................................2V LO+, LO-, I+, I-, Q+, Q-, BUFEN, TXEN, CLK, DATA, EN, SYNEN, OSCIN, OSCOUT, BUFOUT, CHP, SHDN, LOCK, VCC_CP to GND..............-0.3V to (VCC + 0.3V) Digital Input Current .........................................................±10mA Short-Circuit Duration RFOUT, BUFOUT, OSCOUT, Lock, CHP...........................................................................10s Continuous Power Dissipation 28-Pin QFN (TA = +70°C)....................................................2W (derate 28.5mW/°C above +70°C) Operating Temperature Range ...........................-40°C to +85°C Junction Temperature Range ..........................................+150°C Storage Temperature.........................................-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. CAUTION! ESD SENSITIVE DEVICE DC ELECTRICAL CHARACTERISTICS (MAX2150 EV kit. VCC = +2.7V to +3.6V, GND = 0V, SHDN = PLLEN = TXEN = high, BUFEN= low. No AC input signals. RFOUT and BUFOUT output ports are terminated in 50Ω. TA = -40°C to +85°C. Typical values are at VCC = +3V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 2.7 V SUPPLY Supply Voltage Supply Current LO Buffer Supply Current Shutdown Supply Current 3 3.6 TX mode, SHDN = PLLEN = TXEN = high BUFEN = low 72 107 SYNTH mode, SHDN = PLLEN = high, TXEN = BUFEN = low 25 38 MOD mode, SHDN = TXEN = high, SYNEN = BUFEN = low 46 69 Additional current in all modes for BUFEN = high 3.3 5.5 HW_SHDN mode, SHDN = low 0.3 10 SW_SHDN mode, PWDN bit at logic low 35 60 mA mA µA CONTROL INPUT/OUTPUTS (SHDN, TXEN, SYNEN, BUFEN) Input Logic High 2 V Input Logic Low Input Logic High Current 0.5 V 1 µA Input Logic Low Current -1 µA Lock Detect High (Locked) 2 V Lock Detect Low (Unlocked) 0.5 V Power-Up Time MOD mode 25 µs Power-Down Time MOD mode 1 µs 3-WIRE CONTROL INPUT (CLK, DATA, EN) Input Logic High VCC 0.5 Input Logic Low Input Logic High Current Input Logic Low Current 2 -1 _______________________________________________________________________________________ V 0.5 V 1 µA µA Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer (MAX2150 EV kit. VCC = +2.7V to +3.6V, SHDN = PLLEN = TXEN = high, BUFEN =low. Input I/Q signals: FI/Q = 500kHz, VI/Q = 1VP-P. I+, Q+ single-ended input, driven from AC-coupled source. I-, Q- single-ended inputs are AC-coupled to GND. RFOUT and BUFOUT output ports are terminated in 50Ω loads. fLO =1750MHz, PLO = -10dBm, typical values are at VCC = +3V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS MODULATION INPUT I/Q Input Bandwidth I/Q Differential Input Level BW (-1dB) 26 BW (-3dB) 75 Assumes a sine-wave input to achieve the RFOUT output power specified below 1 VP-P 200 kΩ I/Q DC Input Resistance I/Q Common-Mode Input Range (Note 2) 1.5 1.6 MHz 1.7 V 2300 MHz RF OUTPUT Frequency Range 700 TXEN = high, fRF = 1750MHz Output Power -7 TXEN = low, fRF = 1750MHz Output 1dB Compression Point Output IP3 Carrier Suppression fRF = 1750MHz Sideband Suppression fLO - fI/Q, fRF = 1750MHz RF Output Noise Floor fOFFSET > 40MHz (Note 2) Output Return Loss (Note 3) -1 dBm -60 25 1 dBm 14 dBm 34 dBc 34 dBc -148 -143 -9 dBm/Hz dB LO INPUT/OUTPUT Frequency Range 700 LO Input Power (Note 2) LO Input Return Loss fLO =2000MHz LO Buffer Output Level BUFEN = high (Note 2) 2300 MHz -7 dBm -12 -10 -15 dB -14 -9.5 dBm SIGMA-DELTA FRACTIONAL-N SYNTHESIZER SYSTEM REQUIREMENTS Frequency Range (Note 2) Phase-Detector Input-Referred Phase Noise Floor fCOMP = fREF = 20MHz, CP0 = CP1 = CPX = 1 (Note 4) -138 dBc/Hz In-Loop Spurious Emissions fLO = 1740.005MHz, fCOMP = fREF = 20MHz, CP0 = CP1 = CPX = 1 (Note 5) -40 dBc 700 2300 MHz MAIN DIVIDER AND PHASE DETECTOR Minimum Fractional-N Step Size fCOMP/ 228 Phase-Detector Comparison Frequency 20 Maximum N Division 251 Minimum N Division 35 30 MHz _______________________________________________________________________________________ 3 MAX2150 AC ELECTRICAL CHARACTERISTICS MAX2150 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer AC ELECTRICAL CHARACTERISTICS (continued) (MAX2150 EV kit. VCC = +2.7V to +3.6V, SHDN = PLLEN = TXEN = high, BUFEN = low. Input I/Q signals: FI/Q = 500kHz, VI/Q = 1VP-P. I+, Q+ single-ended input, driven from AC-coupled source. I-, Q- single-ended inputs are AC-coupled to GND. RFOUT and BUFOUT output ports are terminated in 50Ω loads. fLO =1750MHz, PLO = -10dBm, typical values are at VCC = +3V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS REFERENCE OSCILLATOR AND DIVIDER Input Frequency Range AC-Coupled Input Sensitivity AC-coupled, single ended (Note 2) Reference Division Ratio (Notes 2, 6) 10 50 MHz 0.4 2.3 VP-P 1 4 CHARGE-PUMP OUTPUT CP1, CP0 = 00 CP1, CP0 = 01 Charge-Pump Current (Note 7) CP1, CP0 = 10 CP1, CP0 = 11 Charge-Pump Voltage Compliance Sink/source currents match within ±5% CPX = 0 0.14 0.17 0.20 CPX = 1 0.23 0.34 0.40 CPX = 0 0.23 0.35 0.42 CPX = 1 0.50 0.67 0.79 CPX = 0 0.40 0.52 0.64 CPX = 1 0.75 1.00 1.20 CPX = 0 0.50 0.69 0.83 CPX = 1 1.05 1.31 1.65 0.5 VCC 0.5 mA V Note 1: Parameters are guaranteed by production testing at +25°C and +85°C. Minimum and maximum values over the temperature and supply voltage range are guaranteed by design and characterization. Note 2: Guaranteed by design and characterization. Note 3: Measured with MAX2150 EV kit. Note 4: Measured with an on-chip crystal oscillator. Note 5: In-loop spurious emissions occur when synthesizing a frequency at an integer multiple of the comparison frequency with fractional offset within the PLL loop BW. Note 6: If an on-chip oscillator is used, a fundamental tone crystal is needed. Note 7: Minimum and maximum values at CPX = 1 are guaranteed by production testing. Values at CPX = 0 are guaranteed by design and characterization. 4 _______________________________________________________________________________________ Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer 60 -40°C 40 20 +85°C -4 +25°C -6 -8 -10 -12 3.0 2.7 3.3 3.6 1100 1500 1900 OUTPUT POWER vs. LO POWER CARRIER AND SIDEBAND SUPPRESSIONS vs. LO POWER MAX2150 toc04 -1.2 -1.3 -1.4 -1.5 -1.6 -1.7 -1.8 -1.9 CARRIER AND SIDEBAND SUPPRESSIONS (dB) FREQUENCY (MHz) -1.1 7 8 9 10 LO POWER (dBm) 11 12 -58 -40°C -61 +25°C -64 +85°C -67 2300 1100 700 1500 1900 2300 FREQUENCY (MHz) 38 MODULATOR OUTPUT POWER vs. I/Q INPUT LEVEL 37 36 SIDEBAND SUPPRESSION 35 34 CARRIER SUPPRESSION 33 32 -2.0 TXEN = LOW -70 700 SUPPLY VOLTAGE (V) -1.0 OUTPUT POWER (dBm) -2 4 MODULATOR OUTPUT POWER (dBm) 0 -40°C 0 -55 MAX2150 toc06 +25°C MAX2150 toc05 SUPPLY CURRENT (mA) 80 TXEN = HIGH 2 MODULATION OUTPUT POWER (dBm) +85°C 4 MODULATION OUTPUT POWER vs. FREQUENCY MAX2150 toc02 TX MODE MODULATION OUTPUT POWER (dBm) MAX2150 toc01 100 MODULATION OUTPUT POWER vs. FREQUENCY MAX2150 toc03 SUPPLY CURRENT vs. SUPPLY VOLTAGE 0 -40°C -4 +25°C -8 -12 +85°C -16 -20 -24 7 8 9 10 LO POWER (dBm) 11 12 0 200 400 600 800 1000 1200 1400 I/Q INPUT LEVEL (mV) _______________________________________________________________________________________ 5 MAX2150 Typical Operating Characteristics (MAX2150 EV kit. VCC = +3V, SHDN = PLLEN = TXEN = high, BUFEN = low. Input I/Q signals: FI/Q = 500kHz, VI/Q = 1VP-P. I+, Q+ single-ended input, driven from AC-coupled source. I-, Q- single-ended inputs are AC-coupled to GND. RFOUT and BUFOUT output ports are terminated in 50Ω loads. fLO =1750MHz, PLO = -10dBm, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (MAX2150 EV kit. VCC = +3V, SHDN = PLLEN = TXEN = high, BUFEN = low. Input I/Q signals: FI/Q = 500kHz, VI/Q = 1VP-P. I+, Q+ single-ended input, driven from AC-coupled source. I-, Q- single-ended inputs are AC-coupled to GND. RFOUT and BUFOUT output ports are terminated in 50Ω loads. fLO =1750MHz, PLO = -10dBm, TA = +25°C, unless otherwise noted.) MODULATOR OUTPUT IP3 vs. VCC +25°C 13 12 -40°C 11 +25°C 1.5 1.0 0.5 0 3.0 3.6 3.3 -5 -10 -15 -20 -25 -40°C -30 -1.0 2.7 MAX2150 toc09 +85°C 2.0 -0.5 10 MAX2150 toc08 2.5 0 LO PORT RETURN LOSS (dB) 14 3.0 MODULATOR OUTPUT P1dB (dBm) +85°C 15 LO PORT INPUT RETURN LOSS vs. FREQUENCY MODULATOR OUTPUT P1dB vs. VCC MAX2150 toc07 3.0 2.7 3.3 700 3.6 1100 1500 1900 VCC (V) VCC (V) FREQUENCY (MHz) BUFOUT PORT RETURN LOSS vs. FREQUENCY LO BUFFER OUTPUT POWER vs. FREQUENCY LO BUFFER OUTPUT POWER vs. FREQUENCY -10 -15 -20 -25 -6 +85°C -7 -8 +25°C -9 -10 -40°C -11 -12 -40 2300 MAX2150 toc12 BUFEN = HIGH -5 BUFEN = LOW LO BUFFER OUTPUT POWER (dBm) -5 -4 LO BUFFER OUTPUT POWER (dBm) MAX2150 toc10 0 MAX2150 toc11 MODULATOR OUTPUT IP3 (dBm) 16 BUFOUT PORT RETURN LOSS (dB) MAX2150 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer -43 -46 +25°C +85°C -49 -52 -40°C -13 -14 -30 700 1100 1500 FREQUENCY (MHz) 6 1900 2300 -55 700 1100 1500 FREQUENCY (MHz) 1900 2300 700 1100 1500 FREQUENCY (MHz) _______________________________________________________________________________________ 1900 2300 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer OSCIN PORT SENSITIVITY (SYNTHESIZER) vs. FREQUENCY OSCIN IMPEDANCE vs. FREQUENCY 0.60 0 REAL 0.50 4 +25°C 0.40 +85°C 0.30 3 +25°C 0.20 2 +85°C 0.10 1 0 15 -200 -300 IMAGINARY -400 -500 -600 -700 -800 -900 -40°C 0 10 OSCIN PORT IMPEDANCE (Ω) -40°C 20 25 30 35 40 45 -1000 50 10 15 FREQUENCY (MHz) SYNTHESIZER PHASE NOISE 0 -10 -8.5dBm -20 30 35 40 45 50 I/Q MODULATOR OUTPUT SPURS -20 -30 -40 -50 -50 N/C = -99dBc/Hz 1 AVG CARRIER SUPPRESSION -34dBc SIDEBAND SUPPRESSION -36dBc -60 -70 -70 -80 -80 -90 -90 -100 -100 SPAN = 20kHz MAX2150 toc16 -10 -40 CENTER = 1.75MHz 25 0 -30 -60 20 FREQUENCY (MHz) MAX2150 toc15 OSCIN PORT SENSITIVITY (V) -100 5 MAX2150 toc14 MAX2150 toc13 6 CENTER = 1.75 GHz SPAN = 2 MHz _______________________________________________________________________________________ 7 MAX2150 Typical Operating Characteristics (continued) (MAX2150 EV kit. VCC = +3V, SHDN = PLLEN = TXEN = high, BUFEN = low. Input I/Q signals: FI/Q = 500kHz, VI/Q = 1VP-P. I+, Q+ single-ended input, driven from AC-coupled source. I-, Q- single-ended inputs are AC-coupled to GND. RFOUT and BUFOUT output ports are terminated in 50Ω loads. fLO =1750MHz, PLO = -10dBm, TA = +25°C, unless otherwise noted.) Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer MAX2150 Pin Description 8 PIN NAME FUNCTION 1 TXEN 2 VCC_PA Supply Voltage Input for RFOUT Output Driver Circuits. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 3 RFOUT Modulator RF Output. This is a wideband, internally matched 50Ω output. A DC-blocking capacitor is required. 4, 5 N.C. 6 LOCK Modulator Enable Input. Set TXEN low to inhibit the RF and modulator circuits. This mode can be used for quiet frequency synthesis. Do Not Connect. (These pins must be left floating.) Lock Status of the PLL. A static logic-level high indicates that the PLL is in the locked condition. 7 VCC_SD Supply Voltage Input for Sigma-Delta Modulator Circuits. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 8, 9, 10 CLK, DATA, EN Input Pins from 3-Wire Serial Bus. An RC lowpass filter on each of these pins can be used to reduce digital noise. 11 SHDN Shutdown Control. Set SHDN low to disable all internal circuits for lowest power consumption. An RC lowpass filter can be used to reduce digital noise. 12 SYNEN Synthesizer Enable Input. Set SYNTH low to disable the internal frequency synthesizer. An RC lowpass filter can be used to reduce digital noise. 13 OSCIN Reference Oscillator Input. Connect a parallel, resonant, fundamental-tone crystal between this pin and ground to facilitate a crystal oscillator circuit. For applications with an external reference oscillator, the OSCIN input can be driven through a large-value series capacitor. 14 VCC_XTAL Supply Voltage Input for Crystal Oscillator. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 15 VCC_CHP Supply Voltage Input for Charge Pump. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 16 CHP 17 VCC_A Supply Voltage Input for PLL. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 18 VCC_D Supply Voltage Input for PLL. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 19 VCC_LO Supply Voltage Input for Internal LO Circuits. Bypass as close to the pin as possible. The bypass capacitor should not share ground vias with other branches. 20, 21 LO-, LO+ Differential Local-Oscillator Input. These inputs require DC-blocking capacitors. The LO can be applied with a single-ended input to the LO+/LO- pin. In this mode, the other pin should be AC-grounded. 22 BUFOUT Buffered LO Output. Internally matched to 50Ω, requires a DC-blocking capacitor. 23 BUFEN LO Output Buffer Amplifier Enable. Set BUFEN high to enable the on-chip output LO buffer for driving external circuits. An RC lowpass filter can be used to reduce digital noise. 24, 25 Q-, Q+ Differential Q-Channel Baseband Inputs to the Modulator. These pins connect directly to the bases of a differential pair and require an external common-mode bias voltage of 1.6V. High-Impedance Charge-Pump Output. Connect to the tune input of the VCO through the PLL loop filter. Keep the line from this pin to the tune input as short as possible to prevent spurious pickup, and connect the loop filter as close to the tune input as possible. _______________________________________________________________________________________ Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer PIN NAME 26, 27 I-, I+ Differential I-Channel Baseband Inputs to the Modulator. These pins connect directly to the bases of a differential pair and require an external common-mode bias voltage of 1.6V. 28 VCC_RF Supply Voltage Input for RF Circuits. Bypass as close to pin as possible. The bypass capacitor should not share ground vias with other branches. — FUNCTION Exposed pad Ground Detailed Description Internally, the MAX2150 includes a broadband I/Q modulator, internally matched broadband output driver amplifier, fine-resolution fractional-N frequency synthesizer, an LO buffer amplifier, and an on-chip low-noise crystal oscillator circuit. A simple 3-wire interface is provided for synthesizer programming and device configuration and control. Independent hardware and software power-down control of the I/Q modulator, frequency synthesizer, and LO buffer amplifier is provided, as well as the ability to shut down the entire chip. I/Q Modulator The MAX2150 modulator is composed of a pair of matched double-balanced mixers, a broadband passive LO quadrature generator, and a summing amplifier. The mixers accept differential I/Q baseband signals that directly modulate the internal 0° and 90° LO signals applied to the I/Q mixers. An external LO source drives an internal LO quadrature generator that shifts the phase of the LO signal applied to the Q mixer by 90° relative to the LO signal applied to the I-channel mixer. The modulated output of the I/Q mixers is summed together, and the undesired sideband is suppressed. The I+, I-, Q+, and Q- input ports feature high-linearity buffer amplifiers with a typical -3dB bandwidth of 75MHz and accept differential input voltages up to 1VP-P. The ports require external biasing and have an input common-mode requirement of 1.6V. For singleended operation, bypass the I and Q ports to ground. See the Typical Application Circuit for recommended component values. The broadband output driver amplifier is matched on chip across the entire operating frequency range and requires an output DC-blocking capacitor. For optimum performance, the output match can be improved with simple L-section and/or PI-section matching networks. Always ensure that DC blocking is provided, because internal bias voltages are present at this output. The modulator can be shut down with both hardware (pin 1) and software (TE bit). This mode is useful for quiet synthesizer programming or to mute the RF output signal. The hardware pin and software bits must be set to logic-1 to enable the modulator. If the hardware pin or software bit is set to logic-0, or if both are set to logic-0, the modulator is disabled. LO Buffer Amplifier The broadband buffer amplifier output is internally matched and requires a DC-blocking capacitor to isolate on-chip bias voltages. Power-down of the LO buffer can be controlled by both BUFEN (pin 23), as well as BUFEN by software by setting the BUFEN (BE) bit through the 3-wire interface. The hardware pin and the software bit must be a logic-1 to enable the buffer. If the hardware or software bit is set to logic-0, the LO buffer is disabled. Frequency Synthesizer The MAX2150 features an internal 28-bit sigma-delta frequency synthesizer. This architecture enables the use of very high (30MHz) comparison frequencies, which significantly reduces the in-loop phase noise as a result of reduced division ratios. The high comparison frequency also allows significantly increased PLL bandwidths for very fast switching speed applications. Divider Programming The MAX2150 frequency programming is determined as follows. The overall division ratio (D) has an integer value (N), as well as a fractional component (F): D = N.F = N +F / 228 The N and F values are encoded as straight binary numbers. Determination of these values is illustrated by the following example: FLO = 1721.125MHz, FCOMP = 20MHz Then: D = 1721.125 / 20 = 86.05625 Therefore: N = 86 and F = 0.05625 x 228 = 15,099,494 _______________________________________________________________________________________ 9 MAX2150 Pin Description (continued) MAX2150 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer Converting each to binary representation results in the following: N register = 86 = 0101,0110 F register value = 0000,1110,0110,0110,0110,0110,0110 The F-register value is then split between an upper 14 bits and a lower 14 bits as follows: Upper 14 bits + address 00 = 0000,1110,0110,0100 Lower 14 bits + address 01 = 1001,1001,1001,1001 Synthesizer Shutdown The synthesizer can be disabled by setting SYNEN (pin 12) to a logic low. This mode is useful when an external frequency synthesizer is employed. Applications Information Serial Interface and Register Definition 3-Wire Interface and Registers The MAX2150 is programmed through a simple 3-wire (CLK, DATA, EN) interface. The programming data is contained within 16-bit words loaded into four unique address locations. Each location contains programming information for setting operational modes and device configuration. Two words (address 00, 01) control the fractional divide number in the sigma-delta synthesizer. The third word (address 10) sets the integer divide value, reference divide value, charge-pump current, and charge-pump compensation DAC settings. The fourth and final word (address 11) contains various device configuration registers and test registers, as well as additional charge-pump compensation registers. See Tables 1 through 11 for details. 3-Wire Interface Timing Diagram Figure 1 shows the programming logic. The 16-bit shift register is programmed by clocking in data at the rising edge of CLK. Pulling enable low allows data to be clocked into the shift register; pulling enable high loads the register addressed. DATA B19 (MSB) B18 B0 Fractional Spurs When synthesizing a frequency that is an integer multiple of the reference divider and having a fractional offset with a value less than the PLL filter bandwidth, fractional spurs can be observed at a typical level of -40dBc. For example, to synthesize 1640.005MHz when using a 20MHz reference and a PLL bandwidth of 25kHz, spurious products offset from the LO by 5kHz can be observed. The 1640MHz is an integer multiple of 20MHz, and the fractional offset of 5kHz is within the PLL bandwidth. It is possible to avoid the above-mentioned spurious products by using two reference oscillators with slightly offset frequencies or by using a higher reference frequency and changing the comparison frequency of the reference divider. Crystal Oscillator The MAX2150 includes a simple-to-use on-chip lownoise reference oscillator circuit. The oscillator is formed by connecting a fundamental mode parallel resonant crystal from OSCIN to ground. The oscillator circuit is useful from 10MHz to 50MHz. The phase noise of the MAX2150 can be improved by using a precision high-frequency external reference oscillator (TCXO). The external oscillator is connected through a DC-blocking capacitor directly to the OSCIN pin. Layout Considerations A properly designed PC board is an essential part of any RF circuit. A ground plane is essential. Keep RF signal lines as short as possible to reduce losses, radiation, and inductance. The exposed pad on the underside of the MAX2150 must be adequately grounded by ensuring that the exposed paddle of the device package is soldered evenly to the board ground plane. Use multiple, low-inductance vias to ground the exposed paddle. A3 A1 A0 (LSB) CLK tCWL tCS tCH tCWH tCS > 50ns tCH > 10ns tCWH > 50ns tES > 50ns tCWL > 50ns tEW > 50ns tES EN tEW Figure 1. 3-Wire Interface Timing Diagram 10 ______________________________________________________________________________________ Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer MAX2150 Table 1. Register Tables MSB SHIFT REGISTER DATA LSB ADDRESS Upper (MSBs) Fractional Divider Value (F) 14 Bits (Default = 8192, 10000000000000) 27 26 25 24 23 22 21 20 19 18 17 16 Address 15 14 0 Lower (LSBs) Fractional Divider Value (F)14 Bits (Default 0 DEC, 00000000000000 13 12 11 R Divider Default = 00 R1 10 CP Bleed Default = 00 R0 LIN1 LIN0 Reset Delay Default = 00 BL1 9 8 7 6 5 CP Current Default = 11 CP1 4 T5 T4 CP0 T3 2 1 0 0 Integer Divide Value (N) 8 Bits Default = 177 DEC 7 6 5 4 Test Registers 6 Bits Default = 0 DEC BL0 3 3 T1 T0 INT PD 2 TE 1 BE 1 Address 0 1 Control Register 6 Bits Default = 15 DEC T2 0 Address 0 Address XX CPX 1 1 Table 2. Reference Divider R1 R0 REFERENCE DIVIDE VALUE 0 0 1 0 1 2 1 0 3 1 1 4 Table 3. Integer Divider-N* N7 N6 N5 N4 N3 N2 N1 N0 INTEGER DIVIDE VALUE 0 0 1 0 0 0 1 1 35 0 0 1 0 0 1 0 0 36 — — — — — — — — — 1 1 1 1 1 0 1 0 250 1 1 1 1 1 0 1 1 251 *N divider is limited to 35 < N < 251. Table 4. Fractional Divider-F (Upper 14 Bits) F27 F26 F25 F24 F23 F22 F21 F20 F19 F18 F17 F16 F15 F14 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 — — — — — — — — — — — — — — 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Table 5. Fractional Divider-F (Lower 14 Bits) F13 F12 F11 F10 F9 F8 F7 F6 F5 F4 F3 F2 F1 F0 INTEGER DIVIDE VALUE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 — — — — — — — — — — — — — — — 1 1 1 1 1 1 1 1 1 1 1 1 1 0 268435454 1 1 1 1 1 1 1 1 1 1 1 1 1 1 268435455 ______________________________________________________________________________________ 11 MAX2150 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer Table 6. Control Register BIT ID BIT NAME PWR-UP STATE BIT LOCATION 0 = LSB CPX CP_MULT 1 0 FUNCTION XX XX XX 1 A logic high doubles the charge pump current selected through registers CP1 and CP0. Logic low sets the charge-pump current to the value selected by registers CP1 and CP0. Unused. BE BUFEN 1 2 High enables the VCO buffer. Low disables this output. TE TXEN 1 3 Low enables SW_MUTE mode, which shuts down the RF circuits while leaving the 3-wire interface, register, and PLL circuits active. PD PWDN 0 4 Low enables register-based shutdown. This mode shuts down all circuits except the 3-wire interface and internal registers. INT INT_MODE 0 5 Logic high disables the sigma-delta modulator. Logic low enables the sigma-delta modulator for normal operation. Table 7. Device Modes HW PINS MODE SOFTWARE CONTROL BITS PWDN TXEN BUFEN DESCRIPTION SHDN TXEN SYNEN BUFEN TX H H H H/L H H H/L All circuits active. MOD H H L H/L H H H/L Modulator circuits active. Synthesizer blocks disabled. Mode is used with external PLL circuit. H/L Serial interface and synthesizer blocks active. RF and modulator blocks disabled. Mode is used to gate RF ON/OFF with external logic control. SYNTH H L H H/L H X SW_MUTE H H H H/L H L H/L Serial interface and synthesizer blocks all active. Modulator blocks disabled. Mode is used to gate RF ON/OFF with software control. HW_SHDN L X X X X X X All circuits disabled. Lowest current mode of operation. X Serial interface and registers active, all other circuits inactive regardless of the state of the HW pins with the exception of HW_SHDN. SW_SHDN H X X X L Power-Supply (VCC) Bypassing Proper voltage-supply bypassing is essential to reduce the spurious emissions mentioned above. It is recommended that each VCC pin be bypassed independently 12 X and share no common vias with any other ground connection. See the Typical Operating Circuit for suggested bypass component values. ______________________________________________________________________________________ Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer TXEN PIN 0 0 1 1 Table 11. BUFEN Pin and Software Bit Definitions BUFEN TX MODE BIT 0 1 0 1 PIN 0 0 1 1 TX off TX off TX off TX enabled Table 9. Charge-Pump Registers CPX 0 0 0 0 1 1 1 1 CP1 0 0 1 1 0 0 1 1 CP0 0 1 0 1 0 1 0 1 MAX2150 Table 8. TXEN Pin and Software Bit Definitions BUF MODE BIT 0 1 0 1 Buffer off Buffer off Buffer off Buffer on Chip Information TRANSISTOR COUNT: 16,321 ICP (µA) 170 350 520 690 340 670 1000 1310 Table 10. Test Register Definition (Default 0 Dec)* TEST MODE T5 T4 T3 T2 T1 T0 TEST PIN Normal Operating Mode 0 0 0 0 0 0 — Charge Pump Forced to Source Icp 0 0 0 0 0 1 CP Charge Pump Forced to Sink Icp 0 0 0 0 1 0 CP Reference Divider Output 0 1 0 0 0 0 Lock Main Divider Output 0 1 1 0 0 0 Lock *All other logic states are undefined. ______________________________________________________________________________________ 13 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer MAX2150 Typical Operating Circuit J1 31-5239-52RFX J2 31-5239-52RFX I IN Q C50 0.1µF R31 3.3kΩ VCC C52 0.1µF R1 OPEN R32 3.3kΩ R29 OPEN R2 OPEN VCC R33 3.3kΩ DCIN C28 0.1µF QN BUFEN R4 OPEN R3 OPEN C1 0.1µF R34 3.3kΩ VCC J6 C3 0.1µF VCC C25 1µF J7 R12 0Ω C2 100pF VCC 28 VCC_RF GND 1 27 I+ 26 I- 25 Q+ 24 Q- 23 BUFEN C5 OPEN 22 BUFOUT LO+ TXEN C33 0.1µF 2 LO- C18 0.1µF J15 VCC 3 RFOUT VCC_LO LO 20 C8 22pF RFOUT C15 OPEN VCC_PA LOn C20 0.1µF C12 100pF U1 J16 4 TEST2 VCC VCC_D MAX2150 C4 100pF 2 18 3 C10 100pF VCC J17 LOCK J20 5 VCC_A TEST1 VT GND GND VCC GND OUT 8 5 4 17 C11 100pF VCC_VCO J19 6 CHP LOCK 16 VCC 7 C27 1.0µF VCC_CHP VCC_SD C14 100pF CLK 8 DATA 9 EN JUMP_PAD EN 10 SHDN SYNEN OSCIN 11 12 13 R18 0Ω J10–15 J10–17 J10–19 J10–16 J10–18 J10–20 VCOSEL J10–13 J10–14 SYNEN J10–11 J10–12 SHDNn J10–9 J10–10 TXEN J10–7 J10–8 FILTVCC J10–5 J10–6 DATA J10–3 J10–4 ENn C21 0.1µF C13 100pF J10–1 CLK C19 0.1µF 14 R24 1.1kΩ R23 245Ω J10–2 C36 0.1µF C30 0.1µF VCCVCO GND VCC L1 OPEN J5 J11 15 VCC_XTAL C37 VCC 0.1µF LOCK C9 100pF SHDN VCCSD C34 0.1µF C35 100pF C22 6800pF VCC 14 U2 VC3R0A230967/ 1750B350FUJI 7 6 GND VSW 19 1 C16 OPEN J14 C32 0.1µF C7 OPEN VCC R13 0Ω C6 OPEN 21 C17 100pF J8 J13 BUFOUT C31 0.1µF C23 .068µF R25 1.1kΩ C24 680pF C26 470pF VTUNE_OUT TUNEOUT Y1 J18 REFL In ______________________________________________________________________________________ R35 OPEN Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer 32L QFN.EPS ______________________________________________________________________________________ 15 MAX2150 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) MAX2150 Wideband I/Q Modulator with Sigma-Delta Fractional-N Synthesizer Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.