19-1715; Rev 0; 4/00 MAX2720/MAX2721 Evaluation Kits Features ♦ Easy MAX2720/MAX2721 Evaluation ♦ All Critical Peripheral Components Included ♦ SMA Input and Output Signal Connectors ♦ RF Ports Matched to 1900MHz (MAX2720) ♦ RF Ports Matched to 2315MHz (MAX2721) ♦ Fully Assembled and Tested Ordering Information TEMP. RANGE IC PACKAGE MAX2720EVKIT PART -40°C to +85°C 20 TSSOP-EP* MAX2721EVKIT -40°C to +85°C 20 TSSOP-EP* *Exposed paddle Components Common to MAX2720/MAX2721 DESIGNATION QTY 470pF ±10% ceramic caps (0402) Murata GRM36X7R471K050A R4 1 20kΩ potentiometer Bournes Digi-Key 3296W-203-ND 1 2pF ±0.25pF ceramic cap (0402) Murata GRM36COG020C050A R5, R7, R9, R11 4 1.00kΩ ±1% resistors (0603) C3, C10, C13 3 1000pF ±10% ceramic caps (0402) Murata GRM36X7R102K050A R6, R8, R10, R45 4 49.9Ω ±1% resistors (0603) C6, C7, C15, C16, C22, C23, C24 7 0.1µF ±10% ceramic caps (0603) Murata GRM39X7R104K016A J1, J3, J4, J5, J7, J8 6 SMA edge-mount connectors EFJohnson 142-0701-801 J2, J6 0 Not installed 1 3.0pF ±0.25pF ceramic cap (0402) Murata GRM36COG030C050A J10, J11, J12 3 Test points C18 1 47pF ±5% ceramic cap (0402) Murata GRM36COG470J050A JU2 0 Not installed 2 1x3-pin headers (0.1in center) 1 10µF ±10% tantalum capacitor AVX TAJC106K010 JU4, JU5 C19 JU6 1 1x2-pin header (0.1in center) DESIGNATION QTY C1, C4, C8, C9, C14, C17 6 C2 C11 DESCRIPTION DESCRIPTION C20, C21 0 Not installed None 3 Shunts (JU4, JU5, JU6) L1 0 Not installed None 1 MAX2720/MAX2721 PC board L2 1 3.9nH ±5% inductor Toko LL1608-FS3N9J None 1 MAX2720/MAX2721 EV kit data sheet R1, R3 2 100kΩ resistors (0402) R2 1 10kΩ resistor (0402) None 1 MAX2720/MAX2721 data sheet ________________________________________________________________ Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. Evaluate: MAX2720/MAX2721 General Description The MAX2720/MAX2721 evaluation kits (EV kits) simplify evaluation of the MAX2720/MAX2721 direct I/Q modulator with variable gain amplifier (VGA) and power amplifier (PA) driver. The MAX2720 is optimized for RF frequencies between 1700MHz and 2100MHz, while the MAX2721 is optimized for RF frequencies between 2100MHz and 2500MHz. The EV kits are fully assembled and tested, allowing simple evaluation of all device functions. All signal ports utilize SMA connectors, providing a convenient interface to RF test equipment. Evaluate: MAX2720/MAX2721 MAX2720/MAX2721 Evaluation Kits MAX2720 EV Kit Specific Components DESIGNATION QTY DESCRIPTION DESIGNATION QTY C5 1 8.0pF ±0.5pF ceramic cap (0402) Murata GRM36COG080D050A C12 1 0Ω resistor (0402) L3 1 1.5nH ±5% inductor Toko LL1608-FS1N5J L4 U1 1 1 1pF ±0.25pF ceramic cap (0402) Murata GRM36COG010C050A PHONE FAX WEB AVX 843-448-9411 843-448-1943 EFJohnson 402-474-4800 402-474-4858 Murata 800-831-9172 814-238-0490 Toko 800-pik-toko 708-699-1194 www.avxcorp. com www.efjohnson. com www.murata. com www.tokoam. com Quick Start Test Equipment Required • One low-noise RF-signal generator (50Ω source) capable of delivering at least -10dBm of output power over 1.7GHz to 2.5GHz (HP 8648C, for example) • One I/Q generator capable of producing two 500kHz sine waves, 90° out of phase with each other, with an amplitude of 300mVp-p (HP 8904A with option 2, for example) • One dual-channel oscilloscope with a 100MHz minimum bandwidth • Two low-capacitance (<3.0pF) oscilloscope probes (Tektronix P6201, for example) • One spectrum analyzer capable of covering the MAX2720/MAX2721 RF frequency range of the HP 8561E, for example • Two 50Ω BNC-to-SMA cables • Two 50Ω SMA cables • One power supply capable of providing a minimum of 150mA of supply current at +3V • (Optional) Digital multimeters (DMMs) to monitor DC supply voltage and supply current 2 DESCRIPTION C5 1 6.0pF ±0.5pF ceramic cap (0402) Murata GRM36COG060D050A C12 1 27pF ±5% ceramic cap (0402) Murata GRM36COG270J050A L3 1 1.2nH ±5% inductor Toko LL 1608-FS1N2J L4 1 3.3nH ±5% inductor Toko LL1608-FS3N3J U1 1 MAX2721EUP, 20-pin TSSOP-EP MAX2720EUP, 20-pin TSSOP-EP Component Suppliers SUPPLIER MAX2721 EV Kit Specific Components • (Optional) A second power supply for varying the gain of the modulator I/Q Modulator Connections and Setup 1) DC Power Supply: Set the power-supply voltage to +3V, and connect it to VCC and GND on the EV kit. If desired, place an ammeter in series with the power supply to measure supply current and a voltmeter in parallel with VCC and GND to measure the supply voltage delivered to the EV kit. Short jumper JU4 to VCC to enable the device. Short jumper JU6 to allow the potentiometer to vary the modulator gain; turn the potentiometer until V PC = 2.5V. If desired, open jumper JU6 and connect to an additional voltage supply to control the modulator gain. 2) LO Signal Source: The MAX2720/MAX2721 LO port can be driven at full or half frequency. Connect jumper JU5 (X2 ENB) to GND to enable the internal LO frequency doubler, allowing the external LO signal source to operate at half frequency. Set the LO signal source operating frequency to 950MHz (MAX2720) or 1157.5MHz (MAX2721) at an output power of -13dBm. Connect jumper JU5 (X2 ENB) to VCC to disable the internal LO frequency doubler, and run the external LO source at the fundamental frequency. Set the LO signal source frequency to 1900MHz (MAX2720) or 2315MHz (MAX2721) at an output power of -13dBm. Connect the LO signal generator to the LO port SMA connector using a 50Ω SMA cable. 3) I/Q Signal Source: Configure the dual-output function generator for a 500kHz IF frequency, with a 300mVp-p amplitude and a 90° phase difference between channels. Connect a 50Ω cable from the I/Q signal source to the EV kit’s I+ and Q+ inputs. The EV kit inputs are terminated with a 50Ω resistor shunted to ground and a 1kΩ resistor in series with _______________________________________________________________________________________ SMA SMA J8 J3 SMA J2 C4 470pF R5 1k C7 0.1µF C20 OPEN C5 8pF (5pF*) VCC C6 0.1µF C2 2.0pF C1 470pF C24 0.1µF C8 470pF VCC L2 3.9nH VCC 1 3 C18 47pF 10 9 8 7 6 5 4 3 2 1 2 GND VCC I+ I- VCC GND VCC SHDN DROUT GND 1 VCC U1 1 PC GND DRIN R4 20k LO VCC Q+ Q- VCC ENX2 11 12 13 14 15 16 17 18 19 20 JU2 2 JU6 MODOUT JU5 3 X2_ENB MAX2720 MAX2721 2 VCC JU4 3 SHDN *COMPONENT VALUES ARE FOR MAX2721 ONLY. R6 49.9Ω R7 1k C23 0.1µF C3 1000pF C19 C22 10µF 0.1µF R45 49.9Ω R1 VCC 100k SHDN J1 SMA J12 J10 VCC VCC C11 3.0pF J11 L1 OPEN C14 470pF C16 0.1µF C15 0.1µF PC R11 1k C21 OPEN R3 100k VCC C13 C9 1000pF 470pF X2_ENB J4 R9 1k L3 1.5nH (1.2nH*) C10 1000pF SMA VCC C17 470pF R10 49.9Ω L4 C12 1pF (3.3nH*) 0Ω (27pF*) R2 10k R8 49.9Ω PC SMA J7 SMA J6 SMA J5 Evaluate: MAX2720/MAX2721 VCC VCC MAX2720/MAX2721 Evaluation Kits Figure 1. MAX2720/MAX2721 EV Kits Schematic _______________________________________________________________________________________ 3 Evaluate: MAX2720/MAX2721 MAX2720/MAX2721 Evaluation Kits the baseband input of the MAX2720/MAX2721, which has a 2kΩ (typ) input impedance. This voltage divider results in a 200mVp-p signal applied to the MAX2720/MAX2721s’ I+ and Q+ inputs. Use the oscilloscope and its two probes to verify that the amplitude difference between the two signals at the I and Q inputs is at a minimum and the phase difference is 90°. 4) Spectrum Analyzer: Connect the spectrum analyzer to the MODOUT SMA connector using a 50Ω SMA cable. Set the spectrum analyzer’s center frequency to 1900MHz (MAX2720) or 2315MHz (MAX2721). Set the spectrum analyzer’s reference level to 0dBm and the span to 1.2MHz. I/Q Modulator Analysis Turn on the power supply and the LO and I/Q signal generators. The ammeter should read approximately 77mA (MAX2720) or 86mA (MAX2721) with the LO doubler enabled, or 72mA (MAX2720) or 81mA (MAX2721) with the LO doubler disabled. Using the spectrum analyzer, observe the modulator output spectrum. Notice three tones: the carrier, and the lower and upper sidebands 500kHz below and above the carrier. In its peak power setting (V PC = 2.5V), the desired sideband will have an amplitude of -8.5dBm (MAX2720) or -5.0dBm (MAX2721). The carrier suppression is typically 33dB (MAX2720) or 31dB (MAX2721), while the sideband suppression is typically 40dB (MAX2720) or 35dB (MAX2721). Phase and amplitude differences at the I and Q inputs result in degradation of the carrier and sideband suppression. Be sure to take into account board losses (0.3dB) when calculating the output power of the device. PA Driver Connections and Setup 1) DC Power Supply: Set the power-supply voltage to +3V, and connect it to VCC and GND on the EV kit. If desired, place an ammeter in series with the 4 power supply to measure supply current and a voltmeter in parallel with the VCC and GND connections to measure the supply voltage delivered to the EV kit. Short jumper JU4 to VCC to enable the device. 2) Spectrum Analyzer: Connect the spectrum analyzer to the DROUT SMA connector using a 50Ω SMA cable. Set the spectrum analyzer’s center frequency to 1900MHz (MAX2720) or 2315MHz (MAX2721). Set the spectrum analyzer’s reference level to 10dBm and the span to 1MHz. 3) RF Signal Source: Set the signal generator to an output power of -12dBm at a frequency of 1900MHz (MAX2720) or 2315MHz (MAX2721). Connect the signal generator to the DRIN SMA connector using a 50Ω SMA cable. PA Driver Analysis Turn on the power supply and RF signal generator. The spectrum analyzer should measure an output power of +1.5dBm (13.5dB gain) for the MAX2720 or -0.5dBm (11.5dB gain) for the MAX2721. Be sure to take into account board losses (0.3dB at the input, 0.3dB at the output) when calculating the output power of the device. Layout and Bypassing Good PC board layout is an essential aspect of RF circuit design. The MAX2720/MAX2721 EV board can serve as a guide for layout of your board. Make sure the input traces to the I and Q input pins are of equal length and in the same environment as much as possible to keep the I and Q signals in quadrature for maximum sideband rejection at the modulated output. Keep PC board trace lengths as short as possible to minimize parasitics and losses. Keep bypass capacitors as close to the device as possible with low-inductance connections to the ground plane. _______________________________________________________________________________________ MAX2720/MAX2721 Evaluation Kits Evaluate: MAX2720/MAX2721 1.0" 1.0" Figure 2. MAX2720/MAX2721 EV Kits PC Board Layout— Component Placement Guide Figure 3. MAX2720/MAX2721 EV Kits PC Board Layout— Component Side (Layer 1, Top) 1.0" Figure 4. MAX2720/MAX2721 EV Kits PC Board Layout— Ground Plane (Layer 2) _______________________________________________________________________________________ 5 Evaluate: MAX2720/MAX2721 MAX2720/MAX2721 Evaluation Kits 1.0" 1.0" Figure 5. MAX2720/MAX2721 EV Kits PC Board Layout— Power Plane (Layer 3) Figure 6. MAX2720/MAX2721 EV Kits PC Board Layout— Power Plane (Layer 4, Bottom) 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.