19-1093; Rev 2; 1/98 MAX2430 Evaluation Kits ____________________________Features The MAX2430EVKIT-SO and MAX2430EVKIT-QSOP evaluation kits (EV kits) simplify evaluation of the MAX2430 silicon RF power amplifier. They enable testing of all MAX2430 functions over the 800MHz to 950MHz band, with no additional support circuitry and with minimal equipment. To evaluate the MAX2430 in the SO package (MAX2430ISE), order the MAX2430EVKIT-SO. To evaluate the MAX2430 in the PwrQSOP package, order the MAX2430EVKIT-QSOP. These are surface-mount packages. ♦ Low-Cost, Silicon RF Power Amplifier _______________Ordering Information ♦ Fully Assembled and Tested Surface-Mount Package PART TEMP. RANGE MAX2430EVKIT-PwrQSOP 0°C to +70°C 16 PwrQSOP MAX2430EVKIT-SO 0°C to +70°C 16 Narrow SO ♦ Delivers More than 125mW Output Power from +3.6V Supply ♦ Single +3V to +5.5V Supply Range, Ideal for 3-Cell NiCd or 1-Cell Lithium-Ion Battery Operation ♦ Output Matching Network is Tunable from 800MHz to 950MHz ♦ TTL/CMOS-Compatible Shutdown Input ♦ Easy Testing of All MAX2430 Features IC PACKAGE ______________________________________________________________Component List MAX2430EVKIT-SO MAX2430EVKIT-PwrQSOP DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION C1–C5 5 1nF, 10% ceramic chip capacitors (0805) C6 1 2.2nF, 10% ceramic chip capacitor (0805) C6 1 2.2nF, 10% ceramic chip capacitor (0603) C7 1 1µF, 10V, 10% tantalum capacitor SMT AVX TAJA105K016 C7 1 1µF, 10V, 10% tantalum capacitor SMT AVX TAJA105K016 CO, CSH 2 0pF to 6pF SMT trimmer capacitors Voltronics JR060 CO, CSH 2 0pF to 6pF SMT trimmer capacitors Voltronics JR060 L1, L2 2 8nH, 10% spring inductors Coilcraft A03T L1 1 8nH, 10% spring inductor Coilcraft A03T LC 1 47nH, 20% inductor Coilcraft 0805CS-470XMBC L2 1 12nH, 10% spring inductor Coilcraft A04T RC 1 470Ω, 5% resistor (0805) LC 1 PIN, POUT 2 SMA connectors 47nH, 20% inductor Coilcraft 0805CS-470XMBC U1 1 MAX2430ISE VCC, GND 2 Supply connectors J1 1 3-pin header None 1 Shunt ______________Component Suppliers SUPPLIER PHONE C1–C5 5 1nF, 10% ceramic chip capacitors (0603) RC 1 470Ω, 5% resistor (0603) PIN, POUT 2 SMA connectors U1 1 MAX2430IEE VCC, GND 2 Supply connectors J1 1 3-pin header None 1 Shunt FAX AVX (803) 946-0690 (803) 626-3123 Coilcraft (847) 639-6400 (847) 639-1469 Sprague (603) 224-1961 (603) 224-1430 Voltronics (201) 586-8585 (201) 586-3404 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. Evaluate: MAX2430 ________________General Description Evaluate: MAX2430 MAX2430 Evaluation Kits _________________________Quick Start The MAX2430 EV kits are fully assembled and factory tested. All measurements described below use a 900MHz test frequency. Do not turn on the power until all connections are made. Test Equipment Required • Signal-Source Sine-Wave Generator with range up to 1000MHz (example: HP8656B) • Spectrum Analyzer with range up to 4GHz (example: TEK2755AP) • +3V to +5.5V, 400mA adjustable output power supply • Current meter that can display up to 400mA 2) Connections and Signal Conditions 1) Connect an SMA cable from the RF signal source to the PIN input on the EV kit. Ensure that the RF powersource input power is off or set below -50dBm. 2) Connect an SMA cable from the spectrum analyzer to the POUT connector on the EV kit. Note that if the front end of the spectrum analyzer can not handle more than 20dBm of input power, you must place an appropriate attenuator between the POUT connector and the spectrum analyzer to prevent damage. 3) Connect the 3V power supply through a current meter to the appropriate VCC and GND terminals on the EV kit, and apply power. 4) Position the J1 shunt across pins 1 and 2 to enable the MAX2430 (SHDN = high). Note that the normal bias current drawn by the MAX2430 EV kit should be approximately 30mA to 60mA over the 3V to 5.5V supply range when no RF input power is applied. 5) Set the input power to -20dBm and the frequency to 900MHz on the signal source. 6) Set the spectrum analyzer’s dynamic range and frequency range for an appropriate setting to view the 900MHz output. 7) Tune the output stage matching network for maximum output power at 900MHz. See the Adjustments and Control section for the CO and CSH trim-capacitor tuning procedure _______________Detailed Description Analysis 1) Set the RF source power to -13dBm. At 900MHz, the spectrum analyzer should display a power level near 20dBm (of course, if you have used an attenuator, adjust your reading accordingly). If necessary, adjust 2 3) 4) 5) the input power up or down in 0.1dB steps to get the equivalent output power equal to 20dBm at the POUT port. The power gain (GP = POUT - PIN) should be greater than 30dB. If you cannot achieve 20dBm output power, verify that the supply voltage between the VCC and GND pads on the EV kit is 3.00V. This ensures that the supply connection wire and current-meter shunt losses are not causing excessive supply voltage drops. Also, make sure the output stage matching network has been properly tuned for the center frequency of interest, according to the CO and CSH trim-capacitor tuning procedure found in the Adjustments and Control section. Disable the MAX2430 by moving the J1 shunt to pins 2 and 3. With the part disabled and RF power still applied to the RF input, you can measure the offstate feedthrough of the MAX2430. Adjust your spectrum analyzer to display the amount of 900MHz leakage power that exists at the POUT port. The isolation should be approximately 50dB, so with an input power of -12dBm, the output power should measure approximately -62dBm. Enable the MAX2430 again by moving the J1 shunt to pins 1 and 2. Note that the output power is again around 20dBm. Set the spectrum analyzer to display the 1800MHz 2nd harmonic frequency. The measured power should be typically 26dB down from the fundamental power at 900MHz. The 3rd harmonic power at 2700MHz should be typically 40dB down. The threeelement output stage matching circuitry provides some rejection of the harmonic products. Set the spectrum analyzer to measure the 900MHz fundamental power. Adjust VCC from 3V up to 5.5V. Note that the output power has risen approximately 2dBm (up to 22dBm) and that the power gain has increased by 2dB. Adjustments and Control CO and CSH The quickest method for tuning the output is to apply -20dBm of input power at the desired frequency, then adjust CO and CSH until the output power is maximized as read from a spectrum analyzer or power-meter display. Only one value of CO and CSH is correct for a given frequency. For best results, use a nonconductive adjustment tool. CO and CSH are surface-mount, 0pF to 6pF trim capacitors used to tune the output transistor matching _______________________________________________________________________________________ MAX2430 Evaluation Kits Shutdown Control The SHDN pin is TTL/CMOS compatible and is used to enable (or disable) the MAX2430. Table 1 lists the options available for the shutdown control jumper, J1. To use an external control signal, remove the shunt on J1 completely, and connect the external signal to the pad marked SHDN. The external control signal should not exceed VCC. Supply current in the disabled mode Table 1. Jumper J1 Functions SHUNT LOCATION SHDN PIN 1&2 Connected to VCC Enabled 2&3 Connected to GND Disabled MAX2430 STATUS is typically less than 1µA. BIAS Pin The BIAS pin regulates the ramp-up and ramp-down times of the output RF envelope. It can also be driven externally to control the output power over a 15dB range. The rampup/down slope is set by a capacitor connected from the BIAS pin to ground. The EV kit comes with a 2.2nF capacitor (C6), which yields an RF envelope ramp-up/down time of approximately 10µs. The BIAS pad on the EV kit allows the user to manipulate the MAX2430 BIAS pin. Refer to the BIAS Pin section of the MAX2430 data sheet for more information on output power control. Layout Considerations The evaluation board can serve as a guide for board layout. Grounding is critical for the proper operation and stability of the MAX2430. The following considerations were taken into account on the evaluation board. C1, C2, and C3 should be small surface-mount capacitors, placed directly from each effective VCC terminal to the ground plane. Make connections short (not through vias or long traces). C5 and C6 should be surface-mount capacitors, located as close to the MAX2430 as possible for best results. C2 should be next to L2. C3 should be next to LC. LC should be perpendicular to L1, and L1 perpendicular to L2 to ensure minimal coupling. The evaluation board has four layers made from FR4 (εR = 4.0 to 4.6) with 1oz. copper. The first two layers (signal and ground planes) are 14 mils apart, which provides a 50Ω characteristic impedance from 25mil-wide traces. These trace widths are used for PIN and POUT to maintain a 50Ω environment out to the SMA connectors. The third layer is used for the V CC supply plane. The fourth layer is used for the SHDN pin jumper connections and BIAS pin signal routing. The ground metal, connected with vias on the first and second layers, acts as a heatsink for the MAX2430, reducing internal operating temperatures. Note that all ground and V CC plane is removed under matching components (L1, L2, LC, RC, CO, CSH) to minimize parasitic capacitance. The MAX2430EVKIT-QSOP includes two large holes under the MAX2430 to aid in attachment and removal of the part. These holes are not necessary for proper circuit operation. Operation Outside the 800MHz to 950MHz Frequency Band With minor modifications to the MAX2430 EV kit matching network components, the operating frequency can be tuned to frequencies outside the specified band. Refer to the Applications Information section of the MAX2430 data sheet for more information. _______________________________________________________________________________________ 3 Evaluate: MAX2430 network to 50Ω. This ensures maximum power transfer and good output VSWR at any selected narrow-band frequency range of interest between 800MHz and 950MHz. The open-collector output transistor (RFOUT pin) should see approximately a 15Ω internal load impedance to achieve maximum power gain with the best efficiency. The internal package inductance (5nH), L1 (8nH), series capacitor C O, and shunt capacitor CSH form a 15Ω to 50Ω tuneable matching network. Resistor RC enhances stability under load mismatch conditions and does not affect normal operation of the circuit. The 47nH supply choke (labeled LC) provides DC bias. Evaluate: MAX2430 MAX2430 Evaluation Kits VCC C7 C4 1µF 1nF 10V 1 2 3 C1 1nF C2 1nF C6 2.2nF L2* VCC J1 2 SHDN 7 VCC1 8 VCC2 6 C3 1nF 10 BIAS LC 47nH OUTPUT BIAS MASTER BIAS SHDN 5nH GND1 PIN 50Ω 4 RFIN CO 0pF to 6pF ~15Ω DRIVER RC 470Ω L1 8nH 9 RFOUT MAX2430 C5 SMA 1nF * L2 = 8nH FOR NARROW SO PACKAGE (MAX2430ISE) L2 = 12nH FOR PwrQSOP PACKAGE (MAX2430IEE) BIAS SMA CSH 0pF to 6pF GAIN GND2 GND3 GND4 3, 5 1, 15, 16 11, 12, 13, 14 POUT 50Ω CO AND CSH TUNED FOR MAXIMUM POWER OUTPUT AT THE DESIRED FREQUENCY BETWEEN 800MHz AND 950MHz. GND Figure 1. MAX2430 EV Kit Schematic 1.0" Figure 2. MAX2430 EVKIT-SO Component Placement Guide— Component Side 4 1.0" Figure 3. MAX2430 EVKIT-SO PC Board Layout— Component Side _______________________________________________________________________________________ MAX2430 Evaluation Kits Evaluate: MAX2430 1.0" 1.0" Figure 4. MAX2430 EVKIT-SO PC Board Layout— Solder Side 1.0" Figure 6. MAX2430 EV Kit-PwrQSOP Component Placement Guide—Component Side Figure 5. MAX2430 EVKIT-SO PC Board Layout—Ground Plane 1.0" Figure 7. MAX2430 EV Kit-PwrQSOP PC Board Layout— Solder Side _______________________________________________________________________________________ 5 Evaluate: MAX2430 MAX2430 Evaluation Kits 1.0" 1.0" Figure 8. MAX2430 EV Kit-PwrQSOP PC Board Layout— Component Side Figure 9. MAX2430 EV Kit-PwrQSOP PC Board Layout— Ground Plane 1.0" Figure 10. MAX2430 EV Kit-PwrQSOP PC Board Layout— Power Plane 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 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.