Evaluates: MAX2601/MAX2602 MAX2602 Evaluation Kit General Description Features The MAX2602 evaluation kit (EV kit) simplifies the evalu- 1W (30dBm) Output Power at 836MHz ation of the MAX2602 1W RF power transistor for 50 Inputs and Outputs 900MHz band applications. The EV kit demonstrates the MAX2602 in a 3.6V, 836MHz, 1W (30dBm) RF +2.7V to +5.5V Supply Range power amplifier for constant-envelope applications. 11dB Gain at 836MHz The EV kit is shipped with a MAX2602, which contains an internal biasing diode. With a simple modification, the MAX2602 EV kit can be used to emulate the Ordering Information MAX2601, which does not have an internal biasing diode. PART TEMP. RANGE BOARD TYPE MAX2602EVKIT-SO -40C to +85C Surface Mount Quick Start Component List The following section provides instructions for setting DESIGNATION QTY DESCRIPTION up the MAX2602 EV kit as a 1W RF power amplifier. C1, C2 2 2pF surface-mount capacitors Test Equipment Required C3 1 10pF surface-mount capacitor RF signal generator capable of at least 20dBm of C4 1 12pF surface-mount capacitor output power at 836MHz C5C8, 6 1000pF surface-mount capacitors Attenuator that can handle at least 30dBm (1W) of C11, C12 RF power (used to protect the test equipment) C9, C11 2 0.1F surface-mount capacitors RF spectrum analyzer for use at 836MHz (alterna- L1 1 100nH surface-mount inductor tively, a power meter can be used) 18.5nH surface-mount spring inductor DC power supply capable of delivering 1A at +2.7V L2 1 Coilcraft A05T (Note 1) to +5.5V R1 1 430 surface-mount resistor Connections and Setup R2 1 24 surface-mount resistor Follow these steps for connecting the EV kit: R3 1 0 resistor 1) Connect a 50 RF signal generator capable of sup- IN, OUT 2 Edge-mount SMA connectors plying at least 20dBm at 836MHz to the RF input MAX2602ESA (8-pin, thermally SMA connector (IN). Set the generators initial out- U1 1 enhanced SO) put to a much lower power (-10dBm, for instance). None 1 MAX2601/MAX2602 data sheet Keep this generators RF output off at this time. None 1 Printed circuit board 2) Connect a fixed attenuator that can handle 1W of power to the output SMA connector (OUT). This Note 1: Contact Coilcraft by phone at (800) 322-2645, by fax at attenuator reduces the power to the test equipment (847) 639-1469, or on the World Wide Web at and protects it from overload. Connect this attenua- MAX2602 Evaluation Kit 4) Connect the same power supply through a separate emitter inductance as low as possible, as excessive lead to the EV kits V terminal. emitter inductance can degrade the performance of B any RF common-emitter amplifier. The bottom-side con- 5) Verify that all the connections are correct to avoid tact is also the principal path for heat dissipation, and damaging the transistor or your test equipment. must be connected to a large ground plane. 6) Turn on the 3.6V supply. Note the supply current with the RF generator off. It should be around Biasing 100mA. Capacitors C5, C9, and C11 provide decoupling for the bias supply. The transistors bias current is set by the 7) Activate the RF signal generator and slowly internal biasing diodes current. This current is set by increase the generators output power to 20dBm. At the following equation: this time, the supply current should be about 500mA, and the output power should be 30dBm. VB - 0.75V IB = R1 Detailed Description Figure 1 is the schematic for the MAX2602 EV kit as The collector current is scaled to the bias current: shipped. The circuit consists of four blocks: power-sup- I = 15I . R3 is used as a jumper. The transistors base C B ply decoupling, a bias network, and both input and out- is biased through R2 and L1 (a choke). For more infor- put matching networks. The amplifier built on this board mation on the internal biasing diodes operation, refer to is biased for class AB operation at 1W of output power, the MAX2601/MAX2602 data sheet. and provides high efficiency. Input Matching Network Supply Decoupling Circuitry The transistors RF input does not present a 50 and Grounding impedance, so a matching network is required for prop- Capacitors C8 and C10 provide decoupling for V . The C er operation in a 50 environment. This network con- collector has two separate pins: one for the V input (con- C sists of capacitor C1 to ground, approximately 1 inch nected through choke L2), and one for the RF output. (or 2.5cm) of the 50 transmission line (T1), a DC- blocking capacitor (C6), and a shunt capacitor at the The most important contact for the MAX2602 is not on transistor base (C4). the top of the board it is the bottom-side emitter con- tact that is connected to ground. This contact keeps C11 C12 V C R1 R3 1000pF 1000pF V 430 0 B C8 C10 L2 1000pF 0.1F C9 C5 18.5nH R2 L1 0.1F 1000pF 3 100nH 24 C7 1000pF 1 OUT C6 4 8 T2 1000pF C3 C2 U1 IN 10pF 2pF 5 T1 2, 6, 7 C1 C4 BACK-SIDE SLUG 2pF 12pF Figure 1. MAX2602 EV Kit Schematic 2 Evaluates: MAX2601/MAX2602