CMX902 Broadband Efficient RF Power Amplifier Features Applications Wide operating frequency range Marine AIS Class-B and Marine AIS-SART 130MHz to 700MHz Wireless data communications: Typical output power: FSK, FFSK/MSK, GFSK/GMSK, Multi-level FSK 2.8W operating at 160MHz (4V) Analogue FM handheld radio terminals 1.75W operating at 435MHz (3.3V) Automatic meter reading (AMR) High power gain 39dB Wireless sensor networks High power added efficiency Mesh/Ad hoc systems greater than 60% at VHF Remote control and sensing systems Single polarity supply voltage Commercial and consumer communications 2.5V to 6V Small 28 pin WQFN package VDD1 RFOUT RFIN RFOUT PAP A1 1 PA 2 PA 3 RFOUT RFIN RFOUT RFOUT CMX902 1 Brief Description The CMX902 is a three stage high-gain and high efficiency RF power amplifier. The device is ideally suited for use in VHF and UHF frequency bands up to 700MHz. The first and second stages of the amplifier operate in a class-A and class-AB mode respectively, and the third stage operates in a class-C mode for maximum efficiency. External components are required to match the device input and output ports to 50 Ohms. The CMX902 is available in a small footprint 5mm x 5mm, low thermal resistance 28-pin WQFN package making it ideal for small form factor applications such as data modules as well as handheld radio terminals. 2021 CML Microsystems Plc D/902/2 March 2021 Page 1 of 16 VGS1 VGS2 VDD2 VGS3 VARF Power Amplifier CMX902 CONTENTS Section Page 1 Brief Description ....................................................................................................................................................... 1 1.1 History ............................................................................................................................................................................... 3 2 Block Diagram .......................................................................................................................................................... 3 3 Performance Specification ........................................................................................................................................ 4 3.1 Electrical Performance ...................................................................................................................................................... 4 3.1.1 Absolute Maximum Ratings .............................................................................................................................................. 4 3.1.2 Operating Limits ................................................................................................................................................................ 4 3.1.3 Operating Characteristics .................................................................................................................................................. 5 3.2 Typical Performance .......................................................................................................................................................... 6 3.2.1 Operation at 160MHz ........................................................................................................................................................ 6 3.2.2 Operation at 435MHz ........................................................................................................................................................ 6 4 Pin and Signal Definitions ......................................................................................................................................... 8 4.1 Pin List ............................................................................................................................................................................... 8 4.2 Signal Definitions ............................................................................................................................................................... 9 5 Application Information ......................................................................................................................................... 10 5.1 General Description ......................................................................................................................................................... 10 5.2 Main Characteristics ........................................................................................................................................................ 10 5.2.1 Input Impedance ............................................................................................................................................................. 10 5.2.2 Thermal Design ................................................................................................................................................................ 11 6 General Application Schematic ............................................................................................................................... 12 7 PCB Layout ............................................................................................................................................................. 13 8 Application Notes ................................................................................................................................................... 13 8.1 Output Power Control ..................................................................................................................................................... 13 8.1.1 TDMA Operation ............................................................................................................................................................. 13 8.2 Operation at 2.7V to 3.3V over 400 to 470 MHz ............................................................................................................. 13 9 Packaging ............................................................................................................................................................... 15 9.1 Ordering .......................................................................................................................................................................... 15 Table Page Table 1 S-parameter data (S ), V = 4V, Vgs1 = 1.65V, Vgs2 = 1.35V and Vgs3 = 0.93V, Ids = 16mA ............................................. 11 11 DD Table 2a Recommended External Components (variations with frequency) .................................................................................... 13 Figure Page Figure 1 CMX902 Block Diagram .......................................................................................................................................................... 3 Figure 2 Input power to output power characteristic, V = 4V .......................................................................................................... 6 DD Figure 3 Variation of output power with frequency and temperature, V = 4V, V = 3.3V, input level = -5dBm ....................... 6 DD PARAMP Figure 4 Output power vs. control voltage characteristics and variation with temperature, V = 4V, input level = -5dBm .............. 6 DD Figure 5 Output power and efficiency variation with temperature, V = 4V, input level = -5dBm, V = 3.3V ............................ 6 DD PARAMP Figure 6 Input power to output power characteristic, V = 4V at 435MHz ........................................................................................ 6 DD Figure 7 Variation in output power with frequency and temperature, V = 4V, V = 3.3V, input level = -5dBm ....................... 6 DD PARAMP Figure 8 Output power vs. control voltage characteristics variation with temperature, V = 4V, input level = -5dBm ..................... 7 DD Figure 9 Output power and efficiency variation with temperature, V = 4V, input level = -5dBm, V = 3.3V ............................ 7 DD PARAMP Figure 10 Pin Configuration ................................................................................................................................................................. 8 Figure 11 S response, V = 4V, Vgs1 = 1.65V, Vgs2 = 1.35V and Vgs3 = 0.93V, Ids = 16mA ........................................................... 10 11 DD Figure 12 CMX902 Recommended External Components ................................................................................................................. 12 Figure 13 Typical Output Power at Lower Supply Voltages ................................................................................................................ 14 Figure 14 QT8 Mechanical Outline of 28-pin WQFN (QT8) ................................................................................................................ 15 2021 CML Microsystems Plc D/902/2 March 2021 Page 2 of 16