CMX901 Broadband Efficient RF Power Amplifier Features Applications Wide operating frequency range Wireless data communications 130MHz to 950MHz FSK, FFSK/MSK, GFSK/GMSK, Multi-level FSK Typical output power: Analogue FM handheld radio terminals 2.5W operating at 160MHz Marine AIS Class-B and Marine AIS-SART 1.8W operating at 435MHz RFID readers/writers 1.5W operating at 915MHz Automatic meter reading (AMR) High power gain 40dB Wireless sensor networks High power added efficiency Mesh/Ad hoc systems up to 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 CMX901 1 Brief Description The CMX901 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 950MHz. 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 CMX901 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/901/7 March 2021 Page 1 of 16 VGS1 VGS2 VDD2 VGS3 VARF Power Amplifier CMX901 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 ........................................................................................................................................................ 7 3.2.3 Operation at 915MHz ........................................................................................................................................................ 8 4 Pin and Signal Definitions ......................................................................................................................................... 9 4.1 Pin List ............................................................................................................................................................................... 9 4.2 Signal Definitions ............................................................................................................................................................. 10 5 Application Information ......................................................................................................................................... 11 5.1 General Description ......................................................................................................................................................... 11 5.2 Main Characteristics ........................................................................................................................................................ 11 5.2.1 Input Impedance ............................................................................................................................................................. 11 5.2.2 Thermal Design ................................................................................................................................................................ 12 6 General Application Schematic ............................................................................................................................... 13 7 PCB Layout ............................................................................................................................................................. 14 8 Application Notes ................................................................................................................................................... 14 8.1 Output Power Control ..................................................................................................................................................... 14 8.1.1 TDMA Operation ............................................................................................................................................................. 14 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 = 18mA ............................................. 12 11 DD Table 2a Recommended External Components (variations with frequency) .................................................................................... 14 Figure Page Figure 1 CMX901 Block Diagram .......................................................................................................................................................... 3 Figure 2 Input power to output power characteristic, V = 4V .......................................................................................................... 6 DD Figure 3 Variation of output power with 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 ........................................................................................ 7 DD Figure 7 Variation in output power with temperature, V = 4V, V = 3.3V, input level = -10dBm ............................................. 7 DD PARAMP Figure 8 Output power vs. control voltage characteristics variation with temperature, V = 4V, input level = -10dBm ................... 7 DD Figure 9 Output power and efficiency variation with temperature, V = 4V, input level = -10dBm, V = 3.3V .......................... 7 DD PARAMP Figure 10 Input power to output power characteristic, V = 4V at 915MHz ...................................................................................... 8 DD Figure 11 Variation in output power with temperature, V = 4V, V = 3.3V, input level = 0dBm .............................................. 8 DD PARAMP Figure 12 Output power vs. control voltage characteristics variation with temperature, V = 4V, input level = 0dBm .................... 8 DD Figure 13 Output power and efficiency variation with temperature, V = 4V, input level = 0dBm, V = 3.3V ........................... 8 DD PARAMP Figure 14 Pin Configuration ................................................................................................................................................................. 9 Figure 15 S response, V = 4V, Vgs1 = 1.65V, Vgs2 = 1.35V and Vgs3 = 0.93V, Ids = 18mA ........................................................... 11 11 DD Figure 16 CMX901 Recommended External Components ................................................................................................................. 13 Figure 17 QT8 Mechanical Outline .................................................................................................................................................... 15 2021 CML Microsystems Plc D/901/7 March 2021 Page 2 of 16