Today Freescale announced three new high-power RFICs for WiMAXbasestations, pushing its LDMOS and overmolded plastic packaging technology up into the 2.7 and 3.5-GHz bands. Because overmolded plastic has a tighter tolerance, base station amplifier designers can keep their PCB slots to tighter tolerances, thereby reducing manufacturing variation. The three new Freescale RFICs include the MW7IC2725N and the MW7IC2750N operating from 2.3 to 2.7 GHz, and the
MW7IC3825N operating from 3.4 to 3.6 GHz. All three of them integrate two stages of gain and are manufactured using Freescale's seventh-generation high-voltage (HV7) LDMOS process technology.
The main difference between the two devices for the 2.3 to 2.7GHz band is output power. When asked why there were not two versions for the 3.4 to 3.6 GHz band, Daniel Ong, Freescale's Product Manager supporting the WiMAX portfolio explained that the 2.3 to 2.7GHz band had more variation in terms of power level requirements, “The power levels being used in the other band are much lower at this point, but we expect them to increase. So, we will address this in the future.”
The company reports that in most cases, the higher RF output power of the RFICs allows for the elimination of the predriver stage in WiMAX basestations. For instance, Ong notes that a 2.7 GHz discrete device offers 17dB gain while the new Freescale devices provide between 25 and 28dB gain. The devices also can be used along with discrete LDMOS FETs to produce even more RFoutput power.
Here's the specifics:
- All three devices operate from a +28 to +32 VDC supply and handle a VSWR of 10:1 at +32 VDC while delivering their rated CW output power. They also incorporate electrostatic-discharge (ESD) protection.
- MW7IC2725N: 25 W CW output power at 1 dB gain compression point (P1dB) and at 4 W average power; 28 dB gain, 17% efficiency, adjacent channel power ratio (ACPR) at 5.25-MHz offset of -50 dBc in 500 kHz channel bandwidth
- MW7IC2750N: 50 W CW output power at 1 dB gain compression point (P1dB) and at 8 W average power; 26 dB gain, 17% efficiency, ACPR at 5.25-MHz offset of -49 dBc in 500 kHz channel bandwidth
- MW7IC3825N: 25 W CW output power at 1 dB gain compression point (P1dB) and at 5 W average RF output power; 23.5 dB gain, 15% efficiency, ACPR at 5.25-MHz offset of -49 dBc in 500 kHz channel bandwidth
The MW7IC2725N, MW7IC2750N and MW7IC3825N devices are sampling now and full production is expected in Q1 2008. Visit www.freescale.com/wimax for more information.