SINGLE-SUPPLY DUAL-MODE LINEAR PAs REDUCE CDMA CURRENT DRAW 50%
SUNNYVALE, CA-September 7, 1999-Maxim Integrated Products introduces the MAX2264/MAX2265 true, +2.7V to +5.0V single-supply power amplifiers (PAs) designed for IS-98-based CDMA, PDC, and IS-136-based TDMA cellular phones operating in the 900MHz range. They have been optimized for highest efficiency at low and medium output power; this is particularly important in CDMA phones that spend 90% of their time outputting less than +16dBm.
When matched for CDMA operation and biased with margin over the adjacent and alternate channel specification (-45dBc/-56dBc), the amplifiers achieve up to 29.5dBm output power with 37% efficiency (MAX2265). At a +16dBm output, the MAX2265 still has 7% efficiency, yielding excellent overall talk time. At the same power level, the MAX2264 has an unprecedented 12% efficiency, while still obtaining 32% efficiency at maximum output power.
The MAX2264/MAX2265 have two internally referenced bias ports that are normally terminated with simple resistors. The bias ports allow customization of ACPR margin and gain. They can also be used to "throttle back" bias current when generating low power levels. The MAX2264/MAX2265 have excellent gain stability over temperature (±0.8dB), so overdesign of driver stages and excess driver current are dramatically reduced, further increasing the phone's talk time. Nonlinear efficiency is 48% when matched for linear operation, or 55% when matched for nonlinear operation only.
The MAX2264/MAX2265 are packaged in a 16-pin TSSOP with exposed paddle. For module or direct chip attach (DCA) applications, the MAX2264 is also available in die form. Prices start from $3.56 (1000-up, FOB USA).
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