Industry’s First 1.8 Volt 2.4GHz Power Amplifier IC Doesn’t Compromise on Power or Performance
By Joe Grimm, Product Marketing Manager, California Eastern Laboratories

As available battery voltages drop, ZigBee, Bluetooth and ISM Band designers will need Power Amplifier (PA) ICs that can run on lower supply voltages — but still deliver the output power their applications demand. NEC’s new UPG2250T5N GaAs Power Amplifier is an ideal candidate (Figure 1). It’s designed to operate at supply voltages of 1.5 to 3.5V and, at 1.8V VDD, delivers +20.0 dBm of output power. At 3.0V VDD, POUT jumps even higher: to +25 dBm (Figures 2 & 3).

The UPG2250T5N PA is no lightweight in the gain department, either. With 25dB gain at 1.8V and 30dB at 3.0V, it helps get you to full power without the need for additional driver devices. Plus, with a Gain Control Range (GCR) of 60dB (typ), you have the ability to back off power and current as needed, which helps prolong battery life. Battery life is further enhanced by the PA’s 55% Power Added Efficiency (PAE) performance.

New Batteries Drive a New Process Technology
New lower-voltage Lithium Ion batteries were a driving force behind the development of the UPG2250T5N. To fully utilize these new batteries, NEC knew they would have to develop lower-voltage Power Amplifiers that delivered both high efficiency and low distortion characteristics. To do so, NEC developed a new Enhancement-Mode (E-Mode) FET process. Unlike heterojunction bipolar transistors (HBTs), E-Mode devices provide zero offset voltage and low on-resistance (Ron), resulting in excellent power performance under low voltage operation. NEC’s new E-Mode process features a buried regrown p+ GaAs gate structure that, besides exhibiting low RON, has negligible drain-current frequency dispersion and achieves high power added efficiency.

Ultra-Miniature Package
NEC also knew that real estate in the next generation handsets would be at a premium. NEC is an acknowledged leader in ultra-miniature RF semiconductor packaging technology, and the UPG2250T5N is a good example of where that technology is headed. At just 1.5mm square and 0.37mm in height, the T5N is approximately half the size of other PA ICs on the market (Figure 4). Engineers faced with the challenge of miniaturizing their handset designs will love it. They’ll also appreciate how the T5N package’s six-pin configuration helps simplify their circuit design. With Control and Enable built into one pin (Figure 5), one less voltage input is needed. T5N packages are also RoHS-compliant, so they can be used in products destined for markets worldwide.

Designed to serve 2.4 to 2.5 GHz applications, the UPG2250T5N enables longer distance transmission at lower supply voltages. It can be combined with NEC’s GaAs RFIC Switches and external LNA devices (see Figure 6) to provide front-end solutions that can significantly increase both the range and sensitivity of cellular handsets and ZigBee, Bluetooth and ISM Band transceivers.

Battery Life a Concern?
The UPG2250T5N joins a growing family of NEC Power Amplifiers. One recently introduced device, the UPG2314T5N, was developed specifically for extended battery operation. At 3.0V VCC, the UPG2314T5N delivers +20dBm POUT with current consumption of just 65mA (Figure 1). Also housed in NEC’s ultra-miniature, simple-to-integrate T5N package, the UPG2314T5N should be considered for any 2.4 – 2.5GHz application in which low current consumption and long battery life are critical.

Evaluation Boards Available
These two PAs and their evaluation boards are in stock and available now from CEL. The low-current UPG2314T5N is available on its own board, or in combination with NEC’s 0.5 Watt SPDT UPG2214TK GaAs Switch ICs in a front-end solution that’s designed to integrate easily with ZigBee, Bluetooth and ISM transceiver ICs. It can be configured to provide either straight-through low-power output, or amplified output for longer-range applications.

The UPG2250T5N is currently available on its own eval board, with integrated boards planned for the near future.

Additional information and data sheets on these devices and their eval boards are available from CEL as well as from its network of reps and distributors.

CALIFORNIA EASTERN LABORATORIES
www.cel.com
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