2.1.3
Doherty amplifier technology for state-of-the-art wireless infrastructure
Best-in-class PA designs enable considerable energy savings
NXP’s latest power amplifier designs let the wireless infrastructure run with significantly higher energy
efficiency – towards “Green Base Stations”. In order to achieve the highest efficiencies currently possible,
NXP combines its latest generations of LDMOS technology (Gen7 & 8) with the Doherty concept. The high
performance of our LDMOS technology, matched with the efficiency of the Doherty technology, creates
power amplifiers that offer high efficiency and high gain, are easily linearizable, and are more cost-effective
to operate.
Developed by W.H. Doherty in 1936, the Doherty amplifier remained largely unused because the dominant
mobile communication system modulation techniques (FM, GMSK, and EDGE) did not require high peak-to-
average ratio (PAR) signals. For today's base stations, however, transmitting 3G, 4G, and multi-carrier signals
makes the high power and added efficiency of the Doherty approach the preferred option for most service
providers.
NXP’s Doherty designs ensure high efficiency while maintaining a very similar peak power capability of two
transistors combined. The input and output sections are internally matched, benefiting the amplifiers with
high gain, good gain flatness, and phase linearity over a wide frequency band.
Integrated Doherty
NXP offers the world’s first fully integrated Doherty designs.
From the outside these devices look like ordinary transistors.
In fact, they are completely integrated Doherty amplifiers that
readily deliver the associated high efficiency levels for base
station applications. With the ease of design-in of an ordinary
Class AB transistor, they also provide significant
space and cost savings.
Key features & benefits
`
Contains splitter, main and peak amplifier, delay lines,
and combiner in one package
- 40% efficiency @ 10 W average power
- No additional tuning in manufacturing
`
Design is as easy as with a single Class AB transistor
`
Ideally suited for space-constrained applications
(e.g. remote radio heads, antenna arrays)
`
Currently available for TD-SCDMA (BLD6G21L(S)-50) and
W-CDMA (BLD22L(S)-50); see section 3.7.1.4 for details
46
NXP Semiconductors RF Manual 16
th
edition
PHILIPS [ NXP SEMICONDUCTORS ]
