+3.6V, 1W Autoramping Power Amplifier for 900MHz Applications

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The MAX2235 low-voltage, silicon RF power amplifier (PA) is designed for use in the 900MHz frequency band. It operates directly from a single +2.7V to +5.5V supply, making it suitable for use with 3-cell NiCd or 1-cell Li-Ion batteries. The device delivers +30dBm (1W) typical output power from a +3.6V supply or +28dBm from a +2.7V supply.

The MAX2235's gain is adjustable over a 37dB range. A power-control pin controls gain and bias to maintain optimum efficiency, even at lower output power levels, thus extending the operating life of the battery. At +30dBm output power, efficiency is typically 47%. An additional power-saving feature is a shutdown mode that typically reduces supply current below 1µA.

A key feature of this PA is its autoramping capability. During turn-on and turn-off periods, the RF envelope is controlled to approximate a raised cosine on the rising and falling edge, thereby minimizing transient noise and spectral splatter. The ramp time is set by selecting the value of an external capacitor.

The MAX2235 is intended for use in constant envelope applications such as AMPS, two-way paging, or FSK-based communications in the 900MHz ISM band. The device is available in a thermally enhanced 20-pin TSSOP package with a heat slug.
MAX2235: Typical Operating Circuit MAX2235: Typical Operating Circuit Enlarge+

Key Features

  • 800MHz to 1000MHz Operation
  • High Output Power at 836MHz
    • +32.5dBm at +5.0V
    • +30dBm at +3.6V
    • +29dBm at +3.0V
    • +28dBm at +2.7V
  • +2.7V to +5.5V Single-Supply Operation
  • Automatic Power-Up/Power-Down Ramp
  • Direct On/Off Keying (OOK) without Intersymbol Interference or VCO Pulling
  • 37dB Power-Control Range
  • 47% Efficiency
  • < 1µA Supply Current in Shutdown Mode
  • Small 20-Pin TSSOP Package with Heat Slug


  • 900MHz ISM-Band Applications
  • Analog Cellular Phones
  • Microcellular GSM (Power Class 5)
  • Two-Way Paging
  • Wireless Data Networks

See parametric specs for Power Amplifiers/Drivers (7)

Part NumberFreq.
Efficiency (%)Low Pwr. ShutdnFootprint
(mm x mm)
minmaxSee Notes
MAX2235 80010003047Yes6.4 x 6.5
$2.27 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX2235EVKIT: MAX2235 Evaluation Kit
Product Reliability Reports: MAX2235.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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Type ID Title
Evaluation Board2015MAX2235EVKIT MAX2235 Evaluation Kit