2.7V, Single-Supply, Cellular-Band

Linear Power Amplifiers

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Detailed Description

The MAX2264/MAX2265/MAX2266 are linear power

amplifiers (PAs) intended for CDMA and TDMA appli-

cations. The devices have been fully characterized in

the 824MHz to 849MHz U.S. cellular band and can be

used from 750MHz to 1000MHz by adjusting the input

and output match. In CDMA applications, they provide

typically 28dBm of output power and up to 37% power-

added efficiency (PAE) from a single +2.7V to +5V sup-

ply. In TDMA applications, efficiency is 42% at 30dBm

of output power.

An inherent drawback of traditional PAs is that their effi-

ciency drops rapidly with reduced output power. For

example, in a PA designed for maximum efficiency at

+28dBm, the efficiency at +15dBm falls well below

4.5% (over 210mA from a +3.3V supply). This behavior

significantly reduces talk time in CDMA phones

because over 90% of the time they are at output pow-

ers below +16dBm. The MAX2264/MAX2265/MAX2266

are optimized for lowest current draw at output powers

that are most likely to occur in real-life situations. This

provides up to 50% reduced average PA current.

High-Power and Low-Power Modes

The MAX2264/MAX2266 are designed to provide opti-

mum PAE in both high- and low-power modes. For a

+3.3V supply, maximum output power is +28dBm in

high-power mode and +16dBm in low-power mode.

Use the system’s microcontroller to determine required

output power, and switch between the two modes as

appropriate with the PWR logic pin.

Bias Control

The bias current of the first stage in low-power mode is

proportional to the current flowing out of BIAS1L. The

voltage at BIAS1L is fixed by an internal bandgap refer-

Pin Description

IN0

RF Input Port. Requires external matching network.

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16

BIAS1L

OUT0

NFP

GND

BIAS2H

BIAS1H

SHDN

BIAS2L

OUT1

PWR

IN1

NAME

Low-Power Mode First Stage Bias Control. See General Description.

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10

RF Output Port. Requires an appropriate output matching network and collector

bias.

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11

Noise Filtering Pin. Connect noise filtering network as described in

Noise Filtering section. If unused, leave open.

12

12

Ground. Solder the package slug to high-thermal-conductivity circuit board

ground plane.

13, Slug

13, Slug

High-Power Mode Second Stage Bias Control. See General Description.

15

15

High-Power Mode First Stage Bias Control. See General Description.

4

4

Shutdown Control Input. Drive SHDN low to enable shutdown. Drive high for normal

operation. On the MAX2265, make sure that both pins get driven simultaneously.

To place the MAX2264/MAX2266 into shutdown mode, also pull the PWR pin low.

2, 6

6

Low-Power Mode Second Stage Bias Control. See General Description.

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7

RF Output Ports. Require an appropriate output matching network and collector

bias.

8, 9

8, 9

Voltage Supply. Bypass with capacitors connected between this pin and GND.

3, 5

3, 5, 14

Mode-Select Input. Drive low to select the low-power mode (BIAS1L and

BIAS2L). Drive high to select high-power mode (BIAS1H and BIAS2H).

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2

PIN

RF Input Port. Requires external matching network.

1

1

MAX2265

MAX2264

MAX2266

FUNCTION

N.C.

Not Internally Connected. Do not make any connections to these pins.

7, 10, 11,

14, 16

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