max2264eue Maxim Integrated Products, Inc., max2264eue Datasheet - Page 12

• Manufacturer Part Number: max2264eue
• Description: 2.7v, Single-supply, Cellular-band Linear Power Amplifiers Integrated Products
• Manufacturer: Maxim Integrated Products, Inc.

2.7V, Single-Supply, Cellular-Band
Linear Power Amplifiers
ence, so the current out of this pin is inversely propor-
tional to the value of the resistor between this pin and
ground. Similarly, the bias current of the first stage in
high-power mode is proportional to the current flowing
out of BIAS1H. The current in the second stage is pro-
portional to the currents out of BIAS2L and BIAS2H for
low- and high-power modes, respectively.
Additionally, these resistors allow for customization of
gain and alternate- and adjacent-channel power ratios.
Increasing the bias current in the first stage increases
the gain and improves alternate-channel power ratio at
the expense of efficiency. Increasing the bias current in
the second stage increases gain at the expense of effi-
ciency as well as adjacent- and alternate-channel power
ratios.
The PA bias current can be dynamically adjusted by
summing a current into the bias pin of interest with an
external source such as a DAC. See the MAX2265
Typical Application Circuit for using a voltage DAC and
current setting resistors RTB1 and RTB2. Choosing
RTB1 = R1 and RTB2 = R2 allows current adjustment
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Figure 1. MAX2264 Typical Application Circuit
______________________________________________________________________________________
C3
L3
C11
C12
V
CC
SHDN
PWR
V
V
CC
CC
C4
L1
RH1
RL2
L4
RFIN
C1
1
2
3
4
5
6
7
8
L2
MAX2264
between 0mA to double the nominal idle current with
DAC voltages between 0V and 2.4V. The DAC must be
able to source approximately 100µA.
Pull pins 2 and 6 low to place the MAX2264/MAX2265/
MAX2266 into shutdown mode. In this mode, all gain
stages are disabled and supply current drops to 0.5µA.
The MAX2266 incorporates an additional external
switch to increase efficiency to 17% at +16dBm and to
32% at +28dBm. This efficiency increase is mainly due
to the additional isolation between the high- and low-
power outputs provided by the external switch.
The MAX2264/MAX2265/MAX2266 require matching
circuits at their inputs and outputs for operation in a
50Ω system. The application circuits in Figures 1, 2,
and 3 describe the topology of the matching circuits for
16
15
14
13
12
11
10
9
C2
C7
Applications Information
Increasing Efficiency Further
RL1
C13
C9
RH2
RFOUT
OPTIONAL NOISE-REDUCTION CIRCUIT
C8
External Components
C6
V
CC
L5
L6
Shutdown Mode
C5
V
CC