MAX2411AEEI Maxim Integrated Products, MAX2411AEEI Datasheet - Page 9

• Manufacturer Part Number: MAX2411AEEI
• Description: RF Wireless Misc 1.9GHz LNA, Downconv erter, Upconverter,
• Manufacturer: Maxim Integrated Products

The MAX2411A consists of five major components: a
transmit mixer followed by a variable-gain power-
amplifier (PA) driver as well as a low-noise amplifier
(LNA), receive mixer, and power-management section.
The following sections describe each of the blocks in
the MAX2411A Functional Diagram .
The LNA is a wideband, single-ended cascode amplifi-
er that can be used over a wide range of frequencies.
Refer to the LNA Gain vs. Frequency graph in the
Typical Operating Characteristics . Its port impedances
are optimized for operation around 1.9GHz, requiring
only a 1pF shunt capacitor at the LNA input for a VSWR
of better than 2:1 and a noise figure of 2.4dB. As with
every LNA, the input match can be traded off for better
noise figure.
The PA driver has typically 15dB of gain, which is
adjustable over a 35dB range via the GC pin. At full gain,
the PA driver has a noise figure of 3.5dB at 1.9GHz.
For input and output matching information, refer to the
Typical Operating Characteristics for plots of PA Driver
Input and Output Impedance vs. Frequency.
The MAX2411A has a unique bidirectional differential IF
port, which can eliminate the need for separate transmit
and receive IF filters, reducing cost and component count.
Consult the Typical Operating Circuit for more information.
For single-ended operation, connect the unused IF port to
V
In receive mode, the IF and IF pins are open-collector
outputs that need external inductive pull-ups to V
_________________________________________________Pin Description (continued)
_______________Detailed Description
CC
and bypass with a 1000pF capacitor to GND.
PIN
24
25
26
27
LNAOUT
RXMXIN
_______________________________________________________________________________________
NAME
GND
GND
Low-Noise Amplifier (LNA)
Bidirectional IF Port
RF Input to Receive Mixer (downconverter). This input typically requires a matching network for
connecting to an external filter. AC couple to this pin. See the Typical Operating Characteristics
for a plot of RXMXIN Impedance vs. Frequency.
Receive Mixer Input Ground. Connect GND to the PC board ground plane with minimal inductance.
LNA Output Ground. Connect GND to the PC board ground plane with minimal inductance.
LNA Output. AC couple to this pin. This output typically provides a VSWR of better than 2:1 at fre-
quencies from 1.7GHz to 3GHz with no external matching components. At other frequencies, a
matching network may be required to match LNAOUT to an external filter. Consult the Typical
Operating Characteristics for a plot of LNA Output Impedance vs. Frequency.
Low-Cost RF Up/Downconverter
PA Driver
CC
for
with LNA and PA Driver
proper operation. These inductors are typically used as
part of an IF matching network.
In transmit mode, IF and IF are high-impedance inputs
that are internally AC coupled to the transmit mixer.
This internal AC coupling prevents the DC bias voltage
required for the receive mixer outputs from reaching
the transmit mixer inputs.
The receive mixer is a wideband, double-balanced
design with excellent noise figure and linearity. Inputs to
the mixer are the RF signal at the RXMXIN pin and the
LO inputs at LO and LO. The downconverted output sig-
nal appears at the IF port. For more information, see the
Bidirectional IF Port section. The conversion gain of the
receive mixer is typically 9.4dB with a 9.2dB noise figure.
The RXMXIN input is typically connected to the LNA out-
put through an off-chip filter. This input is externally
matched to 50Ω. See the Typical Operating Circuit for an
example matching network and the Receive Mixer Input
Impedance vs. Frequency graph in the Typical Operating
Characteristics.
The LO and LO pins are internally terminated with 50Ω
on-chip resistors. AC couple the local-oscillator signal
to these pins. If a single-ended LO source is used, con-
nect LO directly to ground.
The transmit mixer takes an IF signal at the IF port and
upconverts it to an RF frequency at the TXMXOUT pin.
For more information on the IF port, see the Bidirectional
IF Port section. The conversion gain is typically 8.5dB,
and the output 1dB compression point is typically
11.1dBm at 1.9GHz.
FUNCTION
Local-Oscillator Inputs
Transmit Mixer
Receive Mixer
RF Input
9