max2411a Maxim Integrated Products, Inc., max2411a Datasheet - Page 10

• Manufacturer Part Number: max2411a
• Description: Max2411a Low-cost Rf Up/downconverter With Lna And Pa Driver
• Manufacturer: Maxim Integrated Products, Inc.

The transmit mixer output appears on the TXMXOUT
pin, an open-collector output that requires an external
pull-up inductor for DC biasing, which can be part of an
impedance matching network. Consult the Typical
Operating Characteristics for a plot of TXMXOUT
Impedance vs. Frequency.
RXEN and TXEN are the two separate power-control
inputs for the receiver and transmitter. If both inputs
are at logic 0, the part enters shutdown mode, and
the supply current drops below 1µA. When one input
is brought to logic 1, the corresponding function is
enabled. If RXEN and TXEN are both set to logic 1, the
part enters standby mode, as described in the Standby
Mode section. Table 1 summarizes these operating
modes.
Power-down is guaranteed with a control voltage at or
below 0.6V. The power-down function is designed to
reduce the total power consumption to less than 1µA in
less than 2.5µs. Complete power-up happens in the
same amount of time.
When the TXEN and RXEN pins are both set to logic 1,
all functions are disabled, and the supply current drops
to 160µA (typ); this mode is called Standby. This mode
corresponds to a standby mode on the compatible IF
transceiver chips MAX2510 and MAX2511.
The MAX2411A has been characterized at 1.9GHz for
use in PCS-band applications. However, it operates
over a much wider frequency range. The LNA gain and
noise figure, PA driver gain, and mixer conversion gain
are plotted over a wide frequency range in the Typical
Operating Characteristics . When operating the device
Low-Cost RF Up/Downconverter
with LNA and PA Driver
10
__________Applications Information
______________________________________________________________________________________
Advanced System Power Management
Extended Frequency Range
Standby Mode
RF Output
at RF frequencies other than those specified in the AC
Electrical Characteristics table, it may be necessary to
design or alter the matching networks on the RF ports. If
the IF frequency is different from that specified in the AC
Electrical Characteristics table, the IF, IF matching net-
work must also be altered. The Typical Operating
Characteristics provide port impedance data versus fre-
quency on all RF and IF ports for use in designing
matching networks. The LO port (LO and LO) is internal-
ly terminated with 50Ω resistors and provides a VSWR of
approximately 1.2:1 to 2GHz and 2:1 up to 3GHz.
A properly designed PC board is essential to any
RF/microwave circuit. Be sure to use controlled imped-
ance lines on all high-frequency inputs and outputs.
Use low-inductance connections to ground on all GND
pins, and place decoupling capacitors close to all V
connections.
For the power supplies, a star topology works well.
Each V
central V
low impedance at the RF frequency of interest. The
central V
as well. This provides good isolation between the
different sections of the MAX2411A. The MAX2411A
EV kit layout can be used as a guide to integrating the
MAX2411A into your design.
Table 1. Advanced System Power-
Management Function
RXEN
CC
0
0
1
1
CC
CC
node in the circuit has its own path to the
and a decoupling capacitor that provides a
node has a large decoupling capacitor
TXEN
0
1
0
1
Shutdown
Transmit
Receive
Standby mode
Layout Issues
FUNCTION
CC