MAX2511 Ver la hoja de datos (PDF) - Maxim Integrated
Número de pieza
componentes Descripción
Fabricante
MAX2511 Datasheet PDF : 16 Pages
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Low-Voltage IF Transceiver
with Limiter and RSSI
IF BPF
LIMIN
MIXOUT
VREF
CZ
CZ
RECEIVE IMAGE-REJECT MIXER
90°
RXIN
Σ GM
RXIN
0°
OFFSET
CORRECTION
LIMITER
TANK
TANK
OSCOUT
0°
RSSI
VREF = VCC / 2
90°
LO PHASE
SHIFTER
PA
TXOUT
TXOUT
VGA
0°
Σ
90°
TRANSMIT IMAGE-REJECT MIXER AND VGA/PA
MAX2511
VOLTAGE GAIN
AND BIAS CONTROL
LIMOUT
LIMOUT
VGA
RSSI
RXEN
BIAS
TXEN
TXIN
TXIN
GC
Figure 1. Functional Diagram
_______________Detailed Description
The following sections describe each of the blocks
shown in Figure 1.
Receiver
The receiver consists of two basic blocks: the image-
reject downconverter mixer and the limiter/RSSI section.
The receiver inputs are the RXIN, RXIN pins, which
should be AC coupled and may require a matching net-
work, as shown in the Typical Operating Circuit. To
design a matching network for a particular application,
refer to the Applications Information section and the
receiver input impedance plots in the Typical Operating
Characteristics.
Image-Reject Mixer
The downconverter is implemented using an image-
reject mixer consisting of an input buffer with dual out-
puts, each of which is fed to a double-balanced mixer.
The LO signal is generated by an on-chip oscillator and
an external tank circuit. The buffered oscillator signal
drives a quadrature phase generator that provides two
outputs with 90° of phase shift between them. This pair
of LO signals is fed to the two receive mixers. The
mixer’s outputs are then passed through a pair of
phase shifters, which provide 90° of phase shift across
their outputs. The resulting two signals are then
summed together. The final phase relationship is such
that the desired signal is reinforced, and the image sig-
nal is largely canceled. The downconverter mixer’s
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