Rainbow Electronics MAX7033 - Manual (Page 9)

MAX7033
315MHz/433MHz ASK Superheterodyne
Receiver with AGC Lock
_______________________________________________________________________________________ 9
Functional Diagram
LNAOUT MIXIN1 MIXIN2
0˚
90˚
IFIN1 MIXOUT IFIN2
RSSI
R DF2
100k Ω
R DF1
100k Ω
DIVIDE
BY 64
VCO
LOOP
FILTER
PHASE
DETECTOR
CRYSTAL
DRIVER
POWER-
DOWN
IF LIMITING
AMPS
14
LNASRC
DATA
SLICER
DATA
FILTER
Q
∑
I
AUTOMATIC
GAIN
CONTROL
IMAGE
REJECTION
3.2V REG 24
2, 7
IRSEL
13
5, 10
AV DD
V DD5
DV
DD
DGND
AGND
LNAIN
3
XTALSEL
16
XTAL1
1
XTAL2
28
SHDN
27
DATAOUT
25
DSN
20
DSP
23
DFO
19
PDOUT
26
OPP
21
DFFB
22
4 15 6 8 9 11 12 17 18
AC
ч2
ч1
MAX7033
LNA
28-PIN TSSOP
PACKAGE
Pin Description (continued)
PIN
TSSOP THIN QFN
NAME FUNCTION
27 27 SHDN
Power-Down Select Input. Drive high to power up the IC. Internally pulled down to AGND
with a 100k
Ω resistor.
28 28 XTAL2
Crystal Input 2. Can also be driven with an external reference oscillator. (See the Crystal
Oscillator section.)
—
1, 13, 21,
25
N.C No Connection
Detailed Description
The MAX7033 CMOS superheterodyne receiver and a
few external components provide the complete receive
chain from the antenna to the digital output data.
Depending on signal power and component selection,
data rates as high as 33kbps Manchester (66kbps
NRZ) can be achieved.
The MAX7033 is designed to receive binary ASK data
modulated in the 300MHz to 450MHz frequency range.
ASK modulation uses a difference in amplitude of the
carrier to represent logic 0 and logic 1 data.
For operation with a single +3.0V to +3.6V supply voltage,
connect AV
DD
, DV
DD
, and V
DD5
to the supply voltage.
For operation with a single +4.5V to +5.5V supply volt-
age, connect V
DD5 to the supply voltage. An on-chip
voltage regulator drives one of the AV DD pins to
approximately +3.2V. For proper operation, DV DD and
both AV DD pins must be connected together. Bypass
DV
DD
and both AV
DD
pins to AGND with 0.01µF
capacitors placed as close to the pins as possible.
Low-Noise Amplifier
The LNA is an nMOS cascode amplifier with off-chip
inductive degeneration, with a 3.0dB noise figure and
an IIP3 of -12dBm. The gain and noise figures are
dependent on both the antenna matching network at
the LNA input and the LC tank network between the
LNA output and the mixer inputs.