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General Description
The MAX1471 low-power, CMOS, superheterodyne, RF
dual-channel receiver is designed to receive both ampli-
tude-shift-keyed (ASK) and frequency-shift-keyed (FSK)
data without reconfiguring the device or introducing any
time delay normally associated with changing modula-
tion schemes. The MAX1471 requires few external com-
ponents to realize a complete wireless RF digital data
receiver for the 300MHz to 450MHz ISM bands.
The MAX1471 includes all the active components
required in a superheterodyne receiver including: a low-
noise amplifier (LNA), an image-reject (IR) mixer, a fully
integrated phase-locked loop (PLL), local oscillator
(LO), 10.7MHz IF limiting amplifier with received-signal-
strength indicator (RSSI), low-noise FM demodulator,
and a 3V voltage regulator. Differential peak-detecting
data demodulators are included for both the FSK and
ASK analog baseband data recovery. The MAX1471
includes a discontinuous receive (DRX) mode for low-
power operation, which is configured through a serial
interface bus.
The MAX1471 is available in a 32-pin thin QFN package
and is specified over the automotive -40C to +125C
temperature range.
Applications
Automotive Remote Keyless Entry (RKE)
Tire Pressure Monitoring Systems
Garage Door Openers
Wireless Sensors
Wireless Keys
Security Systems
Medical Systems
Home Automation
Local Telemetry Systems
Features
ASK and FSK Demodulated Data on Separate
Outputs
Specified over Automotive -40C to +125C
Temperature Range
Low Operating Supply Voltage Down to 2.4V
On-Chip 3V Regulator for 5V Operation
Low Operating Supply Current
7mA Continuous Receive Mode
1.1A Deep-Sleep Mode
Discontinuous Receive (DRX) Low-Power
Management
Fast-On Startup Feature < 250s
Integrated PLL, VCO, and Loop Filter
45dB Integrated Image Rejection
RF Input Sensitivity*
ASK: -114dBm
FSK: -108dBm
Selectable IF BW with External Filter
Programmable Through Serial User Interface
RSSI Output and High Dynamic Range with AGC
MAX1471
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
________________________________________________________________ Maxim Integrated Products
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27
26
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10
11
12
13
14
15
18
19
20
21
22
23
24
7
6
5
4
3
2
1
MAX1471
THIN QFN
TOP VIEW
DSA+
DSA-
OPA+
DFA
XTAL2
XTAL1
AV
DD
8
LNAIN
PDMAXA
PDMINA
AD
ATA
HV
IN
SCLK
DIO
25
FD
ATA
DV
DD
DGND
DFF
OPF+
DSF+
DSF-
PDMAXF
17
PDMINF
IFIN-
AGND
16
IFIN+
MIXOUT
MIXIN-
MIXIN+
LNAOUT
LNASRC
CS
Pin Configuration
19-3272; Rev 0; 4/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
*0.2% BER, 4kbps, Manchester-encoded data, 280kHz IF BW
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX1471ATJ
-40
C to +125C
32 Thin QFN-EP**
**EP = Exposed pad.
MAX1471
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
High-Voltage Supply, HV
IN
to DGND .......................-0.3V, +6.0V
Low-Voltage Supply, AV
DD
and DV
DD
to AGND .....-0.3V, +4.0V
SCLK, DIO, CS, ADATA,
FDATA ....................................(DGND - 0.3V) to (HV
IN
+ 0.3V)
All Other Pins.............................(AGND - 0.3V) to (AV
DD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70C)
32-Pin Thin QFN (derate 21.3mW/C above +70C) ...1702mW
Operating Temperature Range .........................-40C to +125C
Junction Temperature ......................................................+150C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) ................................ +300C
DC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40C to +125C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL CHARACTERISTICS
Supply Voltage (5V)
HV
IN
AV
DD
and DV
DD
unconnected from HV
IN
,
but connected together
4.5
5.0
5.5
V
Supply Voltage (3V)
V
DD
HV
IN
, AV
DD
, and DV
DD
connected to power
supply
2.4
3.0
3.6
V
Operating
7.0
8.4
mA
Polling duty cycle: 10%
duty cycle
705
855
DRX mode OFF current
5.0
14.2
T
A
< +85C
Deep-sleep current
1.1
7.1
A
Operating
8.5
mA
Polling duty cycle: 10%
duty cycle
865
DRX mode OFF current
15.5
T
A
< +105C
(Note 2)
Deep-sleep current
13.4
A
Operating
8.6
mA
Polling duty cycle: 10%
duty cycle
900
DRX mode OFF current
44.1
Supply Current
I
DD
T
A
< +125C
(Note 2)
Deep-sleep current
36.4
A
Startup Time
t
ON
Time for final signal detection, does not
include baseband filter settling (Note 2)
200
250
s
DIGITAL OUTPUTS (DIO, ADATA, FDATA)
Output High Voltage
V
OH
I
SOURCE
= 250A (Note 2)
HV
IN
-
0.15
V
Output Low Voltage
V
OL
I
SINK
= 250A (Note 2)
0.15
V
DIGITAL INPUTS (
CS, DIO, SCLK)
Input High Threshold
V
IH
0.9 x
HV
IN
V
Input Low Threshold
V
IL
.
0.1 x
HV
IN
V
MAX1471
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
_______________________________________________________________________________________
3
DC ELECTRICAL CHARACTERISTICS (continued)
(Typical Application Circuit, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40C to +125C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input-High Leakage Current
I
IH
(Note 2)
-10
A
Input-Low Leakage Current
I
IL
(Note 2)
10
A
Input Capacitance
C
IN
(Note 2)
2.0
pF
VOLTAGE REGULATOR
Output Voltage
V
REG
HV
IN
= 5.0V, I
LOAD
= 7.0mA
3.0
V
AC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40C to +125C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL CHARACTERISTICS
ASK
-114
Receiver Sensitivity
RF
IN
0.2% BER, 4kbps
Manchester Code, 280kHz
IF BW, 50
FSK
-108
dBm
Maximum Receiver Input Power
Level
RF
MAX
0
dBm
Receiver Input Frequency Range
f
RF
300
450
MHz
Receiver Image Rejection
IR
(Note 3)
45
dB
LNA/MIXER (Note 4)
f
RF
= 315MHz
1 - j4.7
LNA Input Impedance
Z
11
Normalized to 50
f
RF
= 434MHz
1 - j3.4
Voltage Conversion Gain (High-
Gain Mode)
47.5
dB
Input-Referred 3rd-Order
Intercept Point (High-Gain Mode)
-38
dBm
Voltage Conversion Gain (Low-
Gain Mode)
12.2
dB
Input-Referred 3rd-Order
Intercept Point (Low-Gain Mode)
-5
dBm
LO Signal Feedthrough to
Antenna
-90
dBm
Mixer Output Impedance
Z
OUT
330
IF
Input Impedance
Z
11
330
Operating Frequency
f
IF
10.7
MHz
3dB Bandwidth
10
MHz
FM DEMODULATOR
Demodulator Gain
G
FM
2.2
mV/kHz
MAX1471
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
4
_______________________________________________________________________________________
AC ELECTRICAL CHARACTERISTICS (continued)
(Typical Application Circuit, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40C to +125C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ANALOG BASEBAND
Maximum Data Filter Bandwidth
BW
DF
50
kHz
Maximum Data Slicer Bandwidth
BW
DS
100
kHz
Maximum Peak Detector
Bandwidth
BW
PD
50
kHz
Manchester coded
33
Maximum Data Rate
Nonreturn to zero (NRZ)
66
kbps
CRYSTAL OSCILLATOR
Crystal Frequency
f
XTAL
9.04
13.728
MHz
Frequency Pulling by V
DD
3
ppm/V
Maximum Crystal Inductance
50
H
Crystal Load Capacitance
3
pF
DIGITAL INTERFACE TIMING (see Figure 8)
Minimum SCLK Setup to Falling
Edge of CS
t
SC
30
ns
Minimum CS Falling Edge to
SCLK Rising-Edge Setup Time
t
CSS
30
ns
Minimum CS Idle Time
t
CSI
125
ns
Minimum CS Period
t
CS
2.125
s
Maximum SCLK Falling Edge to
Data Valid Delay
t
DO
80
ns
Minimum Data Valid to SCLK
Rising-Edge Setup Time
t
DS
30
ns
Minimum Data Valid to SCLK
Rising-Edge Hold Time
t
DH
30
ns
Minimum SCLK High Pulse Width
t
CH
100
ns
Minimum SCLK Low Pulse Width
t
CL
100
ns
Minimum CS Rising Edge to
SCLK Rising-Edge Hold Time
t
CSH
30
ns
Maximum CS Falling Edge to
Output Enable Time
t
DV
25
ns
Maximum CS Rising Edge to
Output Disable Time
t
TR
25
ns
Note 1: Production tested at T
A
= +85C. Guaranteed by design and characterization over entire temperature range.
Note 2: Guaranteed by design and characterization. Not production tested.
Note 3: The oscillator register (0x3) is set to the nearest integer result of f
XTAL
/ 100kHz (see the Oscillator Frequency Register section).
Note 4: Input impedance is measured at the LNAIN pin. Note that the impedance at 315MHz includes the 15nH inductive degeneration
from the LNA source to ground. The impedance at 434MHz includes a 10nH inductive degeneration connected from the LNA
source to ground. The equivalent input circuit is 50
in series with 2.2pF. The voltage conversion gain is measured with the
LNA input matching inductor, the degeneration inductor, and the LNA/mixer resonator in place, and does not include the IF fil-
ter insertion loss.
MAX1471
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
_______________________________________________________________________________________
5
6.0
6.4
6.8
7.2
7.6
8.0
2.4
2.7
3.0
3.3
3.6
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1471 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
+125
C
+105
C
+85
C
+25
C
-40
C
6.0
6.6
6.4
6.2
6.8
7.0
7.2
7.4
7.6
7.8
8.0
300
325
375
350
400
425
450
SUPPLY CURRENT
vs. RF FREQUENCY
MAX1471 toc02
RF FREQUENCY (MHz)
SUPPLY CURRENT (mA)
+125
C
-40
C
+25
C
+105
C +85C
0
2
6
4
10
8
12
-40
10
-15
35
60
85
110
DEEP-SLEEP CURRENT
vs. TEMPERATURE
MAX1471 toc03
TEMPERATURE (C)
DEEP-SLEEP CURRENT (
A)
100
10
1
0.1
0.01
-123
-121
-119
-117
-115
-113
-111
BIT-ERROR RATE
vs. AVERAGE INPUT POWER (ASK DATA)
MAX1471 toc04
AVERAGE INPUT POWER (dBm)
BIT-ERROR RATE (%)
0.2% BER
f
RF
= 434MHz
f
RF
= 315MHz
280kHz IF BW
100
10
1
0.1
0.01
-115
-110
-113
-108
-105
BIT-ERROR RATE
vs. AVERAGE INPUT POWER (FSK DATA)
MAX1471 toc05
AVERAGE INPUT POWER (dBm)
BIT-ERROR RATE
0.2% BER
f
RF
= 434MHz
f
RF
= 315MHz
280kHz IF BW
FREQUENCY DEVIATION =
50kHz
-120
-117
-111
-114
-105
-108
-102
-40
10
-15
35
60
85
110
SENSITIVITY
vs. TEMPERATURE (ASK DATA)
MAX1471 toc06
TEMPERATURE (C)
SENSITIVITY (dBm)
280kHz IF BW
0.2% BER
f
RF
= 434MHz
f
RF
= 315MHz
-112
-110
-106
-108
-104
-102
-40
10
-15
35
60
85
110
SENSITIVITY
vs. TEMPERATURE (FSK DATA)
MAX1471 toc07
TEMPERATURE (C)
SENSITIVITY (dBm)
280kHz IF BW
0.2% BER
f
RF
= 434MHz
f
RF
= 315MHz
FREQUENCY DEVIATION =
50kHz
-98
-112
1
10
100
SENSITIVITY vs. FREQUENCY
DEVIATION (FSK DATA)
-108
-110
MAX1471 toc08
FREQUENCY DEVIATION (kHz)
SENSITIVITY (dBm)
-106
-102
-104
-100
280kHz IF BW
0.2% BER
RSSI vs. RF INPUT POWER
MAX1471 toc09
0
0.2
0.6
0.4
1.2
1.4
1.0
0.8
1.6
RSSI (V)
-130
-90
-70
-110
-50
-30
-10
10
RF INPUT POWER (dBm)
AGC HYSTERESIS: 3dB
HIGH-GAIN MODE
LOW-GAIN MODE
AGC SWITCH
POINT
Typical Operating Characteristics
(Typical Application Circuit, AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434MHz, T
A
= +25C, unless otherwise noted.)
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