19-3272; Rev 1; 3/05
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
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 -40°C to +125°C
temperature range.
Features
♦
ASK and FSK Demodulated Data on Separate
Outputs
♦
Specified over Automotive -40°C to +125°C
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
1.1µA Deep-Sleep Mode
♦
Discontinuous Receive (DRX) Low-Power
Management
♦
Fast-On Startup Feature < 250µs
♦
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
*0.2%
BER, 4kbps, Manchester-encoded data, 280kHz IF BW
MAX1471
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
Ordering Information
PART
MAX1471ATJ
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
32 Thin QFN-EP**
**EP
= Exposed pad.
Pin Configuration
PDMAXA
ADATA
HV
IN
SCLK
CS
32
DSA-
DSA+
OPA+
DFA
XTAL2
XTAL1
AV
DD
LNAIN
31
30
29
28
27
26
25
24
23
22
21
DV
DD
DGND
DFF
OPF+
DSF+
DSF-
PDMAXF
PDMINF
1
2
3
4
5
6
7
8
9
LNASRC
MAX1471
FDATA
TOP VIEW
PDMINA
DIO
20
19
18
17
10
LNAOUT
11
MIXIN+
12
MIXIN-
13
MIXOUT
14
AGND
15
IFIN-
16
IFIN+
THIN QFN
________________________________________________________________
Maxim Integrated Products
1
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.
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
MAX1471
ABSOLUTE MAXIMUM RATINGS
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
= +70°C)
32-Pin Thin QFN (derate 21.3mW/°C above +70°C) ...1702mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +300°C
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.
DC ELECTRICAL CHARACTERISTICS
(Typical
Application Circuit,
AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40°C to +125°C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
GENERAL CHARACTERISTICS
Supply Voltage (5V)
Supply Voltage (3V)
HV
IN
V
DD
AV
DD
and DV
DD
unconnected from HV
IN
,
but connected together
HV
IN
, AV
DD
, and DV
DD
connected to power
supply
Operating
T
A
< +85°C
Polling duty cycle: 10%
duty cycle
DRX mode OFF current
Deep-sleep current
Operating
Supply Current
I
DD
T
A
< +105°C
(Note 2)
Polling duty cycle: 10%
duty cycle
DRX mode OFF current
Deep-sleep current
Operating
T
A
< +125°C
(Note 2)
Polling duty cycle: 10%
duty cycle
DRX mode OFF current
Deep-sleep current
Startup Time
t
ON
Time for final signal detection, does not
include baseband filter settling (Note 2)
200
4.5
2.4
5.0
3.0
7.0
705
5.0
1.1
5.5
3.6
8.4
855
14.2
7.1
8.5
865
15.5
13.4
8.6
900
44.1
36.4
250
µs
µA
mA
µA
mA
µA
V
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL OUTPUTS (DIO, ADATA, FDATA)
Output High Voltage
Output Low Voltage
DIGITAL INPUTS (CS, DIO, SCLK)
Input High Threshold
Input Low Threshold
V
IH
V
IL
0.9 x
HV
IN
.
0.1 x
HV
IN
V
V
V
OH
V
OL
I
SOURCE
= 250µA (Note 2)
I
SINK
= 250µA (Note 2)
HV
IN
-
0.15
0.15
V
V
2
_______________________________________________________________________________________
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
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
= -40°C to +125°C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Input-High Leakage Current
Input-Low Leakage Current
Input Capacitance
VOLTAGE REGULATOR
Output Voltage
V
REG
HV
IN
= 5.0V, I
LOAD
= 7.0mA
3.0
V
SYMBOL
I
IH
I
IL
C
IN
(Note 2)
(Note 2)
(Note 2)
CONDITIONS
MIN
TYP
MAX
-20
20
2.0
UNITS
µA
µA
pF
MAX1471
AC ELECTRICAL CHARACTERISTICS
(Typical
Application Circuit,
AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40°C to +125°C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
GENERAL CHARACTERISTICS
Receiver Sensitivity
Maximum Receiver Input Power
Level
Receiver Input Frequency Range
Receiver Image Rejection
LNA/MIXER
(Note 4)
LNA Input Impedance
Voltage Conversion Gain (High-
Gain Mode)
Input-Referred 3rd-Order
Intercept Point (High-Gain Mode)
Voltage Conversion Gain (Low-
Gain Mode)
Input-Referred 3rd-Order
Intercept Point (Low-Gain Mode)
LO Signal Feedthrough to
Antenna
Mixer Output Impedance
IF
Input Impedance
Operating Frequency
3dB Bandwidth
FM DEMODULATOR
Demodulator Gain
G
FM
2.2
mV/kHz
Z
11
f
IF
330
10.7
10
Ω
MHz
MHz
Z
OUT
Z
11
Normalized to 50Ω
f
RF
= 315MHz
f
RF
= 434MHz
1 - j4.7
1 - j3.4
47.5
-38
12.2
-5
-90
330
dB
dBm
dB
dBm
dBm
Ω
RF
IN
0.2% BER, 4kbps
Manchester Code, 280kHz
IF BW, 50Ω
ASK
FSK
-114
dBm
-108
0
300
(Note 3)
45
450
dBm
MHz
dB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RF
MAX
f
RF
IR
_______________________________________________________________________________________
3
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
MAX1471
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
= -40°C to +125°C, unless otherwise
noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434 MHz, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
ANALOG BASEBAND
Maximum Data Filter Bandwidth
Maximum Data Slicer Bandwidth
Maximum Peak Detector
Bandwidth
Maximum Data Rate
CRYSTAL OSCILLATOR
Crystal Frequency
Frequency Pulling by V
DD
Maximum Crystal Inductance
Crystal Load Capacitance
DIGITAL INTERFACE TIMING
(see Figure 8)
Minimum SCLK Setup to Falling
Edge of
CS
Minimum
CS
Falling Edge to
SCLK Rising-Edge Setup Time
Minimum
CS
Idle Time
Minimum
CS
Period
Maximum SCLK Falling Edge to
Data Valid Delay
Minimum Data Valid to SCLK
Rising-Edge Setup Time
Minimum Data Valid to SCLK
Rising-Edge Hold Time
Minimum SCLK High Pulse Width
Minimum SCLK Low Pulse Width
Minimum
CS
Rising Edge to
SCLK Rising-Edge Hold Time
Maximum
CS
Falling Edge to
Output Enable Time
Maximum
CS
Rising Edge to
Output Disable Time
t
SC
t
CSS
t
CSI
t
CS
t
DO
t
DS
t
DH
t
CH
t
CL
t
CSH
t
DV
t
TR
30
30
125
2.125
80
30
30
100
100
30
25
25
ns
ns
ns
µs
ns
ns
ns
ns
ns
ns
ns
ns
f
XTAL
9.04
3
50
3
13.728
MHz
ppm/V
µH
pF
BW
DF
BW
DS
BW
PD
Manchester coded
Nonreturn to zero (NRZ)
50
100
50
33
66
kHz
kHz
kHz
kbps
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Note 1:
Note 2:
Note 3:
Note 4:
Production tested at T
A
= +85°C. Guaranteed by design and characterization over entire temperature range.
Guaranteed by design and characterization. Not production tested.
The oscillator register (0x3) is set to the nearest integer result of f
XTAL
/ 100kHz (see the
Oscillator Frequency Register
section).
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 50Ω 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.
4
_______________________________________________________________________________________
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
Typical Operating Characteristics
(Typical
Application Circuit,
AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 434MHz, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1471 toc01
MAX1471
SUPPLY CURRENT
vs. RF FREQUENCY
MAX1471 toc02
DEEP-SLEEP CURRENT
vs. TEMPERATURE
MAX1471 toc03
8.0
+105°C
7.6
SUPPLY CURRENT (mA)
+85°C
+125°C
8.0
7.8
7.6
SUPPLY CURRENT (mA)
7.4
7.2
7.0
6.8
6.6
6.4
6.2
+25°C
-40°C
+125°C
+105°C
+85°C
12
10
DEEP-SLEEP CURRENT (µA)
8
6
4
2
0
7.2
6.8
+25°C
6.4
-40°C
6.0
2.4
2.7
3.0
SUPPLY VOLTAGE (V)
3.3
3.6
6.0
300
325
350
375
400
425
450
RF FREQUENCY (MHz)
-40
-15
10
35
60
85
110
TEMPERATURE (
°
C)
BIT-ERROR RATE
vs. AVERAGE INPUT POWER (ASK DATA)
MAX1471 toc04
BIT-ERROR RATE
vs. AVERAGE INPUT POWER (FSK DATA)
MAX1471 toc05
SENSITIVITY
vs. TEMPERATURE (ASK DATA)
280kHz IF BW
0.2% BER
MAX1471 toc06
100
280kHz IF BW
100
280kHz IF BW
FREQUENCY DEVIATION =
±50kHz
-102
-105
SENSITIVITY (dBm)
-108
-111
-114
-117
-120
10
BIT-ERROR RATE (%)
BIT-ERROR RATE
f
RF
= 434MHz
10
f
RF
= 434MHz
1
0.2% BER
0.1
f
RF
= 315MHz
1
0.2% BER
0.1
f
RF
= 315MHz
f
RF
= 434MHz
f
RF
= 315MHz
0.01
-123
-121
-119
-117
-115
-113
-111
AVERAGE INPUT POWER (dBm)
0.01
-115
-113
-110
-108
-105
AVERAGE INPUT POWER (dBm)
-40
-15
10
60
85
TEMPERATURE (
°
C)
35
110
SENSITIVITY
vs. TEMPERATURE (FSK DATA)
MAX1471 toc07
SENSITIVITY vs. FREQUENCY
DEVIATION (FSK DATA)
MAX1471 toc08
RSSI vs. RF INPUT POWER
AGC HYSTERESIS: 3dB
1.4
1.2
1.0
RSSI (V)
0.8
0.6
HIGH-GAIN MODE
AGC SWITCH
POINT
MAX1471 toc09
-102
-104
SENSITIVITY (dBm)
280kHz IF BW
0.2% BER
FREQUENCY DEVIATION =
±50kHz
-98
-100
SENSITIVITY (dBm)
-102
-104
-106
-108
-110
280kHz IF BW
0.2% BER
1.6
-106
f
RF
= 434MHz
-108
f
RF
= 315MHz
-110
0.4
0.2
0
1
10
FREQUENCY DEVIATION (kHz)
100
-130 -110
-90
-50 -30
RF INPUT POWER (dBm)
-70
-10
10
LOW-GAIN MODE
-112
-40
-15
10
60
85
°
C)
TEMPERATURE (
35
110
-112
_______________________________________________________________________________________
5
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