General Description
The MAX7042 fully integrated, low-power, CMOS
superheterodyne RF receiver is designed to receive
frequency-shift-keyed (FSK) data at rates up to 66kbps
nonreturn-to-zero (NRZ) (33kbps Manchester). The
MAX7042 requires only a few external components to
realize a complete wireless RF receiver at 308, 315,
418, and 433.92MHz.
The MAX7042 includes all the active components
required in a superheterodyne receiver including a low-
noise amplifier (LNA), an image-rejection (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 regulator. Differential peak-detecting data
demodulators are included for baseband data recovery.
The MAX7042 is available in a 32-pin thin QFN and
is specified over the automotive -40°C to +125°C
temperature range.
Applications
Remote Keyless Entry
Tire-Pressure Monitoring
Home and Office Lighting Control
Remote Sensing
Smoke Alarms
Home Automation
Local Telemetry Systems
Security Systems
Features
+2.4V to +3.6V or +4.5V to +5.5V Single-Supply
Operation
Four User-Selectable Carrier Frequencies
308, 315, 418, and 433.92MHz
-110dBm RF Input Sensitivity at 315MHz
-109dBm RF Input Sensitivity at 433.92MHz
Fast Startup (<250µs)
Small 32-Pin Thin QFN Package
Low Operating Supply Current
6.2mA Continuous
20nA Power-Down
Integrated PLL, VCO, and Loop Filter
45dB Integrated Image Rejection
Selectable IF BW with External Filter
Positive and Negative Peak Detectors
RSSI Output
MAX7042
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
________________________________________________________________ Maxim Integrated Products
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14
15
16
31
30
29
28
27
26
25
MAX7042
THIN QFN
TOP VIEW
EN
N.C.
FSEL1
FSEL2
HV
IN
DATA
LNASEL
32
N.C.
N.C.
N.C.
N.C.
RSSI
XT
AL2
XT
AL1
AV
DD
LNAIN
DV
DD
DGND
DF
OP+
DS+
DS-
PDMAX
17
PDMIN
IFIN+
IFIN-
AGND
MIXOUT
MIXIN-
MIXIN+
LNAOUT
9
LNASRC
8
Pin Configuration
Ordering Information
19-3704; Rev 0; 5/05
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.
*EP = Exposed pad.
PART
TEMP
RANGE
PIN-PACKAGE
PKG CODE
MAX7042ATJ
-40°C to
+125°C
32 Thin QFN-EP*
13255-3
Typical Application Circuit appears at end of data sheet.
MAX7042
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, 50
system impedance, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 308, 315, 418, and 433.92MHz;
T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 433.92MHz,
P
RFIN
-80dBm, T
A
= +25°C, unless otherwise noted.)
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.
HVIN to AGND or DGND .......................................-0.3V to +6.0V
AVDD, DVDD to AGND or DGND..........................-0.3V to +4.0V
FSEL1, FSEL2, LNASEL,
EN, DATA...............................(DGND - 0.3V) to (HVIN + 0.3V)
All Other Pins............................(AGND - 0.3V) to (AVDD + 0.3V)
Continuous Power Dissipation (TA = +70°C)
32-Pin Thin QFN (derate 34.5mW/°C above +70°C)....2759mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Maximum RF Input Power ................................................+0dBm
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage (3V)
V
DD
HV
IN
, AV
DD
, and DV
DD
connected
to power supply
2.4
3.0
3.6
V
Supply Voltage (5V)
HV
IN
HV
IN
connected to power supply,
AV
DD
and DV
DD
unconnected from
HV
IN
, but connected together
4.5
5.0
5.5
V
Operating, 1x I
LNA
6.2
315M H z ( 3V )
Operating, 2x I
LNA
6.8
Operating, 1x I
LNA
6.4
315M H z ( 5V )
Operating, 2x I
LNA
7.0
Operating, 1x I
LNA
6.4
8.7
434M H z ( 3V )
Operating, 2x I
LNA
7.0
8.6
Operating, 1x I
LNA
6.6
8.4
Supply Current
I
DD
434M H z ( 5V )
Operating, 2x I
LNA
7.2
9.2
mA
T
A
= +25°C
0.02
T
A
= +85°C
0.1
Shutdown Current (3V)
I
SHDN
All digital
inputs low
T
A
= +125°C
0.85
6
µA
T
A
= +25°C
0.6
T
A
= +85°C
1.4
Shutdown Current (5V)
I
SHDN
All digital
inputs low
T
A
= +125°C
4
7
µA
Startup Time
t
ON
Time from EN = high to final signal
detection; does not include
baseband filter or data-
slicer reference settling
250
µs
DIGITAL I/O
Input High Threshold
V
IH
0.9 x HV
IN
V
Input Low Threshold
V
IL
0.1 x HV
IN
V
MAX7042
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
_______________________________________________________________________________________
3
DC ELECTRICAL CHARACTERISTICS (continued)
(Typical Application Circuit, 50
system impedance, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 308, 315, 418, and 433.92MHz;
T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 433.92MHz,
P
RFIN
-80dBm, T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
HV
IN
= +3.6V
8
15
Input High Pulldown Current
I
IH
HV
IN
= +5.5V
20
40
µA
HV
IN
= +3.6V
<1
1
Input Low-Leakage Current
I
IL
HV
IN
= +5.5V
<1
1
µA
Output High Voltage
V
OH
I
SOURCE
= 500µA
HV
IN
- 0.4
V
Output Low Voltage
V
OL
I
SINK
= 500µA
0.4
V
VOLTAGE REGULATOR
Output Voltage
V
REG
2.5
3.0
3.5
V
AC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, 50
system impedance, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 308, 315, 418, and 433.92MHz;
T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 433.92MHz,
P
RFIN
-80dBm, T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Maximum Input Level
0
dBm
Operating, 1x I
LNA
-107
315MHz
setting
Operating, 2x I
LNA
-110
Operating, 1x I
LNA
-106
Sensitivity (Note 1)
434MHz
setting
Operating, 2x I
LNA
-109
dBm
Receiver Image Rejection
45
dB
LNA/MIXER
2x I
LNA
315MHz
0.94 - j3.2
Input Impedance (Note 2)
Z
11
Normalized to
50
2x I
LNA
433.92MHz
0.94 - j2.1
1x I
LNA
315MHz
-47
1dB Input Compression Point
(Notes 2, 3)
P
1dB
2x I
LNA
315MHz
-52
dBm
1x I
LNA
315MHz
-37
Input-Referred 3rd-Order Intercept
Point (Notes 2, 3)
IIP3
2x I
LNA
315MHz
-42
dBm
LO Signal Feedthrough to
Antenna
-80
dBm
Mixer Output Impedance
Zout
MIX
330
1x I
LNA
315MHz
52
2x I
LNA
315MHz
57
1x I
LNA
433.92MHz
47
Voltage Conversion Gain
330
IF filter
load
(Notes 2, 3)
2x I
LNA
433.92MHz
52
dB
IF LIMITING AMPLIFIER
Input Impedance
Z
11
330
-3dB Bandwidth
10
MHz
MAX7042
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
4
_______________________________________________________________________________________
Note 1: 0.2% BER, 4kbps, Manchester coded, 280kHz IF BW, ±50kHz frequency deviation.
Note 2: Input impedance is measured at the LNAIN pin 2x I
LNA
. Note that the impedance at 315MHz includes the 3.9nH inductive
degeneration from the LNA source to ground. The impedance at 433.92MHz includes a 0nH inductive degeneration con-
nected from the LNA source to ground. The equivalent input circuit is 47
in series with 3.2pF at 315MHz and 47 in series
with 3.5pF at 433.92MHz.
Note 3: 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 filter insertion loss.
AC ELECTRICAL CHARACTERISTICS (continued)
(Typical Application Circuit, 50
system impedance, AV
DD
= DV
DD
= HV
IN
= +2.4V to +3.6V, f
RF
= 308, 315, 418, and 433.92MHz;
T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at AV
DD
= DV
DD
= HV
IN
= +3.0V, f
RF
= 433.92MHz,
P
RFIN
-80dBm, T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Operating Frequency
f
IF
10.7
MHz
RSSI Slope
10
16
21
mV/dB
FSK DEMODULATOR
Conversion Gain
1.1
2.1
3.0
mV/kHz
ANALOG BASEBAND
M axi m um P eak- D etector Band w i d th
50
kHz
Maximum Data-Filter Bandwidth
BW
DF
50
kHz
Maximum Data-Slicer Bandwidth
BW
DS
100
kHz
Manchester coded
33
Maximum Data Rate
NRZ
66
kHz
CRYSTAL OSCILLATOR
Crystal Frequency
f
XTAL
(f
RF
- 10.7)
/ 32
MHz
Crystal Load Capacitance
4.5
pF
5.4
5.8
5.6
6.4
6.2
6.0
7.0
6.8
6.6
7.2
2.4
3.0
2.7
3.3
3.6
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(1x I
LNA
)
MAX7042 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
-40
°C
+125
°C
+85
°C
+25
°C
6.0
6.4
6.2
7.0
6.8
6.6
7.6
7.8
7.4
7.2
8.0
2.4
3.0
2.7
3.3
3.6
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(2x I
LNA
)
MAX7042 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
-40
°C
+25
°C
+125
°C
+85
°C
5.6
6.0
5.8
6.4
6.2
6.8
6.6
7.0
300
350
375
325
400
425
450
SUPPLY CURRENT vs. RF FREQUENCY
(1x I
LNA
)
MAX7042 toc03
RF FREQUENCY (MHz)
SUPPLY CURRENT (mA)
+125
°C
+85
°C
+25
°C
-40
°C
Typical Operating Characteristics
(Typical Application Circuit, V
DD
= 3.0V, f
RF
= 433.92MHz, IF BW = 280kHz, data rate = 4kbps Manchester encoded, frequency
deviation = ±50kHz, BER = 0.2%, T
A
= +25°C, unless otherwise noted.)
MAX7042
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
_______________________________________________________________________________________
5
6.1
6.5
6.3
6.9
6.7
7.3
7.1
7.5
300
350
375
325
400
425
450
SUPPLY CURRENT vs. RF FREQUENCY
(2x I
LNA
)
MAX7042 toc04
RF FREQUENCY (MHz)
SUPPLY CURRENT (mA)
+125
°C
+85
°C
+25
°C
-40
°C
DEEP-SLEEP CURRENT vs. TEMPERATURE
MAX7042 toc05
TEMPERATURE (
°C)
DEEP-SLEEP CURRENT (nA)
110
85
60
35
10
-15
200
400
600
800
1000
0
-40
V
CC
= +3.6V
V
CC
= +3.0V
V
CC
= +2.4V
BIT-ERROR RATE vs. AVERAGE INPUT POWER
(1x I
LNA
)
MAX7042 toc06
AVERAGE INPUT POWER (dBm)
BIT-ERROR RATE
-106
-108
-110
-112
0.1
1
10
100
0.01
-114
-104
f
RF
= 433.92MHz
0.2% BER
f
RF
= 315MHz
BIT-ERROR RATE vs. AVERAGE INPUT POWER
(2x I
LNA
)
MAX7042 toc07
AVERAGE INPUT POWER (dBm)
BIT-ERROR RATE
-109
-113
-111
-115
0.1
1
10
100
0.01
-117
-107
f
RF
= 433.92MHz
0.2% BER
f
RF
= 315MHz
SENSITIVITY (dBm)
-108
-107
-106
-105
-104
-103
-109
SENSITIVITY vs. TEMPERATURE
(1x I
LNA
)
MAX7042 toc08
TEMPERATURE (
°C)
110
85
60
35
10
-15
-40
f
RF
= 433.92MHz
f
RF
= 315MHz
SENSITIVITY (dBm)
-111
-110
-109
-108
-107
-106
-112
SENSITIVITY vs. TEMPERATURE
(2x I
LNA
)
MAX7042 toc09
TEMPERATURE (
°C)
110
85
60
35
10
-15
-40
f
RF
= 433.92MHz
f
RF
= 315MHz
SENSITIVITY
vs. FREQUENCY DEVIATION
MAX7042 toc10
FREQUENCY DEVIATION (kHz)
SENSITIVITY (dBm)
10
-110
-108
-106
-104
-102
-100
-112
1
100
FREQUENCY DEVIATION IS
MEASURED FROM 0 TO PEAK
0
0.6
0.3
1.2
0.9
1.5
1.8
-3
-1
-2
1
0
2
3
-90
-50
-30
-70
-10
10
RSSI AND DELTA
vs. IF INPUT POWER
MAX7042 toc11
RF INPUT POWER (dBm)
RSSI (V)
DELTA (%)
RSSI
DELTA
0
0.8
0.4
1.6
1.2
2.0
10.3
10.5
10.6
10.4
10.8
10.7
10.9
11.0
FSK DEMODULATOR OUTPUT
vs. IF FREQUENCY
MAX7042 toc12
IF FREQUENCY (MHz)
FSK DEMODULATION OUTPUT (V)
Typical Operating Characteristics (continued)
(Typical Application Circuit, V
DD
= 3.0V, f
RF
= 433.92MHz, IF BW = 280kHz, data rate = 4kbps Manchester encoded, frequency
deviation = ±50kHz, BER = 0.2%, T
A
= +25°C, unless otherwise noted.)
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