MAXIM MAX7042 Technical data

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 lownoise amplifier (LNA), an image-rejection (IR) mixer, a fully integrated phase-locked loop (PLL), local oscillator (LO), 10.7MHz IF limiting amplifier with received-signalstrength 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 TQFN 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

o +2.4V to +3.6V or +4.5V to +5.5V Single-Supply

Operation

o Four User-Selectable Carrier Frequencies

308, 315, 418, and 433.92MHz

o -110dBm RF Input Sensitivity at 315MHz

o -109dBm RF Input Sensitivity at 433.92MHz

o Fast Startup (< 250µs)

o Small 32-Pin TQFN Package

o Low Operating Supply Current

6.2mA Continuous 20nA Power-Down

o Integrated PLL, VCO, and Loop Filter

o 45dB Integrated Image Rejection

o Selectable IF BW with External Filter

o Positive and Negative Peak Detectors

o RSSI Output

MAX7042

308MHz/315MHz/418MHz/433.92MHz

Low-Power, FSK Superheterodyne Receiver

________________________________________________________________

Maxim Integrated Products

Pin Configuration

Ordering Information

19-3704; Rev 2; 1/12

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Denotes a lead(Pb)-free/RoHS-compliant package.

EP = Exposed pad.

EVALUATION KIT

AVAILABLE

Typical Application Circuit appears at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX7042ATJ+ -40°C TO +125°C 32 TQFN-EP*

TOP VIEW

N.C.

FSEL1

FSEL2

HVIN

DATA

LNASEL

N.C.

DGND

DVDD

24 23 22 21 20 19 18

1234567

MAX7042

OP+

DS+

DS-

PDMAX

PDMIN

IFIN+

IFIN-

AGND

MIXOUT

MIXIN-

MIXIN+

LNAOUT

LNASRC

RSSI

TQFN

XTAL2

XTAL1

AVDD

LNAIN

N.C.

MAX7042

308MHz/315MHz/418MHz/433.92MHz Low-Power, FSK Superheterodyne Receiver

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(

Typical Application Circuit

, 50Ω system impedance, V

AVDD

= V

DVDD

= V

HVIN

= +2.4V to +3.6V, fRF= 308, 315, 418, and

433.92MHz; T

= -40°C to +125°C, unless otherwise noted. Typical values are at V

AVDD

= V

DVDD

= V

HVIN

= +3.0V,

= 433.92MHz, P

RFIN

≤ -80dBm, TA= +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 TQFN (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

Soldering Temperature (reflow) .......................................+260°C

Supply Voltage (3V) V

Supply Voltage (5V) HVIN

Supply Current I

Shutdown Current (3V) I

Startup Time t

DIGITAL I/O

Input High Threshold V

Input Low Threshold V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

HVIN, AVDD, and DVDD connected

to power supply

HVIN connected to power supply, AVDD and DVDD unconnected from HVIN, but connected together

315M H z ( 3V )

315M H z ( 5V )

434M H z ( 3V )

434M H z ( 5V )

SHDN

All digital inputs low

Time from EN = high to final signal detection; does not include

baseband filter or dataslicer reference settling

Operating, 1x I

Operating, 2x I

Operating, 1x I

Operating, 2x I

Operating, 1x I

Operating, 2x I

Operating, 1x I

Operating, 2x I

TA = +25°C 0.02

TA = +85°C 0.1

= +125°C 0.85 6

TA = +25°C 0.6

TA = +85°C 1.4Shutdown Current (5V) I

= +125°C 4 7

2.4 3.0 3.6 V

4.5 5.0 5.5 V

LNA

0.9 x V

HVIN

6.2

6.8

6.4

7.0

6.4 8.7

7.0 8.6

6.6 8.4

7.2 9.2

250 µs

0.1 x V

HVIN

µA

MAX7042

308MHz/315MHz/418MHz/433.92MHz

Low-Power, FSK Superheterodyne Receiver

_______________________________________________________________________________________ 3

DC ELECTRICAL CHARACTERISTICS (continued)

(

Typical Application Circuit

, 50Ω system impedance, V

AVDD

= V

DVDD

= V

HVIN

= +2.4V to +3.6V, fRF= 308, 315, 418, and

433.92MHz; T

= -40°C to +125°C, unless otherwise noted. Typical values are at V

AVDD

= V

DVDD

= V

HVIN

= +3.0V,

= 433.92MHz, P

RFIN

≤ -80dBm, TA= +25°C, unless otherwise noted.)

AC ELECTRICAL CHARACTERISTICS

(

Typical Application Circuit

, 50Ω system impedance, V

AVDD

= V

DVDD

= V

HVIN

= +2.4V to +3.6V, fRF= 308, 315, 418, and

433.92MHz; T

= -40°C to +125°C, unless otherwise noted. Typical values are at V

AVDD

= V

DVDD

= V

HVIN

= +3.0V,

= 433.92MHz, P

RFIN

≤ -80dBm, TA= +25°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

= +3.6V 8 15

Input High Pulldown Current I

Input Low-Leakage Current I

Output High Voltage V

Output Low Voltage V

OHISOURCE

OLISINK

HVIN

= +5.5V 20 40

HVIN

= +3.6V < 1 1

HVIN

= +5.5V < 1 1

HVIN

= 500µA V

- 0.4 V

HVIN

= 500µA 0.4 V

VOLTAGE REGULATOR

Output Voltage V

REG

2.5 3.0 3.5 V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Maximum Input Level 0 dBm

Sensitivity (Note 1)

Receiver Image Rejection 45 dB

LNA/MIXER

Input Impedance (Note 2) Z

1dB Input Compression Point P

Input-Referred 3rd-Order Intercept Point

LO Signal Feedthrough to Antenna

Mixer Output Impedance Zout

Voltage Conversion Gain

IF LIMITING AMPLIFIER

Input Impedance Z

-3dB Bandwidth 10 MHz

Operating, 1x I

Operating, 2x I

Operating, 1x I

Operating, 2x I

2x I

LNA

2x I

LNA

1x I

LNA

2x I

LNA

1x I

LNA

2x I

LNA

IN_LNA

1dB

IIP3

MIX

IN_IF

315MHz setting

434MHz setting

Normalized to 50Ω

1x I

315MHz -47

LNA

2x I

315MHz -52

LNA

1x I

315MHz -37

LNA

2x I

315MHz -42

LNA

330Ω IF filter load (Note 3)

LNA

-107

-110

-106

-109

315MHz 0.94 - j3.2

433.92MHz 0.94 - j2.1

-80 dBm

330 Ω

315MHz 52

315MHz 57

433.92MHz 47

433.92MHz 52

330 Ω

dBm

µA

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. Note that the impedance at 315MHz includes the 3.9nH inductive degener-

ation from the LNA source to ground. The impedance at 433.92MHz includes a 0nH inductive degeneration connected from the LNA source to ground. The equivalent input circuit is 47Ω in series with 3.2pF at 315MHz and 47Ω 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

, 50Ω system impedance, V

AVDD

= V

DVDD

= V

HVIN

= +2.4V to +3.6V, fRF= 308, 315, 418, and

433.92MHz; T

= -40°C to +125°C, unless otherwise noted. Typical values are at V

AVDD

= V

DVDD

= V

HVIN

= +3.0V,

= 433.92MHz, P

RFIN

≤ -80dBm, TA= +25°C, unless otherwise noted.)

Typical Operating Characteristics

(

Typical Application Circuit

, VDD= 3.0V, fRF= 433.92MHz, IF BW = 280kHz, data rate = 4kbps Manchester encoded, frequency

deviation = ±50kHz, BER = 0.2%, TA= +25°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Frequency f

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

Maximum Data-Slicer Bandwidth BW

Maximum Data Rate

CRYSTAL OSCILLATOR

Crystal Frequency f

Crystal Load Capacitance 4.5 pF

Manchester coded 33

NRZ 66

XTAL

10.7 MHz

50 kHz

100 kHz

(fRF - 10.7)

/ 32

kHz

MHz

SUPPLY CURRENT vs. SUPPLY VOLTAGE

7.2

7.0

6.8

6.6

6.4

6.2

6.0

SUPPLY CURRENT (mA)

5.8

5.6

5.4

+85°C

2.4 3.02.7 3.3 3.6 SUPPLY VOLTAGE (V)

(1x I

+125°C

-40°C

LNA

)

+25°C

SUPPLY CURRENT vs. SUPPLY VOLTAGE

8.0

7.8

MAX7042 toc01

7.6

7.4

7.2

7.0

6.8

6.6

SUPPLY CURRENT (mA)

6.4

6.2

6.0

2.4 3.02.7 3.3 3.6

(2x I

+125°C

+85°C

SUPPLY VOLTAGE (V)

LNA

+25°C

)

MAX7042 toc02

-40°C

SUPPLY CURRENT vs. RF FREQUENCY

7.0

6.8

6.6

6.4

6.2

SUPPLY CURRENT (mA)

6.0

5.8

5.6 300 350 375325 400 425 450

RF FREQUENCY (MHz)

(1x I

+125°C

+85°C

+25°C

-40°C

LNA

)

MAX7042 toc03

MAX7042

308MHz/315MHz/418MHz/433.92MHz

Low-Power, FSK Superheterodyne Receiver

_______________________________________________________________________________________

Typical Operating Characteristics (continued)

(

Typical Application Circuit

, VDD= 3.0V, fRF= 433.92MHz, IF BW = 280kHz, data rate = 4kbps Manchester encoded, frequency

deviation = ±50kHz, BER = 0.2%, T

= +25°C, unless otherwise noted.)

SUPPLY CURRENT vs. RF FREQUENCY

)

(2x I

7.5

7.3

7.1

6.9

6.7

SUPPLY CURRENT (mA)

6.5

6.3

6.1 300 350 375325 400 425 450

LNA

+125°C

+85°C

+25°C

-40°C

RF FREQUENCY (MHz)

BIT-ERROR RATE vs. AVERAGE INPUT POWER

)

(2x I

100

LNA

fRF = 433.92MHz

DEEP-SLEEP CURRENT vs. TEMPERATURE

1000

MAX7042 toc04

800

600

400

DEEP-SLEEP CURRENT (nA)

200

-40

TEMPERATURE (°C)

MAX7042 toc07

SENSITIVITY vs. TEMPERATURE

-103

-104

-105

(1x I

VDD = +3.6V

VDD = +3.0V

VDD = +2.4V

)

LNA

BIT-ERROR RATE vs. AVERAGE INPUT POWER

100

MAX7042 toc05

11085603510-15

0.2% BER

BIT-ERROR RATE (%)

0.1

0.01

-114 -104

fRF = 315MHz

-112 AVERAGE INPUT POWER (dBm)

SENSITIVITY vs. TEMPERATURE

-106

MAX7042 toc08

-107

-108

(1x I

(2x I

)

LNA

fRF = 433.92MHz

-108-110

)

LNA

MAX7042 toc06

-106

MAX7042 toc09

0.2% BER

BIT-ERROR RATE (%)

0.1

fRF = 315MHz

0.01

-117 -107

-113 -111

-115 AVERAGE INPUT POWER (dBm)

SENSITIVITY

vs. FREQUENCY DEVIATION

-100

-102

-104

-106

SENSITIVITY (dBm)

-108

-110

-112 1 100

FREQUENCY DEVIATION IS MEASURED FROM 0 TO PEAK

FREQUENCY DEVIATION (kHz)

-109

MAX7042 toc10

-106

fRF = 433.92MHz

SENSITIVITY (dBm)

-107

-108 fRF = 315MHz

-109

TEMPERATURE (°C)

RSSI AND DELTA

vs. IF INPUT POWER

1.8

1.5

1.2

0.9

RSSI (V)

0.6

0.3

-90 -50 -30-70 -10 10

RSSI

IF INPUT POWER (dBm)

DELTA

11085603510-15-40

MAX7042 toc11

-109

SENSITIVITY (dBm)

-110

-111

-112

-1

-2

-3

2.0

1.6

1.2

DELTA (%)

0.8

0.4

FSK DEMODULATION OUTPUT (V)

10.3 10.5 10.610.4 10.810.7 10.9 11.0

fRF = 433.92MHz

fRF = 315MHz

11085603510-15-40

TEMPERATURE (°C)

FSK DEMODULATOR OUTPUT

vs. IF FREQUENCY

MAX7042 toc12

IF FREQUENCY (MHz)

MAX7042

308MHz/315MHz/418MHz/433.92MHz Low-Power, FSK Superheterodyne Receiver

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(

Typical Application Circuit

, VDD= 3.0V, fRF= 433.92MHz, IF BW = 280kHz, data rate = 4kbps Manchester encoded, frequency

deviation = ±50kHz, BER = 0.2%, T

= +25°C, unless otherwise noted.)

SYSTEM GAIN vs. IF FREQUENCY

SYSTEM GAIN (dB)

-10

45dB IMAGE

REJECTION

030

IF FREQUENCY (MHz)

IMAGE REJECTION vs. TEMPERATURE

IMAGE REJECTION (dB)

)

(1x I

LNA

UPPER SIDEBAND

FROM RFIN

TO MIXOUT

= 433.92MHz

LOWER SIDEBAND

fRF = 433.92MHz

fRF = 315MHz

(2x I

SYSTEM GAIN vs. IF FREQUENCY

)

(2x I

MAX7042 toc13

SYSTEM GAIN (dB)

252015105

-10

45dB IMAGE

REJECTION

030

LNA

UPPER SIDEBAND

FROM RFIN

TO MIXOUT

= 433.92MHz

LOWER SIDEBAND

IF FREQUENCY (MHz)

MAX7042 toc14

252015105

IMAGE REJECTION vs. TEMPERATURE

(1x I

fRF = 433.92MHz

fRF = 315MHz

IMAGE REJECTION (dB)

LNA

TEMPERATURE (°C)

)

MAX7042 toc15

11085603510-15-40

NORMALIZED IF GAIN

LNA

)

MAX7042 toc16

-3

-6

-9

-12

NORMALIZED IF GAIN (dB)

-15

vs. IF FREQUENCY

MAX7042 toc17

TEMPERATURE (°C)

11085603510-15-40

-18 1

IF FREQUENCY (MHz)

S11 vs. RF FREQUENCY

-4

-8

S11 (dB)

433.92MHz

-12

-16 100 1000

RF FREQUENCY (MHz)

MAX7042 toc18

850700550400250

100

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