Rainbow Electronics MAX1471 User Manual

General Description

The MAX1471 low-power, CMOS, superheterodyne, RF
dual-channel receiver is designed to receive both ampli­tude-shift-keyed (ASK) and frequency-shift-keyed (FSK)
data without reconfiguring the device or introducing any
time delay normally associated with changing modula­tion schemes. The MAX1471 requires few external com­ponents 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 low­noise amplifier (LNA), an image-reject (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 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 low­power 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.

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 -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

MAX1471

315MHz/434MHz Low-Power, 3V/5V

ASK/FSK Superheterodyne Receiver

________________________________________________________________ Maxim Integrated Products 1

32 31 30 29 28 27 26

9101112131415

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

FDATA

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 +125°C 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, HVINto DGND.......................-0.3V, +6.0V

Low-Voltage Supply, AV

DD

and DVDDto 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

DC ELECTRICAL CHARACTERISTICS

(Typical Application Circuit, AVDD= DVDD= HVIN= +2.4V to +3.6V, fRF= 300MHz to 450MHz, TA= -40°C to +125°C, unless otherwise
noted. Typical values are at AV

DD

= DVDD= HVIN= +3.0V, fRF= 434 MHz, TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

GENERAL CHARACTERISTICS

Supply Voltage (5V) HV

IN

AVDD and DVDD unconnected from HVIN,
but connected together

4.5 5.0 5.5 V

Supply Voltage (3V) V

DD

HVIN, AVDD, and DVDD connected to power
supply

2.4 3.0 3.6 V

Operating 7.0 8.4 mA

Polling duty cycle: 10%
duty cycle

5.0

TA < +85°C

Deep-sleep current 1.1 7.1

µA

Operating 8.5 mA

Polling duty cycle: 10%
duty cycle

TA < +105°C
(Note 2)

Deep-sleep current

µA

Operating 8.6 mA

Polling duty cycle: 10%
duty cycle

Supply Current I

DD

TA < +125°C
(Note 2)

Deep-sleep current

µA

Startup Time t

ON

Time for final signal detection, does not
include baseband filter settling (Note 2)

µs

DIGITAL OUTPUTS (DIO, ADATA, FDATA)

Output High Voltage V

OH

I

SOURCE

= 250µA (Note 2)

HV

IN

­V

Output Low Voltage V

OL

I

SINK

= 250µA (Note 2)

V

DIGITAL INPUTS (CS, DIO, SCLK)

Input High Threshold V

IH

0.9 x
V

Input Low Threshold V

IL

.

0.1 x
V

DRX mode OFF current

DRX mode OFF current 15.5

DRX mode OFF current 44.1

705 855

200 250

0.15

0.15

HV

IN

14.2

865

13.4

900

36.4

HV

IN

MAX1471

315MHz/434MHz Low-Power, 3V/5V

ASK/FSK Superheterodyne Receiver

_______________________________________________________________________________________ 3

DC ELECTRICAL CHARACTERISTICS (continued)

(Typical Application Circuit, AVDD= DVDD= HVIN= +2.4V to +3.6V, fRF= 300MHz to 450MHz, TA= -40°C to +125°C, unless otherwise
noted. Typical values are at AV

DD

= DVDD= HVIN= +3.0V, fRF= 434 MHz, TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Input-High Leakage Current I

IH

(Note 2) -10 µA

Input-Low Leakage Current I

IL

(Note 2) 10 µA

Input Capacitance C

IN

(Note 2) 2.0 pF

VOLTAGE REGULATOR

Output Voltage V

REG

HVIN = 5.0V, I

LOAD

= 7.0mA 3.0 V

AC ELECTRICAL CHARACTERISTICS

(Typical Application Circuit, AVDD= DVDD= HVIN= +2.4V to +3.6V, fRF= 300MHz to 450MHz, TA= -40°C to +125°C, unless otherwise
noted. Typical values are at AV

DD

= DVDD= HVIN= +3.0V, fRF= 434 MHz, TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

UNITS

GENERAL CHARACTERISTICS

ASK

Receiver Sensitivity RF

IN

0.2% BER, 4kbps
Manchester Code, 280kHz
IF BW, 50Ω

FSK

dBm

Maximum Receiver Input Power
Level

RF

MAX

0

dBm

Receiver Input Frequency Range

f

RF

450

MHz

Receiver Image Rejection IR (Note 3) 45 dB

LNA/MIXER (Note 4)

LNA Input Impedance Z

11

Normalized to 50Ω

Voltage Conversion Gain (High­Gain Mode)

dB

Input-Referred 3rd-Order

Intercept Point (High-Gain Mode)

-38

dBm

Voltage Conversion Gain (Low­Gain Mode)

dB

Input-Referred 3rd-Order

Intercept Point (Low-Gain Mode)

-5

dBm

LO Signal Feedthrough to
Antenna

-90

dBm

Mixer Output Impedance Z

OUT

Ω

IF

Input Impedance Z

11

Ω

Operating Frequency f

IF

MHz

3dB Bandwidth 10

MHz

FM DEMODULATOR

Demodulator Gain G

FM

2.2

mV/kHz

SYMBOL

MIN TYP MAX

300

fRF = 315MHz 1 - j4.7

fRF = 434MHz 1 - j3.4

-114

-108

47.5

12.2

330

330

10.7

MAX1471

315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver

4 _______________________________________________________________________________________

AC ELECTRICAL CHARACTERISTICS (continued)

(Typical Application Circuit, AVDD= DVDD= HVIN= +2.4V to +3.6V, fRF= 300MHz to 450MHz, TA= -40°C to +125°C, unless otherwise
noted. Typical values are at AV

DD

= DVDD= HVIN= +3.0V, fRF= 434 MHz, TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

UNITS

ANALOG BASEBAND

Maximum Data Filter Bandwidth BW

DF

50 kHz

Maximum Data Slicer Bandwidth

BW

DS

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

MHz

Frequency Pulling by V

DD

3

ppm/V

Maximum Crystal Inductance 50 µH

Crystal Load Capacitance 3pF

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

ns

Minimum CS Period t

CS

µs

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

ns

Minimum SCLK Low Pulse Width

t

CL

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 TA= +85°C. 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 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 fil­ter insertion loss.

SYMBOL

MIN TYP MAX

100

9.04 13.728

125

2.125

100

100

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 375350 400 425 450

SUPPLY CURRENT

vs. RF FREQUENCY

MAX1471 toc02

RF FREQUENCY (MHz)

SUPPLY CURRENT (mA)

+125°C

-40°C

+25°C

+105°C

+85°C

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 (µA)

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

fRF = 434MHz

fRF = 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

fRF = 434MHz

fRF = 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

fRF = 434MHz

fRF = 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

fRF = 434MHz

fRF = 315MHz

FREQUENCY DEVIATION = ±50kHz

-98

-112
110100

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, AVDD= DVDD= HVIN= +3.0V, fRF= 434MHz, TA= +25°C, unless otherwise noted.)

MAX1471

315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver

6 _______________________________________________________________________________________

0

0.6

0.3

1.2

0.9

1.8

1.5

2.1

-90 -50-70 -30 -10 10

RSSI AND DELTA vs. IF INPUT POWER

MAX1471 toc10

RF INPUT POWER (dBm)

RSSI (V)

-3.5

-1.5

-2.5

0.5

-0.5

2.5

1.5

3.5

DELTA (%)

RSSI

DELTA

0

0.4

0.8

1.2

1.6

2.0

10.4 10.5 10.710.6 10.8 10.9 11.0

FSK DEMODULATOR OUTPUT

vs. IF FREQUENCY

MAX1471 toc11

IF FREQUENCY (MHz)

FSK DEMODULATOR OUTPUT (V)

-10

10

0

30

20

50

40

60

010155202530

SYSTEM VOLTAGE GAIN

vs. IF FREQUENCY

MAX1471 toc12

IF FREQUENCY (MHz)

SYSTEM GAIN (dB)

45dB IMAGE
REJECTION

UPPER SIDEBAND

LOWER SIDEBAND

FROM RFIN
TO MIXOUT

f

RF

= 434MHz

38

40

44

42

46

48

-40 10-15 35 60 85 110

IMAGE REJECTION

vs. TEMPERATURE

MAX1471 toc13

TEMPERATURE (°C)

IMAGE REJECTION (dB)

fRF = 315MHz

fRF = 434MHz

5

-20
110100

NORMALIZED IF GAIN

vs. IF FREQUENCY

-15

MAX1471 toc14

IF FREQUENCY (MHz)

NORMALIZED IF GAIN (dBm)

-10

-5

0

10dB/

div

START: 50MHz STOP: 1GHz

S11 LOG-MAGNITUDE PLOT WITH

MATCHING NETWORK OF RFIN (434MHz)

MAX1471 toc15

0dB

0dB

434MHz

-16.4dB

S11 SMITH CHART OF RFIN (434MHz)

MAX1471 toc16

500MHz

200MHz

Typical Operating Characteristics (continued)

(Typical Application Circuit, AVDD= DVDD= HVIN= +3.0V, fRF= 434MHz, TA= +25°C, unless otherwise noted.)

MAX1471

315MHz/434MHz Low-Power, 3V/5V

ASK/FSK Superheterodyne Receiver

_______________________________________________________________________________________ 7

INPUT IMPEDANCE vs. INDUCTIVE

DEGENERATION

MAX1471 toc17

INDUCTIVE DEGENERATION (nH)

REAL IMPEDANCE (Ω)

10

10

20

30

40

50

60

70

80

90

0

1 100

fRF = 315MHz
L1 = 0nH

IMAGINARY IMPEDANCE

REAL IMPEDANCE

-325

-300

-275

-250

-225

-200

-175

-150

-125

-350

IMAGINARY IMPEDANCE (Ω)

INPUT IMPEDANCE vs. INDUCTIVE

DEGENERATION

MAX1471 toc18

INDUCTIVE DEGENERATION (nH)

REAL IMPEDANCE (Ω)

10

10

20

30

40

50

60

70

80

90

0

1100

fRF = 434MHz
L1 = 0nH

IMAGINARY
IMPEDANCE

-325

-300

-275

-250

-225

-200

-175

-150

-125

-350

IMAGINARY IMPEDANCE (Ω)

REAL IMPEDANCE

-50

-120
100 1k 1M 10M

PHASE NOISE vs. OFFSET FREQUENCY

-110

-90

-100

-60

-70

-80

MAX1471 toc19

OFFSET FREQUENCY (Hz)

PHASE NOISE (dBc/Hz)

10k 100k

fRF = 315MHz

-50

-120
100 1k 1M 10M

PHASE NOISE vs. OFFSET FREQUENCY

-110

-90

-100

-60

-70

-80

MAX1471 toc20

OFFSET FREQUENCY (Hz)

PHASE NOISE (dBc/Hz)

10k 100k

fRF = 434MHz

Typical Operating Characteristics (continued)

(Typical Application Circuit, AVDD= DVDD= HVIN= +3.0V, fRF= 434MHz, TA= +25°C, unless otherwise noted.)

PIN NAME FUNCTION

1 DSA- Inverting Data Slicer Input for ASK Data

2 DSA+ Noninverting Data Slicer Input for ASK Data

3 OPA+ Noninverting Op-Amp Input for the ASK Sallen-Key Data Filter

4 DFA Data-Filter Feedback Node. Input for the feedback of the ASK Sallen-Key data filter.

5 XTAL2 2nd Crystal Input

Pin Description

MAX1471

315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver

8 _______________________________________________________________________________________

PIN NAME FUNCTION

6 XTAL1 1st Crystal Input

7AV

DD

Analog Power-Supply Voltage for RF Sections. AVDD is connected to an on-chip +3.0V low-dropout
regulator. Decouple to AGND with a 0.1µF capacitor.

8 LNAIN Low-Noise Amplifier Input

9 LNASRC

Low-Noise Amplifier Source for External Inductive Degeneration. Connect an inductor to AGND to set
LNA input impedance.

10

Low-Noise Amplifier Output. Connect to mixer through an LC tank filter.

11 MIXIN+ Differential Mixer Input. Must be AC-coupled to driving input.

12 MIXIN- Differential Mixer Input. Bypass to AGND with a capacitor.

13 MIXOUT 330Ω Mixer Output. Connect to the input of the 10.7MHz IF filter.

14 AGND Analog Ground

15 IFIN- Differential 330Ω IF Limiter Amplifier Input. Bypass to AGND with a capacitor.

16 IFIN+ Differential 330Ω IF Limiter Amplifier Input. Connect to output of the 10.7MHz IF filter.

17 PDMINF Minimum-Level Peak Detector for FSK Data

18

Maximum-Level Peak Detector for FSK Data

19 DSF- Inverting Data Slicer Input for FSK Data

20 DSF+ Noninverting Data Slicer Input for FSK Data

21 OPF+ Noninverting Op-Amp Input for the FSK Sallen-Key Data Filter

22 DFF Data-Filter Feedback Node. Input for the feedback of the FSK Sallen-Key data filter.

23 DGND Digital Ground

24 DV

DD

Digital Power-Supply Voltage for Digital Sections. Connect to AVDD. Decouple to DGND with a 10nF
capacitor.

25 FDATA Digital Baseband FSK Demodulator Data Output

26 CS Active-Low Chip-Select Input

27 DIO Serial Data Input/Output

28 SCLK Serial Interface Clock Input

29 HV

IN

High-Voltage Supply Input. For 3V operation, connect HVIN to AVDD and DVDD.

30 ADATA Digital Baseband ASK Demod Data Output

31 PDMINA Minimum-Level Peak Detector for ASK Output

32

Maximum-Level Peak Detector for ASK Output

EP GND Exposed Paddle. Connect to ground.

Pin Description (continued)

LNAOUT

PDMAXF

PDMAXA