Rainbow Electronics MAX7057 User Manual

General Description

The MAX7057 frequency-programmable UHF transmitter is designed to transmit ASK/FSK data at a wide range of frequencies from 300MHz to 450MHz. The MAX7057 has internal tuning capacitors at the output of the power amplifier that are programmable for matching to an antenna or load. This allows the user to change to a new frequency and match the antenna at the new frequency simultaneously. The MAX7057 transmits at a data rate up to 100kbps nonreturn-to-zero (NRZ) (50kbps Manchester coded). Typical transmitted power into a 50Ω load is +9.2dBm with a +2.7V supply. The device operates from +2.1V to +3.6V and typically draws under 12.5mA of current in FSK mode (8.5mA in ASK mode) when the antenna-matching network is designed to operate over the 315MHz to 433.92MHz frequency range. For narrower operating frequency ranges, the matching network can be redesigned to improve efficiency. The standby current is less than 1μA at room temperature.

The MAX7057 reference frequency from the crystal oscillator is multiplied by a fully integrated fractional-N phase-locked loop (PLL). The multiplying factor of the PLL is set by a 16-bit number, with 4 bits for integer and 12 bits for fraction; the multiplying factor can be anywhere between 19 and 28. The 12-bit fraction in the synthesizer sets a tuning resolution equal to the reference frequency divided by 4096; frequency deviation can be set as low as ±2kHz and as high as ±100kHz. The fractional-N synthesizer eliminates the problems associated with oscillator-pulling FSK signal generation. The MAX7057 has a serial peripheral interface (SPI™) for selecting all the necessary settings.

The MAX7057 is available in a 16-pin SO package and is specified to operate in the -40°C to +125°C automotive temperature range.

Applications

RF Remote Controls

Garage Door Openers

Home Automation

Automotive

Wireless Sensors

Wireless Game Consoles

Wireless Computer Peripherals

Security Systems

Features

♦ Programmable Frequency Operation with Single

Crystal

♦ Internal Variable Capacitor for Antenna Tuning

with Single-Matching Network

♦ 100kbps Data Rate (NRZ)

♦ +2.1V to +3.6V Single-Supply Operation

♦ < 12.5mA (FSK), < 8.5mA (ASK) DC Current Drain

♦ < 1µA Standby Current

♦ ASK/FSK Modulation

♦ 47% Carrier Tuning Range Using One Crystal

MAX7057

300MHz to 450MHz Frequency-Programmable

ASK/FSK Transmitter

________________________________________________________________

Maxim Integrated Products

Pin Configuration

Ordering Information

19-4093; Rev 0; 5/08

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-free package.

PART TEMP RANGE PIN-PACKAGE

MAX7057ASE+

-40°C to +125°C 16 SO

Typical Application Circuit and Functional Diagram appear at end of data sheet.

SPI is a trademark of Motorola, Inc.

DGND

DINPAGND

DVDD

GPOSDI

SCLK

TOP VIEW

AGND

XTAL1

XTAL2

PAVDD

AVDD

5 ENABLEPAOUT

ROUT 6

MAX7057

300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(

Typical Application Circuit

, 50Ω system impedance, tuned for 315MHz to 433.92MHz operation, AVDD = DVDD = PAVDD = +2.1V to

+3.6V, f

= 300MHz to 450MHz, f

CRYSTAL

= 16MHz, TA= -40°C to +125°C, unless otherwise noted. Typical values are at AVDD =

DVDD = PAVDD = +2.7V, T

= +25°C, unless otherwise noted. All min and max values are 100% tested at TA= +125°C, and guaran-

teed by design and characterization over temperature, 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.

Supply Voltage, PAVDD, AVDD, DVDD to AGND,

DGND, PAGND ...................................................-0.3V to +4.0V

All Other Pins..................................._GND - 0.3V to _V

+ 0.3V

Continuous Power Dissipation (T

= +70°C)

16-Pin SO (derate 8.7mW/°C above +70°C)...............695.7mW

Operating Temperature .....................................-40°C to +125°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Supply Voltage V

Supply Current I

DIGITAL I/O

Input High Threshold V

Input Low Threshold V

Input Pulldown Sink Current 13 μA

Input Pullup Source Current 9μA

Output-Voltage High V

Output-Voltage Low V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

STDBY

PAVDD, AVDD, and DVDD connected to power supply, V

PA off, V duty cycle (ASK)

V ( AS K) ( N otes 1, 2, 3)

V cycle (FSK) (Note 1)

DIN

at 50% d uty cycl e

D IN

at 100% duty

DIN

< V

ENABLE

= 500μA (GPO)

SINK

= 500μA (GPO) 0.36 V

SOURCE

2.1 2.7 3.6 V

0.9 x

0.37

at 0%

fRF = 315MHz 3.9 6.5

= 433.92MHz 4.5 7.5

fRF = 315MHz 8.1 15.1

= 433.92MHz 8.5 15.0

fRF = 315MHz 12.2 23.7

= 433.92MHz 12.4 22.4

TA = + 25°C ( N ote 3) 0.8

TA < + 85°C ( N ote 3) 1 6.4Standby Current I

TA < +125°C 6.2 20.1

0.1 x

μA

MAX7057

300MHz to 450MHz Frequency-Programmable

ASK/FSK Transmitter

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS

(

Typical Application Circuit

, 50Ω system impedance, tuned for 315MHz to 433.92MHz operation, AVDD = DVDD = PAVDD = +2.1V to

+3.6V, fRF= 300MHz to 450MHz, f

CRYSTAL

= 16MHz, TA= -40°C to +125°C, unless otherwise noted. Typical values are at AVDD =

DVDD = PAVDD = +2.7V, T

= +25°C, unless otherwise noted. All min and max values are 100% tested at TA= +125°C, and guaran-

teed by design and characterization over temperature, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

GENERAL CHARACTERISTICS

Frequency Range 300 450 MHz

Power-On Time t

Maximum Data Rate

Frequency Switching Time

PHASE-LOCKED LOOP (PLL)

VCO Gain K

PLL Phase Noise

Loop Bandwidth 300 kHz

Reference Frequency Input Level 500 mV

Frequency-Divider Range 19 28

Frequency Deviation (FSK) ±2 ±100 kHz

CRYSTAL OSCILLATOR

Crystal Frequency f

Frequency Pulling by V

Crystal Load Capacitance (Note 4) 10 pF

POWER AMPLIFIER (PA)

Output Power (Note 1) P

Modulation Depth 71 dB

Maximum Carrier Harmonics

Reference Spur -45 dBc

VCO

XTAL

OUT

ENABLE transition low-to-high, frequency settled to within 50kHz of the desired carrier

ENABLE transition low-to-high, frequency settled to within 5kHz of the desired carrier

ASK mode

FSK mode

Time from end of SPI write to frequency settled to within 5kHz of desired carrier

fRF = 315MHz

= 433.92MHz

TA = +25°C (Note 3) 3.8 9.2 16.4

TA = +125°C, AVDD = DVDD = PAVDD = +2.1V

TA = -40°C, AVDD = DVDD = PAVDD = +3.6V (Note 3)

With output matching network

Manchester encoded 50

Nonreturn-to-Zero 100

Manchester encoded 50

Nonreturn-to-Zero 100

10kHz offset -78

1MHz offset -98

10kHz offset -73

1MHz offset -98

10.71 16 23.68 MHz

2.4 5.2

fRF = 315MHz -29

= 433.92MHz -44

120

260

70 μs

320 MHz/V

4 ppm/V

12.6 17.0

dBc/Hz

μs

kbps

P-P

dBm

dBc

MAX7057

300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter

4 _______________________________________________________________________________________

AC ELECTRICAL CHARACTERISTICS (continued)

(

Typical Application Circuit

, 50Ω system impedance, tuned for 315MHz to 433.92MHz operation, AVDD = DVDD = PAVDD = +2.1V to

+3.6V, fRF= 300MHz to 450MHz, f

CRYSTAL

= 16MHz, TA= -40°C to +125°C, unless otherwise noted. Typical values are at AVDD =

DVDD = PAVDD = +2.7V, T

= +25°C, unless otherwise noted. All min and max values are 100% tested at TA= +125°C, and guaran-

teed by design and characterization over temperature, unless otherwise noted.)

Note 1: Supply current and output power are greatly dependent on board layout and PAOUT match. Note 2: 50% duty cycle at 10kHz ASK data (Manchester coded). Note 3: Guaranteed by design and characterization, not production tested. Note 4: Dependent on PCB trace capacitance.

Figure 1. SPI Timing Diagram

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SERIAL INTERFACE (SPI) TIMING CHARACTERISTICS (Figure 1)

Minimum SCLK Low to FallingEdge of CS Setup Time

Minimum CS Low to Rising-Edge of SCLK Setup Time

Minimum SCLK Low to RisingEdge of CS Setup Time

Minimum SCLK Low After RisingEdge of CS Hold Time

Minimum Data Valid to SCLK Rising-Edge Setup Time

Minimum Data Valid to SCLK Rising-Edge Hold Time

Minimum SCLK High Pulse Width t

Minimum SCLK Low Pulse Width t Minimum CS High Pulse Width t

Maximum Transition Time from Falling-Edge of CS to Valid GPO

Maximum Transition Time from Falling-Edge of SCLK to Valid GPO

CSS

HCS

CSH

CSG

CL = 10pF load capacitance from GPO to DGND

10 ns

5ns

20 ns

5ns

10 ns

5ns

40 ns

50 ns

HCS

CSH

SCLK

SDI

GPO

CSG

CSS

MAX7057

300MHz to 450MHz Frequency-Programmable

ASK/FSK Transmitter

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(50Ω system impedance, AVDD = DVDD = PAVDD = +2.1V to +3.6V, fRF= 300MHz to 450MHz, TA= -40°C to +125°C, unless otherwise noted. Typical values are at AVDD = DVDD = PAVDD = +2.7V, T

= +25°C, unless otherwise noted.)

OUTPUT POWER

vs. SUPPLY VOLTAGE

MAX7057 toc07

SUPPLY VOLTAGE (V)

OUTPUT POWER (dBm)

3.33.02.72.4

2.1 3.6

fRF = 315MHz PA ON

TA = +85°C

TA = +125°C

TA = +25°C

TA = -40°C

OUTPUT POWER

vs. SUPPLY VOLTAGE

MAX7057 toc08

SUPPLY VOLTAGE (V)

OUTPUT POWER (dBm)

3.33.02.72.4

2.1 3.6

fRF = 433.92MHz PA ON

TA = +85°C

TA = +125°C

TA = -40°C, +25°C

SUPPLY CURRENT AND OUTPUT POWER

vs. EXTERNAL RESISTOR

MAX7057 toc09

EXTERNAL RESISTOR (Ω)

SUPPLY CURRENT (mA)

OUTPUT POWER (dBm)

1000100101

-15

-10

-5

-25

-20

0.1 10,000

fRF = 315MHz PA ON

SUPPLY CURRENT

OUTPUT POWER

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

fRF = 315MHz

PA ON

TA = +125°C

SUPPLY CURRENT (mA)

2.1 3.6

TA = +85°C

TA = +25°C

TA = -40°C

SUPPLY VOLTAGE (V)

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

fRF = 433.92MHz

PA ON

TA = +125°C

SUPPLY CURRENT (mA)

2.1 3.6

TA = +85°C

TA = +25°C

TA = -40°C

SUPPLY VOLTAGE (V)

MAX7057 toc01

SUPPLY CURRENT (mA)

3.33.02.72.4

2.1 3.6

MAX7057 toc04

SUPPLY CURRENT (mA)

2.1 3.6

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

fRF = 315MHz 50% DUTY CYCLE

TA = +125°C

TA = -40°C

SUPPLY VOLTAGE (V)

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

fRF = 433.92MHz 50% DUTY CYCLE

TA = +125°C

SUPPLY VOLTAGE (V)

TA = +85°C

TA = +25°C

3.33.02.72.4

TA = +85°C

TA = +25°C

TA = -40°C

3.33.02.72.4

MAX7057 toc02

MAX7057 toc05

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

6.0

fRF = 315MHz PA OFF

5.5

5.0

TA = +125°C

4.5

4.0

3.5

SUPPLY CURRENT (mA)

3.0

2.5

2.0

2.1 3.6 SUPPLY VOLTAGE (V)

TA = +85°C

TA = +25°C

TA = -40°C

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

7.0

fRF = 433.92MHz PA OFF

6.5

6.0

TA = +125°C

5.5

5.0

4.5

SUPPLY CURRENT (mA)

4.0

3.5

3.0

2.1 3.6 SUPPLY VOLTAGE (V)

TA = +85°C

TA = -40°C

3.33.02.72.4

TA = +25°C

3.33.02.72.4

MAX7057 toc03

MAX7057 toc06

MAX7057

300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(50Ω system impedance, AVDD = DVDD = PAVDD = +2.1V to +3.6V, fRF= 300MHz to 450MHz, TA= -40°C to +125°C, unless otherwise noted. Typical values are at AVDD = DVDD = PAVDD = +2.7V, T

= +25°C, unless otherwise noted.)

SUPPLY CURRENT AND OUTPUT POWER

vs. EXTERNAL RESISTOR

MAX7057 toc10

EXTERNAL RESISTOR (Ω)

SUPPLY CURRENT (mA)

OUTPUT POWER (dBm)

1000100101

-15

-10

-5

-25

-20

0.1 10,000

fRF = 315MHz 50% DUTY CYCLE

SUPPLY CURRENT

OUTPUT POWER

SUPPLY CURRENT AND OUTPUT POWER

vs. EXTERNAL RESISTOR

MAX7057 toc11

EXTERNAL RESISTOR (Ω)

SUPPLY CURRENT (mA)

OUTPUT POWER (dBm)

1000100101

-15

-10

-5

-25

-20

0.1 10,000

fRF = 433.92MHz PA ON

SUPPLY CURRENT

OUTPUT POWER

SUPPLY CURRENT AND OUTPUT POWER

vs. EXTERNAL RESISTOR

MAX7057 toc12

EXTERNAL RESISTOR (Ω)

SUPPLY CURRENT (mA)

OUTPUT POWER (dBm)

1000100101

-15

-10

-5

-30

-20

0.1 10,000

fRF = 433.92MHz 50% DUTY CYCLE

SUPPLY CURRENT

OUTPUT POWER

-25

MAX7057 toc13

PHASE NOISE vs. OFFSET FREQUENCY

-60

-70

-80

-90

-100

-110

-120

-130

-140 100 10k 100k 1M 10M1k

OFFSET FREQUENCY (Hz)

PHASE NOISE (dBc/Hz)

fRF = 315MHz

-50

-60

-70

-80

-90

-100

-110

-120

-130 100 10k 100k 1M 10M1k

PHASE NOISE vs. OFFSET FREQUENCY

MAX7057 toc14

OFFSET FREQUENCY (Hz)

PHASE NOISE (dBc/Hz)

fRF = 433.92MHz

-60

-50

-55

-40

-45

-35

-30

2.1 3.6

REFERENCE SPUR MAGNITUDE

vs. SUPPLY VOLTAGE

MAX7057 toc15

SUPPLY VOLTAGE (V)

REFERENCE SPUR MAGNITUDE (dBc)

2.72.4 3.0 3.3

fRF = 433.92MHz

fRF = 315MHz

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