Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsMAX7057ASE+

Typical Application Circuit and Functional Diagram appear

at end of data sheet.

● RF Remote Controls

● Garage Door Openers

● Home Automation

● Wireless Sensors

● Wireless Game Consoles

● Wireless Computer

Peripherals

● Security Systems

Applications

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 oscil-

lator 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-pull-

ing 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.

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

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

PART TEMP RANGE PIN-PACKAGE

MAX7057ASE+ -40°C to +125°C 16 SO

DGND

DINPAGND

DVDD

GPOSDI

SCLK

TOP VIEW

AGND

XTAL1

XTAL2

PAVDD

AVDD

5 ENABLEPAOUT

ROUT 6

MAX7057

MAX7057 300MHz to 450MHz Frequency-Programmable

ASK/FSK Transmitter

19-4093; Rev 2; 7/14

Pin Conguration

Ordering Information

EVALUATION KIT AVAILABLE

Summary of content (20 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter 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.
PAGE 2
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Absolute Maximum Ratings Supply Voltage, PAVDD, AVDD, DVDD to AGND, DGND, PAGND.................................................-0.3V to +4.0V All Other Pins............................_GND - 0.3V to _VDD + 0.3V Continuous Power Dissipation (TA = +70°C) 16-Pin SO (derate 8.7mW/°C above +70°C).............695.7mW Operating Temperature..................................... -40°C to +125°C Storage Temperature Range..........................
PAGE 3
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter AC Electrical Characteristics (Typical Application Circuit, 50Ω system impedance, tuned for 315MHz to 433.92MHz operation, VAVDD = VDVDD = VPAVDD = +2.1V to +3.6V, fRF = 300MHz to 450MHz, fCRYSTAL = 16MHz, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VAVDD = VDVDD = VPAVDD = +2.7V, TA = +25°C, unless otherwise noted.
PAGE 4
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter AC Electrical Characteristics (continued) (Typical Application Circuit, 50Ω system impedance, tuned for 315MHz to 433.92MHz operation, VAVDD = VDVDD = VPAVDD = +2.1V to +3.6V, fRF = 300MHz to 450MHz, fCRYSTAL = 16MHz, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VAVDD = VDVDD = VPAVDD = +2.7V, TA = +25°C, unless otherwise noted.
PAGE 5
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Typical Operating Characteristics (50Ω system impedance, VAVDD = VDVDD = VPAVDD = +2.1V to +3.6V, fRF = 300MHz to 450MHz, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VAVDD = VDVDD = VPAVDD = +2.7V, TA = +25°C, unless otherwise noted.) TA = +25°C 12 11 TA = -40°C 10 2.7 TA = -40°C 3.3 3.0 3.3 12 2.7 3.0 10 3.3 9 TA = +25°C 8 7 5 3.6 TA = +85°C TA = +125°C TA = -40°C 6 9 2.4 fRF = 433.
PAGE 6
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Typical Operating Characteristics(continued) (50Ω system impedance, VAVDD = VDVDD = VPAVDD = +2.1V to +3.6V, fRF = 300MHz to 450MHz, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VAVDD = VDVDD = VPAVDD = +2.7V, TA = +25°C, unless otherwise noted.) 7 14 5 12 0 6 5 -5 4 -10 3 OUTPUT POWER -15 2 fRF = 315MHz 50% DUTY CYCLE 1 0 1 0.
PAGE 7
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Typical Operating Characteristics(continued) (50Ω system impedance, VAVDD = VDVDD = VPAVDD = +2.1V to +3.6V, fRF = 300MHz to 450MHz, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VAVDD = VDVDD = VPAVDD = +2.7V, TA = +25°C, unless otherwise noted.) 8 6 fRF = 315MHz 4 2 0 fRF = 433.92MHz -2 -4 fRF = 315MHz PA ON TA = -40°C 30 EFFICIENCY (%) FREQUENCY STABILITY (ppm) 35 MAX7057 toc16 10 EFFICIENCY vs.
PAGE 8
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Pin Description PIN NAME FUNCTION 1 CS Serial Interface Active-Low Chip Select. Internally pulled up to DVDD. 2 SDI Serial Interface Data Input. Internally pulled down to GND. 3 SCLK Serial Interface Clock Input. Internally pulled down to GND. 4 PAGND Power Amplifier Ground 5 PAOUT Power Amplifier Output. Requires a pullup inductor to the supply voltage or ROUT.
PAGE 9
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter nates the problems associated with crystal-pulling FSK signal generation. The multiplying factor of the PLL is set by a 16-bit number, with 4 bits for integer and 12 bits for fraction. The 12-bit fraction in the synthesizer results in a tuning resolution that is equal to the reference frequency divided by 4096. The MAX7057 has an internal variable shunt capacitor connected at the PA output.
PAGE 10
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Due to the nature of the transmit PLL frequency divider, a fixed offset of 16 must be subtracted from the transmit PLL divider ratio for programming the MAX7057’s transmit frequency registers.
PAGE 11
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter CS SCLK SDI D7 D6 D5 D4 D3 D2 D1 D0 D7 DATA 1 D6 D5 D4 D3 D2 D1 D0 DATA N Figure 2. SPI Format CS SCLK A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 SDI WRITE COMMAND (0x01) INITIAL ADDRESS (A[7:0]) DATA 0 D7 D0 DATA N Figure 3. SPI Write Command Format Depending on the command, byte 1 through byte N may assume different functions.
PAGE 12
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter CS SCLK SDI A7 A6 A5 A4 A3 A2 A1 A0 A7 A6 A5 A4 A3 A2 A1 A0 READ COMMAND (0x02) ADDRESS 0 GPO ADDRESS 1 D7 D6 D5 D4 D3 D2 D1 D0 DATA 0 A7 A0 ADDRESS N 0x00 D0 D7 D7 DATA N-1 D0 DATA N Figure 4. SPI Read Command Format CS SCLK SDI A7 A6 A5 A4 A3 A2 A1 A0 READ ALL COMMAND (0x03) ADDRESS N GPO D7 D6 D5 D4 D3 D2 D1 D0 D7 DATA N D0 DATA N+1 D7 D0 DATA N+n Figure 5.
PAGE 13
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Variable Capacitor CS SCLK SDI RESET COMMAND (0x04) Figure 6. Reset Command Format Using a byte descriptive notation, the reset command can be viewed as the following sequence, within the same CS cycle: SDI: <0x04> Features and Settings Values and parameters are set through registers in the MAX7057 that are addressable through the SPI. These registers contain bits that either turn functions on and off or program numerical settings.
PAGE 14
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Table 3.
PAGE 15
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Table 6. ckdiv[2:0] of Configuration 0 Register (Address: 0x01) DECIMAL BINARY CRYSTAL FREQUENCY DIVIDED BY 0 000 1 1 001 2 2 010 4 3 011 8 4-7 1XX 16 Table 7. High-Frequency 1 Register (Address: 0x02) BIT NAME 7-0 fhi[15:8] FUNCTION 8-bit upper byte of high-frequency divider for FSK The 4 MSBs of HIFREQ1 (fhi[15:12]) are the integer portion of the divider, excluding offset of 16.
PAGE 16
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter These values are internally summed with 16, and thus, the min and max divider becomes approximately 19 and 28. These limits MUST be followed, to prevent the delta-sigma number generator from overflowing. Whenever all of the fhi[11:0] and flo[11:0] are an integer divider is used, and the delta-sigma is not in operation. This allows lower current The 600kHz PLL bandwidth could be used in to reduce phase noise.
PAGE 17
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Table 17. Status Register (Address: 0x0C) BIT NAME 0 NoXTAL 1 TxREADY 2 RESERVED “0” 3 X 7-4 fhi/lo[15]–fhi/lo[12] FUNCTION Internal Crystal Oscillator Status. High means oscillator is not in operation. Transmitter Ready Status. High means PLL is locked and MAX7057 is ready to transmit data. RESERVED. Set to 0 for normal operation. RESERVED ASK mode: Outputs flo[15:12].
PAGE 18
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Typical Application Circuit SCLK SDI 3 4 C1 L1 RFOUT C3 C2 5 1 SDI CS VDD DVDD SCLK PAOUT GPO MAX7057 DGND C4 6 ROUT DIN VDD ENABLE 7 C7 PAVDD C6 VDD C9 16 C12 PAGND L2 R1 C5 CS 2 AVDD 8 XTAL2 9 C10 C8 C15 XTAL1 10 AGND 15 C13 GPO 14 13 12 11 DIN ENABLE C11 Y1 C14 Component List DESIGNATION QTY C1, C2 1 C3 1 C4, C7 2 C5 1 C6, C9, C12 3 C8, C13 2 C10, C11 2 C14, C15 2 L1 1 L2
PAGE 19
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Functional Diagram SCLK 3 SDI 2 DVDD 16 CS 1 MAX7057 14 DGND SERIAL INTERFACE AND DIGITAL CONTROL PAGND 4 PAOUT 5 Chip Information PROCESS: CMOS www.maximintegrated.
PAGE 20
MAX7057 300MHz to 450MHz Frequency-Programmable ASK/FSK Transmitter Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 5/08 Initial release 1 4/11 Added reflow soldering information to Absolute Maximum Ratings, added bandwidth notation to TOC21, and corrected SPI format in Figure 2 2 7/14 Removed automotive reference from data sheet DESCRIPTION — 2, 7, 11 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s