MAX7044 MAXIM | Alldatasheet

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Technical content

Features

♦ +2.1V to +3.6V Single-Supply Operation ♦ OOK/ASK Transmit Data Format ♦ Up to 100kbps Data Rate ♦ +13dBm Output Power into 50Ω Load ♦ Low 7.7mA (typ) Operating Supply Current* ♦ Uses Small, Low-Cost Crystal ♦ Small 3mm x 3mm 8-Pin SOT23 Package ♦ Fast-On Oscillator: 250µs Startup Time * At 50% duty cycle (315MHz, 2.7V supply, +13dBm output power) MAX7044 300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter DATA CLKOUTPAOUT XTAL2 VDDGND PAGND XTAL1 SOT23 TOP VIEW MAX7044 Pin Configuration

Ordering Information

3.0V 3.0V 680pF220pF100nF 100nF XTAL2 fXTAL GND VDD PAGND DATA INPUT CLOCK OUTPUT CLKOUT = fXTAL/16) DATA PAOUT CLKOUT Typical Application Circuit 19-3221; Rev 0; 1/04 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. EVALUATION KIT AVAILABLE PART TEMP RANGE PIN- PACKAGE TOP MARK MAX7044AKA-T -40°C to +125°C 8 SOT23-8 AEJW

300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Typical Application Circuit, all RF inputs and outputs are referenced to 50 Ω, VDD = +2.1V to +3.6V, T A = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1) 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 specificatio ns is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Continuous Power Dissipation (TA = +70°C) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SYSTEM PERFORMANCE Supply Voltage V DD 2.1 3.6 V VDATA at 50% duty cycle, (Notes 3, 4) 7.7 14.1 PA on (Note 5) 13.8 25.4fRF = 315MHz PA off (Note 6) 1.7 2.8 VDATA at 50% duty cycle, (Notes 3, 4) 8.0 14.4 PA on (Note 5) 14.0 25.7 Supply Current (Note 2) IDD fRF = 433MHz PA off (Note 6) 1.9 3.1 mA TA < +25°C 40 130 Standby Current I STDBY VDATA < VIL for more than WAIT time (Notes 4, 7) TA < +125°C 550 2900 nA Frequency Range (Note 4) f RF 300 450 MHz Data Rate (Note 4) 0 100 kbps Modulation Depth (Note 8) ON to OFF P OUT ratio 90 dB TA = +25°C, VDD = TA = +125°C, VDD = +2.1V 5.9 9.0 12.0Output Power, PA On (Notes 4, 5) POUT fRF = 300MHz to 450MHz TA = -40°C, VDD = +3.6V 13.1 15.8 18.5 dBm Oscillator settled to within 50kHz 220Turn-On Time (Note 8) t ON Oscillator settled to within 5kHz 450 µs fRF = 315MHz 48Transmit Efficiency with CW (Notes 5, 10) fRF = 433MHz 47 fRF = 315MHz 43Transmit Efficiency with 50% OOK (Notes 3, 10) fRF = 433MHz 41

300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter ELECTRICAL CHARACTERISTICS (continued) (Typical Application Circuit, all RF inputs and outputs are referenced to 50 Ω, VDD = +2.1V to +3.6V, T A = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1) Note 1: Supply current, output power, and efficiency are greatly dependent on board layout and PAOUT match. Note 2: Production tested at T A = +25°C with f RF = 300MHz and 450MHz. Guaranteed by design and characterization over tem- perature and frequency. Note 3: 50% duty cycle at 10kbps with Manchester coding. Note 4: Guaranteed by design and characterization, not production tested. Note 5: PA output is turned on in test mode by VDATA = VCC/2 + 100mV. Note 6: PA output is turned off in test mode by VDATA = VCC/2 – 100mV. Note 7: Wait time: tWAIT = (216 x 32) / fRF. Note 8: Generally limited by PC board layout. Note 9: VDATA = VIL to VDATA = VIH after VDATA = VIL for WAIT time: tWAIT = (216 x 32) / fRF. Note 10: VDATA = VIH. Efficiency = POUT/(VDD x IDD). PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS PHASE-LOCKED LOOP (PLL) VCO Gain 330 MHz/V fOFFSET = 100kHz -80fRF = 315MHz fOFFSET = 1MHz -90 fOFFSET = 100kHz -77Phase Noise fRF = 433MHz fOFFSET = 1MHz -87 dBc/Hz fRF = 315MHz -50Maximum Carrier Harmonics fRF = 433MHz -50 dBc fRF = 315MHz -74Reference Spur fRF = 433MHz -80 dBc Loop Bandwidth 1.6 MHz Crystal Frequency f XTAL fRF/32 MHz Frequency Pulling by VDD 3 ppm/V Maximum Crystal Inductance 50 µH Crystal Load Capacitance 3p F DATA INPUT Data Input High V IH VDD - 0.25 V Data Input Low V IL 0.25 V Maximum Input Current 10 µA Pulldown Current 10 µA CLKOUT OUTPUT Output Voltage Low V OL ISINK = 650µA (Note 4) 0.25 V Output Voltage High V OH ISOURCE = 350µA (Note 4) VDD - 0.25 V Load Capacitance C LOAD (Note 4) 10 pF CLKOUT Frequency fXTAL / 16 Hz

300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter Typical Operating Characteristics (Typical Application Circuit, VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1) SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX7044 toc01 SUPPLY VOLTAGE (V) SUPPLY CURRENT (mA) fRF = 315MHz PA ON TA = -40°C TA = +25°C TA = +85°C TA = +125°C SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX7044 toc02 SUPPLY VOLTAGE (V) SUPPLY CURRENT (mA) TA = +25°C fRF = 315MHz PA 50% DUTY CYCLE AT 10kHz TA = -40°C TA = +85°C TA = +125°C SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX7044 toc03 SUPPLY VOLTAGE (V) SUPPLY CURRENT (mA) TA = +25°C fRF = 433MHz PA ON TA = -40°C TA = +85°C TA = +125°C SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX7044 toc04 SUPPLY VOLTAGE (V) SUPPLY CURRENT (mA) TA = +25°C fRF = 433MHz PA 50% DUTY CYCLE AT 10kHz TA = -40°C TA = +85°C TA = +125°C OUTPUT POWER vs. SUPPLY VOLTAGE MAX7044 toc05 SUPPLY VOLTAGE (V) OUTPUT POWER (dBm) fRF = 315MHz PA ON TA = +25°C TA = -40°C TA = +85°C TA = +125°C OUTPUT POWER vs. SUPPLY VOLTAGE MAX7044 toc06 SUPPLY VOLTAGE (V) OUTPUT POWER (dBm) fRF = 433MHz PA ON TA = +25°C TA = -40°C TA = +85°C TA = +125°C -80 -78 -74 -76 -72 -70 REFERENCE SPUR MAGNITUDE vs. SUPPLY VOLTAGE MAX7044 toc07 SUPPLY VOLTAGE (V) REFERENCE SPUR MAGNITUDE (dBc) REFERENCE SPUR = fRF ± fXTAL fRF = 433MHz fRF = 315MHz FREQUENCY STABILITY vs. SUPPLY VOLTAGE MAX7044 toc08 SUPPLY VOLTAGE (V) FREQUENCY STABILITY (ppm) fRF = 433MHz fRF = 315MHz TRANSMIT POWER EFFICIENCY vs. SUPPLY VOLTAGE MAX7044 toc09 SUPPLY VOLTAGE (V) TRANSMIT POWER EFFICIENCY (%) fRF = 315MHz PA ON TA = -40°C TA = +85°C TA = +125°C TA = +25°C

300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter TRANSMIT POWER EFFICIENCY vs. SUPPLY VOLTAGE MAX7044 toc10 SUPPLY VOLTAGE (V) TRANSMIT POWER EFFICIENCY (%) fRF = 315MHz PA 50% DUTY CYCLE AT 10kHz TA = -40°C TA = +85°C TA = +125°C TA = +25°C TRANSMIT POWER EFFICIENCY vs. SUPPLY VOLTAGE MAX7044 toc11 SUPPLY VOLTAGE (V) TRANSMIT POWER EFFICIENCY (%) fRF = 433MHz PA ON TA = -40°C TA = +85°C TA = +125°C TA = +25°C TRANSMIT POWER EFFICIENCY vs. SUPPLY VOLTAGE MAX7044 toc12 SUPPLY VOLTAGE (V) TRANSMIT POWER EFFICIENCY (%) fRF = 433MHz PA 50% DUTY CYCLE AT 10kHz TA = +25°C TA = -40°C TA = +85°C TA = +125°C -140 -110 -120 -130 -100 -90 -80 -70 -60 -50 -40 0.01 1 0.1 10 100 1k 10k PHASE NOISE vs. OFFSET FREQUENCY MAX7044 toc13 OFFSET FREQUENCY (Hz) PHASE NOISE (dBc/Hz) 01 10 100 1000 10,000 SUPPLY CURRENT AND OUTPUT POWER vs. EXTERNAL RESISTOR MAX7044 toc14 EXTERNAL RESISTOR (Ω) SUPPLY CURRENT (mA) -16 -12 POWER CURRENT fRF = 315MHz PA ON OUTPUT POWER (dBm) -10 -2 2 -6 6 10 14 SUPPLY CURRENT vs. OUTPUT POWER MAX7044 toc15 OUTPUT POWER (dBm) SUPPLY CURRENT (mA) fRF = 315MHz PA ON 50% DUTY CYCLE 50kHz/div FREQUENCY SETTLING TIME MAX7044 toc16 AM DEMODULATION OF PA OUTPUT DATA RATE = 100kHz MAX7044 toc17 OUTPUT SPECTRUM MAX7044 toc18 Typical Operating Characteristics (continued) (Typical Application Circuit, VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)

The MAX7044 is a highly integrated ASK transmitter operating over the 300MHz to 450MHz frequency band. The IC requires only a few external components to complete a transmit solution. The MAX7044 includes a complete PLL and a highly efficient power amplifier. The device is automatically placed into a low-power shutdown mode and powers up when data is detected on the data input. Shutdown Mode The MAX7044 has an automatic shutdown mode that places the device in low-power mode if the DATA input has not toggled for a specific amount of time (wait time). The wait time is equal to 2 16 clock cycles of the crystal. This equates to a wait time of approximately 6.66ms for MAX7044 300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter Pin Description PIN NAME FUNCTION 1 XTAL1 1st Crystal Input. f XTAL = fRF / 32. 2 GND Ground. Connect to system ground. 3 PAGND Ground for the Power Amplifier (PA). Connect to system ground. 4 PAOUT Power-Amplifier Output. The PA output requires a pullup inductor to the supply voltage, which can be part of the output-matching network to an antenna. 5 CLKOUT Buffered Clock Output. The frequency of CLKOUT is fXTAL / 16. 6 DATA OOK Data Input. DATA also controls the power-up state (see the Shutdown Mode section). 7V DD Supply Voltage. Bypass to GND with a 100nF capacitor as close to the pin as possible. 8 XTAL2 2nd Crystal Input. f XTAL = fRF / 32. MAX7044 CLKOUT PAGND PAOUT GND DATA XTAL1 /16 DATA ACTIVITY DETECTOR LOCK DETECT 32x PLL PA CRYSTAL- OSCILLATOR DRIVERXTAL2 VDD Functional Diagram -55 -52 -46 -49 -43 -40 CLKOUT SPUR MAGNITUDE vs. SUPPLY VOLTAGE MAX7044 toc19 SUPPLY VOLTAGE (V) CLKOUT SPUR MAGNITUDE (dBc) fRF = 315MHz Typical Operating Characteristics (continued) (Typical Application Circuit, VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)

count, the counter is reset and the process starts over. impedance at PAOUT, which is about 125Ω. the power amplifier transmits power with high efficiency. amplifier itself greater than 54%. the clock output is stable after approximately 220µs. capacitor as shown in Figure 1. Figure 1. Output Power Adjustment Circuit

quency, thus introducing an error in the reference fre- quency. Crystals designed to operate with higher differ- ential load capacitance always pull the reference frequency higher. For example, a 9.84375MHz crystal designed to operate with a 10pF load capacitance oscillates at 9.84688MHz with the MAX7044, causing the transmitter to be transmitting at 315.1MHz rather than 315.0MHz, an error of about 100kHz, or 320ppm. In actuality, the oscillator pulls every crystal. The crys- tal’s natural frequency is really below its specified fre- quency, but when loaded with the specified load capacitance, the crystal is pulled and oscillates at its specified frequency. This pulling is already accounted for in the specification of the load capacitance. Additional pulling can be calculated if the electrical parameters of the crystal are known. The frequency pulling is given by: where: f p is the amount the crystal frequency is pulled in ppm. Cm is the motional capacitance of the crystal. Ccase is the case capacitance. Cspec is the specified load capacitance. Cload is the actual load capacitance. When the crystal is loaded as specified, i.e., C load = Cspec, the frequency pulling equals zero. Output Matching to 50Ω When matched to a 50 Ω system, the MAX7044 PA is capable of delivering up to +13dBm of output power at V DD = 2.7V. The output of the PA is an open-drain tran- sistor that requires external impedance matching and pullup inductance for proper biasing. The pullup induc- tance from PA to V DD serves three main purposes: it resonates the capacitance of the PA output, provides biasing for the PA, and becomes a high-frequency choke to reduce the RF energy coupling into V DD. The recommended output-matching network topology is shown in the Typical Application Circuit . The matching network transforms the 50 Ω load to approximately 125Ω at the output of the PA in addition to forming a bandpass filter that provides attenuation for the higher order harmonics. Output Matching to PC Board Loop Antenna In some applications, the MAX7044 power amplifier output has to be impedance matched to a small-loop antenna. The antenna is usually fabricated out of a cop- per trace on a PC board in a rectangular, circular, or square pattern. The antenna will have an impedance that consists of a lossy component and a radiative component. To achieve high radiating efficiency, the radiative component should be as high as possible, while minimizing the lossy component. In addition, the loop antenna will have an inherent loop inductance associated with it (assuming the antenna is terminated to ground). For example, in a typical application, the radiative impedance is less than 0.5Ω, the lossy imped- ance is less than 0.7 Ω, and the inductance is approxi- mately 50nH to 100nH. The objective of the matching network is to match the power amplifier output to the small-loop antenna. The matching components thus transform the low radiative and resistive parts of the antenna into the much higher value of the PA output. This gives higher efficiency. The low radiative and lossy components of the small-loop antenna result in a higher Q matching network than the 50Ω network; thus, the harmonics are lower. Layout Considerations A properly designed PC board is an essential part of any RF/microwave circuit. At the power amplifier out- put, use controlled-impedance lines and keep them as short as possible to minimize losses and radiation. At high frequencies, trace lengths that are approximately 1/20 the wavelength or longer become antennas. For example, a 2in trace at 315MHz can act as an antenna. Keeping the traces short also reduces parasitic induc- tance. Generally, 1in of PC board trace adds about 20nH of parasitic inductance. The parasitic inductance can have a dramatic effect on the effective inductance. For example, a 0.5in trace connecting a 100nH induc- tor adds an extra 10nH of inductance, or 10%. To reduce the parasitic inductance, use wider traces and a solid ground or power plane below the signal traces. Using a solid ground plane can reduce the par- asitic inductance from approximately 20nH/in to 7nH/in. Also, use low-inductance connections to ground on all GND pins, and place decoupling capacitors close to all V DD connections. Chip Information TRANSISTOR COUNT: 2489 PROCESS: CMOS f C Ccase CCC xp m load case spec = + − + 2 11 106 300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter

300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circu it patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline info rmation, go to www.maxim-ic.com/packages). SOT23, 8L .EPS REV.DOCUMENT CONTROL NO.APPROVAL PROPRIETARY INFORMATION TITLE: 3.002.60EC E1E BETWEEN 0.08mm AND 0.15mm FROM LEAD TIP. 8. MEETS JEDEC MO178. 0.60 1.75 0.30 e L 1.50E1 0.65 BSC. 1.95 REF. 0.25 BSC. GAUGE PLANE SEATING PLANE C C L PIN 1 I.D. DOT (SEE NOTE 6) LC LC D DETAIL "A" 5. COPLANARITY 4 MILS. MAX. NOTE: 7. SOLDER THICKNESS MEASURED AT FLAT SECTION OF LEAD 4. PACKAGE OUTLINE INCLUSIVE OF SOLDER PLATING. 3. PACKAGE OUTLINE EXCLUSIVE OF MOLD FLASH & METAL BURR. HEEL OF THE LEAD PARALLEL TO SEATING PLANE C. 2. FOOT LENGTH MEASURED FROM LEAD TIP TO UPPER RADIUS OF 1. ALL DIMENSIONS ARE IN MILLIMETERS. L A1A 0.45 1.30 0.15 1.45 MAX 0.28b 0.90A2 0.00A1 0.90A MINSYMBOL 3.00 0.20 2.80D 0.09C SEE DETAIL "A" LC b e D 121-0078 PACKAGE OUTLINE, SOT-23, 8L BODY