19-2145; Rev 1; 8/03 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands Features ♦ Versions for U.S. 902MHz to 928MHz Band and European 868MHz Band ♦ -7dBm to +23dBm Adjustable Differential RF Output Power ♦ +23dBm Output Power at 4.5V, +20dBm Output Power at 3.0V ♦ Support BPSK, OOK, ASK, and FM Modulations ♦ Modulation Filter for Direct Sequence BPSK up to 8Mchips/s ♦ Fully Integrated VCO with On-Chip Tank ♦ Extremely Low Frequency Pulling for OOK Modulation (typ 60kHz peak, 5kHz RMS) ♦ Integrated Frequency Synthesizer for up to 8 Channels (MAX2900) ♦ +2.7V to +4.5V Supply Operation ♦ Small 28-Pin QFN Package with Exposed Pad (5mm ✕ 5mm) Ordering Information Applications Automatic Meter Reading Wireless Security Systems/Alarms Wireless Sensors Wireless Data Networks Wireless Building Control PART MAX2900EGI TEMP RANGE -40°C to +85°C PIN-PACKAGE 28 QFN-EP* MAX2901EGI -40°C to +85°C 28 QFN-EP* MAX2902EGI -40°C to +85°C 28 QFN-EP* MAX2903EGI MAX2904EGI -40°C to +85°C -40°C to +85°C 28 QFN-EP* 28 QFN-EP* *Exposed pad Functional Diagrams/Pin Configurations VTUNE CPOUT VCC5 D2 28 27 26 REFOUT VCC4 25 REFIN OSC CPOUT VCC5 23 22 28 27 24 1 21 D0 VTUNE 1 2 20 D1 GND 2 VREG OSC 23 22 24 21 VCO+ 20 VCO- ÷4 CP REFIN 25 26 MAX2901/ MAX2903 MAX2900 GND DIV63 REFOUT VCC4 CP 19 N.C. 3 8-CHANNEL SYNTHESIZER REG VREG 19 DIVOUT 3 DUALCHANNEL (/62 OR /63) SYNTHESIZER REG 18 GND 18 N.C. VCC1 4 5 17 RF+ RLPF 5 17 RF+ EN 6 16 RF- EN 6 16 RF- REFEN 7 REFEN 7 VCC1 4 RLPF GATE 8 9 MODIN OOKIN 15 GND 10 VCC2 11 12 VASK LD 13 14 PWRSET VCC3 GATE 8 9 MODIN OOKIN 15 GND 10 11 12 VCC2 VASK LD 13 14 PWRSET VCC3 Functional Diagrams/Pin Configurations are continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX2900–MAX2904 General Description The MAX2900–MAX2904 complete single-chip 200mW transmitters are designed for use in the 868MHz/ 915MHz frequency bands. The MAX2900/MAX2901/ MAX2902 are compliant with the FCC CFR47 part 15.247 902MHz to 928MHz ISM-band specifications. MAX2903/ MAX2904 are compliant with the ETSI EN330-220 specification for the European 868MHz ISM band. These transmitter ICs offer a high level of integration while minimizing the number of external components. This is achieved by full integration of the transmit modulator, power amplifier, RF VCO, 8-channel frequency synthesizer, and baseband PN sequence lowpass filter. By filtering the BPSK modulation, the spurious emissions are reduced, enabling up to eight independent transmit channels in the U.S. ISM band. Inputs are provided for spread-spectrum BPSK, ASK, and OOK. FM can be achieved by directly modulating the VCO. The devices are intended primarily for use with an external differential antenna. MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +5.0V Analog/Digital Input Voltage to GND..........-0.3V to (VCC + 0.3V) Analog/Digital Input Current ..............................................±10µA Continuous Power Dissipation (TA = +70°C) 28-Pin QFN-EP (derate 28.5mW/°C above +70°C)............2W Operating Temperature Range ...........................-40°C to +85°C Junction Temperature .....................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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. CAUTION! ESD SENSITIVE DEVICE Part Selection Information Five different versions are available. The versions differ by their frequency band of operation, and by the synthesizer’s mode of operation. The MAX2900 has an internal 8-channel synthesizer. The MAX2901 and MAX2903 are dual-channel versions with a selectable internal synthesizer division ratio of 62 or 63. The MAX2901 operates in the 902MHz to 928MHz ISM band and the MAX2903 operates in the 867MHz to 870MHz European ISM band. The MAX2902 and MAX2904 require an off-chip frequency synthesizer. The MAX2902 operates in the 902MHz– 928MHz ISM band and MAX2904 operates in the 867MHz–870MHz European ISM band. The MAX2901–MAX2904 provide LO outputs to drive a receiver and/or an external synthesizer. PART FREQUENCY RANGE (MHz) SYNTHESIZER MAX2900EGI 902 to 928 Internal 8 selectable channels LO OUTPUTS No MAX2901EGI 902 to 928 Internal 2 selectable channels Yes MAX2902EGI 902 to 928 Off-chip Yes MAX2903EGI 867 to 870 Internal 2 selectable channels Yes MAX2904EGI 867 to 870 Off-chip Yes DC ELECTRICAL CHARACTERISTICS (VCC = +2.7V to +4.5V, EN = OOKIN = REFEN = high, TA = -40°C to +85°C. Typical values are at VCC = +4.5V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN Supply Voltage 2.7 2 TYP +3σ MAX UNITS V 4.5 4.5 VCC = +4.0V 0.7 10 VCC = +4.5V 60 200 Synth mode: OOKIN = low (MAX2900/MAX2901/MAX2903 only) 32 40 Transmit mode with output matching optimized for +23dBm at +4.5V: PWRSET loaded with 22kΩ resistor TA = -40°C to +85°C 150 Transmit mode with output matching optimized for +20dBm at +3.0V: PWRSET loaded with 22kΩ resistor TA = -40°C to +85°C 110 Shutdown mode: EN = REFEN = low Supply Current -3σ µA 200 mA 135 _______________________________________________________________________________________ 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands (VCC = +2.7V to +4.5V, EN = OOKIN = REFEN = high, TA = -40°C to +85°C. Typical values are at VCC = +4.5V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER Supply Current (continued) VCO Input Tuning Pin Current CONDITIONS MIN -3σ TYP Transmit mode with output matching optimized for +17dBm at +3.0V: PWRSET loaded with 36kΩ resistor TA = +25°C 75 Transmit mode with output matching optimized for +14dBm at +3.0V: PWRSET loaded with 51kΩ resistor TA = +25°C 57 +3σ MAX mA Reference-only mode: EN = low 2 3 PA standby mode: OOKIN = low (MAX2902/MAX2904 only) 29 33 0.02 2 VTUNE = +4.5V, TA = +25°C VREG VCO Regulator Voltage UNITS 2.0 µA V DIGITAL INPUT/OUTPUTS (PINS EN, REFEN, D0, D1, D2, MODIN, OOKIN, LD) VCC - 0.5V Input Level High V Input Level Low Input Bias Current -10 Output Level High VCC - 0.4 V 10 µA V Output Level Low Output Current 0.5 -100 0.4 V 100 µA ANALOG CONTROL INPUTS (PINS PWRSET, RLPF, VASK) PWRSET Voltage 1.2 RLPF Voltage 1.2 VASK Input Impedance 100 220 V V 400 kΩ _______________________________________________________________________________________ 3 MAX2900–MAX2904 DC ELECTRICAL CHARACTERISTICS (continued) MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands AC ELECTRICAL CHARACTERISTICS (MAX290_ EV kits. VCC = +2.7V to +4.5V, RRLPF = 68kΩ, RPWRSET = 22kΩ, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF = 868MHz (MAX2903/MAX2904), VASK = VREG, f REF = 14.56MHz (MAX2900/MAX2901/MAX2902) or f REF = 13.62MHz (MAX2903/MAX2904), chip rate on MODIN = 1.22Mbps, POUT = +23dBm, TA = -40°C to +85°C. Typical values are at VCC = +4.5V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN -3σ TYP +3σ MAX UNITS ANALOG INPUT PINS VTUNE Input Capacitance VTUNE = +1.35V 15 pF 3 pF DIGITAL INPUT PINS Digital Input Pin Capacitance VCO AND SYNTHESIZERS SECTION RFOUT Frequency Range REFIN Reference Frequency Range REFDIV Fixed Reference Divider Ratio Main Divider Ratios PLL Comparison Frequency (MAX2900/MAX2901/MAX2902) 902 917.28 928 (MAX2903/MAX2904) 867 868 870 (MAX2900/MAX2901/MAX2902) 14 14.56 15 (MAX2903/MAX2904) 13 13.78 14.5 (MAX2900) 4 4 4 Table 4 (MAX2900) 249 (MAX2901/MAX2903) 62 (MAX2900) 3.5 (MAX2901/MAX2903) 13 MHz MHz 256 63 3.64 3.75 15 VCO Buffer Output Power 300Ω differential load (MAX2901–MAX2904) REFDIV Fixed Reference Divider Ratio (MAX2901/MAX2903) VCO Phase Noise At 100kHz offset, measured at RFOUT, PLL loop BW = 5kHz VCO Tuning Gain VTUNE = +1.35V VCO Frequency Pulling with OOK Modulation OOKIN clocked at 19kHz, internal (crystal) or external reference frequency 5 60 kHz RMS kHz peak PLL Phase Noise Measured at RFOUT, 5kHz offset, PLL loop BW = 50kHz -96 dBc/Hz REFOUT Voltage Swing -12 MHz 1 1 dBm 1 -101 44 65 dBc/Hz 86 100 MHz/V mVp-p CPOUT Charge Pump Current 500 µA Reference Spurs -62 dBc 300 mV Reference Input Voltage for Nominal Operation Using an external frequency reference 200 BPSK, OOK MODULATOR, AND PA MODIN Frequency Range 1.2 Modulation Filter Nominal 3dB Bandwidth Modulation Filter Final Attenuation Measured at 30MHz Carrier Suppression Noise Power Density 4 At 960MHz (measured at RFOUT at +23dBm output power) 28 8 Mb/s 1 MHz 41 dB 28 dB -150 dBc/Hz _______________________________________________________________________________________ 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands (MAX290_ EV kits. VCC = +2.7V to +4.5V, RRLPF = 68kΩ, RPWRSET = 22kΩ, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF = 868MHz (MAX2903/MAX2904), VASK = VREG, f REF = 14.56MHz (MAX2900/MAX2901/MAX2902) or f REF = 13.62MHz (MAX2903/MAX2904), chip rate on MODIN = 1.22Mbps, POUT = +23dBm, TA = -40°C to +85°C. Typical values are at VCC = +4.5V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER RF Output Power CONDITIONS MIN -3σ TYP +3σ PWRSET = 22kΩ, VCC = +4.5V, TA = +25°C 21 23.5 25 PWRSET = 22kΩ, VCC = +4.5V, TA = -40°C to +85°C 20.5 PWRSET = 22kΩ, VCC = +3.0V, TA = +25°C RF Output Power Flatness 18 fRF = 900MHz to 930MHz (MAX2900/MAX2901/MAX2902) MAX dBm 25 20 UNITS 21 0.3 dB fRF = 867MHz to 870MHz 0.1 Adjacent Channel Power Ratio PN sequence at 1.22MHz -17 dBc Alternate Channel Power Ratio PN sequence at 1.22MHz -26 dBc 80 dB OOK Control Range ASK Output Power Adjustment Range RFOUT Rise and Fall Time Spurious Emissions Unlocked, Out-of-Band Spurious Output Level 40 ASK output power backoff relative to max power OOKIN = high, VASK = 0 41 OOKIN = high, VASK = 1V 16 dB Square-wave signal applied on OOK 1 At 2nd harmonic of RF output frequency with external matching network -50 At 3rd harmonic of RF output frequency with external matching network -51 At 4th harmonic of RF output frequency with external matching network -63 µs dBc Out of 902MHz to 928MHz band other than harmonics with external matching network (MAX2900/MAX2901/MAX2902) < -70 Out of 867MHz to 870MHz band other than harmonics with external matching network (MAX2903/MAX2904) < -70 Any condition when synthesizer unlocked (pin LD low) < -50 Modulation off, measured at 960MHz, any gain setting (MAX2900/MAX2901/MAX2902) -126 -120 Modulation off, measured at 900MHz, any gain setting (MAX2903/MAX2904) -126 -120 dBm Noise Level Out of Band dBm/Hz Output VSWR for Guaranteed Stability 2:1 Maximum Allowable Output VSWR 2:1 Note 1: Devices are production tested at TA = +25°C and +85°C. Min/Max values are guaranteed by design and characterization over temperature and supply voltage. _______________________________________________________________________________________ 5 MAX2900–MAX2904 AC ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (MAX290_ EV kits. VCC = +4.5V, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF = 868MHz (MAX2903/MAX2904), RRLPF = 68kΩ, RPWRSET = 22kΩ, VASK = VREG, fREF = 14.56MHz (MAX2900/MAX2901/MAX2902) or fREF = 13.78MHz (MAX2903/MAX2904), chip rate on MODIN = 1.22 Mbps, RF output matching network optimized for +23dBm, V CC = 4.5V, T A = +25°C, unless otherwise noted.) SHUTDOWN CURRENT vs. VCC 120 TA = -40°C 110 100 24 OUTPUT POWER (dBm) 130 26 MAX2900 toc02 TA = +25°C 140 SHUTDOWN CURRENT (µA) 10 TA = +85°C 1 TA = +85°C TA = +25°C 22 TA = -40°C 20 18 90 TA = -40°C TA = +25°C 0.1 80 3.0 2.5 3.5 4.0 16 2.5 4.5 3.0 3.5 4.0 4.5 3.0 2.5 3.5 VCC (V) VCC (V) VCO PHASE NOISE AT 917.28MHz MAX2900 toc05 917.5 OUTPUT FREQUENCY (MHz) 4.5 PLL LOCK TIME VCO SUPPLY PUSHING vs. VCC 918.0 MAX2900 toc04 -40dBc/Hz 4.0 VCC (V) 100kHz MAX2900 toc06 SUPPLY CURRENT (mA) MAX2900 toc01 TA = +85°C 150 OUTPUT POWER vs. VCC 100 MAX2900 toc03 SUPPLY CURRENT vs. VCC 160 917.0 20kHz/div 916.5 916.0 915.5 915.0 -140dBc/Hz FREQUENCY OFFSET (MHz) -100kHz 2.5 3.0 3.5 4.0 4.5 STOP 30µs START 0s VCC (V) 3000 25 C RF POWER (dBm) 2000 45deg/div 1500 22 21 20 500 19 -225deg 20 30 40 RRLPF (kΩ) 50 60 70 START 0s STOP 40µs A: VCC = 4.5V, TA = -40°C B: VCC = 4.5V, TA = +25°C C: VCC = 4.5V, TA = +85°C D: VCC = 2.7V, TA = -40°C E: VCC = 2.7V, TA = +25°C F: VCC = 2.7V, TA = +85°C 23 1000 10 A B 24 2500 0 6 225deg MAX2900 toc08 MAX2900 toc07 3500 RF POWER vs. FREQUENCY (MAX2900/MAX2901/MAX2902) BPSK MODULATION OUTPUT vs. TIME MAX2900 toc09 LOWPASS FILTER 3-dB RESPONSE vs. RRLPF LOWPASS FILTER 3-dB BANDWIDTH (kHz) MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands E D F 18 900 905 910 915 920 FREQUENCY (MHz) _______________________________________________________________________________________ 925 930 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands RF POWER (dBm) RF OUTPUT MATCHING OPTIMIZED FOR +14dBm OUTPUT AT VCC = +3.0V 30dBm 30dBm MAX2900 toc11 16 MAX2900 toc10 17 OUTPUT SPECTRUM WITH PN SEQUENCE AT 1.22MHz AT MODIN OUTPUT SPECTRUM WITH 600kHz SQUARE WAVE INPUT AT MODIN MKR 917.31MHz -16.33dBm MAX2900 toc12 RF POWER vs. FREQUENCY (MAX2903/MAX2904) MKR 917.35MHz 8.17dBm VCC = +3.6V 15 10dB/div 10dB/div VCC = +3.0V 14 VCC = +2.7V 13 12 -70dBm 864 860 868 872 876 CENTER 917.28MHz -70dBm SPAN 20MHz SPAN 20MHz CENTER 917.28MHz FREQUENCY (MHz) 30dBm MKR 910MHz 23.17dBm MAX2900 toc15 22dBVp-p MAX2900 toc14 Tf Tr MAX2900 toc13 0dBVp-p SPURIOUS LEVEL FROM DC TO 7TH HARMONIC RF OUT RISE AND FALL TIME TRANSIENT WITH SQUARE ASK RF OUT RISE AND FALL TIME TRANSIENT WITH SQUARE OOK Tf Tr 10dB/div 10dB/div -100dBVp-p STOP 86µs START 46µs -78dBVp-p -70dBm SPURIOUS LEVEL BETWEEN ±50MHz FROM CARRIER FREQUENCY TRANSMITTER EFFICIENCY vs. RPWRSET 10dB/div 45 TRANSMITTER EFFICIENCY (%) MAX2900 toc16 30dBm 40 35 A B C D E F 30 25 A: VCC = 4.5V, TA = -40°C B: VCC = 4.5V, TA = +25°C C: VCC = 4.5V, TA = +85°C D: VCC = 2.7V, TA = -40°C E: VCC = 2.7V, TA = +25°C F: VCC = 2.7V, TA = +85°C 20 15 10 -70dBm CENTER 917.28MHz SPAN 100MHz STOP 7GHz START 0Hz STOP 85µs START 45µs MAX2900 toc17 10dB/div 14 18 22 26 30 34 38 RPWRSET (kΩ) _______________________________________________________________________________________ 7 MAX2900–MAX2904 Typical Operating Characteristics (continued) (MAX290_ EV kits. VCC = +4.5V, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF = 868MHz (MAX2903/MAX2904), RRLPF = 68kΩ, RPWRSET = 22kΩ, VASK = VREG, fREF = 14.56MHz (MAX2900/MAX2901/MAX2902) or fREF = 13.78MHz (MAX2903/MAX2904), chip rate on MODIN = 1.22 Mbps, RF output matching network optimized for +23dBm, V CC = 4.5V, T A = +25°C, unless otherwise noted.) 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands MAX2900–MAX2904 Pin Description MAX2902 MAX2904 1 NAME PIN TYPE 1 PIN MAX2901 MAX2903 1 VTUNE Analog Input 2 2 2 GND Supply Pin 3 3 3 VREG Analog Input/Output Regulated voltage output to supply the VCO. Bypass with a 0.01µF capacitor to GND as close to the part as possible. 4 4 4 VCC1 Supply Pin Power supply pin for VCO circuits. Bypass with a 1000pF and a 10µF capacitor to GND as close to the part as possible. 5 5 5 RLPF 6 6 6 EN Digital Input Chip-enable digital input pin. Set EN low maintain the chip in power-down mode. 7 7 7 REFEN Digital Input Enable for crystal oscillator and frequency reference buffer. 8 8 8 MODIN Digital Input BPSK modulation input 9 9 9 OOKIN Digital Input On-off keying modulation. On state = high. Power supply pin for internal RF buffer circuits. Bypass with a 100pF and a 0.01µF capacitor to GND as close to the part as possible. MAX2900 8 FUNCTION VCO tuning voltage input Ground Analog Input Resistor to ground on this pin sets the Resistor to Ground modulation filter bandwidth. 10 10 10 VCC2 Supply 11 11 11 VASK Analog Voltage Input 12 12 — LD Digital Output — — 12 D.C. 13 13 13 PWRSET 14 14 14 VCC3 ASK voltage input pin Lock detector output digital pin. Level is high when PLL is inside lock range. Do NOT Connect — Analog Input Current input set to adjust output power. Resistor to Ground Supply Power supply pin for RF power amplifier circuits. Bypass with a 100pF capacitor to GND as close to the part as possible. _______________________________________________________________________________________ 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands PIN MAX2900 MAX2901 MAX2903 MAX2902 MAX2904 NAME PIN TYPE FUNCTION 15 15 15 GND Supply Pin Ground 16, 17 16, 17 16, 17 RF-, RF+ RF Output RF differential output, open-collector type 18 — — N.C. Not Connected — 18 — GND Supply Pin — — 18 D.C. Do Not Connect — 19 — 19 N.C. Not Connected — — 19 — DIVOUT ECL Output — Ground Divider output — 20, 21 20, 21 VCO-, VCO+ Open Collector RF 20 — — D1 Digital Input Channel selection bit 1 21 — — D0 Digital Input Channel selection bit 0 22 22 22 OSC Analog Input Crystal oscillator connection. See Typical Operating Circuit. 23 23 23 REFIN Analog Voltage Input Reference input pin analog (can be used as input or as crystal oscillator driver). See Typical Operating Circuit. 24 24 — VCC4 Supply Pin Power-supply pin for the synthesizer circuits. Bypass with a 1000pF capacitor to GND as close to the part as possible. — — 24 VCC4 Supply Pin Power-supply pin for the digital circuits. Bypass with a 100pF capacitor to GND as close to the part as possible. 25 25 25 REFOUT Analog Output 26 — — D2 Digital Input Channel selection bit 2 — 26 — DIV63 Digital Input Division ratio selections (division ratio = 62 when DIV63 = high; division ratio = 63 when DIV63 = low). — — 26 N.C. Not Connected 27 27 — VCC5 Supply Pin Power-supply pin for charge pump circuits. Bypass with a 100pF capacitor to GND as close to the part as possible. — — 27 VCC5 Supply Pin Power-supply pin. Bypass with a 100pF capacitor to GND as close to the part as possible. 28 28 — CPOUT Analog Output — — 28 D.C. Do Not Connect GROUND GROUND GROUND GROUND Electrical Ground VCO output (differential) Buffered clock analog output pin — Charge pump output pin — Back side of package is connected to ground. _______________________________________________________________________________________ 9 MAX2900–MAX2904 Pin Description (continued) MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands Detailed Description Principles of Operation When EN goes high, the reference and the VCO start while the PA stays in the off mode. For MAX2900/ MAX2901/MAX2903, the PLL also starts when EN goes high. After the lock-detect pin LD goes high, the PA is set to stand-by mode. For the MAX2902/MAX2904, the VCO loop has to be closed by using an external synthesizer. After this, pulling OOKIN high turns on the PA. The internal modulation filter smoothes the power ramp-up of the PA. The modulation filter BW is typically 0.8MHz, used for a 1.22Mbps chip rate, and can be adjusted by varying RLPF. A high value can be used for RLPF to get a slow PA ramping up when BPSK is not used. The reference blocks can be turned on separately (and earlier) by pulling REFEN high, to allow the crystal frequency to settle. The device supports various modulation modes: • • BPSK, filtered by the internal modulation filter, is obtained through the MODIN pin. This is the preferred mode of operation for MAX2900. OOK is obtained digitally with the OOKIN pin. • ASK is obtained through the ASK pin. • • FM is imposed on the VCO or the reference. FM is the preferred mode of operation for the MAX2903/MAX2904 due to the narrowband operation common in Europe. The maximum output power is set by the output matching network and the external biasing resistor on the PWRSET pin. For the MAX2901–MAX2904, differential LO outputs are provided to drive a companion receiver and/or an external synthesizer. Power-Up Modes The circuit has four modes of operations, defined as follows: 1) Shutdown mode: Pin EN and REFEN are low, all functions are off, and the current consumption is leakage only. 2) Synth mode: Pin EN and REFEN are high, pin OOKIN is low. The reference circuits, VCO, and synthesizer are turned on. The power amplifier is in stand-by mode. Total current is less than 50mA. Note that as long as the LD pin is not going high, indicating that the PLL is unlocked, OOKIN high is ignored. 10 3) Transmit mode: Pin EN and REFEN are high. If output pin LD is high, the device is ready to transmit. When OOKIN is high, the power amplifier is turned on. The current consumption varies between 50mA and 120mA, depending on the output power requested by the combination of the OOK duty cycle, the PWRSET value, and output matching circuit. 4) Reference Only mode: This mode enables the use of the crystal reference from the IC to drive the external logic ICs. To obtain this mode, set the REFEN pin high and EN low. In this mode, only the reference circuit turns on, the crystal oscillator starts, and the clock is present at the REFOUT pin. The current consumption remains much lower than that in the SYNTH mode because the VCO, synthesizer, and PA standby circuits are off. When EN goes high, the IC goes into the SYNTH mode. Synthesizer Programming The three pins D0–D2 (MAX2900) and DIV63 (MAX2901/ MAX2903) are used as digital entries to program the synthesizer division ratios. Tables 4 and 5 show the division ratios obtained for the various pin logic levels. TO INTERNAL CONTROL CIRCUIT PIN PWRSET 100Ω 1.2V INTERNAL CIRCUITS EXTERNAL RESISTOR Figure 1. PIN PWRSET Equivalent Circuit Analog Input Control Pins The two pins PWRSET and VASK are analog inputs used to control the power of the transmitter. The equivalent input schematics are defined in Figures 1, 2, and 3. The PWRSET pin sets the biasing of the amplification chain. Because the last stage of the amplifier operates in saturation, the output power mostly depends on the load and supply voltage. The purpose of the PWRSET resistor is to achieve optimum biasing (and therefore efficiency) for various maximum output power configurations. For a given application with a known operating voltage and peak power, a fixed value of resistor is determined. The output power range of -7dBm to +23dBm at 4.5V is obtained by choosing a combination of output load line and the resistor on PWRSET; 22kΩ is ______________________________________________________________________________________ 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands TO VREG (2.1V) TO INTERNAL CONTROL CIRCUIT PIN VASK >200kΩ 1.5V EXTERNAL RESISTOR BRIDGE INTERNAL CIRCUITS Figure 2. PIN VASK Equivalent Circuit The VASK pin is an input to the internal gain control circuitry. The gain control is greater than 30dB over the full range of input voltages from 0 to VREG = 2.1V. This input is used for ASK modulation. At 1V, a typical 15dB attenuation is obtained from the peak power. When this input is not used, connect VASK to VREG. The RLPF input controls the modulation filter center frequency. TO INTERNAL CONTROL CIRCUIT Data Filter Characteristics The data filter approximates a 3rd-order Butterworth filter. The 3dB cut-off frequency is adjusted through the resistor on pin RLPF, which controls the first two poles of the filter (the last high-frequency pole is fixed and set around 10MHz). The filter is adjustable in a range from approximately 700kHz to 7MHz. With the nominal setting (3dB cut off at 0.8MHz), the filter attenuation is 10dB at 3.6MHz. If used with a BPSK at 1.22MHz, this provides about 30dB of modulation rolloff at 3.6MHz. Hence, a significant channelization effect is obtained. In the wideband setting (3dB cut off at 5MHz), the attenuation at 30MHz is still 30dB, helping to pass the FCC spurious emissions at 960MHz. PIN RLPF 100Ω 1.2V The RLPF pin sets the bandwidth of the modulation filter. The default filter bandwidth, obtained with a 68kΩ resistor, is for 1.2Mchips/s. The bandwidth is increased to accommodate 5Mchips/s by decreasing the resistor value to about 26kΩ. The minimum value for the resistor is 12kΩ, which generates the maximum filter bandwidth. A higher value can be used in FM mode to set up a slow ramp-up time for the PA. INTERNAL CIRCUITS EXTERNAL RESISTOR Figure 3. PIN RLPF Equivalent Circuit ______________________________________________________________________________________ 11 MAX2900–MAX2904 used on the EV kit board for +23dBm output power at 4.5V, and 22kΩ is also recommended for +20dBm output power at +3.0V. For +17dBm at 3.0V, 36kΩ is recommended. The current consumption, efficiency, and distortion in the amplification chain are affected by the choice of the resistor RPWRSET, offering a lot of design flexibility. MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands Table 1. MAX2900 Power-Up Modes LOGIC LEVEL INTERNAL BLOCK STATUS REFEN EN OOKIN REFERENCE VCO MOD FILTER SYNTHESIZER PA 0 0 X Off Off Off Off 1 0 X On Off Off Off 1 1 0 On On On Off 1 1 1 On On On On only after LD goes high Table 2. MAX2901/MAX2903 Power-Up Modes REFEN EN OOKIN REFERENCE VCO MOD FILTER SYNTHESIZER PA 0 0 X Off Off Off Off 1 0 X On Off Off Off 1 1 0 On On On Off 1 1 1 On On On On only after LD goes high Table 3. MAX2902/MAX2904 Power-Up Modes REFEN EN OOKIN REFERENCE VCO MOD FILTER 0 0 X Off Off Off 1 0 0 On Off Off 0 1 0 Off On Off 1 1 0 On On Off 0 1 1 Off On On 1 1 1 On On On Table 4. MAX2900 Synthesizer Programming 12 PA Table 5. MAX2901/MAX2903 Synthesizer Programming D0 D1 D2 DIVISION RATIO DIV 63 DIVISION RATIO 0 1 1 249 0 62 0 1 0 250 1 63 0 0 1 251 0 0 0 252 1 1 1 253 1 1 0 254 1 0 1 255 1 0 0 256 ______________________________________________________________________________________ C2 WBFM (OPT) C3 R4 R3 R5 C13 C35 OOK MODIN (PN) C4 C1 R1 REFEN EN RLPF VCC1 VREG GND VTUNE 7 6 5 4 3 2 1 MODIN 8 28 CPOUT C28 9 C8 VCC2 10 ÷4 REFOUT VASK VCC4 24 R7 R8 ASK (OPT) VREG LD 12 8-CHANNEL SYNTHESIZER R6 11 25 C26 13 23 REFIN C18 D1 D0 15 16 17 GND RF- RF+ 18 N.C. 19 N.C. 20 21 VCC_DRV VCC3 OSC 14 22 C24 C23 MAX2900 TYPICAL OPERATING CIRCUIT OOKIN 26 D2 MAX2900 GATE REG CP VCC5 27 REFOUT L2 L1 D1 D0 C12 C32 C31 Y1 (OPT) VCC_PA C16 L4 L3 C15 C34 C33 EXT REFERENCE (OPT) L5 LOOP ANTENNA Typical Operating Circuits ______________________________________________________________________________________ 13 MAX2900–MAX2904 PWRSET C25 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands C2 WBFM (OPT) C3 R4 R3 C1 C13 C35 OOK MODIN (PN) R5 C4 R1 REFEN EN RLPF VCC1 VREG GND VTUNE 7 6 5 4 3 2 1 ______________________________________________________________________________________ 9 OOKIN 26 DIV63 C8 VCC2 10 MAX2901/ MAX2903 GATE REG CP VCC5 27 R7 R6 11 VASK C26 VCC4 24 LD R8 ASK (OPT) VREG 12 DUALCHANNEL (/62 OR /63) SYNTHESIZER 25 REFOUT 13 23 C18 15 16 17 18 19 20 21 VCC_DRV VCC3 OSC 14 22 C24 C23 GND RF- RF+ GND L2 DIVOUT VCO- VCO+ MAX2901/MAX2903 TYPICAL OPERATING CIRCUIT MODIN 8 28 CPOUT C28 REFOUT REFIN 14 PWRSET L1 C12 C32 C31 R11 Y1 C25 VCC_PA C16 L4 L3 C15 VCOOUT C37 R10 VCC EXT REFERENCE /FM INPUT C34 C33 L5 LOOP ANTENNA MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands Typical Operating Circuits (continued) C2 C3 R4 R3 R5 C13 C35 OOK MODIN (PN) C4 C1 R1 REFEN EN RLPF VCC1 VREG GND VTUNE 7 6 5 4 3 2 1 OOKIN 9 GATE REG 27 C8 VCC2 10 26 VCC5 N.C. VASK R7 R6 11 25 REFOUT C26 R8 ASK (OPT) VREG D.C. 12 MAX2902/ MAX2904 24 13 23 C18 14 22 R11 VCO- VCO+ 15 16 17 GND RF- RF+ 18 D.C. 19 N.C. 20 21 VCC_DRV VCC3 VCC4 REFIN OSC L2 MAX2902/MAX2904 TYPICAL OPERATING CIRCUIT MODIN 8 28 D.C. C28 L1 C12 C32 C31 VCOOUT C37 R10 VCC L4 L3 C15 VCC_PA C16 RFIN 1GHz FREQUENCY SYNTH CPOUT REFIN C34 C33 L5 LOOP ANTENNA Typical Operating Circuits (continued) ______________________________________________________________________________________ 15 MAX2900–MAX2904 WBFM (OPT) PWRSET REFFREQ /FM 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands Functional Diagrams/ Pin Configurations (continued) Chip Information TRANSISTOR COUNT: 898 D.C. VCC5 N.C. 28 27 26 REFOUT VCC4 25 REFIN OSC 23 22 24 VTUNE 1 21 VCO+ GND 2 20 VCO- VREG 3 19 N.C. VCC1 4 RLPF 5 17 RF+ EN 6 16 RF- REFEN 7 REG GATE 8 9 MODIN OOKIN 16 18 D.C. MAX2902/ MAX2904 15 GND 10 11 12 VCC2 VASK D.C. 13 14 PWRSET VCC3 ______________________________________________________________________________________ 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands 32L QFN.EPS ______________________________________________________________________________________ 17 MAX2900–MAX2904 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) MAX2900–MAX2904 200mW Single-Chip Transmitter ICs for 868MHz/915MHz ISM Bands Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.