MAX2510EEI+T

19-1296; Rev 2; 1/01 L MANUA ION KIT HEET T A U L EVA TA S WS DA FOLLO Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator ____________________________Features ♦ +2.7V to +5.5V Single-Supply Operation ♦ Complete Receive Path: 600MHz (max) 1st IF to 30MHz (max) 2nd IF ♦ Unique, Wide-Dynamic-Range Downconverter Mixer Offers -8dBm IIP3, 11dB NF ♦ 90dB Dynamic-Range Limiter with High-Accuracy RSSI Function ♦ Differential Limiter Output Directly Drives CMOS Input ♦ 100MHz to 600MHz Transmit Quadrature Modulator with 41dB Sideband Suppression ♦ 40dB Transmit Gain-Control Range; Up to +1dBm Output Power ♦ Advanced Power Management (four modes) ♦ 0.2µA Shutdown Supply Current _______________Ordering Information PART MAX2510EEI ________________________Applications PWT1900, Wireless Handsets, and Base Stations PACS, PHS, DECT, and Other PCS Wireless Handsets and Base Stations 400MHz ISM Transceivers IF Transceivers Wireless Data Links TEMP. RANGE -40°C to +85°C ___________________Pin Configuration TOP VIEW LIMIN 1 28 VREF CZ 2 27 MIXOUT CZ 3 26 GND RSSI 4 25 RXIN GC 5 LO 6 Typical Operating Circuit appears on last page. PIN-PACKAGE 28 QSOP 24 TXOUT MAX2510 23 TXOUT GND 7 22 RXIN VCC 8 21 VCC LO 9 20 GND GND 10 19 VCC TXEN 11 18 Q RXEN 12 17 Q LIMOUT 13 16 I LIMOUT 14 15 I QSOP ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX2510 ________________General Description The MAX2510 is a highly integrated IF transceiver for digital wireless applications. It operates from a +2.7V to +5.5V supply voltage and features four operating modes for advanced system power management. Supply current is reduced to 0.2µA in shutdown mode. In a typical application, the receiver downconverts a high IF/RF (up to 600MHz) to a low IF (up to 30MHz) using a double-balanced mixer. Additional functions included in the receiver section are an IF buffer that can drive an off-chip filter, an on-chip limiting amplifier offering 90dB of received-signal-strength indication (RSSI), and a robust differential limiter output driver designed to directly drive a CMOS input. The transmitter section upconverts I and Q baseband signals to an IF in the 100MHz to 600MHz range using a quadrature modulator. The transmit output is easily matched to drive a SAW filter with an adjustable output from 0dBm to -40dBm and excellent linearity. The MAX2511 has features similar to the MAX2510, but upconverts a low IF with an image-reject mixer. The MAX2511 downconverter also offers image rejection with a limiter/RSSI stage similar to that of the MAX2510. MAX2510 Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator ABSOLUTE MAXIMUM RATINGS VCC to GND .............................................................-0.3V to 8.0V VCC to Any Other VCC ........................................................±0.3V I, I, Q, Q to GND .........................................-0.3V to (VCC + 0.3V) I to I, Q to Q Differential Voltage ............................................±2V RXIN to RXIN Differential Voltage ..........................................±2V LOIN to LOIN Differential Voltage..........................................±2V LIMIN Voltage .............................(VREF - 1.3V) to (VREF + 1.3V) RXEN, TXEN, GC Voltage...........................-0.3V to (VCC + 0.3V) RXEN, TXEN, GC Input Current ............................................1mA RSSI Voltage...............................................-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70°C) QSOP (derate 10mW/°C above +70°C) ........................650mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +165°C Lead Temperature (soldering, 10sec) .............................+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. DC ELECTRICAL CHARACTERISTICS (VCC = +2.7V to +5.5V; 0.01µF across CZ and CZ; LO, LO open; MIXOUT tied to VREF through a 165Ω resistor; GC = 0.5V; RXIN, RXIN open; LIMIN tied through 50Ω to VREF; LIMOUT, LIMOUT = open; RXEN, TXEN = high; bias voltage at I, I, Q, Q = 1.4V; TA = -40°C to +85°C; unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS Operating Voltage Range Digital Input Voltage High RXEN, TXEN Digital Input Voltage Low RXEN, TXEN Digital Input Current High RXEN, TXEN = 2.0V Digital Input Current Low RXEN, TXEN = 0.4V MIN TYP MAX UNITS 2.7 3.0 5.5 V 2.0 6 -5 µA 0.1 µA 20 Transmit mode, RXEN = low, TXEN = high 17 25 Standby mode, RXEN = high, TXEN = high 0.5 1 Shutdown mode, RXEN = low, TXEN = low 0.2 5 µA VCC / 2 100mV VCC / 2 VCC / 2 + 100mV V 50 85 VREF Voltage GC Input Resistance V 30 14 Receive mode, RXEN = high, TXEN = low Supply Current V 0.4 (Note 1) mA kΩ AC ELECTRICAL CHARACTERISTICS (MAX2510 test fixture; VCC = +3.0V; RXEN = TXEN = low; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω, LO AC grounded; GC open; LIMOUT, LIMOUT are AC coupled to 250Ω load; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; PRXIN, RXIN = -30dBm differentially driven (input matched); fRXIN, RXIN = 240MHz; bias voltage at I, I, Q, Q = 1.4V; VI,Q = 500mVp-p; fI,Q = 200kHz; fLO, LO = 230MHz; PLO = -13dBm; TA = +25°C; unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS 600 MHz DOWNCONVERTER (RXEN = high) Input Frequency Range Conversion Gain (Note 2) 100 TA = +25°C 20.5 TA = -40°C to +85°C (Note 3) 19.9 Noise Figure Single sideband Input 1dB Compression Point (Note 4) Input Third-Order Intercept Two tones at 240MHz and 240.2MHz, -30dBm per tone LO to RXIN Isolation Power-Up Time 2 22.5 25 25.5 dB 11 dB -18.5 dBm -8 dBm 49 Standby to RX or TX (Note 5) _______________________________________________________________________________________ dBc 5 µs Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator (MAX2510 test fixture; VCC = +3.0V; RXEN = TXEN = low; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω, LO AC grounded; GC open; LIMOUT, LIMOUT are AC coupled to 250Ω load; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; PRXIN, RXIN = -30dBm differentially driven (input matched); fRXIN, RXIN = 240MHz; bias voltage at I, I, Q, Q = 1.4V; VI,Q = 500mVp-p; fI,Q = 200kHz; fLO, LO = 230MHz; PLO = -13dBm; TA = +25°C; unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS LIMITING AMPLIFIER AND RSSI (RXEN = high, fLIMIN = 10MHz, PLIMIN = -30dBm from 50Ω source, unless otherwise noted) Limiter Output Voltage Swing LIMOUT, LIMOUT Phase Variation -75dBm to 5dBm ±4.5 degrees Minimum Linear RSSI Range -75dBm to 5dBm 80 dB Minimum Monotonic RSSI Range -85dBm to 5dBm 90 dB RSSI Slope -75dBm to 5dBm from 50Ω 20 mV/dB ±270 RSSI Maximum Zero-Scale Intercept (Note 6) RSSI Relative Error (Notes 6, 7) ±300 ±350 -86 TA = +25°C ±0.5 TA = -40°C to +85°C (Note 3) mV dBm ±2.0 ±3.0 dB Minimum-Scale RSSI Voltage At LIMIN input of -75dBm 0.25 V Maximum-Scale RSSI Voltage At LIMIN input of +5dBm 1.8 V TRANSMITTER (TXEN = high) Frequency Range (Note 8) I, I, Q, Q Allowable Common-Mode Voltage Range 100 600 I, I, Q, Q inputs are 250mVp-p centered around this voltage, GC = 2.0V (Note 9) 1.3 VCC 1.2 I, Q are 500mVp-p while I, Q are held at this DC voltage (Note 9) 1.4 VCC 1.3 V GC = 0.5V -41 GC = open Output Power GC = 2.0V (Note 9) MHz -16 TA = +25°C TA = -40°C to +85°C -2.5 1 dBm -3 I, I, Q, Q 1dB Bandwidth (Note 3) 70 80 MHz Unwanted Sideband Suppression 90° phase difference between I and Q inputs; GC = 2V 30 40 dBc LO Rejection 90° phase difference between I and Q inputs; measured to fundamental tone; GC = 2V 30 44 dBc Output IM3 Level Output IM5 Level GC = 0.5V (Note 11) -49 GC = 2V (Note 11) -33 GC = 2V (Note 11) -51 dBc dBc Note 1: This pin is internally terminated to approximately 1.35V through the specified resistance. Note 2: Downconverter gain is typically greater than 20dB. Operation outside this frequency range is possible but has not been characterized. Note 3: Guaranteed by design and characterization. _______________________________________________________________________________________ 3 MAX2510 AC ELECTRICAL CHARACTERISTICS (continued) Note 4: Driving RXIN or RXIN with a power level greater than the 1dB compression level forces the input stage out of its linear range, causing harmonic and intermodulation distortion. The RSSI output increases monotonically with increasing input levels beyond the mixer’s 1dB compression level. Input 1dB compression point is limited by MIXOUT voltage swing, which is approximately 2Vp-p into a 165Ω load. Note 5: Assuming the supply voltage has been applied, this includes limiter offset-correction settling and Rx or Tx bias stabilization time. Guaranteed by design and characterization. Note 6: The RSSI maximum zero-scale intercept is the maximum (over a statistical sample of parts) input power at which the RSSI output would be 0V. This point is extrapolated from the linear portion of the RSSI Output Voltage vs. Limiter Input Power graph in the Typical Operating Characteristics. This specification and the RSSI slope define the RSSI function’s ideal behavior (the slope and intercept of a straight line), while the RSSI relative error specification defines the deviations from this line. See the Typical Operating Characteristics for the RSSI Output Voltage vs. Limiter Input Power graph. Note 7: The RSSI relative error is the deviation from the best-fitting straight line of the RSSI output voltage versus the limiter input power. This number represents the worst-case deviation at any point along this line. A 0dB relative error is exactly on the ideal RSSI transfer function. The limiter input power range for this test is -75dBm to 5dBm from 50Ω. See the Typical Operating Characteristics for the RSSI Relative Error graph. Note 8: Transmit sideband suppression is typically better than 35dB. Operation outside this frequency range is possible but has not been characterized. Note 9: Output IM3 level is typically better than -29dBc. Note 10: The output power can be increased by raising GC above 2V. Refer to the Transmitter Output Power vs. GC Voltage and Frequency graph in the Typical Operating Characteristics. Note 11: Using two tones at 400kHz and 500kHz, 250mVp-p differential per tone at I, I, Q, Q. __________________________________________Typical Operating Characteristics (MAX2510 EV kit; VCC = +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; PRXIN, RXIN = -30dBm differentially driven (input matched); fRXIN, RXIN = 240MHz; bias voltage at I, I, Q, Q = 1.4V; VI,Q = 500mVp-p; f I, Q = 200kHz; fLO, LO = 230MHz; PLO = -13dBm; TA = +25°C; unless otherwise noted.) SUPPLY CURRENT vs. TEMPERATURE 10 5 14 12 10 8 6 4 0 -20 0 20 40 60 TEMPERATURE (°C) 80 100 20 15 10 STANDBY 0 0 -40 25 5 2 STANDBY 30 SUPPLY CURRENT (mA) 15 Rx MAX2510toc03 16 SUPPLY CURRENT (mA) Rx Tx 18 35 MAX2510toc02 20 MAX2510toc01 Tx 20 4 TRANSMITTER SUPPLY CURRENT vs. GC VOLTAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE 25 SUPPLY CURRENT (mA) MAX2510 Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 GC VOLTAGE (V) _______________________________________________________________________________________ Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator MAX2510 ____________________________ Typical Operating Characteristics (continued) (MAX2510 EV kit; VCC = +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; PRXIN, RXIN = -30dBm differentially driven (input matched); fRXIN, RXIN = 240MHz; bias voltage at I, I, Q, Q = 1.4V; VI,Q = 500mVp-p; f I, Q = 200kHz; fLO, LO = 230MHz; PLO = -13dBm; TA = +25°C; unless otherwise noted.) DOWNCONVERTER MIXER CONVERSION GAIN vs. SUPPLY VOLTAGE AND TEMPERATURE 25 MAX2510toc05 25 MAX2510toc04 1.0 TA = -40°C 24 20 0.8 GAIN (dB) TA = +85°C 0.6 TA = -40°C 22 GAIN (dB) 23 TA = +85°C TA = +25°C 21 0.4 15 10 20 TA = +25°C 0.2 5 19 MISMATCH LOSS COMPENSATED 18 3.0 3.5 4.0 4.5 5.0 2.5 5.5 3.0 3.5 4.0 4.5 5.0 5.5 0 100 200 300 400 500 600 700 800 900 1000 VOLTAGE (V) SUPPLY VOLTAGE (V) RF FREQUENCY (MHz) RECEIVE MIXER INPUT 1dB COMPRESSION POINT vs. SUPPLY VOLTAGE -13 TA = +85°C -14 -15 -16 TA = +25°C -17 -18 TA = -40°C -19 500 400 350 300 250 IMAGINARY 200 150 -20 100 -21 50 -22 SINGLE-ENDED 450 REAL IMPEDANCE (Ω) -12 RXIN INPUT IMPEDANCE vs. FREQUENCY MAX2510toc07 2.5 0 MAX2510toc08 0 INPUT 1dB COMPRESSION (dBm) SHUTDOWN SUPPLY CURRENT (µA) 1.2 DOWNCONVERTER MIXER CONVERSION GAIN vs. RXIN FREQUENCY MAX2510toc06 SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE REAL 0 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 30 90 150 210 270 330 390 450 510 FREQENCY (MHz) _______________________________________________________________________________________ 5 ____________________________ Typical Operating Characteristics (continued) (MAX2510 EV kit; VCC = +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; PRXIN, RXIN = -30dBm differentially driven (input matched); fRXIN, RXIN = 240MHz; bias voltage at I, I, Q, Q = 1.4V; VI,Q = 500mVp-p; f I, Q = 200kHz; fLO, LO = 230MHz; PLO = -13dBm; TA = +25°C; unless otherwise noted.) RSSI ERROR (dB) 1.4 1.2 1.0 VOUT = +85°C 0.6 0.2 TATA= =+25°C +25°C 2 1 0 -1 -2 VOUT = +25°C 0.4 VOUT = -40°C 0 -80 -60 -40 -20 0 1.2 1.0 0.8 0.4 0.2 20 0 -95 -75 -55 -35 -15 -80 -70 5 -30 5 GC = 2.0V 0 OUTPUT POWER (dBm) 230MHz -40 -20 -10 TRANSMITTER OUTPUT POWER vs. FREQUENCY MAX2510toc12 0 -60 -50 RXIN INPUT POWER (dBm) LIMITER INPUT POWER (dBm, 50Ω) 10 -10 -20 500MHz -30 200MHz -40 -5 -10 -15 -20 -50 -25 -60 0.7 0.9 1.1 1.3 1.5 1.7 0 1.9 200 400 600 800 1000 GC VOLTAGE (V) FREQUENCY (MHz) TRANSMITTER IM3 LEVELS vs. GC VOLTAGE TRANSMITTER OUTPUT 1dB COMPRESSION POINT vs. GC VOLTAGE MAX2510toc13 -30 -35 -40 -45 -50 -55 10 OUTPUT 1dB COMPRESSION (dBm) 0.5 MAX2510toc15 OUTPUT POWER (dBm) 1.4 -4 TRANSMITTER OUTPUT POWER vs. GC VOLTAGE AND FREQUENCY IM3 LEVELS (dBc) 1.6 -3 LIMITER INPUT POWER (dBm, 50Ω) 0 -10 -20 TA = +85°C -30 TA = -40°C -40 -50 TA = +25°C -60 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 GC VOLTAGE (V) 6 1.8 0.6 TA = +85°C -5 -120 -100 MAX2510toc11 TA = -40°C 3 2.0 MAX2510toc10 1.6 4 RSSI VOLTAGE (V) 1.8 0.8 5 MAX2510toc10a 2.0 RSSI OUTPUT VOLTAGE vs. RXIN INPUT POWER RSSI RELATIVE ERROR vs. LIMIN INPUT POWER AND TEMPERATURE MAX2510toc12a RSSI OUTPUT VOLTAGE vs. LIMIN INPUT POWER AND TEMPERATURE RSSI VOLTAGE (V) MAX2510 Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 GC VOLTAGE (V) _______________________________________________________________________________________ 0 Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator (MAX2510 EV kit; VCC = +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; PRXIN, RXIN = -30dBm differentially driven (input matched); fRXIN, RXIN = 240MHz; bias voltage at I, I, Q, Q = 1.4V; VI,Q = 500mVp-p; f I, Q = 200kHz; fLO, LO = 230MHz; PLO = -13dBm; TA = +25°C; unless otherwise noted.) 0.4 -14 TA = -40°C 0.2 -16 -18 -20 -22 -24 -26 50 SIDEBAND SUPPRESSION (dB) TA = +85°C GC = OPEN -12 OUTPUT POWER (dBm) TA = +25°C MAX2510toc16 0.8 OUTPUT POWER (dBm) -10 MAX2510toc15 1.0 0.6 TRANSMITTER SIDEBAND SUPPRESSION vs. RF FREQUENCY OUTPUT POWER vs. BASEBAND INPUT VOLTAGE MAX2510toc17 TRANSMITTER OUTPUT POWER vs. SUPPLY VOLTAGE 40 30 20 10 -28 0 3.5 4.0 4.5 5.0 5.5 50 100 150 200 250 300 350 0 400 200 400 600 800 1000 SUPPLY VOLTAGE (V) BASEBAND INPUT VOLTAGE (mVp) RF FREQUENCY (MHz) TRANSMITTER DIFFERENTIAL OUTPUT IMPEDANCE vs. FREQUENCY TRANSMIT NOISE POWER vs. GC VOLTAGE TRANSMITTER OUTPUT POWER vs. LO POWER -200 -300 -400 Tx OFF IMAGINARY -500 Tx MODE IMAGINARY -600 -700 -13.0 -138 -140 -142 -144 -146 -148 -13.5 -14.0 -14.5 -15.0 -15.5 -16.0 -16.5 -150 -17.0 -900 -152 -17.5 -1000 -154 -800 200 300 400 FREQUENCY (MHz) 500 MAX2510toc20 Af = 200kHz -136 OUTPUT POWER (dBm) Tx OFF REAL -100 -134 MAX2510toc19 Tx MODE REAL OUTPUT NOISE POWER (dBm/Hz) 0 3.0 MAX2510toc18 REAL AND IMAGINARY IMPEDANCE (Ω) 100 0 -30 2.5 -18.0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 GC VOLTAGE (V) -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 LO POWER (dBm) _______________________________________________________________________________________ 7 MAX2510 ____________________________ Typical Operating Characteristics (continued) Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator MAX2510 Pin Description 8 PIN NAME FUNCTION 1 LIMIN 2, 3 CZ, CZ 4 RSSI 5 GC 6, 9 LO, LO 7 GND Local-Oscillator Input Ground. Connect to PC board ground plane with minimal inductance. Limiter Input. Connect a 330Ω (typical) resistor to VREF for DC bias, as shown in the Typical Operating Circuit. Offset-Correction Capacitor Pins. Connect a 0.01µF capacitor between CZ and CZ. Received Signal-Strength Indicator Output. The voltage on RSSI is proportional to the signal power at LIMIN. The RSSI output sources current pulses into a 330pF (typical) external capacitor. This output is internally terminated with 11kΩ, and this RC time constant sets the decay time. Gain-Control Pin. Applying a DC voltage to GC between 0V and 2.0V adjusts the transmitter gain by more than 40dB. GC is internally terminated to 1.35V via an 85kΩ resistor. Differential LO Inputs. In a typical application, externally terminate LO with 50Ω to ground, then AC couple into LO. AC terminate LO directly to ground for single-ended operation, as shown in the Typical Operating Circuit. 8 VCC Local-Oscillator Input VCC Pin. Bypass directly to local-oscillator input ground (pin 8). 10 GND Limiter Ground. Connect to PC board ground plane with minimal inductance. 11 TXEN Transmitter-Enable Pin. When high, TXEN enables the transmitter if RXEN is low. If both TXEN and RXEN are high, the part is in standby mode; if both are low, the part is in shutdown. See the Power Management section for details. 12 RXEN Receiver Enable Pin. When high, RXEN enables the receiver if TXEN is low. If both RXEN and TXEN are high, the part is in standby mode; if both are low, the part is in shutdown. See the Power Management section for details. 13, 14 LIMOUT, LIMOUT Differential Outputs of the Limiting Amplifier. These outputs are complementary emitter followers capable of driving 250Ω single-ended loads to ±300mV. 15, 16 I, I Baseband In-Phase Inputs. The differential voltage across these inputs forms the quadrature modulator’s I-channel input. The signal input level is typically up to 500mVp-p centered around a 1.4V (typical) DC bias level on I. 17, 18 Q, Q Baseband Quadrature-Phase Inputs. The differential voltage across these inputs forms the quadrature modulator’s Q-channel input. The signal input level is typically up to 500mVp-p, centered around a 1.4V (typical) DC bias level on Q. 19, 21 VCC General-Purpose VCC Pins. Bypass with a 0.047µF low-inductance capacitor to GND. 20 GND Receiver/Transmitter Ground. Connect to PC board ground plane with minimal inductance. 22, 25 RXIN, RXIN Differential Inputs of the Downconverter Mixer. An impedance-matching network may be required in some applications. See the Applications Information section for details. 23, 24 TXOUT, TXOUT 26 GND 27 MIXOUT 28 VREF Differential Outputs of the Upconverter. In a typical application, these open-collector outputs are pulled up to VCC with two external inductors and AC coupled to the load. See the Applications Information section for more details, including information on impedance matching these outputs to a load. Receiver Mixer Ground. Connect to PC board ground plane with minimal inductance. Single-Ended Output of the Downconverter Mixer. This pin is high-impedance and must be biased to the VREF pin through an external terminating resistor whose value depends on the interstage filter characteristics. See the Applications Information section for details. Reference Voltage Pin. VREF provides an external bias voltage for the MIXOUT and LIMIN pins. Bypass this pin with a 0.1µF capacitor to ground. The VREF voltage is equal to VCC / 2. See the Typical Operating Circuit for more information. _______________________________________________________________________________________ Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator MAX2510 IF BPF LIMIN VREF MIXOUT CZ CZ OFFSET CORRECTION RXIN LIMITER gm LIMOUT RXIN LIMOUT VREF = VCC / 2 LO LO RXEN TXEN RSSI RSSI POWER MANAGEMENT I GC I VGA TXOUT Σ PA 0° 90° LO PHASE SHIFTER MAX2510 TXOUT Q TRANSMIT VGA/PA Q Figure 1. Functional Diagram _______________Detailed Description The following sections describe each of the blocks shown in Figure 1. Receiver The receiver consists of two basic blocks: the downconverter mixer and the limiter/received-signal-strength indicator (RSSI) section. The receiver inputs are the RXIN and RXIN pins, which should be AC coupled and may require a matching network as shown in the Typical Operating Circuit. To design a matching network for a particular application, consult the RXIN Input Impedance plots in the Typical Operating Characteristics, as well as the Applications Information sections. Downconverter Mixer The downconverter consists of an a double-balanced mixer and an output buffer. The MIXOUT output, a singleended current source, can drive a shunt-terminated 330Ω filter (165Ω load) to more than 2Vp-p over the entire supply range, providing excellent dynamic range. The local oscillator (LO) input is buffered and drives the mixer. Limiter The signal passes through an external IF bandpass filter into the limiter input (LIMIN). LIMIN is a singleended input that is biased at the VREF pin voltage. The open-circuit input impedance is typically greater than 10kΩ to VREF. For proper operation, LIMIN must be tied to VREF through the filter-terminating impedance (which should be less than 1kΩ). The limiter provides a constant output level, which is largely independent of the limiter input signal level over a 90dB input range. The low-impedance limiter outputs provide 600mVp-p single-ended swing (1.2Vp-p differential swing) and can drive CMOS inputs directly. _______________________________________________________________________________________ 9 MAX2510 Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator Received Signal-Strength Indicator The RSSI output provides a linear indication of the received power level on the LIMIN input. The RSSI monotonic dynamic range exceeds 90dB while providing better than 80dB linear range. The RSSI output pulses current into a 330pF (typical) external filter capacitor. The output is internally terminated to ground with 11kΩ, and this R-C time constant sets the decay time. The rise time is limited by the RSSI pin’s output drive current. The rise time is typically less than 100ns with no capacitor connected. Larger capacitor values slow the rise time. Transmitter The I, I and Q, Q baseband signals are input to a pair of double-balanced mixers, which are driven from a quadrature LO source. The quadrature LO is generated on-chip from the oscillator input present at the LO and LO pins. The two mixers’ outputs are summed. With quadrature baseband inputs at the I, I and Q, Q pins, the unwanted sideband is largely canceled. The resulting signal from the mixers is fed through a variable-gain amplifier (VGA) with more than 40dB of gain-adjust range. The VGA output is connected to a driver amplifier with an output 1dB compression point of +2dBm. The output power can be adjusted from approximately +2dBm to -40dBm by controlling the GC pin. The resulting signal appears as a differential output on the TXOUT and TXOUT pins. TXOUT and TXOUT are open-collector outputs and need external pull-up inductors to VCC for proper operation, as well as a DC block so the load does not affect DC biasing. A shunt resistor across TXOUT and TXOUT (100Ω typical) can be used to back terminate an external filter, as shown in the Typical Operating Circuit. Alternatively, a single-ended load can be connected to TXOUT, as long as TXOUT is tied directly to VCC. Refer to the Applications Information section for details. Local-Oscillator Inputs The MAX2510 requires an external LO source for the mixers. LO and LO are high-impedance inputs (>1kΩ). The external LO signal is buffered internally and fed to both the receive mixer and the LO phase shifter used for the transmit mixers. In a typical application, externally terminate the LO source with a 50Ω resistor and then AC couple into LO. Typically, the LO power range should be -13dBm to 10 0dBm (into 50Ω). Connect a bypass capacitor from LO to ground. Alternatively, a differential LO source (externally terminated) can drive LO and LO through series coupling capacitors. Power Management To provide advanced system power management, the MAX2510 features four operating modes that are selected via the RXEN and TXEN pins, according to Table 1 (supply currents assume GC = 0.5V). In shutdown mode, all part functions are off. Standby mode allows fastest enabling of either transmit or receive mode by keeping the VREF generator active. This avoids delays in stabilizing the limiter input circuitry and the offset correction loop. Transmit mode enables the LO buffer, LO phase shifter, upconverter mixer, transmit VGA, and transmit output driver amplifier. Receive mode enables the LO buffer, downconverter mixer, limiting amplifier, and RSSI functions. Table 1. Power-Supply Mode Selection TXEN STATE MODE TYPICAL SUPPLY CURRENT (A) Low Low Shutdown 0.2µ Low High Transmit 17m RXEN STATE High Low Receive 14m High High Standby 0.5m __________Applications Information RX Input Matching The RXIN, RXIN port typically needs an impedance matching network for proper connection to external circuitry, such as a filter. See the Typical Operating Circuit for an example circuit topology. Note that the receiver input can be driven either single-ended or differentially. The component values used in the matching network depend on the desired operating frequency as well as on filter impedance. The following table indicates the RXIN, RXIN single-ended input impedance (that is, the impedance looking into either RXIN or RXIN). The information in Table 2 is also plotted in the Typical Operating Characteristics. ______________________________________________________________________________________ Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator FREQUENCY (MHz) SERIES IMPEDANCE (Ω) 100 275 - j203 200 149 - j184 300 94 - j143 400 64 - j109 500 53 - j87 Receive IF Filter The interstage filter, located between the MIXOUT pin and the LIMIN pin, is typically a three-terminal, 330Ω, 10.7MHz bandpass filter. This filter prevents the limiter from acting on any undesired signals that are present at the mixer’s output, such as LO feedthrough, out-ofband channel leakage, and spurious mixer products. The filter connections are also set up to feed DC bias from VREF into LIMIN and MIXOUT through two 330Ω filter-termination resistors. (See the Typical Operating Circuit for more information). Transmit Output Matching The transmit outputs, TXOUT and TXOUT, are opencollector outputs and therefore present a high impedance. For differential drive, TXOUT and TXOUT are connected to VCC via chokes, and each side is AC coupled to the load. A terminating resistor between TXOUT and TXOUT sets the output impedance. This resistor provides a stable means of matching to the load. TXOUT and TXOUT are voltage-swing limited, and therefore cannot drive the specified maximum power across more than 150Ω load impedance. This load impedance typically consists of a shunt-terminating resistor in parallel with a filter load impedance. To drive higher output load impedances, the gain must be reduced (via the GC pin) to avoid saturating the TX output stage. For single-ended applications, connect the unused TX output output pin directly to VCC. noise amplifier (LNA) that can operate over the same supply voltage range. The MAX2630–MAX2633 family of amplifiers meets this requirement. In many applications, the MAX2510’s transmit output power is sufficient to eliminate the need for an external power amplifier. ______________________Layout Issues A well-designed PC board is an essential part of an RF circuit. Use the MAX2510 evaluation kit and the recommendations below as guides to generate your own layout. Power-Supply Layout A star topology, which has a heavily decoupled central VCC node, is the ideal power-supply layout for minimizing coupling between different sections of the chip. The VCC traces branch out from this node, each going to one VCC connection in the MAX2510 typical operating circuit. At the end of each of these traces is a bypass capacitor that presents low impedance at the RF frequency of interest. This method provides local decoupling at each VCC pin. At high frequencies, any signal leaking out of a supply pin sees a relatively high impedance (formed by the VCC trace impedance) to the central VCC node, and an even higher impedance to any other supply pin, minimizing Vcc supply-pin coupling. A single ground plane suffices. Where possible, multiple parallel vias aid in reducing inductance to the ground plane. Place the VREF decoupling capacitor (0.1µF typical) as close to the MAX2510 as possible for best interstage filter performance. For best results, use a high-quality, low-ESR capacitor. Matching/biasing networks around the receive and transmit pins should be symmetric and as close to the chip as possible. A cutout in the ground plane under the matching network components can be used to reduce parasitic capacitance. Decouple pins 19 and 21 (VCC) directly to pin 20 (Rx, Tx ground), which should be directly connected the ground plane. Similarly, decouple pin 8 directly to pin 7. Refer to the Pin Description table for more information. 400MHz ISM Applications The MAX2510 can be used as a front-end IC in applications where the RF carrier frequency is in the 400MHz ISM band. In this case, Maxim recommends preceding the MAX2510 receiver section with a low- ______________________________________________________________________________________ 11 MAX2510 Table 2. RXIN or RXIN Input Impedance Low-Voltage IF Transceiver with Limiter/RSSI and Quadrature Modulator MAX2510 Typical Operating Circuit VCC 100pF FOR SINGLE-ENDED TX OPERATION VCC 220nH 100Ω 23 TXOUT I I TX OUTPUT (TO FILTER) Q 24 MAX2510 TXOUT Q 0.001µF 25 MATCH LIMOUT RXIN LIMOUT 10pF FOR SINGLE-ENDED RX OPERATION RXEN 22 TXEN RXIN 15 BASEBAND I INPUT 16 18 BASEBAND Q INPUT 17 13 RECEIVE IF OUTPUT 14 12 CONTROL LOGIC 11 VCC 330pF VCC LO 8 0.001µF GNDLO 26 GND LOIN VCC VCC 21 LOIN VCC GND 19 0.001µF VCC GC 0.001µF 20 27 7 RSSI GND CZ 6 9 47pF 10 47pF 5 GAIN CONTROL 4 0.001µF 3 RSSI OUTPUT MIXOUT LIMIN 10.7MHz BpF, Z0 = 330Ω 1 VREF 28 330pF CZ 2 0.01µF IF BYPASS FILTER 330Ω 330Ω 0.1µF 12 FROM LOCAL OSCILLATOR 5OΩ ______________________________________________________________________________________