Features: `Combines Quadrature Modulator and Demodulator
`Integrated Quadrature Phase Shifters
`On-Chip Oscillator (Requires External Tuning Circuit)
`On-Chip Divide-by-8 Prescaler
`Modulator Input Bandwidth Up to 15MHz
`Demodulator Output Bandwidth Up to 9MHz
`51dB Demodulator Voltage Conversion Gain
`CMOS-Compatible Enable
`5.9mA Operating Supply Current 1A Shutdown Supply CurrentApplication·Digital Cordless Phones
·GSM and North American Cellular Phones
·Wireless LANs
·Digital Communications
·Two-Way PagersPinout
SpecificationsVCC, LO_VCC to GND...............................................-0.3V to +4.5V
ENABLE, TANK, TANK, I_IN, I_IN, Q_IN,
Q_IN to GND.................................................-0.3V to (VCC + 0.3V)
IF_IN to GND ..........................................................-0.3V to +1.5V
Continuous Power Dissipation (TA = +70°C)
QSOP (derate 9.1mW/°C above +70°C)..........................727mW
Operating Temperature Range..............................0°C to +70°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.
DescriptionThe MAX2450 combines a quadrature modulator and quadrature demodulator with a supporting oscillator and divide-by-8 prescaler on a monolithic IC. It operates from a single +3V supply and draws only 5.9mA. The demodulator accepts an amplified and filtered IF signal in the 35MHz to 80MHz range, and demodulates it into I and Q baseband signals with 51dB of voltage conversion gain. The IF input is terminated with a 400½ thinfilm resistor for matching to an external IF filter. The baseband outputs are fully differential and have 1.2Vp-p signal swings. The modulator accepts differential I and Q baseband signals with amplitudes up to 1.35Vp-p and bandwidths to 15MHz, and produces a differential IF signal in the 35MHz to 80MHz range.
Pulling the CMOS-compatible ENABLE pin low shuts down the MAX2450 and reduces the supply current to less than 1A. To minimize spurious feedback, the MAX2450's internal oscillator is set at twice the IF via external tuning components. The oscillator and associated phase shifters produce differential signals exhibiting low amplitude and phase imbalance, yielding modulator sideband rejection of 38dB. The MAX2450 comes in a QSOP package.
MAX2450 Data Sheet
