Upstream CATV Amplifier

The MAX3507 is a variable-gain power amplifier for use in CATV upstream transmitters. The variable-gain feature has 55dB of dynamic range and is controlled by a 3-wire SPI™ bus. The device is capable of generating +64dBmV output (16QAM/QPSK) when driven with a +34dBmV nominal input signal. The on-chip anti-alias lowpass filter with 75MHz cutoff frequency saves system design cost and space. The optional positive slope generator provides system design flexibility.

The device operates from a single +5V supply and draws 220mA nominal during transmit at max gain (100% duty cycle). For burst-type transmissions, the device is shut off between bursts to minimize noise and save power while still maintaining a match at the output. The device is optimized for high linearity with harmonic levels below -55dBc.

The MAX3507 is available in a 28-pin QFN package and operates over the extended industrial temperature range (-40°C to +85°C).

Applications

* Cable Modem Upstream Transmitter * Set-Top Box Upstream Transmitter * Telephony-Over-Cable

* Built-In 5th-Order Elliptic Anti-Aliasing Filter

* 5MHz to 65MHz Operation

* 55dB Gain Control Range

* Optional Positive Slope Generator

* 55dB Spurious-Free Dynamic Range Over Transmit Band