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