Overview
The LA7790M is a QPSK data transmitter for digital cable TV applications. By integrating the I/Q quadrature modulator, RF amplifier, electronic volume control, mute control, and other functions onto a single chip, parts count is reduced and set size is miniaturized.

FEATUREs
• Maximum RF amplifier output level of +10 dBm (75Ω terminator), suitable for directly driving the cable.
• RF output frequency range of 5 to 70 MHz. Frequency range selection function permits broadband designs.
• Electronic volume control for direct-current control of RF output level.
• Muting ensures ample attenuation during periods with no transmission.
• Support for both internal and external bias for I/Q modulation inputs.
• Support for I/Q modulation frequencies up to 10 MHz. (typ: 500 mVp-p)

Functions
• I/Q quadrature modulator
• I/Q input bias power supply
• RF amplifier
• Varactor diode-based VCO
• Muting
• Electronic volume control
• Power-saving modes
• Switchable output frequency range
• Power supply voltage of 5 V (4.5 to 5.5 V)