1 Features
The MC44BS373CA is a multi-standard, PAL/SECAM/NTSC modulator.
The channel is set by an on-chip high-speed I2C-compatible bus receiver. A phase-locked loop (PLL) tunes
the modulator over the full UHF range.
The modulator incorporates a sound subcarrier oscillator and uses a second PLL to derive 4.5-, 5.5-, 6.0-,
and 6.5-MHz subcarrier frequencies. These frequencies are selectable by bus.
The modulation standard can be chosen using a control bit that selects between positive and negative
modulation.
The picture-to-sound ratio may be adjusted using the bus. In addition, an on-chip video test pattern generator
can be switched on with a 1-kHz audio test signal.
The MC44BS373CA also has the following features:
• Integrated on-chip programmable UHF oscillator
• No external varicaps diodes/inductor or tuned components
• Extremely low external component count
• Channel 21–69 UHF operation
• VHF range possible by internal dividers (30–450 MHz)
• Boosted TVOUT level (82 dBμV typical)
• High-speed read and write I2C bus compatible (800 kHz)
• I2C address selectable by pin (four choices) using external resistor (available only in QFN20
package)
• I2C bus 5- and 3.3-V compatible
• Fixed video modulation depth (93% typical in system L and 82% typical in the other standards)
• Peak white clip disabled by bus
• Programmable picture/sound carrier ratio (12 and 16 dB)
• Integrated on-chip programmable sound subcarrier oscillator (4.5, 5.5, 6.0 and 6.5 MHz)—no
external varicaps
• Programmable sound reference frequency (31.25 and 62.5 kHz)
• Direct RF sound modulator input (FM and AM modulator bypassed) for NICAM or stereo sound
applications (available only in QFN20 package)
• On-chip video test pattern generator with sound test signal (1 kHz)
• Low-power programmable modulator standby mode
• Transient output inhibit during PLL lock-up at power-on
• Logical output port controlled by bus
• ESD protection, minimum 4 KV
