
MC44BS373CA Data Sheet
Features
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 dB
V 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
2 Comparing the MC44BS373CA to the MC44BC373/4C
Compared to the MC44BC373/4C devices, the MC44BS373CA has the following improvements:
Higher output level (82 versus 74.5 dB
V)
Higher video signal to noise (+3 dB)