mc44bc375u Freescale Semiconductor, Inc, mc44bc375u Datasheet - Page 3

• Manufacturer Part Number: mc44bc375u
• Description: Pll Tuned Vhf Channel 3 / 4 Audio / Video Modulator
• Manufacturer: Freescale Semiconductor, Inc

Application Specific Products
Freescale Semiconductor
MC44BS375U and MC33BS375UA devices.
1.
POWER SUPPLY
the same time to ensure all internal blocks are correctly bi-
ased. Do NOT bias any other pin before V
device.
STANDBY MODES
power consumption. The sound oscillator, UHF oscillator and
VHF dividers, video and sound modulator sections bias are
internally turned OFF.
Figure 2 shows a simplified block diagram of the
There are two main sections:
The two device V
During standby mode, the modulator is switched to low
Channel Select
A PLL section to synthesize the VHF output channel
frequency for channel 3 or channel 4.
save Psave/
Sound Freq
RFOV
RF
LOP
— CHS
— SFS
Power
OUT
Select
LOP
CC
13
16
14
1
3
9
CCS
75Ω
(pins 11 and 14) must be applied at
GND
12
Figure 2. MC44BS375U/UA Simplified Block Diagram
Prescaler
Modulator
Modulator
Sound
Video
÷
LPF
LPF
8
CC
is applied to the
FUNCTIONAL OVERVIEW
VHF Divider
White Clip
OSC.
Divider
UHF
Prog.
÷
Peak
8
31.25 kHz
VIDEO
Divider
Sound
PLLFLT
Prog.
PFD
10
Phase
Comp.
Clamp
15
2.
of the VHF tank circuit and certain filtering functions eliminat-
ing the need for a number of external components.
pin 9, PSave/LO, is set to a “LO” level (see
page
LOGIC OUTPUT PORT
(such as an antenna switch or an attenuator). This pin is an
open collector transistor able to sink up to 15 mA at a low volt-
age.
with pin 9, Psave/LO (see
IN
The high frequency BiCMOS technology allows integration
The modulator is programmed in standby mode when
The Logic Output Port is used to control an external switch
The LOP output is switched between a “HI” and “LO” level
A modulator section which accepts audio and video
inputs and modulates the VHF carrier.
31.25 kHz
4).
LPF
SPLLFLT
Modulator
VCO & PLL
Oscillator
and FM
SECTION
Sound
8
ALC
Ref Divider
÷
128
MODULATOR
SECTION
Amplifier
Audio
“Pin Selection” on page
XTAL
4 MHz
XCO
4
11
6
2
7
5
“Pin Selection” on
Picture-Sound
Select
— PSS
AUDIO
PREEM
V
GND
CC
MC44BC375U
IN
4).
3