1.4 GHz I2C-bus controlled multimedia
• Complete 1.4 GHz single-chip system
• Adaptive DC/DC converter driver output
• On-board tuning amplifier output
• Varicap drive disable
• Four NPN open-collector output ports (10 mA)
• Four bus-controlled bidirectional ports
(NPN open-collector outputs)
• In-lock detector
• 5-step Analog-to-Digital Converter (ADC)
• Mixer/Oscillator (M/O) band-switch output
• 15-bit programmable divider
• Programmable reference divider ratio
(512, 640 or 1024)
• Programmable charge-pump current (50 or 250 µA)
• I2C-bus format
– Address plus four data bytes transmission
– Address plus one status byte transmission
– Four independent addresses
• Low power, low radiation.
The device is a single chip PLL frequency synthesizer
designed for TV and VCR tuning systems. The circuit
consists of a divide-by-eight prescaler with its own
preamplifier, a 15-bit programmable divider, a crystal
oscillator and its programmable reference divider, a
phase/frequency detector combined with a charge-pump
which drives the tuning amplifier, including 33 V output.
Three NPN open-collector outputs are provided for band
switching together with five open-collector NPN outputs.
Four of these ports can also be used as input ports
(one ADC and three general purpose I/O ports).
An output is provided to control a Philips mixer/oscillator IC
controlled by bits P7, P5 and P4. Depending on the
reference divider ratio (512, 640 or 1024), the phase
comparator operates at 3.90625, 6.25 or 7.8125 kHz with
a 4 MHz crystal.
The lock detector bit FL is set to logic 1 when the loop is
locked and is read on the SDA line (status byte) during a
read operation. The ADC is available for digital AFC
control. The ADC code is read during a read operation on
the I2C-bus. The ADC input is combined with the port P6.
In the test mode, this port is also used as a test output for
fref and fdiv/2 (see Table 4). In addition, the circuit includes
a DC/DC converter driver connected to the IDC pin to
control the amplitude of an external oscillator followed by
a voltage rectifier.
The voltage rectifier is used to generate the correct tuning
supply voltage to maintain a constant current into the
tuning amplifier. The DC/DC converter driver can be
disabled by setting the IDC pin to VCC1 in this event the
tuning supply voltage is delivered by a fixed 33 V supply.
Five serial bytes (including address byte) are required to
address the device, select the VCO frequency, program
the ports, set the charge-pump current and set the
reference divider ratio. The device has four independent
I2C-bus addresses which can be selected by applying a
specific voltage on the AS input (see Table 3).
• Multimedia TV tuners and front-ends
• VCR tuners.
plastic shrink small outline package; 20 leads; body width 4.4 mm
1996 Dec 17