TDA6402

Features:

` Single-chip 5 V mixer/oscillator and synthesizer for
    cable TV and VCR tuners
` Synthesizer function compatible with existing TSA5526
` Universal bus protocol (I2C-bus or 3-wire bus)
    Bus protocol for 18 or 19-bit transmission (3-wire bus)
   Extra protocol for 27-bit transmission (test modes and
    features for 3-wire bus)
  Address + 4 data bytes transmission (I2C-bus 'write' mode)
  Address + 1 status byte (I2C-bus 'read' mode)
  4 independent I2C-bus addresses.
` 1 PNP buffer for UHF band selection (25 mA)
` 3 PNP buffers for general purpose, e.g. 2 VHF
    sub-bands, FM sound trap (25 mA)
` 33 V tuning voltage output
` In-lock detector
` 5-step A/D converter (3 bits in I2C-bus mode)
` 15-bit programmable divider
` Programmable reference divider ratio (512, 640 or 1024)
` Programmable charge pump current (60 or 280 mA)
` Programmable automatic charge pump current switch
` Varicap drive disable
` Mixer/oscillator function compatible with existing TDA5732
` Balanced mixer with a common emitter input for VHF
    (single input)
` Balanced mixer with a common base input for UHF
    (balanced input)
` 2-pin common emitter oscillator for VHF
` 4-pin common emitter oscillator for UHF
` IF preamplifier with asymmetrical 75 W output
    impedance to drive a low-ohmic impedance (75 W)
` Low power
` Low radiation
` Small size
` The TDA6402A and TDA6403A differ from the TDA6402
    and TDA6403 by the UHF port protocol in the I2C-bus
    mode (see Tables 3 and 4).


Application

· Cable tuners for TV and VCR (switched concept for VHF)
· Recommended RF bands for the USA:
    55.25 to 133.25 MHz, 139.25 to 361.25 MHz and
    367.25 to 801.25 MHz.


Pinout




Description

The TDA6402, TDA6402A, TDA6403 and TDA6403A are programmable 2-band mixers/oscillators and synthesizers intended for VHF/UHF cable tuners (see Fig.1).

The TDA6402, TDA6402A, TDA6403 and TDA6403A include two double balanced mixers and two oscillators for the VHF and UHF band respectively, an IF amplifier and a PLL synthesizer. The VHF band can be split-up into two sub-bands using a proper oscillator application and a switchable inductor. Two pins of TDA6402, TDA6402A, TDA6403 and TDA6403A are available between the mixer output and the IF amplifier input to enable IF filtering for improved signal handling. Four PNP ports are provided. Band selection is provided by using pin PUHF. When PUHF is 'ON', the UHF mixer-oscillator is active and the VHF band is switched off. When PUHF is 'OFF', the VHF mixer-oscillator is active and the UHF band is 'OFF'. PVHFL and PVHFH are used to select the VHF sub-bands. FMST is a general purpose port, TDA6402, TDA6402A, TDA6403 and TDA6403A can be used to switch an FM sound trap. When it is used, the sum of the collector currents has to be limited to 30 mA.

The synthesizer TDA6402, TDA6402A, TDA6403 and TDA6403A consists of a divide-by-eight prescaler, a 15-bit programmable divider, a crystal oscillator and its programmable reference divider and a phase/frequency detector combined with a charge pump which drives the tuning amplifier, including 33 V output (V33) at pin VT.

Depending on the reference divider ratio (512, 640 or 1024), the phase comparator TDA6402, TDA6402A, TDA6403 and TDA6403A operates at 7.8125 kHz, 6.25 kHz or 3.90625 kHz with a 4 MHz crystal.