Features: ` Single-chip 5 V mixer/oscillator and synthesizer for
cable TV and VCR tuners
` Pin-to-pin compatible with TDA6402, TDA6402A,
TDA6403 and TDA6403A
` 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 PMOS buffer for UHF band selection (25 mA)
` 3 PMOS 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 analog-to-digital converter (3 bits in I2C-bus
mode)
` 15-bit programmable divider
` Programmable reference divider ratio (64, 80 or 128)
` Programmable charge pump current (60 or 280 mA)
` Varicap drive disable
` 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 able to drive loads from 75 W upwards
` Low power
` Low radiation
` Small size
` The TDA6502A and TDA6503A differ from the TDA6502
and TDA6503 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).Pinout
DescriptionThe TDA6502, TDA6502A, TDA6503 and TDA6503A are programmable 2-band mixers/oscillators and synthesizers intended for VHF/UHF TV and VCR tuners (see Fig.1). Partitioning of the bands is the responsibility of the customer providing VHF is below 500 MHz and UHF is below 900 MHz.
The TDA6502, TDA6502A, TDA6503 and TDA6503A 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 of TDA6502, TDA6502A, TDA6503 and TDA6503A can be split-up into two sub-bands using a proper oscillator application and a switchable inductor.
Two pins of TDA6502, TDA6502A, TDA6503 and TDA6503A are available between the mixer output and the IF amplifier input to enable IF filtering for improved signal handling.
The port register TDA6502, TDA6502A, TDA6503 and TDA6503A provides four PMOS ports. Band selection is provided by port register UHF. When port register UHF is 'on', the UHF mixer-oscillator is active and the VHF band is switched off. When port register UHF is 'off', the VHF mixer-oscillator is active and the UHF band is off. Port registers VHFL and VHFH are used to select the VHF sub-bands. Port register FMST is a general purpose port, TDA6502, TDA6502A, TDA6503 and TDA6503A can be used to switch an FM sound trap. When the ports are used, the sum of the drain currents has to be limited to 30 mA.
The synthesizer TDA6502, TDA6502A, TDA6503 and TDA6503A consists of a 15-bit programmable divider, a crystal oscillator and its programmable reference divider and a phase comparator (phase/frequency detector) combined with a charge pump which drives the tuning amplifier, TDA6502, TDA6502A, TDA6503 and TDA6503A including the 33 V output at pin VT. Depending on the reference divider ratio (64, 80 or 128), the phase comparator operates at 62.5, 50 or 31.25 kHz with a 4 MHz crystal.
TDA6502A Data Sheet
