Microchip Technology TDA4470-MFLY

Overview

TDA4470-MFLY from Atmel (now Microchip Technology) is a multistandard bipolar video/sound IF signal processor IC for TV/VCR and multimedia systems. It performs synchronous video demodulation via FPLL-based carrier regeneration, processes negative- and positive-modulated VIF signals (e.g., B/G and L standards), handles FM/NICAM sound IF, and delivers gain-controlled video (2 V_PP), intercarrier (FM/NICAM), and AM audio outputs - all in a single SO28 Pb-free package.

For engineers reviewing the TDA4470-MFLY datasheet, TDA4470-MFLY pinout, TDA4470-MFLY application, or TDA4470-MFLY equivalent, key selection considerations include its alignment-free AFC with switchable polarity, dual SIF inputs with average-detection AGC, L'-mode VCO frequency switching, parallel AM + QPS operation for NICAM-L stereo, and 5 V supply compatibility with 93 mA typical current draw.

Technical Context

The TDA4470-MFLY implements a Frequency-Phase-Locked Loop (FPLL) architecture to generate a precise 38.9 MHz picture carrier for true synchronous video demodulation, with VCO center frequency switchable between L and L' standards via pin 14. Its vision IF amplifier features three-stage differential gain control (60–65 dB range) using VIF-AGC at pin 8 and black-level detection at pin 15 for fast response to positive modulation.

Sound processing includes two independent symmetrical SIF inputs (pins 1–2, 27–28), a quasi-parallel sound (QPS) mixer that converts FM/NICAM carriers to intercarrier frequencies using the quadrature VCO output, and separate SIF-AGC with adjustable time constant (pin 5). The IC supports standard-selectable operation (pin 13), AFC curve polarity selection (pin 19), and tuner AGC take-over point adjustment (pin 10).

Key Specifications

Pinout & Package

Package: SO28 (Small Outline, 28-pin), Pb-free, RoHS-compliant, 18.05 mm × 7.5 mm body size, 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multistandard video/sound IF processing applications.

Compared with TDA4470-MFLY, the TDA4471-MFLY offers identical functionality with enhanced intermodulation rejection and integrated sound trap, while the LA76810N trades multistandard flexibility and alignment-free tuning for lower power and reduced cost in single-standard applications.

Availability

TDA4470-MFLY is available at Aetrix Electronics and suitable for TV broadcast receivers, VCR playback systems, PAL-L/L' multistandard TVs, and NICAM stereo decoder modules requiring stable component supply and long-term industrial availability.

Supply support for TDA4470-MFLY includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Atmel Corporation (acquired by Microchip Technology in 2016) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and analog/mixed-signal ICs for embedded and consumer applications.

The TDA4470-MFLY belongs to Atmel's TV/VCR analog signal processing product line, designed specifically for multistandard analog broadcast reception with emphasis on alignment-free operation, thermal stability, and compliance with European PAL standards.

FAQ

What is the primary function of the TDA4470-MFLY in a TV receiver system?

The TDA4470-MFLY serves as the core multistandard video/sound IF processor in analog TV receivers. It performs synchronous video demodulation using an FPLL-generated carrier, processes both negatively modulated (B/G) and positively modulated (L/L') video IF signals, extracts FM/NICAM sound via quasi-parallel mixing, and delivers gain-controlled video, intercarrier, and AM audio outputs - all within a single SO28 package. Its alignment-free architecture eliminates manual tuning steps during manufacturing.

Does the TDA4470-MFLY support both PAL-B/G and PAL-L broadcast standards?

Yes, the TDA4470-MFLY natively supports both PAL-B/G and PAL-L standards. Pin 13 (standard switch) configures the IC for negative (B/G) or positive (L) modulation modes, automatically selecting appropriate VIF-AGC characteristics, DC level shifts, and AM output enablement. For PAL-L', pin 14 (L' switch) adjusts the VCO center frequency from 38.9 MHz to the required L' value - confirmed in the datasheet's electrical characteristics and Figure 8-14.

How does the alignment-free AFC work in the TDA4470-MFLY?

The TDA4470-MFLY implements alignment-free AFC by generating a current-mode output at pin 22 proportional to VCO frequency error (0.7 µA/kHz). During production, the external LC tank is adjusted until the AFC output current reads zero at the desired center frequency (e.g., 38.9 MHz), eliminating manual coil trimming. Polarity of the AFC curve is selectable via pin 19, and the circuit requires no external reference - all functions are self-contained within the IC.

Can the TDA4470-MFLY handle two different sound IF sources simultaneously?

Yes, the TDA4470-MFLY supports two independent symmetrical SIF inputs (pins 1–2 and 27–28) with pin 3 controlling selection between them. This allows simultaneous connection of separate SAW filters - for example, one optimized for AM sound and another for FM/NICAM - enabling flexible RF front-end design. Cross-talk attenuation between inputs is excellent, and input impedance remains stable regardless of switching state, as verified in Section 2.5 and Table 7-1.

What is the recommended external VCO tank configuration for the TDA4470-MFLY?

The datasheet specifies a VCO resonance circuit for 38.9 MHz operation using an external coil (e.g., TOKO® 7 KM, 292 XNS-4051Z) with unloaded Q ≥ 60 and a capacitor of 8.2–10 pF (CVCO). This configuration ensures ≥100 mV_RMS oscillator voltage at pins 20–21 and meets drift specifications (–0.3%/55°C). The LC network connects directly to pins 20 and 21, with no additional buffering or isolation required - as shown in Figure 7-1 and Figure 7-2.