Texas Instruments SN761683DAR

Overview

SN761683DAR from Texas Instruments is a single-chip synthesized TV tuner IC integrating a three-band local oscillator, mixer, PLL synthesizer, 30-V tuning-voltage amplifier, and four NPN band-switch drivers. It operates from a 5-V supply, supports UHF/VHF-L/VHF-H RF input bands (up to 804 MHz), delivers 22–32 dB conversion gain, and features I²C bus control with 15-bit programmable frequency word. It targets analog TV signal reception in consumer broadcast equipment.

For engineers reviewing the SN761683DAR datasheet, SN761683DAR pinout, SN761683DAR application, or SN761683DAR equivalent, key selection considerations include its triple-band oscillator architecture, 32-pin TSSOP package with dedicated RF/IF/oscillator terminals, 4-MHz crystal reference, 512/640/1024 selectable reference divider, and 30-V VTU output for varactor tuning in terrestrial TV front-ends.

Technical Context

The SN761683DAR implements a fully integrated PLL-based frequency synthesis architecture with a 4-MHz crystal oscillator feeding a programmable reference divider (512/640/1024), followed by a 15-bit counter and dual prescalers (1/32 or 1/33, 1/8) driving a phase detector and charge-pump output (CP). Its three independent oscillator sections-VHF-L, VHF-H, and UHF-each drive dedicated mixer cores with separate RF inputs and base/collector bias terminals.

Band selection is executed via four NPN emitter-follower BS outputs (BS1–BS4), controlled through I²C register writes; the device supports eight valid band-switch combinations, with forbidden patterns explicitly documented to prevent overcurrent. The 5-level ADC (ADC pin) provides on-chip signal monitoring, while AS pin enables hardware address selection across four I²C addresses.

Key Specifications

Pinout & Package

SN761683DAR is housed in a 32-pin Thin Shrink Small-Outline Package (TSSOP, DA drawing), 7.0 mm × 4.4 mm body, 0.65 mm pitch, RoHS-compliant with CU NIPDAU finish and JEDEC MSL Level-2-260°C-1 year rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TV tuner IC applications.

Compared with TDA9886HN/N1 and SI2151-A10-GM, the SN761683DAR uniquely combines analog RF mixing, triple-band oscillator synthesis, and 30-V tuning voltage generation in a single 5-V device-making it irreplaceable in cost-sensitive analog TV tuner modules where external HV circuitry must be avoided.

Availability

SN761683DAR is available at Aetrix Electronics and suitable for analog TV receivers, VCR/DVD recorder tuners, and set-top box front-ends requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for SN761683DAR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in broadcast and consumer electronics IC design.

The SN761683DAR belongs to TI's legacy TV tuner product line, engineered specifically for high-integration analog broadcast reception-emphasizing low-noise RF performance, robust PLL stability, and simplified system-level tuning via integrated VTU and band-switch drivers.

FAQ

What is the primary function of the SN761683DAR in a TV signal chain?

The SN761683DAR serves as a complete analog TV tuner IC, performing RF-to-IF downconversion across VHF-L, VHF-H, and UHF bands using integrated oscillators, mixers, and a PLL synthesizer. It generates a 43-MHz differential IF output, provides 30-V tuning voltage (VTU) for varactor control, and enables band selection via four NPN band-switch drivers-all under I²C command. The SN761683DAR eliminates the need for discrete oscillator, mixer, and tuning amplifier stages in legacy broadcast receivers.

Does the SN761683DAR support digital TV standards such as ATSC or DVB-T?

No, the SN761683DAR is designed exclusively for analog TV broadcast reception (NTSC, PAL, SECAM) and does not support digital modulation schemes like 8-VSB, QAM, or COFDM. Its IF output is fixed at 43 MHz with analog characteristics optimized for analog demodulators. For digital TV applications, TI recommends newer silicon tuners such as the SI2151 family. The SN761683DAR remains relevant only in analog-only or hybrid analog/digital systems where legacy tuner functionality is required.

How is band selection implemented on the SN761683DAR, and what are the valid configurations?

Band selection on the SN761683DAR is controlled via the four NPN band-switch outputs (BS1–BS4), programmed through the I²C band-switch byte. Eight configurations are valid-including UHF (BS4 active), VHF-LOW (BS1 active), and VHF-HIGH (BS2 active)-while combinations like BS1+BS2+BS4 are explicitly forbidden due to band-switch output current limits. Each active BS pin sinks up to 10 mA to ground, enabling direct drive of external band-switch diodes or transistor bases without additional buffering. The SN761683DAR enforces these constraints in hardware to prevent damage.

What is the role of the VTU pin on the SN761683DAR, and what load can it drive?

VTU is the 30-V tuning voltage amplifier output that supplies bias to varactor diodes in the tuner's RF front-end. It delivers 0.4 V to 33 V with low output impedance, supporting loads up to 27 kΩ (per datasheet test condition). The SN761683DAR's VTU stage replaces external high-voltage op-amps, simplifying tuner design. When OS = 0 (tuning on), VTU operates actively; when OS = 1, it enters high-impedance shutdown mode with ≤10 µA leakage. This capability is essential for analog TV channel tuning and is not replicated in most modern digital tuners.

Can the SN761683DAR operate with a crystal other than 4 MHz?

No-the SN761683DAR's internal crystal oscillator circuit is optimized for a 4-MHz fundamental-mode crystal, with specified operating range of 3.2 MHz to 4.48 MHz and input impedance of 1.6 kΩ. Deviations outside this range risk failure to start or unstable PLL operation. The device uses this 4-MHz reference with programmable dividers (512/640/1024) to generate appropriate comparison frequencies for the 15-bit counter. Substituting a different crystal frequency would invalidate all channel tuning calculations and is not supported. The SN761683DAR requires strict adherence to the 4-MHz specification for reliable operation.