Texas Instruments SN761677DA

Overview

SN761677DA from Texas Instruments is a single-chip TV/VCR tuner IC integrating PLL synthesizer, 3-band (VHF-L/VHF-H/UHF) local oscillator/mixer, low-noise 30-V DC/DC converter for tuning amplifier bias, four NPN emitter-follower band switch drivers, and four NPN open-collector ports. It operates from a 5-V supply, uses I²C bus control, and delivers 26 dB typical conversion gain with 11 dB noise figure across VHF/UHF bands - deployed in analog broadcast receiver front-ends.

For engineers reviewing the SN761677DA datasheet, SN761677DA pinout, SN761677DA application, or SN761677DA equivalent, key selection considerations include its integrated DC/DC output voltage (35 V), I²C programmable reference divider (31.25/50/62 kHz), 38-pin TSSOP package, 4-MHz crystal oscillator interface, and band-switch driver sourcing capability (10 mA per channel).

Technical Context

The SN761677DA implements a 15-bit programmable counter and selectable reference divider (512/640/1024) to generate tuning frequencies for VHF-L (55–135 MHz), VHF-H (135–370 MHz), and UHF (370–805 MHz) bands using internal VHF/UHF oscillator cores. Its I²C interface supports address selection via AS pin and transmits four data bytes per transaction.

It integrates a dedicated 30-V DC/DC converter (VDC output) with 230 µA output current and 100 ms settling time, plus on-chip ADC (3-bit, 0–VCC input range) and test functionality via ADC/TEST pin. Band switching is controlled by BS1–BS4 outputs (NPN emitter followers), while P5–P8 provide NPN open-collector logic-level ports.

Key Specifications

Pinout & Package

SN761677DA is housed in a 38-pin TSSOP (DA package), 0.65 mm pitch, with exposed thermal pad (not electrically connected). Pin functions are validated per TI SLES066A datasheet Rev A (Dec 2002).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TDA9886 and LA75530, the SN761677DA uniquely combines I²C programmability, integrated 30-V DC/DC, and 38-pin TSSOP packaging - reducing system-level component count and layout complexity in compact analog tuner designs.

Availability

SN761677DA is available at Aetrix Electronics and suitable for analog broadcast receiver development, legacy TV service replacement, and industrial video monitoring systems requiring stable component supply and long-term obsolescence support.

Supply support for SN761677DA 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 company founded in 1930, specializing in analog, embedded processing, and connectivity technologies with broad industrial and consumer applications.

The SN761677DA belongs to TI's legacy TV tuner IC product line, designed specifically for cost-sensitive, high-volume analog broadcast receivers requiring integrated frequency synthesis, RF signal conditioning, and tuning voltage generation.

FAQ

What is the function of the VDC pin on the SN761677DA?

The VDC pin on the SN761677DA is the output of the integrated 30-V DC/DC converter. It delivers a regulated 35 V (minimum) at up to 230 µA to bias varactor diodes in RF tuning amplifiers. This eliminates the need for an external high-voltage supply, and the pin must be connected only to a decoupling capacitor - not to other circuits - per datasheet guidance.

Does the SN761677DA support I²C multi-master operation?

The SN761677DA supports standard I²C bus operation as a slave device only. It does not implement arbitration or clock stretching, and its SCL/SDA pins lack multi-master conflict resolution logic. The device responds to one of eight possible addresses set via the AS pin voltage, and it operates strictly in slave transmit/receive mode per SLES066A timing specifications.

How is band selection implemented on the SN761677DA?

Band selection on the SN761677DA is performed using the BS1–BS4 pins (terminals 31,30,29,28), which are NPN emitter-follower outputs. BS1 active selects VHF-L, BS2 active selects VHF-H, and BS4 active selects UHF - with combinations disabled per datasheet truth table. These outputs source 10 mA each and drive PIN diode switches directly without external buffers.

Can the SN761677DA operate with a crystal other than 4 MHz?

No - the SN761677DA is designed exclusively for use with a 4-MHz fundamental-mode crystal, as specified in the oscillator section of SLES066A. The internal PLL architecture, prescaler ratios (1/8, 1/32, etc.), and reference divider settings assume this exact frequency. Using any other crystal frequency will result in incorrect tuning step size and failure to achieve lock across VHF/UHF bands.

What is the purpose of the ADC/TEST pin on the SN761677DA?

On the SN761677DA, the ADC/TEST pin (terminal 26) serves dual roles: as a 3-bit analog-to-digital converter input (0–VCC range, ±3% accuracy) for monitoring external analog signals, and as a test output during diagnostic modes. When configured for ADC, it returns digital values A2–A0 corresponding to input voltage ranges defined in Table 9 of SLES066A.