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Texas Instruments SN761678DBTR
- Part No.:
- SN761678DBTR
- Manufacturer:
- Texas Instruments
- Category:
- Video Processing
- Package:
- -
- Datasheet:
-
SN761678DBTR.pdf
- Description:
- TV/VCR TUNER MOP IC
- Quantity:
- Payment:
- Shipping:
Inventory:46,000
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Product details
Overview
SN761678DBTR from Texas Instruments is a single-chip synthesized TV tuner IC integrating a PLL synthesizer, three-band (VHF-LOW/VHF-HIGH/UHF) local oscillator, dual mixer, 30-V tuning voltage amplifier, and four NPN band-switch drivers. It operates from a 5-V supply, supports I²C bus control, and delivers typical conversion gain of 25 dB and noise figure of 9.5 dB across VHF/UHF bands for analog broadcast reception.
For engineers reviewing the SN761678DBTR datasheet, SN761678DBTR pinout, SN761678DBTR application, or SN761678DBTR equivalent, this device is selected for legacy analog TV tuner designs requiring integrated RF-to-IF downconversion, programmable reference division (512/640/1024), and 30-pin TSSOP packaging with I²C-configurable band switching and tuning voltage output.
Technical Context
The SN761678DBTR implements a fully integrated PLL-based frequency synthesis architecture with a 15-bit programmable counter and selectable reference divider (512/640/1024) driven by a 4-MHz crystal oscillator input. Its three-band oscillator structure uses separate VHI/VLO/UHF transistor-based oscillator cores with dedicated base/collector pins for independent tuning.
It features dual IF outputs (MIX OUT1/MIX OUT2), two IF amplifier inputs (IF IN1/IF IN2), and an external 43-MHz IF filter interface - enabling simultaneous processing of primary and secondary IF paths. Band selection is executed via four open-emitter NPN drivers (BS1–BS4) with 10-mA sink capability and 3.5-V output swing at 5-V VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V analog TV system rails; absolute max 6.5 V. |
| Tuning Voltage Output | 0.4 V to 33 V - 30-V capable VTU pin drives varactor diodes in front-end VCOs without external amplification. |
| Crystal Input Frequency | 3.2 MHz to 4.48 MHz - supports 4-MHz fundamental-mode crystal with 25–300 Ω series resistance. |
| Conversion Gain (Typ) | 25 dB - measured at 43-MHz IF with 80 dBµV RF input; enables direct connection to downstream IF amplifiers. |
| Noise Figure (Typ) | 9.5 dB - specified at VHF-LOW (55.25 MHz); critical for maintaining C/N in weak-signal terrestrial reception. |
| I²C Interface Speed | 100 kHz to 400 kHz - standard/fast-mode support allows host MCU to configure PLL, band switch, and OS/CP bits in real time. |
| Operating Temperature | –20°C to +85°C - qualified for consumer electronics enclosures including set-top boxes and DVD recorders. |
Pinout & Package
SN761678DBTR is housed in a 30-pin Thin Shrink Small-Outline Package (TSSOP), DBT package drawing, with 0.65-mm lead pitch and exposed thermal pad (not electrically connected). Pin 1 is VHI OSC C; pin 30 is UHF RF IN. The package is RoHS-compliant and rated MSL-3 per JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VHI OSC C (Pin 1) | VHF-HIGH oscillator collector | Active output node for VHF-HIGH oscillator stage; connects to external tank circuit for 130–136 MHz operation. |
| VHI OSC B (Pin 2) | VHF-HIGH oscillator base | Bias control point for VHF-HIGH oscillator transistor; used with external resistor for current setting. |
| OSC GND (Pin 3) | Oscillator ground reference | Dedicated low-noise ground return for all oscillator sections; must be isolated from digital/RF grounds. |
| VLO OSC C (Pin 4) | VHF-LOW oscillator collector | Active output node for VHF-LOW oscillator stage; supports 58 MHz band with external LC tank. |
| VLO OSC B (Pin 5) | VHF-LOW oscillator base | Bias control for VHF-LOW oscillator transistor; enables independent tuning from VHF-HIGH section. |
| UHF OSC B1 (Pin 6) | UHF oscillator base 1 | First base terminal for UHF oscillator transistor pair; used with UHF OSC B2 for push-pull configuration. |
| UHF OSC C1 (Pin 7) | UHF oscillator collector 1 | Primary collector output for UHF oscillator; supports 364–804 MHz bands with external matching network. |
| UHF OSC C2 (Pin 8) | UHF oscillator collector 2 | Secondary collector output for UHF oscillator; enables harmonic suppression and improved phase noise. |
| UHF OSC B2 (Pin 9) | UHF oscillator base 2 | Second base terminal for UHF oscillator; complements UHF OSC B1 for balanced drive. |
| IF GND (Pin 10) | IF amplifier ground | Dedicated ground for IF signal path; separates sensitive IF stages from RF/oscillator noise sources. |
| VCC (Pin 11) | Main supply voltage | 5-V power for mixer, oscillator, PLL, and band-switch drivers; requires local 2.2-nF bypassing. |
| IF OUT (Pin 12) | Main IF output | Differential-capable IF output driving external 43-MHz ceramic or SAW filter; 117 dBµV typical level. |
| CP (Pin 13) | Charge-pump output | PLL loop filter connection point; 1.95-V nominal locked voltage with 280 µA high/60 µA low current. |
| VTU (Pin 14) | Tuning voltage amplifier output | 30-V capable output driving varactor diodes; 0.4–0.5 V low-level voltage when OS = 1 (off state). |
| XTAL (Pin 15) | Crystal oscillator input | 4-MHz crystal connection point; internal oscillator circuitry provides 1.6-kΩ input impedance. |
| SCL (Pin 16) | I²C serial clock input | Host-controlled clock line; accepts 100–400 kHz signals with 2.8–5 V logic thresholds. |
| SDA (Pin 17) | I²C serial data I/O | Open-drain bidirectional data line; supports ACK/NACK handshaking per I²C protocol. |
| AS (Pin 18) | Address select input | Configures I²C slave address via voltage levels (LOW/MID1/MID2/HIGH) per Table 3 in datasheet. |
| ADC (Pin 19) | Analog-to-digital converter input | 3-bit ADC input measuring external voltage; resolution 0.03 × VCC with five defined threshold ranges. |
| BS3 (Pin 20) | Band-switch driver 3 output | NPN emitter-follower output; sinks up to 10 mA to enable VHF/UHF front-end filters or switches. |
| BS1 (Pin 21) | Band-switch driver 1 output | NPN emitter-follower output; active-low control for VHF-LOW band selection (BS1=1, BS2=0, BS4=0). |
| BS2 (Pin 22) | Band-switch driver 2 output | NPN emitter-follower output; active-low control for VHF-HIGH band (BS1=0, BS2=1, BS4=0). |
| IF IN2 (Pin 24) | Secondary IF amplifier input | Second IF path input for diversity or dual-tuner architectures; shares same 43-MHz IF center frequency. |
| IF IN1 (Pin 23) | Primary IF amplifier input | Main IF input from external filter; designed for 50-Ω source impedance and 45.75-MHz IF output level. |
| MIX OUT2 (Pin 26) | Secondary mixer output | Second mixer output stage; provides alternate IF path with 16–26 dB conversion gain depending on band. |
| MIX OUT1 (Pin 25) | Primary mixer output | Main mixer output feeding IF amplifier; delivers 22–32 dB conversion gain across full VHF/UHF range. |
| RF GND (Pin 27) | RF ground reference | Shielded ground for RF input paths; must be tied to chassis or low-impedance RF ground plane. |
| BS4 (Pin 28) | Band-switch driver 4 output | NPN emitter-follower output; active-low control for UHF band selection (BS1=0, BS2=0, BS4=1). |
| VHF RF IN (Pin 29) | VHF RF input | 50-Ω input for VHF signals (58–136 MHz); includes internal ESD protection and DC blocking. |
| UHF RF IN (Pin 30) | UHF RF input | 50-Ω input for UHF signals (364–804 MHz); optimized for high-frequency matching and low noise. |
Key Features
| Feature | Design Value |
|---|---|
| Three-band oscillator architecture | Independent VHF-LOW, VHF-HIGH, and UHF oscillator cores eliminate band-switching dead zones and improve tuning continuity. |
| 30-V tuning voltage amplifier | Integrated VTU output eliminates need for external high-voltage op-amp, reducing BOM count and layout complexity. |
| I²C programmable reference divider | Selectable 512/640/1024 ratios enable precise channel spacing (e.g., 6-MHz NTSC, 7-MHz PAL) without crystal change. |
| Four NPN band-switch drivers | On-chip 10-mA sink drivers replace discrete transistors, simplifying front-end switching for multi-band antenna systems. |
| Dual IF output paths | MIX OUT1/MIX OUT2 and IF IN1/IF IN2 support dual IF processing or diversity reception without external splitters. |
Applications
| Analog TV Receivers | VCR/DVD Recorders |
|---|---|
|
Use Scenario: Terrestrial analog broadcast signal reception in CRT or LCD TVs with built-in tuners. IC Role / Device Role / Timing Role: Primary RF-to-IF downconverter and frequency synthesizer controlling VHF/UHF channel selection. Use Value: Single-chip integration reduces component count and PCB area while maintaining 9.5-dB noise figure for reliable weak-signal capture. |
Use Scenario: Recording live TV broadcasts onto tape or disc media with real-time channel tuning. IC Role / Device Role / Timing Role: Tuner subsystem providing stable IF output synchronized to video timing circuits. Use Value: 43-MHz IF output and dual IF paths support simultaneous playback/recording with minimal crosstalk. |
| Set-Top Boxes | Cable TV Descramblers |
|
Use Scenario: Digital-to-analog conversion gateway receiving QAM-modulated cable signals. IC Role / Device Role / Timing Role: Analog front-end tuner delivering clean IF to demodulator ICs in hybrid STBs. Use Value: 30-V VTU output interfaces directly with cable-ready varactor-tuned front-ends, eliminating level-shifting circuitry. |
Use Scenario: Legacy descrambler modules requiring analog IF input for conditional access processing. IC Role / Device Role / Timing Role: Channel-selective downconverter generating standardized 45.75-MHz IF for descrambler ASICs. Use Value: Programmable reference divider ensures exact alignment with cable channel raster (6/7/8 MHz spacing) across all bands. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TV tuner IC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN761677DBTR | Same pinout and package; lacks UHF OSC C2 and UHF OSC B2 pins - reduced UHF harmonic suppression capability. | Optimized for cost-sensitive VHF-only or limited-UHF applications; not suitable for full 804-MHz UHF coverage. | Select SN761677DBTR only if UHF band requirement excludes upper UHF (698–806 MHz) and phase noise <84 dBc/Hz @10 kHz is not critical. |
| SI2150-A10-GM | Single-die silicon tuner with integrated IF filter and digital output; no analog IF output or VTU pin; uses SPI, not I²C. | Targets modern digital TV platforms with embedded demodulators; requires redesign of IF path and control interface. | Choose SI2150-A10-GM for new designs migrating to digital IF and software-defined tuning; not a drop-in replacement for SN761678DBTR. |
Compared with SN761677DBTR, SN761678DBTR adds dual UHF oscillator bases/collectors for improved phase noise and spurious performance above 600 MHz; compared with SI2150-A10-GM, it retains analog IF output and 30-V VTU for legacy analog signal chains but requires external IF filtering and I²C host firmware.
Availability
SN761678DBTR is available at Aetrix Electronics and suitable for analog TV receivers, VCR/DVD recorders, set-top boxes, and cable TV descramblers requiring stable component supply for legacy production and service programs.
Supply support for SN761678DBTR 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 over 50 years of innovation in signal chain and power management ICs.
The SN761678DBTR belongs to TI's legacy TV tuner product line, engineered specifically for high-performance analog broadcast reception in consumer electronics with integrated PLL synthesis, multi-band oscillation, and I²C configurability.
FAQ
What is the maximum tuning voltage output of the SN761678DBTR?
The SN761678DBTR provides a maximum tuning voltage output of 33 V on the VTU pin, with a guaranteed operational range of 0.4 V to 33 V under load. This 30-V capability enables direct drive of varactor diodes in wideband VHF/UHF front-end oscillators without external amplification, and the leakage current remains below 10 µA when the OS bit disables the amplifier.
Does the SN761678DBTR support both VHF and UHF bands simultaneously?
No - the SN761678DBTR supports VHF-LOW (58 MHz), VHF-HIGH (130–136 MHz), and UHF (364–804 MHz) bands, but only one band is active at a time via BS1–BS4 control. Band selection is mutually exclusive: BS1=1 selects VHF-LOW; BS2=1 selects VHF-HIGH; BS4=1 selects UHF. Simultaneous operation is not supported due to shared oscillator core resources and IF path routing.
What crystal frequency is required for the SN761678DBTR?
The SN761678DBTR requires a 4-MHz fundamental-mode crystal connected to the XTAL pin, with specified operating range of 3.2 MHz to 4.48 MHz and recommended series resistance of 25–300 Ω. The internal oscillator circuit presents 1.6-kΩ input impedance and requires ac coupling via a 0.1-µF capacitor for minimum 100-mVp-p sensitivity.
How many bits does the SN761678DBTR ADC provide, and what is its input voltage range?
The SN761678DBTR integrates a 3-bit ADC on the ADC pin (Pin 19), providing eight discrete output codes (A2/A1/A0) corresponding to five voltage ranges from 0 V to VCC. Each range spans approximately 0.15×VCC, with accuracy of ±0.03×VCC. For VCC = 5 V, the full-scale input range is 0–5 V with 0.15-V step resolution.
Is the SN761678DBTR pin-compatible with other members of the SN7616xx family?
Yes - the SN761678DBTR shares identical 30-pin TSSOP (DBT) packaging and pinout with SN761677DBTR and SN761679DBTR, enabling mechanical compatibility. However, functional differences exist: SN761677DBTR omits UHF OSC B2/C2 pins, and SN761679DBTR adds enhanced phase noise filtering. Register maps and I²C command sets are fully compatible across the family.
SN761678DBTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- -
- Applications:
- -
- Standards:
- -
- Control Interface:
- -
- Voltage - Supply:
- -
- Mounting Type:
- -
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- -
SN761678DBTR FAQ
1.How can I place an order for SN761678DBTR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN761678DBTR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN761678DBTR reliable?
The price and inventory of SN761678DBTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN761678DBTR is usually 5 days.
3.What payment methods are accepted for SN761678DBTR?
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Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN761678DBTR?
SN761678DBTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN761678DBTR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN761678DBTR?
For technical support, including SN761678DBTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN761678DBTR requirements.
6.How does Aetrix verify that SN761678DBTR is sourced from the original manufacturer or authorized distributors?
All SN761678DBTR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN761678DBTR meets industry standards.
7.What is the process for return or replacement of SN761678DBTR?
All SN761678DBTR units undergo pre-shipment inspection (PSI). If there is an issue with SN761678DBTR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN761678DBTR part is unused and in its original packaging.
Return procedure for SN761678DBTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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