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Texas Instruments SN761681DBTR
- Part No.:
- SN761681DBTR
- Manufacturer:
- Texas Instruments
- Category:
- Video Processing
- Package:
- 30-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN761681DBTR.pdf
- Description:
- IC VIDEO TUNER 30TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:34,000
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Product details
Overview
SN761681DBTR from Texas Instruments is a single-chip synthesized TV tuner IC integrating a PLL synthesizer, three-band (VHF-LOW/VHF-HIGH/UHF) local oscillator, mixer, 30-V tuning voltage amplifier, four NPN band-switch drivers, and I²C interface. It operates from a 5-V supply, delivers 25 dB typical conversion gain across 55–804 MHz RF input range, and targets analog TV signal reception with 43-MHz IF output.
For engineers reviewing the SN761681DBTR datasheet, SN761681DBTR pinout, SN761681DBTR application, or SN761681DBTR equivalent, key selection criteria include its 30-pin TSSOP package, programmable reference divider (512/640/1024), 4-MHz crystal oscillator input, 30-V VTU output, and I²C-controlled band switching for VHF/UHF channel selection in legacy broadcast systems.
Technical Context
The SN761681DBTR implements a fully integrated PLL-based frequency synthesis architecture with a 15-bit programmable counter and selectable reference divider (512/640/1024) to set tuning step resolution. Its three independent oscillator sections-VHI/VLO for VHF bands and UHF OSC B1/C1/B2/C2-feed dedicated mixer stages, each optimized for specific frequency ranges.
Band selection is executed via four NPN emitter-follower outputs (BS1–BS4), controlled through I²C register writes, enabling discrete transistor switching of external VHF-LOW, VHF-HIGH, and UHF RF paths. The 30-V tuning voltage amplifier (VTU) drives varactor diodes in external LC tank circuits, while the charge pump (CP) provides PLL loop filter interface with 280 µA/60 µA sink-source current options.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - powers internal mixer, oscillator, PLL, and I²C logic; requires stable 5-V rail with ≤1071 mW max dissipation at TA ≤25°C |
| Tuning Voltage Output | 0.3 V to 33 V - VTU pin delivers 30-V tuning range for external varactor biasing in VHF/UHF LC oscillators |
| Crystal Frequency | 4 MHz nominal (3.2–4.48 MHz range) - drives internal XTAL oscillator; requires 25–300 Ω series resistor per datasheet layout guidance |
| Conversion Gain | 22–32 dB - measured at 43-MHz IF output across VHF-LOW (55 MHz), VHF-HIGH (133 MHz), and UHF (804 MHz) bands |
| Noise Figure | 9.5–11 dB - specifies RF-to-IF signal degradation; lowest at VHF-LOW (9.5 dB), highest at UHF (11 dB) |
| I²C Interface | 100–400 kHz clock, 5-V tolerant SDA/SCL - supports standard-mode and fast-mode communication for register configuration and status readback |
| Band-Switch Drivers | Four NPN emitter followers (BS1–BS4), 10 mA max output - directly drive external band-switch transistors without external buffers |
Pinout & Package
SN761681DBTR is housed in a 30-pin Thin Shrink Small Outline Package (TSSOP), DBT drawing, with 0.65 mm pitch, RoHS-compliant green finish, and JEDEC MSL Level-2-260°C-1 year moisture sensitivity rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VHI OSC C (Pin 1) | VHF HIGH oscillator collector | Output node for high-band VHF oscillator stage; connects to external LC tank collector path |
| VHI OSC B (Pin 2) | VHF HIGH oscillator base | Base drive for VHF-HIGH oscillator transistor; requires external bias network per Figure 12 |
| OSC GND (Pin 3) | Oscillator ground | Dedicated low-noise ground return for all oscillator sections; must be isolated from RF/IF grounds |
| VLO OSC C (Pin 4) | VHF LOW oscillator collector | Collector node for low-band VHF oscillator; used with BS1/BS2 to select VHF-LOW operation |
| VLO OSC B (Pin 5) | VHF LOW oscillator base | Base drive for VHF-LOW oscillator transistor; referenced to OSC GND |
| UHF OSC B1 (Pin 6) | UHF oscillator base 1 | Primary base connection for UHF oscillator; used with BS4 to enable UHF band |
| UHF OSC C1 (Pin 7) | UHF oscillator collector 1 | Main collector node for UHF oscillator; interfaces with external UHF tank circuit |
| UHF OSC C2 (Pin 8) | UHF oscillator collector 2 | Secondary collector node for UHF oscillator; supports dual-tuned UHF configurations |
| UHF OSC B2 (Pin 9) | UHF oscillator base 2 | Secondary base connection for UHF oscillator; improves stability in wideband UHF operation |
| IF GND (Pin 10) | IF ground | Dedicated ground for IF amplifier and IF output pins; must be separated from RF/OSC grounds |
| VCC (Pin 11) | Supply voltage | 5-V power for entire IC; requires local 4.7-nF bypass capacitor per Figure 17 |
| IF OUT1 (Pin 12) | IF output 1 | Primary 43-MHz IF output; differential pair with IF OUT2; 117 dBµV typical output level |
| IF OUT2 (Pin 13) | IF output 2 | Secondary 43-MHz IF output; complements IF OUT1 for balanced IF signal routing |
| CP (Pin 14) | Charge pump output | PLL loop filter interface; sinks 280 µA or sources 60 µA depending on CP register bit |
| VTU (Pin 15) | Tuning voltage amplifier output | 30-V capable output driving external varactors; leakage <10 µA when disabled (OS=1) |
| XTAL (Pin 16) | Crystal oscillator input | 4-MHz crystal connection point; requires 68-pF load capacitor and 25–300 Ω series resistor |
| SCL (Pin 17) | I²C serial clock | Input-only clock line for I²C bus; supports up to 400 kHz; requires 330-Ω pull-up |
| SDA (Pin 18) | I²C serial data | Bidirectional data line; open-drain with 330-Ω pull-up; supports ACK/NACK handshaking |
| AS (Pin 19) | Address selection | Hardware address configuration pin; sets I²C slave address via voltage thresholds (LOW/MID2/MID1/HIGH) |
| ADC (Pin 20) | ADC input | Analog input for on-chip 3-bit ADC; maps 0–VCC to five discrete levels per Table 8 |
| BS3 (Pin 21) | Band switch 3 output | NPN emitter follower output; enables third band-switch transistor (e.g., VHF-HI auxiliary path) |
| BS1 (Pin 22) | Band switch 1 output | NPN emitter follower output; controls VHF-LOW RF path selection |
| BS2 (Pin 23) | Band switch 2 output | NPN emitter follower output; controls VHF-HIGH RF path selection |
| BS4 (Pin 24) | Band switch 4 output | NPN emitter follower output; controls UHF RF path selection |
| MIX OUT2 (Pin 25) | Mixer output 2 | Secondary mixer output; used with MIX OUT1 for balanced mixing in VHF/UHF front-end |
| MIX OUT1 (Pin 26) | Mixer output 1 | Primary mixer output; feeds internal IF amplifier chain; referenced to IF GND |
| RF GND (Pin 27) | RF ground | Dedicated ground for RF input pins; must be low-inductance connection to system RF ground plane |
| VHF RF IN (Pin 28) | VHF RF input | Single-ended RF input for VHF bands; matched to 50 Ω; connects to antenna or RF switch output |
| UHF RF IN2 (Pin 29) | UHF RF input 2 | Secondary UHF RF input; supports diversity or dual-tuner configurations |
| UHF RF IN1 (Pin 30) | UHF RF input 1 | Primary UHF RF input; main antenna path for UHF band reception |
Key Features
| Feature | Design Value |
|---|---|
| Three-band oscillator architecture | Independent VHF-LOW, VHF-HIGH, and UHF oscillator sections enable full analog TV broadcast band coverage (45–860 MHz) without external band-switching ICs |
| I²C programmable reference divider | Selectable 512/640/1024 ratios allow precise tuning step definition (e.g., 62.5 kHz or 100 kHz steps) for regional channel plans |
| Integrated 30-V tuning amplifier | VTU output eliminates need for external high-voltage op-amp or transistor stage when driving varactor diodes in LC tanks |
| Four NPN band-switch drivers | On-die emitter followers (BS1–BS4) directly drive external NPN transistors, reducing BOM count and PCB area vs. discrete driver solutions |
| 43-MHz IF output with 25 dB gain | Internal IF amplifier delivers standardized 43-MHz intermediate frequency with sufficient gain to drive SAW filters and demodulators without external amplification |
Applications
| Analog TV Receiver | VCR/DVD Recorder Tuner |
|---|---|
Use Scenario: Reception of terrestrial analog NTSC/PAL/SECAM broadcast signals in standalone TVs or integrated display systems. IC Role / Device Role / Timing Role: Primary tuner IC performing RF-to-IF downconversion, frequency synthesis, and band selection under microcontroller I²C control. Use Value: Single-chip integration reduces component count and layout complexity while maintaining 9.5 dB noise figure and 25 dB conversion gain required for weak-signal analog TV reception. | Use Scenario: Channel selection and signal conditioning in consumer-grade VCRs and DVD recorders with analog broadcast input capability. IC Role / Device Role / Timing Role: Front-end tuner providing 43-MHz IF output compatible with legacy MPEG-2 encoder ICs and analog video processors. Use Value: 30-V VTU output ensures reliable varactor tuning across temperature for stable channel lock; I²C interface simplifies firmware integration with existing recorder SoCs. |
| Set-Top Box (Analog) | Cable TV Descrambler Module |
Use Scenario: Analog cable TV signal processing in early-generation digital hybrid STBs supporting both analog passthrough and digital decoding. IC Role / Device Role / Timing Role: Analog tuner subsystem delivering IF output to separate analog demodulator or A/D converter path. Use Value: Four band-switch drivers (BS1–BS4) support complex multi-path RF architectures needed for cable drop-level signal variation compensation. | Use Scenario: Signal acquisition in legacy cable descramblers requiring robust VHF/UHF reception before conditional access decryption. IC Role / Device Role / Timing Role: RF front-end tuner generating clean 43-MHz IF for analog video demodulation prior to descrambling logic. Use Value: Phase noise performance (84–88 dBc/Hz @10 kHz offset) meets analog CATV carrier-to-noise requirements; 117 dBµV IF output drives downstream SAW filters without gain staging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TV tuner IC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SI2151-A10-GM | Single-chip digital tuner (QAM/8VSB), 1.8-V core, integrated demodulator, no VTU output | Designed for digital cable/terrestrial reception; lacks analog IF output and 30-V tuning capability | Choose SI2151-A10-GM only for digital-only systems requiring embedded demodulation; not suitable as drop-in replacement for analog IF path |
| MAX2165ETJ+ | 3.3-V silicon tuner, 36–862 MHz, integrated IF filter, no band-switch drivers, 12-bit ADC | Targets modern digital TV but supports analog IF output; requires external band-switch control logic | Select MAX2165ETJ+ when migrating to smaller footprint and lower power; verify external driver circuit compatibility for VHF/UHF switching |
Compared with SN761681DBTR, SI2151-A10-GM replaces analog IF generation with digital demodulation, while MAX2165ETJ+ retains analog IF output but removes integrated band-switch drivers-both require PCB redesign and firmware adaptation, making SN761681DBTR irreplaceable in legacy analog tuner designs requiring 30-V VTU and direct NPN drive.
Availability
SN761681DBTR is available at Aetrix Electronics and suitable for analog TV receivers, VCR/DVD recorders, and legacy set-top boxes requiring stable component supply for maintenance and repair programs.
Supply support for SN761681DBTR 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 90 years of innovation in electronic components.
The SN761681DBTR belongs to TI's legacy TV tuner IC product line, engineered specifically for cost-sensitive, high-volume analog broadcast reception systems requiring integrated PLL synthesis, multi-band oscillation, and I²C configurability.
FAQ
What is the operating supply voltage range for the SN761681DBTR?
The SN761681DBTR operates from a 4.5-V to 5.5-V supply on Pin 11 (VCC). This 5-V nominal rail powers the internal mixer, oscillator, PLL, and I²C interface. Operation outside this range risks functional failure or permanent damage, as absolute maximum ratings specify –0.4 V to 6.5 V, but recommended conditions strictly require 4.5–5.5 V for reliable performance across –20°C to 85°C ambient temperature.
Does the SN761681DBTR support digital television standards like ATSC or DVB?
No, the SN761681DBTR is designed exclusively for analog TV broadcast reception (NTSC, PAL, SECAM) and delivers a 43-MHz IF output compatible with analog demodulators. It lacks integrated digital demodulation, QAM/8VSB decoding, or MPEG processing. For ATSC/DVB systems, TI offers later-generation tuners such as the TDA18271 or Si21xx family-SN761681DBTR remains purpose-built for legacy analog signal chains.
How is band selection implemented on the SN761681DBTR?
Band selection on the SN761681DBTR is executed via four NPN emitter-follower outputs (BS1–BS4) controlled by an I²C register write to the Band-switch byte. BS1 enables VHF-LOW, BS2 enables VHF-HIGH, and BS4 enables UHF; BS3 supports auxiliary switching. Each driver sources up to 10 mA into external NPN base resistors, eliminating need for discrete level-shifting or buffering stages in the RF front-end.
What is the function of the VTU pin on the SN761681DBTR?
The VTU (Pin 15) on the SN761681DBTR is a 30-V capable tuning voltage amplifier output that directly biases varactor diodes in external VHF/UHF LC oscillator tanks. When enabled (OS = 0), it delivers 0.3–33 V with <10 µA leakage in off-state (OS = 1), replacing external high-voltage op-amps or transistor stages and simplifying tuner module design for analog broadcast applications.
Can the SN761681DBTR operate with a crystal other than 4 MHz?
The SN761681DBTR is specified for a 4-MHz crystal oscillator input (Pin 16), with electrical characteristics validated across 3.2–4.48 MHz. While the XTAL input accepts frequencies within that range, deviation beyond ±12% may impact PLL lock stability, tuning step accuracy, and phase noise due to prescaler timing dependencies. TI's reference design and test data assume 4-MHz operation; using other crystals requires full system revalidation.
SN761681DBTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 30-TFSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Function:
- Tuner
- Applications:
- Consumer Video
- Standards:
- -
- Control Interface:
- I2C
- Voltage - Supply:
- 4.5V ~ 5.5V
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 30-TSSOP
SN761681DBTR FAQ
1.How can I place an order for SN761681DBTR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN761681DBTR 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 SN761681DBTR reliable?
The price and inventory of SN761681DBTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN761681DBTR is usually 5 days.
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Note: Certain payment methods may incur a processing fee.
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SN761681DBTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN761681DBTR 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 SN761681DBTR?
For technical support, including SN761681DBTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN761681DBTR requirements.
6.How does Aetrix verify that SN761681DBTR is sourced from the original manufacturer or authorized distributors?
All SN761681DBTR 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 SN761681DBTR meets industry standards.
7.What is the process for return or replacement of SN761681DBTR?
All SN761681DBTR units undergo pre-shipment inspection (PSI). If there is an issue with SN761681DBTR, 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 SN761681DBTR part is unused and in its original packaging.
Return procedure for SN761681DBTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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