My Inquiry
My Account
Texas Instruments SN65LBC179QDR
- Part No.:
- SN65LBC179QDR
- Manufacturer:
- Texas Instruments
- Category:
- Drivers, Receivers, Transceivers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN65LBC179QDR.pdf
- Description:
- IC TRANSCEIVER FULL 1/1 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,791
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN65LBC179QDR from Texas Instruments is a low-power, full-duplex RS-485 transceiver IC combining one differential line driver and one differential line receiver in a single SOIC-8 package. It operates from a single 5-V supply, supports −40°C to +125°C extended industrial/automotive temperature range, delivers ≥1.1 V differential output voltage into 54 Ω, and features thermal shutdown and ±100 µA bus leakage with VCC = 0 - enabling robust point-to-point or multipoint industrial communication over long cables.
For engineers reviewing the SN65LBC179QDR datasheet, SN65LBC179QDR pinout, SN65LBC179QDR application, or SN65LBC179QDR equivalent, key selection criteria include its guaranteed operation up to 125°C ambient, driver/receiver switching times ≤30 ns, common-mode input range of −7 V to +12 V, current-limiting protection, and compatibility with ANSI RS-485 and ISO 8482:1987(E) standards.
Technical Context
The SN65LBC179QDR implements a balanced differential voltage-mode architecture using TI's LinBiCMOS™ process, integrating CMOS-level power efficiency (≤7 mA max ICC) with bipolar precision for noise immunity and bus fault resilience. Its driver provides positive/negative current limiting and thermal shutdown at ~172°C junction temperature, while the receiver includes 45 mV hysteresis and failsafe logic for open-circuit bus conditions.
Full-duplex operation is enabled by physically separate driver outputs (Y, Z) and receiver inputs (A, B), with high-impedance bus terminals when powered off (VCC = 0). The device supports bidirectional data transmission over transmission-line-like cables, meeting RS-485 requirements for unit load, slew rate control, and DC common-mode tolerance without external biasing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75 V to 5.25 V - ensures stable operation across industrial 5-V rail tolerances without regulation overhead. |
| Differential Output Voltage (VOD) | ≥1.1 V (min) into 54 Ω - meets RS-485 minimum signal level requirement for reliable detection at longest cable distances. |
| Common-Mode Range | −7 V to +12 V - enables interoperability across multi-node buses with ground potential differences up to 19 V. |
| Driver Propagation Delay | 7 ns to 18 ns - supports data rates up to 10 Mbps in short-haul configurations with minimal timing skew. |
| Receiver Threshold Hysteresis | 45 mV - suppresses false triggering from bus noise or slow edge transitions in electrically noisy environments. |
| Quiescent Supply Current | ≤7 mA (max) - reduces system power budget in battery-backed or thermally constrained nodes. |
| Operating Temperature | −40°C to +125°C - qualified for under-hood automotive, motor drive, and harsh industrial control applications. |
Pinout & Package
SN65LBC179QDR is housed in an 8-pin SOIC (D) package measuring 4.9 mm × 3.91 mm with 1.27 mm lead pitch and 1.75 mm max height. The package is RoHS-compliant, moisture-sensitivity Level-1 rated, and compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VCC) | Power supply input | 5-V supply connection; decoupling capacitor must be placed within 10 mm for EMI suppression and transient response. |
| 2 (R) | Receiver logic output | Single-ended TTL/CMOS-compatible output driving controller input; high-impedance when disabled via enable control (not present on this variant). |
| 3 (D) | Driver logic input | CMOS-level digital input accepting 0.8 V / 2.0 V thresholds; directly driven by microcontroller GPIO without level shifting. |
| 4 (GND) | Ground reference | System ground return path shared by driver and receiver; requires low-inductance connection to minimize ground bounce. |
| 5 (Y) | Non-inverting bus output | Active-high differential driver output; paired with Z to generate complementary RS-485 bus signals (A–B polarity defined externally). |
| 6 (Z) | Inverted bus output | Active-low differential driver output; forms differential pair with Y; must be routed as matched-length controlled-impedance traces. |
| 7 (B) | Inverted bus input | Receiver's inverted differential input; connects to bus wire B; internal fail-safe bias ensures logic-high output if bus floats. |
| 8 (A) | Non-inverting bus input | Receiver's non-inverting differential input; connects to bus wire A; complements B to reject common-mode noise up to ±12 V. |
Key Features
| Feature | Design Value |
|---|---|
| RS-485 Compliance | Meets or exceeds ANSI TIA/EIA-485-A and ISO 8482:1987(E) - guarantees interoperability with certified infrastructure and avoids protocol-level validation effort. |
| Thermal Shutdown Protection | Activates at ~172°C junction temperature - prevents permanent damage during sustained bus short-circuit or overtemperature events without external circuitry. |
| Bus-Fault Tolerance | Withstands −10 V to +15 V on A/B/Y/Z pins - eliminates need for external TVS diodes in moderate-voltage industrial environments. |
| Zero-Power Bus Isolation | ≤±100 µA leakage current with VCC = 0 - allows hot-plug capability and safe bus sharing among multiple transceivers on same segment. |
| Low-Power LinBiCMOS™ Process | Combines <5 mA typical ICC with bipolar noise immunity - achieves 3× lower power than legacy bipolar RS-485 parts without sacrificing robustness. |
Applications
| Industrial PLC Backplane | Automotive Body Control Module |
|---|---|
|
Use Scenario: Bidirectional sensor and actuator data exchange between CPU and I/O modules over 1-meter backplane traces. IC Role / Device Role / Timing Role: Full-duplex RS-485 transceiver providing galvanically isolated, noise-immune physical layer interface between microcontroller UART and distributed I/O nodes. Use Value: −40°C to +125°C rating ensures uninterrupted operation during thermal cycling; 45 mV receiver hysteresis rejects switching noise from adjacent motor drivers. |
Use Scenario: Central gateway communication with door module ECUs via twisted-pair wiring harness in passenger compartment. IC Role / Device Role / Timing Role: RS-485 line driver/receiver translating UART signals to differential bus format compliant with OEM electrical specifications. Use Value: ±100 µA bus leakage at VCC = 0 enables safe module replacement without disconnecting battery; −7 V to +12 V common-mode range accommodates chassis ground offsets. |
| Smart Energy Meter Interface | Factory Automation Fieldbus Node |
|
Use Scenario: Secure two-wire communication between meter MCU and external HAN (Home Area Network) concentrator over 30-m cable. IC Role / Device Role / Timing Role: Low-power RS-485 transceiver enabling long-cable, multi-drop data collection with integrated current limiting and thermal protection. Use Value: ≤7 mA max supply current extends battery life in backup-powered meters; driver thermal shutdown prevents latch-up during lightning-induced surges. |
Use Scenario: Real-time motion control feedback loop linking servo drives and motion controller across 100-m factory floor cabling. IC Role / Device Role / Timing Role: High-speed differential transceiver supporting deterministic 10 Mbps updates with sub-30 ns propagation delay and pulse skew ≤6 ns. Use Value: 7–18 ns driver delay and 15–30 ns receiver delay ensure tight timing margins for closed-loop control; 54 Ω load compliance maintains signal integrity at maximum data rate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RS-485 transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN65HVD179D | Higher 12-kV ESD protection (IEC 61000-4-2), 1/8 unit load, but narrower −40°C to +105°C temp range. | Better suited for consumer-facing interfaces requiring surge immunity; not qualified for 125°C automotive use. | Select SN65HVD179D only if ESD robustness >12 kV is mandatory and ambient temperature stays below 105°C. |
| THVD1550DR | Integrated 3.3-V LDO regulator, 1/8 unit load, ±16-kV ESD, but no thermal shutdown and 70°C max operating temperature. | Designed for 3.3-V systems needing simplified power architecture; lacks fault protection for high-temp industrial deployment. | Choose THVD1550DR only for cost-sensitive 3.3-V designs where thermal stress and bus faults are mitigated externally. |
Compared with SN65HVD179D and THVD1550DR, the SN65LBC179QDR uniquely combines 125°C qualification, thermal shutdown, and proven RS-485 compliance without added ESD or LDO complexity - making it optimal for thermally demanding, safety-critical industrial and automotive nodes where reliability outweighs feature bloat.
Availability
SN65LBC179QDR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, smart energy meter interfaces, and factory automation fieldbus nodes requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN65LBC179QDR 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 RS-485 product development and automotive qualification expertise.
The SN65LBC179QDR belongs to TI's industrial-grade RS-485 transceiver portfolio, engineered specifically for high-reliability, extended-temperature communication in harsh environments such as motor drives, factory automation, and automotive subsystems.
FAQ
What is the maximum data rate supported by the SN65LBC179QDR?
The SN65LBC179QDR supports data rates up to 10 Mbps under typical conditions (VCC = 5 V, TA = 25°C, RL = 54 Ω), with driver transition time ≤20 ns and receiver propagation delay ≤30 ns. At longer cable lengths or elevated temperatures, derating is required - consult Figure 5-5 and Figure 5-11 in the SN65LBC179QDR datasheet for temperature-dependent timing limits.
Does the SN65LBC179QDR include enable/disable control for the driver or receiver?
No, the SN65LBC179QDR does not feature driver-enable (DE) or receiver-enable (RE) pins. It operates in permanently active full-duplex mode. For half-duplex or bus-controlled operation, external logic or a different transceiver (e.g., SN65HVD72) must be used. The SN65LBC179QDR relies on its high-impedance bus terminals at VCC = 0 for isolation instead.
What is the purpose of the thermal shutdown function in the SN65LBC179QDR?
The thermal shutdown function in the SN65LBC179QDR disables the driver output when the junction temperature reaches approximately 172°C, preventing irreversible damage during sustained bus short-circuits, excessive ambient heat, or inadequate PCB thermal relief. Recovery occurs automatically once the die cools below the hysteresis threshold (~155°C), restoring normal operation without external intervention.
Can the SN65LBC179QDR be used in a 3.3-V system?
No, the SN65LBC179QDR is specified only for 4.75 V to 5.25 V operation. Applying 3.3 V will result in undefined behavior, including insufficient differential output voltage (<1.1 V), degraded noise margin, and possible failure to meet RS-485 compliance. For 3.3-V systems, consider TI's SN65HVD7x or THVD15xx families, which are explicitly characterized at 3.3 V.
How does the SN65LBC179QDR handle bus idle or open-circuit conditions?
The SN65LBC179QDR receiver incorporates internal fail-safe biasing that forces the R output high when the A–B differential input voltage is near zero (e.g., open bus or unterminated line). This ensures a known logic state during idle periods, eliminating the need for external pull-up/pull-down resistors and preventing spurious interrupts in microcontroller UART receivers.
SN65LBC179QDR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Transceiver
- Protocol:
- RS422, RS485
- Number of Drivers/Receivers:
- 1/1
- Duplex:
- Full
- Receiver Hysteresis:
- 45 mV
- Data Rate:
- -
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
SN65LBC179QDR FAQ
1.How can I place an order for SN65LBC179QDR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN65LBC179QDR 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 SN65LBC179QDR reliable?
The price and inventory of SN65LBC179QDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN65LBC179QDR is usually 5 days.
3.What payment methods are accepted for SN65LBC179QDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN65LBC179QDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN65LBC179QDR?
SN65LBC179QDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN65LBC179QDR 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 SN65LBC179QDR?
For technical support, including SN65LBC179QDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN65LBC179QDR requirements.
6.How does Aetrix verify that SN65LBC179QDR is sourced from the original manufacturer or authorized distributors?
All SN65LBC179QDR 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 SN65LBC179QDR meets industry standards.
7.What is the process for return or replacement of SN65LBC179QDR?
All SN65LBC179QDR units undergo pre-shipment inspection (PSI). If there is an issue with SN65LBC179QDR, 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 SN65LBC179QDR part is unused and in its original packaging.
Return procedure for SN65LBC179QDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN65LBC179QDR Tags
-
ATA6561-GAQW-N
Microchip Technology
-
ATA6561-GBQW-N
Microchip Technology
-
AM26LS32ACDR
Texas Instruments
-
SP485CN-L/TR
MaxLinear, Inc.
-
SP485EN-L/TR
MaxLinear, Inc.
-
SP485EEN-L/TR
MaxLinear, Inc.
-
SP485ECN-L/TR
MaxLinear, Inc.
-
THVD1400DR
Texas Instruments
-
AM26C31IDR
Texas Instruments
-
TLIN1021ADRQ1
Texas Instruments
-
MAX232IDR
Texas Instruments
-
AM26C32IDR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
