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Texas Instruments DS485N
- Part No.:
- DS485N
- Manufacturer:
- Texas Instruments
- Category:
- Drivers, Receivers, Transceivers
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
DS485N.pdf
- Description:
- IC TRANSCEIVER HALF 1/1 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,281
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Product details
Overview
DS485N from Texas Instruments is a low-power, half-duplex RS-485/RS-422 multipoint transceiver in an 8-pin PDIP package, featuring 200 μA typical quiescent current, −7V to +12V common-mode input range, and guaranteed 1.5V differential output voltage under full load (VOD3). It operates from a single 5V supply and supports up to 2.5 Mbps data rates in industrial bus systems.
For engineers reviewing the DS485N datasheet, DS485N pinout, DS485N application, or DS485N equivalent, this transceiver is selected for robust multi-drop communication in factory automation, building control networks, and industrial PLC backplanes where low power, thermal fault protection, and failsafe receiver operation are critical design requirements.
Technical Context
The DS485N integrates one driver and one receiver with TRI-STATE enable control on both sections (RE* for receiver, DE for driver), enabling half-duplex bus arbitration. Its driver uses short-circuit current limiting and thermal shutdown to force outputs into high-impedance state at junction temperatures ≥+150°C.
The receiver implements a failsafe feature that asserts logic-high RO when A/B inputs are open-circuited, and guarantees differential threshold voltage (VTH) between −0.2V and +0.2V across −7V to +12V common-mode range, with 70 mV hysteresis for noise immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | +4.75V to +5.25V - ensures stable operation across standard 5V rail tolerances in industrial environments. |
| Quiescent Current | 200 μA typ - enables battery-backed or energy-constrained nodes without compromising bus node count. |
| Differential Output (VOD3) | ≥1.5V min into 54Ω/375Ω load at VCM = −7V to +12V - guarantees reliable signal detection margin over full industrial common-mode range. |
| Max Data Rate | 2.5 Mbps - ensured for 50 ft twisted-pair cable, derived from 25 ns typ driver transition time and 10% unit-interval ratio. |
| Common-Mode Range | −7V to +12V - supports long-distance, electrically noisy industrial cabling with ground potential differences. |
| Receiver Input Resistance | 12 kΩ - allows up to 32 standard unit-load transceivers on a single RS-485 bus segment. |
| Driver Propagation Delay | 40 ns typ - enables precise timing alignment in synchronous multi-node protocols. |
| Thermal Shutdown Threshold | +150°C junction temperature - protects against latch-up or permanent damage during sustained bus contention or short circuits. |
Pinout & Package
DS485N is housed in an 8-pin Plastic Dual Inline Package (PDIP) with 0.3-inch body width and through-hole mounting. Pin spacing conforms to JEDEC MS-001.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RO) | Receiver Output | Active-high TTL-compatible output; asserts high during open-circuit or A > B by ≥200 mV. |
| 2 (RE*) | Receiver Enable (active-low) | Controls receiver output state: low enables RO, high places RO in TRI-STATE. |
| 3 (DE) | Driver Enable (active-high) | Controls driver output state: high enables A/B, low places A/B in TRI-STATE. |
| 4 (DI) | Driver Input | Direct logic-level input controlling differential polarity: DI = H → A = H, B = L; DI = L → A = L, B = H. |
| 5 (GND) | Ground Reference | System return path for all internal circuitry and I/O biasing. |
| 6 (A) | Non-inverting I/O | Shared driver output / receiver input; RS-485-compliant voltage levels with ±7V fault tolerance. |
| 7 (B) | Inverting I/O | Shared driver output / receiver input; complements A to generate differential signaling. |
| 8 (VCC) | Power Supply | +5V supply input with 4.75–5.25V operating window; powers internal logic and driver/receiver stages. |
Key Features
| Feature | Design Value |
|---|---|
| Failsafe Receiver | Guarantees logic-high RO output when A/B inputs are open-circuited - eliminates need for external bias resistors in many configurations. |
| Thermal Shutdown Protection | Automatically disables driver outputs above +150°C junction temperature - prevents thermal runaway during bus contention or short circuits. |
| Half-Duplex Flow-Through Pinout | Pins 1–4 (RO, RE*, DE, DI) and 6–8 (A, B, VCC) align logically left-to-right - simplifies PCB layout and reduces trace crossovers in bus node designs. |
| Full RS-485 Compliance | Meets TIA/EIA-485-A electrical specifications including VOD3 ≥1.5V, RIN = 12 kΩ, and −7V to +12V common-mode range - ensures interoperability with legacy and modern RS-485 devices. |
| Low-Power Operation | 200 μA typical supply current with driver disabled - extends uptime in remote sensor nodes powered by small batteries or energy harvesters. |
Applications
| Factory Automation Network | Building Management System (BMS) |
|---|---|
|
Use Scenario: Connecting programmable logic controllers (PLCs), I/O modules, and HMIs over daisy-chained RS-485 bus in manufacturing cells. IC Role / Device Role / Timing Role: Half-duplex transceiver managing bidirectional serial data exchange between master and up to 32 slave nodes. Use Value: Low 200 μA quiescent current reduces heat buildup in densely packed control cabinets; thermal shutdown prevents field failures during wiring faults. |
Use Scenario: Interfacing HVAC controllers, lighting panels, and fire alarm interfaces across multi-floor commercial buildings. IC Role / Device Role / Timing Role: RS-485 physical layer interface enabling noise-immune communication over 100+ meter twisted-pair runs. Use Value: −7V to +12V common-mode range accommodates ground potential shifts between floors; failsafe receiver ensures default-safe state during cable disconnection. |
| Industrial Sensor Hub | Energy Metering Gateway |
|
Use Scenario: Aggregating Modbus RTU data from analog/digital sensors (temperature, pressure, flow) in oil & gas field equipment. IC Role / Device Role / Timing Role: Bus node transceiver converting microcontroller UART signals to robust differential RS-485 for long-haul transmission. Use Value: Guaranteed 1.5V VOD3 ensures reliable signal integrity even with 32-node loading and worst-case termination; 2.5 Mbps supports burst telemetry uploads. |
Use Scenario: Collecting consumption data from smart electricity meters using RS-485-based DLMS/COSEM protocol in utility substations. IC Role / Device Role / Timing Role: Isolated or non-isolated bus interface providing ESD-tolerant, thermally protected physical layer connectivity. Use Value: 2 kV HBM ESD rating and driver short-circuit current limiting (35–250 mA) withstand repeated lightning-induced surges on outdoor metering lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RS-485 transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX485CPA+ | Same 8-pin PDIP package, pin-compatible, but higher quiescent current (300 μA typ) and no guaranteed VOD3 specification across full common-mode range. | Valid for lower-node-count or less-noisy environments; lacks DS485N's failsafe open-circuit behavior guarantee. | Select MAX485CPA+ only if legacy board compatibility is required and thermal shutdown is not mission-critical. |
| LTC485CN8#PBF | 8-pin PDIP, functionally compatible, but rated for −40°C to +85°C industrial range vs. DS485N's 0°C to +70°C; higher ESD rating (±15 kV contact). | Better suited for extended-temperature outdoor deployments; identical 200 μA quiescent current and VOD3 compliance. | Choose LTC485CN8#PBF when operating ambient exceeds +70°C or when enhanced ESD robustness is mandatory. |
Compared with MAX485CPA+, DS485N delivers lower power and stronger failsafe assurance; versus LTC485CN8#PBF, DS485N offers cost advantage and TI's long-term industrial support, though with narrower temperature range and lower ESD rating.
Availability
DS485N is available at Aetrix Electronics and suitable for factory automation networks, building management systems, and industrial sensor hubs requiring stable component supply across extended production lifecycles.
Supply support for DS485N 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The DS485N belongs to TI's legacy RS-485 transceiver product line, engineered specifically for low-power, thermally resilient, and fail-operational industrial bus nodes in harsh electrical environments.
FAQ
What is the maximum data rate supported by the DS485N?
The DS485N ensures reliable operation up to 2.5 Mbps over 50 ft of twisted-pair cable. This rate is derived from its 25 ns typical driver transition time and a conservative 10% unit-interval ratio. While higher speeds may be achievable under ideal conditions, 2.5 Mbps is the manufacturer-guaranteed limit specified in the DS485N datasheet for robust noise margin and timing compliance.
Does the DS485N include failsafe receiver functionality?
Yes, the DS485N features a built-in failsafe receiver that drives the RO output high when the A and B inputs are open-circuited or unterminated. This behavior is explicitly guaranteed in the DS485N truth table and applications information, eliminating the need for external pull-up/pull-down resistors in many multi-drop configurations where bus idle states must default to a known logic level.
What protection mechanisms does the DS485N driver incorporate?
The DS485N driver includes two key protection mechanisms: short-circuit current limiting (35–250 mA) and thermal shutdown activation at approximately +150°C junction temperature. When either condition occurs, the driver outputs (A and B) are forced into TRI-STATE, preventing damage during bus contention, wiring faults, or prolonged overload - a critical reliability feature confirmed in the DS485N absolute maximum ratings and applications section.
Can the DS485N operate from a 3.3V supply?
No, the DS485N is specified only for operation from a single +5V supply, with recommended operating range of +4.75V to +5.25V. Its internal circuitry, including driver output stage and receiver threshold levels, is designed and characterized exclusively for 5V operation. Using 3.3V will result in undefined behavior, failure to meet VOD3 or propagation delay specifications, and potential non-compliance with RS-485 standards - as confirmed in the DS485N recommended operating conditions table.
How many DS485N transceivers can be connected to a single RS-485 bus?
Up to 32 DS485N transceivers can be connected to one RS-485 bus segment, as each presents a standard unit load (12 kΩ receiver input resistance). This count is explicitly stated in the DS485N datasheet and verified by its RIN = 12 kΩ specification. Adding more nodes requires transceivers with fractional unit loads (e.g., 1/2 or 1/4 load), which the DS485N does not support.
DS485N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Transceiver
- Protocol:
- RS422, RS485
- Number of Drivers/Receivers:
- 1/1
- Duplex:
- Half
- Receiver Hysteresis:
- 70 mV
- Data Rate:
- 2.5Mbps
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
DS485N FAQ
1.How can I place an order for DS485N through Aetrix?
Please submit a Request for Quotation (RFQ) for DS485N 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 DS485N reliable?
The price and inventory of DS485N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS485N is usually 5 days.
3.What payment methods are accepted for DS485N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS485N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS485N?
DS485N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS485N 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 DS485N?
For technical support, including DS485N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS485N requirements.
6.How does Aetrix verify that DS485N is sourced from the original manufacturer or authorized distributors?
All DS485N 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 DS485N meets industry standards.
7.What is the process for return or replacement of DS485N?
All DS485N units undergo pre-shipment inspection (PSI). If there is an issue with DS485N, 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 DS485N part is unused and in its original packaging.
Return procedure for DS485N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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