My Inquiry
My Account
STMicroelectronics ST485CN
- Part No.:
- ST485CN
- Manufacturer:
- STMicroelectronics
- Category:
- Drivers, Receivers, Transceivers
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
ST485CN.pdf
- Description:
- IC TRANSCEIVER HALF 1/1 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,265
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
ST485CN from STMicroelectronics is a low-power, half-duplex RS-485/RS-422 transceiver in DIP-8 package, featuring 300 µA quiescent current, ±7 V to +12 V common-mode input range, and 30 ns driver propagation delay. It integrates one driver and one receiver for bidirectional multipoint bus communication and is rated for 0 °C to 70 °C operation.
For engineers reviewing the ST485CN datasheet, ST485CN pinout, ST485CN application, or ST485CN equivalent, key selection criteria include driver thermal shutdown behavior, receiver hysteresis (70 mV typ.), 5 V single-supply operation, and compatibility with legacy industrial serial networks requiring robust noise immunity and bus loading up to 64 nodes.
Technical Context
The ST485CN implements a true half-duplex RS-485 transceiver architecture with independent driver enable (DE) and receiver enable (RE) controls, enabling precise bus arbitration. Its driver features short-circuit current limiting and thermal shutdown that forces outputs into high-impedance state under overload - critical for fault-tolerant fieldbus designs.
The receiver delivers 70 mV typical hysteresis and operates across –7 V to +12 V common-mode voltage, supporting long-cable, noisy industrial environments. Propagation delays are tightly controlled: 30 ns (driver) and 130 ns (receiver, typ.), with 5 ns output skew, ensuring timing integrity at up to 2.5 Mbps data rate.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 5 V ±5% - enables direct integration with standard logic rails without level-shifting or auxiliary regulation. |
| Quiescent Current | 300 µA (typ.) - reduces standby power in battery-backed or energy-constrained remote nodes. |
| Common-Mode Range | –7 V to +12 V - supports reliable operation over long cables with ground potential differences in factory automation. |
| Driver Propagation Delay | 30 ns (typ.) - allows stable full-duplex-equivalent timing margins at 2.5 Mbps on 54 Ω differential loads. |
| Receiver Hysteresis | 70 mV (typ.) - suppresses false triggering from EMI-induced noise on unterminated or stubbed RS-485 buses. |
| Bus Node Capacity | Up to 64 transceivers - enables scalable multi-drop topology without repeaters in building management or PLC backplanes. |
| Thermal Shutdown | Integrated - automatically disables driver outputs during sustained short-circuit events, preventing latch-up or permanent damage. |
Pinout & Package
DIP-8 (Plastic Dual In-line Package), 0.3-inch body width, through-hole mounting compatible with legacy PCB layouts and manual prototyping.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RO | Receiver Output | CMOS-compatible logic-level output reflecting differential A–B state; sinks/sourcing ±4 mA. |
| 2 RE | Receiver Enable (active-low) | When low, enables receiver; when high, places RO in high-impedance - essential for bus arbitration in multidrop systems. |
| 3 DE | Driver Enable (active-high) | When high, enables driver output on A/B; when low, forces A/B into high-Z - prevents bus contention during receive mode. |
| 4 DI | Driver Input | TTL/CMOS-compatible digital input controlling driver polarity; referenced to VCC/GND, not bus signals. |
| 5 GND | Ground Reference | Signal return for internal circuitry; must be connected to local system ground - not isolated from bus reference. |
| 6 A | Non-inverting Bus Terminal | Transmits/receives positive half of differential pair; connects directly to RS-485 bus A line. |
| 7 B | Inverting Bus Terminal | Transmits/receives negative half of differential pair; connects directly to RS-485 bus B line. |
| 8 VCC | Positive Supply | 5 V DC input powering both driver and receiver; bypass capacitor (0.1 µF) required at pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Power Operation | 300 µA supply current enables use in always-on industrial sensors and gateways with strict thermal budgets. |
| Robust Bus Protection | Driver thermal shutdown + current limiting prevents failure during cable shorts or miswiring in field installations. |
| Wide Common-Mode Tolerance | –7 V to +12 V input range accommodates ground offsets >10 V across 1 km cable runs in factory settings. |
| Controlled Timing Behavior | 5 ns max output skew and 30 ns driver delay ensure deterministic setup/hold timing for microcontroller UART peripherals. |
| Legacy-Compatible Packaging | DIP-8 footprint supports hand-soldering, socket-based testing, and drop-in replacement of older RS-485 parts. |
Applications
| Industrial PLC Backplane | Building Automation Network |
|---|---|
|
Use Scenario: Interconnecting I/O modules and CPU units across DIN-rail mounted PLC chassis using twisted-pair backplane wiring. IC Role / Device Role / Timing Role: Half-duplex transceiver managing bidirectional command/response traffic between master controller and distributed slave modules. Use Value: 300 µA quiescent current minimizes heat buildup in densely packed enclosures; thermal shutdown protects against bus faults caused by module hot-swapping. |
Use Scenario: Linking HVAC controllers, lighting panels, and occupancy sensors over shared RS-485 trunk cabling in commercial buildings. IC Role / Device Role / Timing Role: Physical-layer interface converting UART signals to differential bus signaling for noise-immune multi-node communication. Use Value: ±7 V to +12 V common-mode range maintains signal integrity despite ground potential shifts between floors or zones. |
| Remote Metering Interface | Legacy Equipment Retrofit |
|
Use Scenario: Connecting smart electricity/water meters to concentrator gateways via long-distance RS-485 links in utility substations. IC Role / Device Role / Timing Role: Bus node transceiver handling polled data reads and firmware updates in low-bandwidth, high-noise outdoor environments. Use Value: 70 mV receiver hysteresis rejects induced noise from nearby switching transformers and RF sources near meter cabinets. |
Use Scenario: Replacing obsolete RS-485 transceivers (e.g., SN75176) on aging CNC machine control boards without PCB redesign. IC Role / Device Role / Timing Role: Pin-compatible functional upgrade delivering lower power and enhanced fault protection while retaining DIP-8 footprint. Use Value: DIP-8 package and identical pinout allow direct socket replacement; thermal shutdown extends service life in unventilated control cabinets. |
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 | Higher quiescent current (300 µA vs. 230 µA typ.), no thermal shutdown, same DIP-8 pinout. | Lacks driver fault protection - unsuitable where bus wiring faults are probable. | Select MAX485CPA only if thermal shutdown is unnecessary and lowest possible BOM cost is prioritized. |
| SN65HVD72DR | SO-8 only, 3.3 V supply, ±15 kV ESD protection, higher speed (16 Mbps), no DIP-8 option. | Requires PCB redesign and level-shifting for 5 V systems; adds ESD robustness for exposed ports. | Choose SN65HVD72DR for new 3.3 V designs needing ESD hardening; not suitable for ST485CN drop-in replacement. |
Compared with MAX485CPA and SN65HVD72DR, the ST485CN uniquely balances legacy DIP-8 compatibility, integrated thermal protection, and 5 V operation - making it optimal for retrofitting and thermally constrained industrial nodes where bus reliability outweighs raw speed.
Availability
ST485CN is available at Aetrix Electronics and suitable for industrial PLC backplanes, building automation networks, and remote metering interfaces requiring stable component supply and long-term obsolescence management.
Supply support for ST485CN 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with vertical manufacturing capability and broad analog/mixed-signal portfolio.
The ST485CN belongs to ST's legacy RS-485 transceiver product line, designed specifically for cost-sensitive, thermally constrained industrial serial communication where robustness, pin compatibility, and long-lifecycle support are prioritized over ultra-high speed.
FAQ
Is the ST485CN pin-compatible with the SN75176B?
Yes - ST485CN uses identical DIP-8 pinout and logic mapping (RO, RE, DE, DI, GND, A, B, VCC) as SN75176B. Driver/receiver thresholds, hysteresis, and enable timing are functionally aligned, enabling direct socket replacement without layout changes.
Does the ST485CN support full-duplex RS-422 operation?
No - ST485CN is strictly half-duplex. It shares A/B terminals between driver and receiver, with no separate transmit/receive differential pairs. Full-duplex RS-422 requires four dedicated bus lines (Y/Z for TX, A/B for RX), which this device does not provide.
What is the maximum recommended cable length at 2.5 Mbps?
At 2.5 Mbps, STMicroelectronics specifies ≤100 m for reliable operation with proper termination and 120 Ω characteristic impedance cable. Longer distances require reduced data rates: e.g., 1 km is feasible at 100 kbps with appropriate drivers and receivers.
Can the ST485CN operate with a 3.3 V supply?
No - the ST485CN is specified only for 5 V ±5% operation. Input thresholds (VIH = 2.0 V, VIL = 0.8 V) and driver output swing depend on 5 V rail; using 3.3 V results in undefined logic levels, degraded noise margin, and noncompliant RS-485 output voltage.
ST485CN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- 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-DIP
ST485CN FAQ
1.How can I place an order for ST485CN through Aetrix?
Please submit a Request for Quotation (RFQ) for ST485CN 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 ST485CN reliable?
The price and inventory of ST485CN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST485CN is usually 5 days.
3.What payment methods are accepted for ST485CN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST485CN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ST485CN?
ST485CN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ST485CN 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 ST485CN?
For technical support, including ST485CN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST485CN requirements.
6.How does Aetrix verify that ST485CN is sourced from the original manufacturer or authorized distributors?
All ST485CN 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 ST485CN meets industry standards.
7.What is the process for return or replacement of ST485CN?
All ST485CN units undergo pre-shipment inspection (PSI). If there is an issue with ST485CN, 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 ST485CN part is unused and in its original packaging.
Return procedure for ST485CN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ST485CN 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
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…
LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…
Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…
Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.
18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…
Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…
Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…
A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…
