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STMicroelectronics ST490ABDR
- Part No.:
- ST490ABDR
- Manufacturer:
- STMicroelectronics
- Category:
- Drivers, Receivers, Transceivers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ST490ABDR.pdf
- Description:
- IC TRANSCEIVER FULL 1/1 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:59,173
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Product details
Overview
ST490ABDR from STMicroelectronics is a low-power, high-speed RS-485/RS-422 transceiver in SO-8 package, featuring full-duplex operation with one driver and one receiver, 25 Mbps maximum data rate, ±4 kV ESD protection, and -7 V to 12 V common-mode input range. It operates from a single 5 V supply and includes thermal shutdown and current limiting for driver overload protection.
For engineers reviewing the ST490ABDR datasheet, ST490ABDR pinout, ST490ABDR application, or ST490ABDR equivalent, key selection criteria include differential output voltage (1.5–2.6 V), receiver hysteresis (70 mV typ.), propagation delay (10–30 ns), fail-safe receiver logic, and SO-8 tape-and-reel packaging for automated assembly.
Technical Context
The ST490ABDR implements a true full-duplex RS-485/RS-422 interface with independent driver and receiver paths. Its driver supports short-circuit current limiting and thermal shutdown, while the receiver incorporates fail-safe biasing that outputs logic high when inputs are open or floating.
Electrical behavior is specified across -40°C to +85°C with supply voltage 4.5–5.5 V. Differential thresholds are ±0.2 V with 70 mV hysteresis, and common-mode rejection is maintained over -7 V to 12 V, enabling robust operation in electrically noisy industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max data rate | 25 Mbps - supports high-speed industrial fieldbus and point-to-point serial links |
| Supply current (no load) | 5 mA max - enables low-power remote nodes and battery-backed systems |
| Differential output voltage | 1.5–2.6 V (RL = 54 Ω) - meets RS-422 minimum swing for reliable signal integrity |
| Receiver hysteresis | 70 mV typ. - suppresses noise-induced output toggling on marginal differential inputs |
| Common-mode input range | -7 V to 12 V - accommodates ground potential differences in distributed systems |
| ESD protection | ±4 kV HBM - reduces need for external TVS diodes in board-level ESD design |
| Propagation delay (driver) | 10–16 ns - enables tight timing budgets in synchronous multi-drop networks |
Pinout & Package
ST490ABDR is housed in an SO-8 (Small Outline-8) surface-mount package per JEDEC MS-012, with 1.27 mm pitch, lead-free ECOPACK® construction, and tape-and-reel packaging (2500 units/reel).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VCC | Power supply input | 5 V nominal supply rail; decoupling capacitor required near pin for noise immunity |
| 2 RO | Receiver output | CMOS-compatible logic output; high-impedance when disabled via /RE control (not present on ST490A) |
| 3 DI | Driver input | TTL/CMOS-compatible digital input controlling Y/Z differential driver state |
| 4 GND | Ground reference | Signal and power return path; must be low-impedance connection to system ground plane |
| 5 Y | Non-inverting driver output | Positive half of differential pair; connects to A-line of RS-485 bus |
| 6 Z | Inverting driver output | Negative half of differential pair; connects to B-line of RS-485 bus |
| 7 B | Inverting receiver input | RS-485/RS-422 differential input (B line); referenced to A for polarity detection |
| 8 A | Non-inverting receiver input | RS-485/RS-422 differential input (A line); referenced to B for polarity detection |
Key Features
| Feature | Design Value |
|---|---|
| Fail-safe receiver | Guarantees logic-high RO when A/B inputs are open, shorted, or unterminated - prevents undefined bus states |
| Thermal shutdown | Disables driver outputs into high-impedance state during sustained overload - protects against PCB trace damage |
| Driver short-circuit current limit | ±35 mA typical short-circuit output current - limits fault energy without external current-sense circuitry |
| Low input capacitance | 1.8 pF typical CIN - minimizes loading on upstream logic and preserves signal edge rates |
| High receiver input resistance | 12–24 kΩ RRIN - allows up to 32 unit loads on a single RS-485 bus segment |
Applications
| Industrial PLC Backplane | Point-to-Point Sensor Interface |
|---|---|
|
Use Scenario: Bidirectional serial communication between CPU module and I/O expansion cards in modular PLC chassis. IC Role / Device Role / Timing Role: Full-duplex transceiver handling command/response traffic at 10–25 Mbps over backplane traces up to 30 cm. Use Value: Low 5 mA supply current reduces localized heat buildup; 70 mV hysteresis rejects crosstalk-induced glitches on densely routed backplanes. |
Use Scenario: Connecting a remote temperature sensor node to a central gateway over twisted-pair cable in HVAC ducts. IC Role / Device Role / Timing Role: RS-422 line driver/receiver enabling noise-immune 1 Mbps telemetry over 150 m cable runs. Use Value: -7 V to 12 V common-mode range tolerates ground offset between sensor and gateway; ±4 kV ESD withstands installation-handling events. |
| Factory Floor HMI Link | Building Automation Controller |
|
Use Scenario: Serial link between touchscreen HMI panel and programmable logic controller in dusty, EMI-heavy production areas. IC Role / Device Role / Timing Role: Robust physical layer interface supporting Modbus RTU at 19.2 kbps with galvanic isolation on controller side. Use Value: Fail-safe receiver ensures default 'idle' state during cable disconnect or power loss; SO-8 package supports reflow soldering for high-volume panel assembly. |
Use Scenario: Interfacing lighting control modules and occupancy sensors in commercial office buildings using daisy-chained RS-485. IC Role / Device Role / Timing Role: Bus node transceiver enabling multi-drop topology with up to 32 devices per segment at 100 kbps. Use Value: 24 kΩ receiver input resistance meets RS-485 standard load count; thermal shutdown prevents latch-up during accidental bus short circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RS-485/RS-422 transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX485ESA+ | Lower max data rate (2.5 Mbps), no thermal shutdown, 0.3 mA quiescent current | Optimized for low-power, low-speed sensor networks - not suitable for >5 Mbps links | Select when ultra-low standby current outweighs speed and fault protection requirements |
| SN65HVD72DR | Higher ESD rating (±16 kV), 50 Mbps data rate, integrated slew-rate control, 3.3 V supply only | Designed for high-noise automotive and industrial CAN/RS-485 hybrid systems | Select when operating in harsh ESD environments or requiring 3.3 V compatibility and faster edge control |
Compared with MAX485ESA+ and SN65HVD72DR, ST490ABDR uniquely balances 25 Mbps speed, 5 V single-supply operation, thermal protection, and SO-8 footprint - making it optimal for cost-sensitive industrial automation where moderate speed and robustness are prioritized over ultra-low power or extreme ESD immunity.
Availability
ST490ABDR is available at Aetrix Electronics and suitable for industrial PLC backplanes, factory-floor HMIs, and building automation controllers requiring stable component supply, long-lifecycle support, and RoHS-compliant SO-8 packaging.
Supply support for ST490ABDR 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, designing and manufacturing microcontrollers, analog ICs, power management devices, and discrete components for industrial, automotive, and consumer markets.
The ST490ABDR belongs to ST's legacy RS-485/RS-422 transceiver product line, engineered specifically for noise-immune, full-duplex serial communication in industrial control and automation infrastructure.
FAQ
Does ST490ABDR support half-duplex operation?
No. ST490ABDR is a fixed full-duplex transceiver with separate driver (DI → Y/Z) and receiver (A/B → RO) paths and no direction-control pin. It lacks /RE or DE pins required for half-duplex RS-485 bus sharing. For half-duplex designs, ST offers ST485 series variants with enable controls.
What is the minimum load impedance the driver can drive reliably?
The ST490ABDR driver is characterized with RL = 54 Ω (RS-422) and RL = 100 Ω (RS-485). Its differential output voltage remains within specification down to 54 Ω, and short-circuit current is limited to ±250 mA. Driving loads below 54 Ω risks violating VOH/VOL specs and triggering thermal shutdown.
Is the receiver truly fail-safe with open inputs?
Yes. Per datasheet Table 4, when both A and B inputs are open-circuit, RO outputs logic high. This behavior is guaranteed by internal fail-safe biasing circuitry and holds across -40°C to +85°C and 4.5–5.5 V supply, eliminating need for external pull-up/pull-down resistors in unpowered or disconnected states.
Can ST490ABDR be used with 3.3 V logic interfaces?
DI input accepts TTL/CMOS levels: VIH ≥ 2.0 V and VIL ≤ 0.8 V, so it is compatible with 3.3 V logic driving DI. However, VCC must be 5 V - the device does not operate from 3.3 V supply. RO output swings 0.2–4.7 V, which is compatible with 5 V or 3.3 V receivers having 5 V-tolerant inputs.
ST490ABDR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- 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:
- 70 mV
- Data Rate:
- 25Mbps
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
ST490ABDR FAQ
1.How can I place an order for ST490ABDR through Aetrix?
Please submit a Request for Quotation (RFQ) for ST490ABDR 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 ST490ABDR reliable?
The price and inventory of ST490ABDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST490ABDR is usually 5 days.
3.What payment methods are accepted for ST490ABDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST490ABDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ST490ABDR?
ST490ABDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ST490ABDR 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 ST490ABDR?
For technical support, including ST490ABDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST490ABDR requirements.
6.How does Aetrix verify that ST490ABDR is sourced from the original manufacturer or authorized distributors?
All ST490ABDR 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 ST490ABDR meets industry standards.
7.What is the process for return or replacement of ST490ABDR?
All ST490ABDR units undergo pre-shipment inspection (PSI). If there is an issue with ST490ABDR, 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 ST490ABDR part is unused and in its original packaging.
Return procedure for ST490ABDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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