ST75185CTR - 3.3V/5V RS-232 Transceiver | STMicroelectronics
MPN: ST75185CTR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.25 | $1.25 |
| 10 | $1.1 | $11.00 |
| 100 | $0.95 | $95.00 |
| 500 | $0.85 | $425.00 |
| 1,000 | $0.75 | $750.00 |
Drop-in alternatives for ST75185CTR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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ST75185CTR
✅ Drop-In✓ 99,999 In Stock
$0.75 / Unit
View Datasheet →ST75185C
✅ Drop-In📋 Reference alternative (not in catalog)
ST75185CTR Maximum Ratings & Electrical Characteristics
| Number of Drivers | 3 |
| Number of Receivers | 5 |
| Supply Voltage | 3.3 V to 5 V |
| Data Rate | 120 kbps |
| ESD Protection | ±2 kV (HBM) |
| Shutdown Current | 1 µA |
| Operating Temperature | -40°C to +85°C |
| Package | SOIC-20 |
| Mounting Type | Surface Mount |
| Charge Pump Capacitors | 4 x 0.1 µF |
| RS-232 Output Voltage | ±10 V (typical) |
| Receiver Input Voltage Range | ±30 V |
| RoHS Status | Compliant |
| MSL Level | 1 |
| Standards | EIA-232, ITU-T V.28 |
ST75185CTR Pin Configuration
| Pin 1 | C1+ — Charge pump capacitor positive terminal |
| Pin 2 | V+ — Positive charge pump output |
| Pin 3 | C1- — Charge pump capacitor negative terminal |
| Pin 4 | C2+ — Charge pump capacitor positive terminal |
| Pin 5 | C2- — Charge pump capacitor negative terminal |
| Pin 6 | V- — Negative charge pump output |
| Pin 7 | T1OUT — Transmitter 1 output |
| Pin 8 | R1IN — Receiver 1 input |
| Pin 9 | R2IN — Receiver 2 input |
| Pin 10 | R3IN — Receiver 3 input |
| Pin 11 | R4IN — Receiver 4 input |
| Pin 12 | R5IN — Receiver 5 input |
| Pin 13 | T2OUT — Transmitter 2 output |
| Pin 14 | T3OUT — Transmitter 3 output |
| Pin 15 | GND — Ground |
| Pin 16 | T1IN — Transmitter 1 input |
| Pin 17 | T2IN — Transmitter 2 input |
| Pin 18 | T3IN — Transmitter 3 input |
| Pin 19 | R1OUT — Receiver 1 output |
| Pin 20 | VCC — Power supply (3.3V or 5V) |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
ST75185CTR is suitable for 6 applications: Industrial Automation, Point-of-Sale (POS) Terminals, Data Acquisition Systems, Embedded Systems, Networking Equipment, Test and Measurement Instruments.
Industrial Automation
The ST75185CTR is used in industrial automation for serial communication between PLCs, sensors, and controllers. Its 3 drivers and 5 receivers support multiple channels, and the wide operating temperature range (-40°C to +85°C) ensures reliable operation in harsh factory environments. The device operates from a 3.3V or 5V supply, making it compatible with common industrial logic levels. The integrated charge pump eliminates the need for a negative supply, simplifying PCB design. With a data rate of 120 kbps, it can handle typical industrial protocols like Modbus. The ±2 kV ESD protection provides robustness against electrostatic discharge in industrial settings. The low shutdown current of 1 µA helps reduce power consumption in energy-efficient systems.
Recommended
Point-of-Sale (POS) Terminals
In POS terminals, the ST75185CTR provides reliable RS-232 communication with peripherals such as barcode scanners, receipt printers, and cash drawers. Its 3 drivers and 5 receivers allow connection of multiple devices. The device operates from a single 3.3V or 5V supply, which is common in POS systems. The integrated charge pump generates the required RS-232 voltage levels without a negative supply, reducing component count. The low shutdown current of 1 µA is beneficial for power-saving modes in battery-backed POS systems. The SOIC-20 package is compact, fitting into space-constrained terminal designs. The wide operating temperature range ensures operation in various retail environments.
Recommended
Data Acquisition Systems
The ST75185CTR is used in data acquisition systems to interface with sensors and instruments that communicate via RS-232. Its 3 drivers and 5 receivers enable connection to multiple data sources. The device operates from a 3.3V or 5V supply, compatible with typical data acquisition boards. The integrated charge pump simplifies power supply design. The data rate of 120 kbps is sufficient for most sensor data streams. The ±2 kV ESD protection ensures reliability in field environments. The low shutdown current is useful for portable data loggers. The SOIC-20 package is suitable for PCB integration.
Recommended
Embedded Systems
In embedded systems, the ST75185CTR provides a simple interface for serial communication with PCs or other devices. Its 3 drivers and 5 receivers offer flexibility for multiple serial ports. The device operates from a 3.3V or 5V supply, matching common microcontroller logic levels. The integrated charge pump eliminates the need for a negative supply, reducing board space. The low shutdown current of 1 µA is ideal for battery-powered embedded devices. The SOIC-20 package is easy to solder and fits in compact designs. The wide operating temperature range supports various embedded applications.
Recommended
Networking Equipment
The ST75185CTR is used in networking equipment such as routers and switches for console management ports. These ports allow administrators to configure devices via a serial connection. The device's 3 drivers and 5 receivers support multiple console connections. It operates from a 3.3V or 5V supply, common in networking hardware. The integrated charge pump simplifies power design. The data rate of 120 kbps is sufficient for console communication. The ±2 kV ESD protection is important for ports that may be exposed to static discharge. The SOIC-20 package is suitable for PCB assembly.
Recommended
Test and Measurement Instruments
In test and measurement instruments, the ST75185CTR provides RS-232 communication for remote control and data logging. Its 3 drivers and 5 receivers allow connection to multiple instruments. The device operates from a 3.3V or 5V supply, compatible with instrument power rails. The integrated charge pump eliminates the need for a negative supply. The data rate of 120 kbps is adequate for command and data transfer. The ±2 kV ESD protection ensures reliability in lab environments. The low shutdown current is useful for power-saving modes. The SOIC-20 package is suitable for instrument PCBs.
Recommended
Recommended Products Summary
Engineering reference data for ST75185CTR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ST75185C | MAX3243ECAI | ADM3202ARUZ |
|---|---|---|---|---|
| Package | SOIC-20 | SOIC-20 | SSOP-28 | TSSOP-16 |
| Brand | STMicroelectronics | STMicroelectronics | Maxim Integrated | Analog Devices |
| Number of Drivers | 3 | 3 | 3 | 2 |
| Number of Receivers | 5 | 5 | 5 | 2 |
| Supply Voltage | 3.3V to 5V | 3.3V to 5V | 3V to 5.5V | 3V to 5.5V |
| Data Rate | 120 kbps | 120 kbps | 250 kbps | 460 kbps |
| ESD Protection | ±2 kV (HBM) | ±2 kV (HBM) | ±15 kV (HBM) | ±15 kV (HBM) |
| Shutdown Current | 1 µA | 1 µA | 1 µA | 1 µA |
Key Differentiators
- Higher driver/receiver count (vs ADM3202ARUZ)
- Wide supply voltage range (vs MAX3243ECAI)
- Lower ESD protection (vs MAX3243ECAI)
Design Notes
Place the four charge pump capacitors (0.1 µF) as close as possible to the ST75185CTR pins (C1+, C1-, C2+, C2-) to minimize noise and ensure stable voltage generation. Use low-ESR ceramic capacitors for best performance. Keep the traces short and wide to reduce parasitic inductance.
The ST75185CTR operates from a 3.3V or 5V supply. Ensure the supply voltage is within the specified range and has adequate decoupling. A 0.1 µF capacitor on the VCC pin is recommended. The charge pump generates ±10V internally, so no external negative supply is needed.
Do not exceed the absolute maximum ratings, especially on the RS-232 pins. The receiver inputs can handle ±30V, but the transmitter outputs should not be shorted to ground for extended periods. Use the shutdown pin to reduce power consumption when idle. Ensure the charge pump capacitors are correctly polarized if using electrolytic types (though ceramic is recommended).
Compliance Information
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified. Halogen-free status not specified in available data.
