ADM235LJN - 5V RS-232 Transceiver | Analog Devices
MPN: ADM235LJN ✓ ActiveADM235LJN Overview
An RS-232 transceiver is an interface IC that combines a transmitter and receiver for serial data links using differential voltage signaling. It belongs to the RS-232 line transceiver and interface IC hierarchy, where EIA-232-E and V.28 define the electrical behavior expected by compatible computer and industrial equipment. The ADM235LJN is intended for systems that need an RS-232 port but cannot conveniently provide both positive and negative supply rails.
Key features include operation from one 5 V supply, onboard DC-DC conversion, 120 kB/s data throughput, a 9 V output swing, and support for low-power shutdown. The receivers remain active during shutdown and tolerate input voltages to 30 V. These characteristics make the device useful when an existing embedded system must deliver conventional RS-232 levels from a single low-voltage rail.
The internal charge-pump and DC-DC circuitry eliminates the external negative supply normally associated with older RS-232 implementations. A 9 V output swing provides useful margin against the RS-232 voltage thresholds, while the 30 V receiver input rating helps protect the interface when connected to exposed or longer cables. Receiver and driver performance should still be evaluated against the system’s grounding and noise environment.
Typical applications include industrial control consoles, POS terminals, service equipment, data acquisition systems, and embedded instrumentation. The device is especially appropriate where a 5 V logic rail is available but a separate negative voltage rail would increase power-supply complexity or reduce reliability. Cable length and data rate must be considered when designing the physical link.
For implementation, place the device close to the RS-232 connector and keep the unprotected transceiver-side traces away from sensitive analog and high-speed digital signals. Verify bypass-capacitor placement and grounding against the manufacturer application guidance. The 24-pin PDIP format favors through-hole assembly and prototype or industrial equipment where a socket or leaded component is appropriate.
This page organizes the electrical capabilities, interface use cases, comparison points, and implementation considerations of the ADM235LJN. It also distinguishes true package-level replacement options from related RS-232 devices that require different supplies, different packages, or different interface functions.
Drop-in alternatives for ADM235LJN — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
No drop-in alternatives available for this product.
Request AlternativesADM235LJN Specifications
| Product Type | RS-232 line driver and receiver transceiver |
| Supply Voltage | 5 V |
| Number of RS-232 Functions | 5 functions |
| Data Rate | 120 kB/s |
| RS-232 Output Swing | 9 V |
| Onboard DC-DC Converters | Yes |
| Receiver Input Tolerance | 30 V |
| Receiver State During Shutdown | Active |
| Low-Power Shutdown | Supported |
| Interface Standard | EIA-232-E |
| Interface Standard | V.28 |
| Package | 24-PDIP, 0.600 inch (15.24 mm) lead span |
| Terminal Count | 24 terminals |
| Maximum Operating Temperature | 70 °C |
| Mounting Type | Through-hole |
| RoHS Status | unknown |
| REACH Status | unknown |
| Automotive AEC-Q100 Qualification | not_applicable |
ADM235LJN 24-pdip, 0.600 inch (15.24 mm) lead span Pin Configuration Guide
Pin configuration for ADM235LJN (24-pdip, 0.600 inch (15.24 mm) lead span package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for ADM235LJN.
Refer to the datasheet for full pin configuration.
Typical Applications
ADM235LJN is suitable for 6 applications: Industrial Control Console, Point-of-Sale Terminal, Data Acquisition Instrument, Service and Diagnostic Equipment, Embedded Serial Communication Port, Security and Access Controller.
Industrial Control Console
The ADM235LJN fits industrial control consoles that already operate from a 5 V logic rail but need to communicate with RS-232 equipment. Its single 5 V supply and onboard DC-DC converters remove the need for a separate negative rail, while the 120 kB/s data rate supports configuration transfer, status reporting, and service commands. The 9 V output swing provides useful drive margin relative to standard RS-232 thresholds. Place the transceiver near the serial connector, route the ground return carefully, and verify that the enclosure environment remains within the specified 70 °C maximum temperature. External surge protection should be considered when the cable leaves the controlled enclosure.
Recommended
Point-of-Sale Terminal
The ADM235LJN is well suited to point-of-sale terminals that expose an RS-232 port for receipt printers, scanners, or service equipment. A single 5 V supply simplifies adapter design, and the integrated DC-DC circuitry provides the bipolar signal levels required by RS-232 without external negative-voltage generation. Its 120 kB/s rate is more than adequate for transactional and configuration traffic. Keep the data and ground conductors together where possible, minimize the unprotected trace length between the chip and connector, and confirm the peripheral’s voltage-level and handshake requirements before finalizing the wiring.
Recommended
Data Acquisition Instrument
The ADM235LJN can connect laboratory and industrial data-acquisition instruments to legacy RS-232 controllers. The 120 kB/s data rate supports command traffic and periodic measurement results, while the single 5 V supply allows the interface to share the instrument’s existing low-voltage power architecture. The 30 V receiver input rating improves tolerance to interface transients, although it does not replace formal surge protection. Use a low-impedance ground reference, keep the connector-side traces away from sensor inputs, and verify the UART baud rate and electrical thresholds used by the controller.
Recommended
Service and Diagnostic Equipment
The ADM235LJN is appropriate for service equipment that communicates with legacy RS-232 ports in printers, instruments, or controllers. Its 5 V operating supply supports compact portable and rack-mounted designs, while onboard DC-DC conversion reduces the number of power rails required. The 9 V output swing improves compatibility with systems using conventional RS-232 thresholds, and the 120 kB/s limit comfortably handles diagnostic commands and firmware-transfer traffic. Protect exposed connector pins with appropriately rated surge components, provide a solid chassis-to-logic ground strategy, and verify whether the connected equipment requires hardware handshake signals.
Recommended
Embedded Serial Communication Port
The ADM235LJN gives an embedded controller a conventional RS-232 port when only a 5 V rail is present. Its integrated converters avoid adding a negative-voltage regulator and bulk charge-pump capacitors to the surrounding design. The transceiver supports data rates up to 120 kB/s, making it suitable for configuration consoles, module updates, and supervisory communication. Assign its driver, receiver, shutdown, and ground pins according to the manufacturer pin-description table, and place bypass capacitors close to the supply pins. If the system must support both RS-232 and another bus, isolate the interfaces physically to prevent ground currents and unused driver outputs from disturbing sensitive circuitry.
Recommended
Security and Access Controller
The ADM235LJN can support legacy access-control or security equipment that offers an RS-232 configuration interface. Its single-supply operation is useful in compact controller boards, and the 120 kB/s rate is adequate for command exchange and short firmware-update sequences. The active receivers during shutdown permit selected incoming signals to remain monitored while reducing transmitter power. Do not expose the interface directly to untrusted outdoor cabling without suitable protection. The specified 70 °C maximum operating temperature also requires attention in sealed cabinets, and the security design should prevent command injection through the physical serial interface.
Recommended
Recommended Products Summary
Engineering reference data for ADM235LJN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product |
|---|---|
| Product Type | 5 V powered RS-232 transceiver |
| Brand | Analog Devices |
| Package | 24-PDIP (0.600 inch, 15.24 mm) |
| Supply Voltage | 5 V single supply |
| Data Rate | 120 kB/s |
| RS-232 Output Swing | 9 V |
| Onboard DC-DC Converters | Yes |
| Receiver Input Tolerance | 30 V |
| Shutdown Support | Yes, receivers active during shutdown |
| Maximum Operating Temperature | 70 °C |
Key Differentiators
- Single 5 V supply with integrated bipolar voltage generation (vs ADM232LJN)
- No external negative-rail conversion stage (vs MAX232NSR)
- Active receiver monitoring during shutdown (vs MAX3070EESD+)
- 120 kB/s operation with a 9 V output swing (vs SP232EET-L/TR)
Design Notes
Route the RS-232 connector-side traces directly to the transceiver and keep them short and away from clocks, sensor inputs, and switching-converter nodes. Place the device-side supply bypass capacitor immediately between the supply and ground pins, and use a continuous ground path beneath the interface area. Because RS-232 is a bipolar voltage interface, connector ground must be referenced carefully to the equipment ground rather than floated independently.
Do not assume that every RS-232 transceiver is electrically interchangeable with the ADM235LJN. A valid drop-in design must preserve the 24-pin leaded footprint, pin functions, 5 V supply arrangement, 120 kB/s capability, shutdown behavior, and relevant receiver and driver connections. Before substituting a related MAX, SP, or ADM device, compare its power requirements and active levels; a matching package name alone does not establish compatibility.
Treat the cable-side interface as an electrostatic-discharge and surge entry point. Use appropriately rated protection components at the connector, maintain a short return path for surge current, and coordinate their capacitance so they do not degrade the 120 kB/s signal rate. For exposed or industrial cables, validate the completed assembly for conducted and radiated emissions rather than relying only on the transceiver datasheet limits.
The onboard DC-DC converters remove the external negative supply but still require a clean 5 V input and correct bypass-capacitor implementation. Follow the manufacturer’s recommended capacitor values and placement to preserve stable operation and acceptable output levels. Check the 5 V source tolerance, startup behavior, and simultaneous receiver load at the highest intended data rate before releasing the design for production.
Compliance Information
EIA-232-E and V.28 interface compliance is documented, but no RoHS, REACH, lead-free, halogen-free, or conflict-minerals status was identified for the exact ADM235LJN ordering code. Automotive qualification is treated as not applicable because the listed device is an industrial-temperature interface transceiver rather than an automotive-qualified variant.
