ADM238LAQ - 4/4 RS-232 Transceiver, 120 kB/s | Analog Devices
料号： ADM238LAQ ✓ 量产中ADM238LAQ 概述
An RS-232 transceiver is an interface integrated circuit that combines line drivers and line receivers for bidirectional or unidirectional serial communication. It belongs to the interface IC hierarchy, converting between low-voltage CMOS logic levels and the positive and negative voltage levels used by RS-232 links. The ADM238LAQ provides four driver channels and four receiver channels, allowing one package to support several data paths or to provide transmit-only and receive-only groups on the same board.
Key features include a single 5 V power supply, operation to 120 kB/s, integrated DC-DC converters, a 9 V output swing, and low-power shutdown with receivers remaining active. The receiver input withstands voltages up to 30 V according to the product information. A 1 uF charge-pump capacitor requirement and integrated conversion circuitry reduce the external component count compared with discrete RS-232 implementations. The 24-CDIP package is 0.300 inches wide, or 7.62 mm.
Technically, the device integrates four CMOS RS-232 drivers, four receivers, and the supporting charge-pump converters needed to generate bipolar output levels from one 5 V rail. This architecture suits equipment with multiple asynchronous serial ports, including test systems, industrial controllers, service interfaces, and data-logging equipment. Shutdown behavior is especially useful for systems where transmitters must stop driving while incoming data must still be monitored.
Typical applications include four-channel RS-232 instrument control, factory automation equipment with multiple serial links, legacy peripheral connections, and embedded control systems that retain an RS-232 interface. The 120 kB/s rate is substantially faster than the original 20 kB/s RS-232 target, although actual application throughput remains constrained by protocol overhead and cable characteristics.
A key design consideration is the ceramic DIP footprint: unlike a surface-mount alternative, it requires through-hole insertion and adequate spacing for assembly and service. Designers should preserve the pinout assigned to the 24-CDIP variant, validate signal levels at the connector, and confirm that the selected charge-pump capacitors meet the manufacturer's stability and temperature requirements.
This page consolidates the confirmed electrical characteristics, package information, interface use cases, and design considerations for engineers evaluating the ADM238LAQ as a four-channel RS-232 interface solution.
直接替换替代料： ADM238LAQ ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
该产品暂无直接替换替代料。
请求替代料ADM238LAQ 规格参数
| Product Type | RS-232 transceiver |
| Driver Channels | 4 channels |
| Receiver Channels | 4 channels |
| 电源电压 | 5 V |
| Maximum Data Rate | 120 kB/s |
| RS-232 Output Swing | 9 V |
| Receiver Input Voltage | 30 V |
| Charge-Pump Capacitor | 1 uF |
| Shutdown Feature | Low-power shutdown |
| Receivers During Shutdown | Active |
| DC-DC Converter | On-board |
| RS-232 Compliance | EIA-232-E and V.28 |
| 封装 | 24-CDIP, 0.300 in (7.62 mm) wide |
| 安装类型 | Through-hole |
ADM238LAQ 24-cdip, 0.300 in (7.62 mm) wide 引脚配置指南
ADM238LAQ（24-cdip, 0.300 in (7.62 mm) wide 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： ADM238LAQ.
请参阅 数据手册 以查看完整引脚配置。
典型应用
ADM238LAQ 适用于 6 应用s: Industrial Instrument Control, Data Acquisition Equipment, Factory Automation Controllers, Legacy Peripheral Interfaces, Point-of-Sale and Service Terminals, Communication and Networking Equipment.
Industrial Instrument Control
The ADM238LAQ suits industrial instruments that expose several legacy RS-232 control ports. Its four driver and four receiver channels consolidate as much as eight directional lines into one 24-CDIP device, while the single 5 V supply simplifies system power planning. The 120 kB/s maximum data rate accommodates typical command, response, and measurement-data transfers. The integrated on-board DC-DC converters generate the required bipolar RS-232 levels without separate voltage-conversion ICs. Designers should use the manufacturer pin table to assign each transceiver channel, validate connector polarity, and place the specified 1 uF charge-pump capacitors close to the device pins.
推荐
Data Acquisition Equipment
The ADM238LAQ can support multi-channel RS-232 links in laboratory and process data-acquisition systems. Four transmitter channels allow the controller to address multiple peripherals, while four receiver channels can collect status or measurement responses. Operation from one 5 V rail simplifies mixed-signal power architecture, and the 120 kB/s capability supports many short command-oriented protocols. Because long cables can experience noise and ground-offset problems, place the interface close to the connector and use a solid ground strategy. Keep charge-pump routing compact and verify that each connected legacy peripheral recognizes the device's 9 V output swing and shutdown behavior.
推荐
Factory Automation Controllers
The ADM238LAQ is appropriate for factory automation controllers that must connect to older serial equipment while retaining a single 5 V power rail. Four RS-232 drivers can initiate commands to several actuators or test stations, and four receivers can monitor their responses. The 24-CDIP package favors rugged, serviceable assemblies where through-hole soldering and connector accessibility are priorities. The interface's receiver input rating of 30 V adds margin for legacy equipment connections, but installers should still control cable transients and ground currents. Production designs should confirm the ordering code's temperature range and validate every port's idle, mark, and active voltage levels during system integration.
推荐
Legacy Peripheral Interfaces
The ADM238LAQ provides a practical bridge for embedded systems that must retain compatibility with legacy RS-232 peripherals. Four bidirectional channel groups can reduce the number of interface packages when several ports operate at similar speeds, and the 120 kB/s rate exceeds common low-speed control links. Its integrated DC-DC converters reduce the component count compared with a discrete charge-pump design. Software should confirm the peripheral's electrical standard, connector gender, and handshaking protocol before deployment. Do not assume that an RS-232 connector automatically defines logic polarity; test both driver output and receiver input at the system boundary.
推荐
Point-of-Sale and Service Terminals
The ADM238LAQ can support service terminals and older point-of-sale peripherals that use multiple RS-232 links. The four transmitters are useful for command outputs, while four receivers can support status devices or bidirectional peripherals. A single 5 V operating supply reduces power-tree complexity, and the 24-CDIP footprint provides generous lead spacing for equipment designed for manual service. The low-power shutdown function allows transmitters to stop driving while receivers remain active, helping avoid bus contention during controlled transitions. Firmware and hardware integration should verify that shutdown does not conflict with peripheral expectations and that each cable uses the correct signal and ground conductors.
推荐
Communication and Networking Equipment
The ADM238LAQ is useful in communication equipment that bridges modern control logic to legacy RS-232 peripherals. Four independently available driver and receiver channels support multiple equipment bays, diagnostic ports, or configuration interfaces without requiring separate single-channel transceivers. Its 120 kB/s capability is suitable for short-distance management protocols rather than high-rate networking, while the integrated DC-DC circuitry keeps the external support network small. In multiport systems, maintain consistent connector pinouts, isolate grounds where required, and prevent unused outputs from driving a shared bus. The receiver's ability to remain active during shutdown supports monitoring, but software must avoid expecting transmission while the shutdown state is active.
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推荐产品汇总
工程参考数据： ADM238LAQ ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 |
|---|---|
| Package | 24-CDIP, 0.300 in (7.62 mm) wide |
| Brand | Analog Devices |
| Driver Channels | 4 channels |
| Receiver Channels | 4 channels |
| Supply Voltage | 5 V |
| Maximum Data Rate | 120 kB/s |
| RS-232 Output Swing | 9 V |
| Charge-Pump Capacitor | 1 uF |
| Receiver Input Voltage | 30 V |
| Shutdown Behavior | Low-power shutdown with receivers active |
| RS-232 Compliance | EIA-232-E and V.28 |
关键差异点
- Four-channel interface consolidation （对比 MAX232NSR)
- Integrated single-rail voltage conversion （对比 MAX3232IPW)
- Through-hole serviceability （对比 ADM238LARZ-REEL)
设计说明
Route the 1 uF charge-pump capacitors using the shortest practical paths between the specified pins and their grounding or flying-capacitor connections. Keep the high-current switching loops compact, keep serial outputs away from sensitive analog nodes, and place the interface close to the RS-232 connector. This reduces radiated charge-pump noise and limits susceptibility to ESD or cable transients. Use the manufacturer data-sheet reference layout as the controlling guide.
Do not treat ADM238LAQ as a pin-compatible substitute for ADM238LARZ-REEL. The former uses a 24-CDIP footprint and the latter uses SOIC-24, so a board change is required. Likewise, a generic four-channel RS-232 transceiver is not automatically interchangeable: verify every pin, the power-down state, receiver behavior during shutdown, charge-pump capacitor value, and the 9 V output-swing requirement before approving a replacement.
RS-232 uses bipolar signaling, so confirm positive and negative output polarity at the connector and provide a common ground path between communicating equipment. Although the receiver input is rated up to 30 V, do not rely on that rating as a substitute for surge or ESD protection. Keep external protection close to the connector, and validate the complete interface with the longest intended cable because reflections and ground offsets can affect reliability more than nominal data rate.
合规信息
The EIA-232-E and V.28 interface compliance is identified in the manufacturer product information. No RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status is stated in the product information, so those fields remain unknown.
