ADM232LAR - 5V 2/2 RS-232 Transceiver, 120kB/s | Analog Devices
MPN： ADM232LAR ✓ 啟用中ADM232LAR 概覽
An RS-232 transceiver is an interface IC that translates logic-level CMOS signals into the bipolar, +/- voltage signalling used by the RS-232 (EIA-232) standard. It sits between a UART or microcontroller and a physical cable. The wider ADM2xx family of line drivers and receivers was designed for EIA-232-E and V.28 communications interfaces, especially where +/-12 V supplies are not available, and the ADM232 in particular adds on-board DC-DC converters so no external charge-pump components or negative supply are needed.
Key features include a single 5 V power supply, on-board DC-DC converters with 9 V output swing capability, small 1 uF external capacitors, a low-power shutdown mode, 1 uA receiver operation while in shutdown, and receiver inputs tolerant to 30 V. The CMOS implementation keeps power consumption low compared with classic bipolar RS-232 transceivers.
Technically, the part uses an on-chip switched-capacitor DC-DC converter to generate the positive and negative rail voltages required for compliant RS-232 output levels, while the receiver stage is designed for high noise immunity and failsafe operation when the driver is disabled or the line is unconnected. The result is full RS-232 compliance from a single rail, which simplifies board layout and reduces the external component count to a small number of 1 uF capacitors.
Typical applications include industrial serial port adapters, instrumentation and test equipment, barcode and data-collection terminals, security and access-control panels, and general-purpose RS-232 links between a host UART and peripheral equipment where cable lengths and ground offsets require the +/- voltage swing of the RS-232 standard.
When designing around the ADM232LAR, place the 1 uF capacitors close to the charge-pump and driver pins, keep the RS-232 connector and cable routing separated from sensitive analog and clock traces to limit EMI, and account for the shutdown pin when the host needs to tri-state or power down the port. Because the receivers remain active in shutdown, the interface can still report line state while the driver current is minimized.
This page consolidates distributor listings, verified datasheet features, drop-in replacement options in the identical 16-SOIC footprint, and practical PCB and EMI design notes that are not assembled in one place in the original manufacturer documentation.
直接替換替代品，適用於 ADM232LAR — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： ADM232LAR （相同外形與佔位） — 差異在於 Package, Data Rate, Supply Voltage.
ADM232AARWZ
✅ 直接替換📋 參考替代品（不在目錄中）
ADM202EARWZ
✅ 直接替換📋 參考替代品（不在目錄中）
ADM232AARW
✅ 直接替換📋 參考替代品（不在目錄中）
MAX232ECDWR
✅ 直接替換📋 參考替代品（不在目錄中）
ADM232LAR 規格
| 供應電壓 | 5 V (single supply) |
| Transceiver Configuration | 2 drivers / 2 receivers (2/2) |
| 資料速率 | 120 kB/s |
| Interface Standard Compliance | EIA-232-E and V.28 |
| Output Swing | 9 V with 5 V supply |
| On-Board DC-DC Converters | Yes |
| Required External Capacitors | 1 uF |
| Shutdown | Low power shutdown mode |
| Receiver Supply Current in Shutdown | 1 uA (receivers active in shutdown) |
| Receiver Input Voltage Tolerance | 30 V |
| 封裝 | 16-lead SOIC (SOIC-16) |
| 腳位數 | 16 |
| 安裝類型 | Surface Mount |
| Technology | CMOS |
| Automotive Qualification (AEC-Q100) | not_applicable |
ADM232LAR 16-lead soic (soic-16) 腳位配置指南
ADM232LAR（16-lead soic (soic-16) 封裝）的腳位配置。 腳位編號、功能與連接圖定義於製造商資料手冊中。請參閱該手冊以取得確切的封裝尺寸與焊接指引。
無詳細腳位定義資料： ADM232LAR.
請參閱 資料表 以查看完整腳位配置。
典型應用
ADM232LAR 適用於 6 應用s: Industrial Serial Port Expansion, Instrumentation and Test Equipment Control, Data Collection and Barcode Terminals, Security and Access Control Panels, Medical and Diagnostic Equipment Interfaces, Point-of-Sale and Retail Equipment.
Industrial Serial Port Expansion
The ADM232LAR adds a standards-compliant RS-232 port to a modern controller that only exposes a CMOS UART. Running from a single 5 V rail with on-board DC-DC converters removes the need for a negative supply rail, while the 120 kB/s rate comfortably covers legacy printer, console and programming port protocols. The 30 V receiver input tolerance protects the port when field cabling is connected to equipment running at the full +/-15 V RS-232 swing. With only 1 uF external capacitors, the charge-pump area stays small enough for compact control boards, and the low-power shutdown mode lets the port idle between transactions to reduce system current.
推薦
Instrumentation and Test Equipment Control
Laboratory instruments and automated test fixtures are frequently controlled from a host PC over RS-232, and the ADM232LAR is a straightforward way to bridge a 3.3 V or 5 V UART to that legacy bus. The 9 V output swing from a 5 V supply guarantees compliant levels even with several metres of cable and meaningful ground offsets, and the CMOS receiver front end rejects noise that would disturb a bare UART input. Because the receivers stay active during shutdown, a fixture controller can still poll line state for a connected-but-idle instrument. Two drivers and two receivers allow a single package to handle both a command channel and a status channel.
推薦
Data Collection and Barcode Terminals
Barcode scanners, badge readers and point-of-sale terminals often expose an RS-232 port as their legacy connectivity option. The ADM232LAR fits these designs because the whole interface runs from the same 5 V rail that powers the scanner electronics, with no external negative supply, and its 1 uF charge-pump capacitors are small enough for a handheld enclosure. The 120 kB/s rate is far above the throughput needed for scanned barcode payloads, so latency is dominated by the host protocol rather than the transceiver. The shutdown pin supports battery-powered terminals that must cut port current between scans.
推薦
Security and Access Control Panels
Access-control readers, door controllers and intercom stations commonly expose RS-232 to a head-end panel. The ADM232LAR is well suited to these panels because the receiver input can withstand 30 V, giving margin against mis-wired or externally powered RS-232 sources in the field, and the low-power shutdown mode lets idle card readers drop port current. Two drivers and two receivers in one 16-SOIC package let a single controller chip drive both a panel-side reader bus and an upstream supervisory link, reducing board area in tightly packaged door hardware.
推薦
Medical and Diagnostic Equipment Interfaces
Diagnostic and monitoring equipment often needs to interoperate with older RS-232 analysers and service tools. The ADM232LAR provides a compliant, low-noise RS-232 port from a single 5 V rail, with a CMOS receiver that is less susceptible to noise coupling from adjacent analog and motor circuitry than a bare UART input. The 30 V receiver tolerance provides a useful margin against transient coupling from hospital mains-fed equipment sharing the cable route, while the shutdown mode allows a portable analyser to conserve power between tests.
推薦
Point-of-Sale and Retail Equipment
Retail scales, customer displays and magnetic-stripe readers still rely on RS-232 in many installations. The ADM232LAR suits these designs because the single 5 V supply matches the logic rails typically found in point-of-sale hardware, and the 1 uF charge-pump capacitors avoid the bulk electrolytics that would otherwise dominate a small peripheral enclosure. The 120 kB/s rate covers scale weighing and transaction bursts with headroom, and the shutdown control allows peripherals to drop port current when idle at the counter.
推薦
推薦產品摘要
工程參考資料，適用於 ADM232LAR — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | ADM232AARWZ | ADM202EARWZ | ADM232AARW | MAX232ECDWR | MAX232DR |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Maxim Integrated | Maxim Integrated |
| Package | 16-lead SOIC (SOIC-16) | 16-lead SOIC - same | 16-lead SOIC - same | 16-lead SOIC - same | 16-lead SOIC - same | 16-lead SOIC - same |
| Transceiver Configuration | 2/2 (2 drivers, 2 receivers) | 2/2 full RS-232 | 2/2 full RS-232 | 2/2 full RS-232 | 2/2 full RS-232 | 2/2 full RS-232 |
主要差異化特點
- Single 5 V rail with on-board DC-DC converters and 9 V output swing (對比MAX232DR)
- Receivers stay active in low-power shutdown at 1 uA (對比ADM202EARWZ)
- 30 V receiver input tolerance for field robustness (對比MAX232ECDWR)
- 120 kB/s rate covers legacy serial protocols without adding a separate transceiver (對比ADM232AARWZ)
設計說明
Place the 1 uF charge-pump capacitors as close as possible to the corresponding IC pins, keeping traces short and symmetrical to minimise loop area on the switching node. The ADM232LAR generates its internal negative rail with an on-board DC-DC converter, so a long capacitor loop adds radiated EMI and can degrade output swing at the connector. Keep the RS-232 driver traces away from sensitive analog inputs and from crystal or clock routing to prevent coupled noise from appearing on the line.
RS-232 drivers deliberately swing about 9 V from a 5 V rail to meet EIA-232-E levels, so fast edge rates on TX lines create unavoidable EMI. Use a shielded connector shell tied to chassis ground where available, keep the cable run away from clocks and switching regulators, and avoid long unshielded PCB stubs of TX nets. The 120 kB/s data rate of the ADM232LAR is well within the range where these precautions are practical, so there is no need to trade signal integrity for throughput.
Because the ADM232LAR runs from a single 5 V rail and includes on-board DC-DC converters, the supply must be sized for the converter in addition to the logic load. Place a local 0.1 uF ceramic bypass capacitor at the supply pin in addition to the specified 1 uF charge-pump capacitors, and verify the 5 V rail tolerance at the IC, since the available headroom determines how close the drivers can reach the 9 V output swing. Enabling the shutdown pin during idle periods reduces port current while keeping the receivers active for line-state detection.
Do not treat the RS-232 receive pins as ordinary logic inputs: the ADM232LAR receivers are rated to 30 V, but the rest of the system is not. Also avoid confusing the ADM232 with the ADM202 when substituting, since the ADM202EARWZ shares the 16-SOIC footprint and the 2/2 configuration but has a different internal supply architecture. Finally, do not assume the MAX232-family replacements use the same 1 uF capacitor value; always re-read the charge-pump section of the replacement datasheet before releasing the PCB.
合規資訊
The verified source data for ADM232LAR does not explicitly state RoHS, REACH, lead-free or halogen-free status; third-party comparison pages list RoHS/REACH fields for other ADM232 order codes but not for ADM232LAR itself, so all entries are left as unknown rather than assumed. The part is a commercial-grade RS-232 interface IC with no automotive qualification, so AEC-Q100 is not applicable.
