MAX211CAI+ - +5V RS-232 Transceiver, 4 Drivers/5 Receivers, SSOP-28
料号： MAX211CAI+ ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $9.34 | $9.34 |
| 10 | $8.2 | $82.00 |
| 100 | $6.95 | $695.00 |
| 500 | $5.85 | $2,925.00 |
| 1,000 | $5.3 | $5,300.00 |
MAX211CAI+ 概述
An RS-232 transceiver is an interface IC that converts logic-level UART signals (0/5V CMOS/TTL) to the bipolar ±5V to ±12V voltage levels required by the legacy EIA/TIA-232E serial communication standard. RS-232 transceivers sit between a microcontroller UART and an external DB9/DB25 connector, providing level shifting, inverting, and electrostatic discharge protection. In the broader component taxonomy, the MAX211CAI+ belongs to line transceivers -> interface ICs -> integrated circuits.
Key features include single +5V supply operation (no ±12V rails needed), 4 drivers + 5 receivers, integrated charge pump with four small 0.1µF capacitors, ±5V RS-232 output levels compliant with EIA/TIA-232E, and guaranteed data rate above 120 kbps. The 28-pin SSOP (Shrink Small Outline Package) occupies approximately 40% of the board area of an equivalent 28-pin SO package.
The MAX211CAI+ uses Maxim's proprietary charge-pump architecture with a flying capacitor and reservoir capacitors to generate the +10V and -10V rails needed for true RS-232-compliant signaling from a single +5V input. This eliminates the need for multiple system power rails and permits direct connection to any 5V microcontroller UART. The device is built on a BiCMOS process that combines bipolar drivers for robust ±5V output swing with CMOS logic for low power consumption.
Typical applications include point-of-sale terminals, industrial control serial ports, legacy PC serial ports, embedded debugging consoles, and any MCU-to-RS232 interface. The MAX211CAI+ is widely used in designs that need to retain compatibility with older RS-232 peripherals while running off a single 5V rail.
When designing with the MAX211CAI+, place the four 0.1µF charge-pump capacitors (C1+, C1-, C2+, C2-) as close to the IC pins as possible to minimize parasitic inductance. Use 10µF tantalum or ceramic bypass capacitors on VCC and V+ pins to suppress ripple from the charge-pump switching. For ESD protection on the RS-232 side, add an external TVS diode array rated for ±15kV HBM.
This page consolidates distributor pricing (DigiKey, Mouser, LCSC), drop-in alternatives, and practical PCB-layout notes for the MAX211CAI+ that the bare datasheet does not provide.
直接替换替代料： MAX211CAI+ ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： MAX211CAI+ （相同外形与封装尺寸） ——差异在于 Package, Product Type, Data Rate, Mounting Type, Interface Standard.
快速对比工具——选择替代料号进行并排对比：
MAX211CAI
✅ 直接替换📋 参考替代料（不在目录中）
MAX211ECAI
✅ 直接替换📋 参考替代料（不在目录中）
MAX211CAI-T
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MAX211CAI+G071
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MAX211CAI+ 规格参数
| Part Number | MAX211CAI+ |
| 功能 | RS-232 Transceiver (4 Drivers / 5 Receivers) |
| Supply Voltage (VCC) | 4.5 V to 5.5 V |
| RS-232 Driver Output Swing | ±5 V (EIA/TIA-232E compliant) |
| Number of Drivers | 4 |
| Number of Receivers | 5 |
| Maximum Data Rate | 120 kbps |
| External Charge-Pump Capacitors | 4 x 0.1 µF |
| Charge Pump Topology | Integrated, switches at ~250 kHz |
| Transmitter Logic Input Logic Levels | TTL/CMOS compatible |
| Receiver Output Logic Levels | TTL/CMOS compatible |
| 封装 | 28-pin SSOP (5.30 mm width) |
| 安装类型 | Surface Mount |
| 工作温度范围 | 0 °C to +70 °C |
| Lead-Free / RoHS | Lead Free / RoHS Compliant |
MAX211CAI+ 引脚配置
| 引脚 1 | T2OUT — TTL/CMOS input to RS-232 driver 2 output |
| 引脚 2 | T1OUT — TTL/CMOS input to RS-232 driver 1 output |
| 引脚 3 | R1IN — RS-232 receiver 1 input |
| 引脚 4 | R2IN — RS-232 receiver 2 input |
| 引脚 5 | R3IN — RS-232 receiver 3 input |
| 引脚 6 | R4IN — RS-232 receiver 4 input |
| 引脚 7 | R5IN — RS-232 receiver 5 input |
| 引脚 8 | T3OUT — TTL input to RS-232 driver 3 output |
| 引脚 9 | T4OUT — TTL input to RS-232 driver 4 output |
| 引脚 10 | GND — Ground |
| 引脚 11 | V+ — Charge-pump positive supply (typically +10V internally generated) |
| 引脚 12 | C2+ — Charge-pump flying capacitor 2 positive terminal |
| 引脚 13 | C2- — Charge-pump flying capacitor 2 negative terminal |
| 引脚 14 | V- — Charge-pump negative supply (typically -10V internally generated) |
| 引脚 15 | C1+ — Charge-pump flying capacitor 1 positive terminal |
| 引脚 16 | C1- — Charge-pump flying capacitor 1 negative terminal |
| 引脚 17 | VCC — +4.5V to +5.5V supply |
| 引脚 18 | T5IN — TTL/CMOS input to RS-232 driver 5 (not used; only 4 drivers wired) |
| 引脚 19 | T1IN — TTL/CMOS input to RS-232 driver 1 |
| 引脚 20 | T2IN — TTL/CMOS input to RS-232 driver 2 |
| 引脚 21 | T3IN — TTL/CMOS input to RS-232 driver 3 |
| 引脚 22 | T4IN — TTL/CMOS input to RS-232 driver 4 |
| 引脚 23 | R5OUT — Receiver 5 TTL/CMOS output |
| 引脚 24 | R4OUT — Receiver 4 TTL/CMOS output |
| 引脚 25 | R3OUT — Receiver 3 TTL/CMOS output |
| 引脚 26 | R2OUT — Receiver 2 TTL/CMOS output |
| 引脚 27 | R1OUT — Receiver 1 TTL/CMOS output |
| 引脚 28 | NC — Not connected (per datasheet pin map; reserved) |
典型应用
MAX211CAI+ 适用于 6 应用s: Legacy PC COM Port Interface, Industrial Control RS-232 Link, Point-of-Sale (POS) Terminal, Embedded Debug / Console Port, Modem / Dial-up Communication, Medical Instrument Serial Port.
Legacy PC COM Port Interface
The MAX211CAI+ is purpose-built for legacy PC serial port (DB9/DB25) interfaces where the host runs on a single +5V rail and needs to communicate with EIA/TIA-232E peripherals. Its 4 drivers and 5 receivers mirror the exact signal set of a traditional PC COM port (TX, RX, RTS, CTS plus optional RI/DCD/DSR/DTR), and the integrated +5V-only charge pump removes the need for the ±12V rails that historical desktop ATX power supplies once provided. With >120 kbps data rate support, the MAX211CAI+ covers every legacy baud rate up to and beyond 115200. Place the four 0.1µF charge-pump capacitors within 5 mm of the C1±/C2± pins for reliable level generation.
推荐
Industrial Control RS-232 Link
In factory automation cabinets where 24V supply rails are common but UART-to-RS232 bridges are needed, the MAX211CAI+ enables a small 5V DC-DC tap to drive a robust RS-232 link. The 0°C to +70°C commercial temp range covers most indoor control panels, while the wider MAX211ECAI variant serves outdoor or harsher enclosures. Five receivers allow simultaneous monitoring of multiple control lines (handshake plus a secondary alarm), while four drivers can independently control four downstream devices. Add a bidirectional TVS diode array (e.g., SP3010-04UTG) on the RS-232 connector side for ±15kV ESD/air-discharge protection.
推荐
Point-of-Sale (POS) Terminal
POS terminals need a reliable UART-to-RS232 link to talk to legacy peripherals (Pole Displays, Cash Drawers with serial trigger, Barcode Scanners, Receipt Printers) and the MAX211CAI+ is the canonical solution. The 4-driver / 5-receiver symmetry provides the 4-RX/4-TX handshake set plus one extra receiver for ring-Indicator (RI) or another status signal. The integrated +5V charge pump keeps the bill-of-materials small (only four 0.1µF caps) and the SSOP-28 footprint fits in slimline terminal enclosures. Pair with a Cortex-M0+ MCU such as an MK20DN32VFT5 for deterministic low-latency UART handshaking at 9600 to 115200 baud.
推荐
Embedded Debug / Console Port
Any embedded board needing a debug console UART exposed via a DB9 connector benefits from the MAX211CAI+ plus a +5V supply. Development boards often have a +3.3V UART and a separate +5V rail; a MAX211CAI+ powered from the +5V rail provides a true 5V-UART-to-RS232 bridge while the 3.3V MCU's UART sees 5V-logic inputs on its RX pin (which most modern MCUs tolerate). Four drivers can be used simultaneously for TX + RTS + DTR + user-defined GPIO (as 3.3V logic input passing through to RS232 levels). Use 0.1µF X7R ceramic capacitors for the charge pump to handle the wide temperature and voltage variations in development environments.
推荐
Modem / Dial-up Communication
Although dial-up modems are increasingly legacy, the MAX211CAI+ remains relevant for industrial telemetry, alarm panels, and remote-sensor networks that still leverage 56k V.90 modems over PSTN lines. The four drivers drive modem TX/TELCO/RESET/AA handshake lines to the modem module, while five receivers monitor incoming ring-indicator, carrier-detect, data-terminal-ready, and TX/RX. The 0.1µF external capacitors maintain the charge pump's ±5V swings at all PTT/PSTN line impedances. For longer-distance runs see the MAX211E variant with surge protection built in.
推荐
Medical Instrument Serial Port
Many medical instruments still expose RS-232 ports for service-mode diagnostics, calibration, or integration with hospital information systems (HIS). The MAX211CAI+ provides a small-footprint +5V-to-RS232 bridge with the reliability required by medical-grade hardware. Its low EMI (charge pump operates at ~250 kHz with very low dV/dt on the bipolar rails) suits noise-sensitive ECG, SpO2, and patient-monitoring equipment. The SSOP-28 package allows miniaturized integration into handheld patient monitors where every millimeter matters. Refer to IEC 60601-1 system-level isolation requirements — this device does NOT provide galvanic isolation by itself, but it can be paired with isolated DC-DC converters for compliance.
推荐
推荐产品汇总
工程参考数据： MAX211CAI+ ——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 | MAX211CAI | MAX211ECAI | MAX211CAI-T | MAX211CAI+G071 | MAX211IDB |
|---|---|---|---|---|---|---|
| Package | 28-SSOP (5.30 mm) | 28-SSOP (5.30 mm) | 28-SSOP (5.30 mm) | 28-SSOP (5.30 mm) | 28-SSOP (5.30 mm) | 16-SO narrow (NOT pin-compatible) |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Supply Voltage | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V |
| Operating Temperature | 0°C to +70°C | 0°C to +70°C | -40°C to +85°C | 0°C to +70°C | 0°C to +70°C | -40°C to +85°C (industrial) |
| Drivers / Receivers | 4 / 5 | 4 / 5 | 4 / 5 | 4 / 5 | 4 / 5 | 4 / 5 |
| External Capacitors | 4 x 0.1 µF | 4 x 0.1 µF | 4 x 0.1 µF | 4 x 0.1 µF | 4 x 0.1 µF | 4 x 0.1 µF |
| Max Data Rate | 120 kbps | 120 kbps | 120 kbps | 120 kbps | 120 kbps | 120 kbps |
| Lead-Free / RoHS | Yes (+) | No (lead-bearing, non-RoHS) | Yes (+) | Yes (+) | Yes (+) | Yes |
关键差异点
- +5V single-supply operation with integrated charge pump （对比 MAX211CWI (28-SOIC variant))
- Five receivers (4+1) for full RS-232 signal set （对比 ADM3202ARNZ (2/2))
- RoHS lead-free with '+' suffix qualifier （对比 MAX211CAI (no '+', lead-bearing))
设计说明
Place the four 0.1µF charge-pump capacitors (C1+, C1-, C2+, C2-) within 5 mm of their respective IC pins to minimize parasitic inductance that otherwise degrades the ±10V charge-pump output. Use X7R ceramic dielectrics (not Y5V) so capacitance holds over voltage and temperature. Add 10µF bulk capacitors on V+ and V- to suppress ripple on the bipolar supplies when driving heavier RS-232 loads (>3kΩ termination).
Keep the SSOP-28 GND pin on a solid ground plane. Route all four charge-pump node traces (V+, V-, C1+, C1-, C2+, C2-) on the same layer as the IC; avoid vias on these high-di/dt paths. Provide at least a 0.5mm guard trace between the charge-pump traces and the digital TTL inputs/outputs to prevent coupling of the ~250 kHz charge-pump switching into the UART logic lines.
Do NOT assume the receivers can be left floating — unused receiver inputs (R_IN) must be tied to GND through 5kΩ or to VCC through 5kΩ to avoid ~1mA supply increase. The driver outputs (T_OUT) can typically be left floating when unused, but check whether your downstream equipment terminates them. Tie the unused T5IN (pin 18) to GND or VCC if you are using only 4 drivers — the MAX211CAI+ has a 5th TTL input pin that goes nowhere.
合规信息
RoHS compliant and lead-free per the '+' suffix in MAX211CAI+. Not AEC-Q100 qualified (this is a commercial/industrial IC, not automotive-grade). REACH compliance per Maxim product declaration. Halogen-free status not explicitly listed in retrieved data.
