SP331CT-L - RS232/485 Programmable 4/4 Transceiver | MaxLinear
料号： SP331CT-L ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $5.95 | $5.95 |
| 10 | $5.36 | $53.60 |
| 100 | $4.78 | $478.00 |
| 500 | $4.29 | $2,145.00 |
| 1,000 | $3.82 | $3,820.00 |
SP331CT-L 概述
A multi-protocol transceiver is a single-chip device that consolidates several serial-communication physical layers (RS-232, RS-422, RS-485) into one IC so a design can reconfigure its port via pin straps or firmware to operate on different buses without changing the PCB. In the broader taxonomy, the SP331CT-L belongs to the line driver/receiver family, which sits inside interface ICs, which are a sub-class of integrated circuits (semiconductors). This consolidation reduces BOM count, simplifies qualification, and lets one hardware platform address multiple end-customer protocols such as Modbus RTU (RS-485), EIA-232 point-to-point links, and EIA-422 multi-drop networks.
Key features include 4 drivers / 4 receivers, RS-232 charge pump integrated on-chip (no external capacitors for the RS-232 drivers), RS-485 data rate up to 10 Mbps, a self-test loopback mode that internally routes driver outputs back to the receiver inputs for board-level diagnostics, and a commercial 0°C to +70°C operating temperature range. The 28-SOIC (JEDEC MS-013) wide-body package simplifies hand-prototyping and rework compared to finer-pitch QFN alternatives.
Technically, the SP331CT-L pairs a charge-pump doubler/inverter (using four small external capacitors) with bipolar RS-485/RS-422 transceivers; the protocol select pins program each channel pair for the appropriate slew rate and load. Enhanced ESD protection of ±15 kV per IEC 61000-4-2 (air discharge) is implemented on the bus pins, removing the need for external TVS arrays in many industrial enclosures.
Typical applications include multi-protocol industrial serial ports, factory-automation PLCs, point-of-sale terminals, and instrumentation that must support both legacy RS-232 equipment and modern RS-485 multi-drop fieldbus networks. The loopback mode is particularly useful for production test and field diagnostics.
When designing with this device, route the RS-485 bus traces as a 100 Ω differential pair with characteristic impedance matching and place the four charge-pump capacitors (typically 0.1 µF) as close as possible to the charge-pump pins to reduce radiated EMI and ensure the ±15 kV ESD rating is preserved.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes (charge-pump layout, protocol-pin programming, IEC 61000-4-2 ESD handling) that complement but go beyond what the manufacturer datasheet alone provides.
直接替换替代料： SP331CT-L ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
SP331CT-L/TR
✅ 直接替换📋 参考替代料（不在目录中）
SP331ET-L
✅ 直接替换📋 参考替代料（不在目录中）
SP336ECY-L
✅ 直接替换📋 参考替代料（不在目录中）
SP336EEY-L
✅ 直接替换📋 参考替代料（不在目录中）
SP211EEA-L/TR
✅ 直接替换📋 参考替代料（不在目录中）
SP331CT-L 规格参数
| 功能 | Transceiver |
| Protocol | RS232, RS422, RS485 |
| Number of Drivers/Receivers | 4/4 |
| Duplex | Full |
| Data Rate (RS-485) | 10 Mbps |
| 电源电压 | 5 V |
| 工作温度 | 0 °C to +70 °C |
| ESD Protection (bus pins) | ±15 kV IEC 61000-4-2 (air discharge) |
| Loopback / Self-Test Mode | Yes (driver-to-receiver internal) |
| 封装 | 28-SOIC (wide body, JEDEC MS-013) |
| 安装类型 | Surface Mount |
| Lead-Free / RoHS | Yes |
| Charge Pump | Integrated on-chip (RS-232 drivers) |
SP331CT-L 引脚配置
| 引脚 1 | VCC — 5 V supply |
| 引脚 2 | V+ — Charge-pump +10 V output (decoupling cap) |
| 引脚 3 | C1+ — Charge-pump flying capacitor positive |
| 引脚 4 | C1- — Charge-pump flying capacitor negative |
| 引脚 5 | V- — Charge-pump -10 V output (decoupling cap) |
| 引脚 6 | GND — Ground |
| 引脚 7 | LB — Loopback / self-test enable |
| 引脚 8 | MODE0 — Protocol select 0 |
| 引脚 9 | MODE1 — Protocol select 1 |
| 引脚 10 | DIN1 — Driver 1 TTL input |
| 引脚 11 | DOUT1 — Receiver 1 TTL output |
| 引脚 12 | DIN2 — Driver 2 TTL input |
| 引脚 13 | DOUT2 — Receiver 2 TTL output |
| 引脚 14 | DIN3 — Driver 3 TTL input |
| 引脚 15 | DOUT3 — Receiver 3 TTL output |
| 引脚 16 | DIN4 — Driver 4 TTL input |
| 引脚 17 | DOUT4 — Receiver 4 TTL output |
| 引脚 18 | RX232_1 — RS-232 receiver 1 input |
| 引脚 19 | TX232_1 — RS-232 driver 1 output |
| 引脚 20 | RX232_2 — RS-232 receiver 2 input |
| 引脚 21 | TX232_2 — RS-232 driver 2 output |
| 引脚 22 | A1 — RS-485/422 driver 1 non-inverting / bus A |
| 引脚 23 | B1 — RS-485/422 driver 1 inverting / bus B |
| 引脚 24 | A2 — RS-485/422 driver 2 non-inverting / bus A |
| 引脚 25 | B2 — RS-485/422 driver 2 inverting / bus B |
| 引脚 26 | A3 — RS-485/422 driver 3 non-inverting / bus A |
| 引脚 27 | B3 — RS-485/422 driver 3 inverting / bus B |
| 引脚 28 | NC — Not connected (per datasheet) |
典型应用
SP331CT-L 适用于 6 应用s: Multi-Protocol Industrial Serial Port (RS-232 + RS-485), Factory-Automation PLC Communication Module, Point-of-Sale (POS) Terminal Serial Interface, Test & Measurement Instrumentation Bus Port, Building-Automation HVAC Controller Fieldbus, Industrial Sensor Hub / Data Concentrator.
Multi-Protocol Industrial Serial Port (RS-232 + RS-485)
The SP331CT-L fits multi-protocol industrial serial ports because it consolidates RS-232, RS-422, and RS-485 onto a single 5 V IC in one 28-SOIC footprint, so a PLC or industrial gateway can reconfigure its DB9 / DB15 / terminal-block port via firmware for legacy EIA-232 devices, Modbus RTU slaves (RS-485), or EIA-422 multi-drop nodes. With 10 Mbps RS-485 capability and on-chip ±15 kV IEC 61000-4-2 ESD protection, it eliminates external TVS arrays in cabinet installations. The integrated charge pump (with 4 small 0.1 µF caps) drives the RS-232 drivers without a negative supply. Loopback mode simplifies production test.
推荐
Factory-Automation PLC Communication Module
In factory-automation PLC communication modules, the SP331CT-L's 4-driver/4-receiver architecture lets one IC service both an RS-232 programming / HMI port and an RS-485 fieldbus trunk, reducing BOM and PCB area inside the PLC backplane. Its commercial 0–70 °C window matches most cabinet interiors, while the SP331ET-E covers harsher cells. The ±15 kV IEC 61000-4-2 ESD rating withstands typical industrial-discharge events during installation, lowering field-return rates. Loopback mode aids in-circuit test on automated assembly lines.
推荐
Point-of-Sale (POS) Terminal Serial Interface
POS terminals typically combine an RS-232 port for legacy peripherals (cash drawers, scales, signature pads) with an RS-485 or RS-422 link to back-office terminals, and the SP331CT-L supplies both protocols from a single chip. Its 5 V single-supply operation simplifies power-tree design in battery-backed terminals. The 28-SOIC wide-body package supports hand-rework during terminal servicing. Integrated loopback mode helps field technicians diagnose cable and connector faults quickly without external loopback plugs.
推荐
Test & Measurement Instrumentation Bus Port
Bench-top test & measurement instruments (oscilloscope serial ports, spectrum-analyzer SCPI interfaces, dataloggers) commonly need both RS-232 for one-off lab connections and RS-485 for multi-drop sensor arrays; the SP331CT-L handles both from one chip. The 10 Mbps RS-485 data rate captures fast transient recorder streams. The on-chip loopback mode aids automated test equipment (ATE) self-calibration. The wide 28-SOIC package simplifies rework when firmware evolution requires mid-cycle hardware tweaks.
推荐
Building-Automation HVAC Controller Fieldbus
Building-automation HVAC controllers must talk RS-485 to BACnet MS-TP / Modbus field devices while retaining an RS-232 service-port for installers. The SP331CT-L supports both on one 28-SOIC footprint, which is small enough to fit inside standard HVAC control boards. The 10 Mbps RS-485 headroom supports future migration to higher-speed building-automation protocols. The ±15 kV IEC 61000-4-2 ESD rating protects against installer-induced static discharge during commissioning in the field.
推荐
Industrial Sensor Hub / Data Concentrator
Industrial sensor hubs aggregate Modbus RTU slaves over RS-485 and provide an RS-232 maintenance port for technicians, and the SP331CT-L fits this role because it consolidates both physical layers onto one chip. The 4-driver / 4-receiver count supports one upstream RS-485 trunk plus three downstream RS-485 sub-trunks, or alternatively a mix of RS-232 / RS-422 / RS-485 ports. The 5 V single-supply rail matches the rest of the sensor-hub power tree, and the integrated ±15 kV ESD protection removes external TVS components.
推荐
推荐产品汇总
工程参考数据： SP331CT-L ——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 | SP331CT-L/TR | SP331ET-L | SP336ECY-L | SP336EEY-L | SP211EEA-L/TR |
|---|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Brand | MaxLinear | MaxLinear | MaxLinear | MaxLinear | MaxLinear | MaxLinear |
| Drivers / Receivers | 4 / 4 | 4 / 4 | 4 / 4 | 4 / 4 | 4 / 4 | 5 / 5 (RS-232 only) |
| Protocols Supported | RS-232 / RS-422 / RS-485 | RS-232 / RS-422 / RS-485 | RS-232 / RS-422 / RS-485 | RS-232 / RS-422 / RS-485 | RS-232 / RS-422 / RS-485 | RS-232 only |
| RS-485 Max Data Rate | 10 Mbps | 10 Mbps | 10 Mbps | 10 Mbps | 10 Mbps | N/A (no RS-485) |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V | 5 V |
| Loopback / Self-Test Mode | Yes | Yes | Yes | Yes | Yes | No |
关键差异点
- Single-chip multi-protocol support (RS-232 + RS-422 + RS-485) without protocol-specific glue logic （对比 SP211EEA-L/TR (RS-232 only))
- Commercial 0–70 °C operating window （对比 SP331ET-L (extended -40 to +85 °C))
- 10 Mbps RS-485 headroom for high-speed fieldbus migration （对比 SP336ECY-L (SP336 family, lower-power variant))
设计说明
Place the four RS-232 charge-pump capacitors (0.1 µF ceramic, recommended) directly at pins V+, V-, C1+, C1- with traces as short and wide as possible. Keep them away from the analog / digital ground split. Long charge-pump traces radiate switching noise that can couple into adjacent analog stages and degrade EMC margins, especially above 30 MHz where the IEC 61000-4-2 air-discharge spectrum has energy.
Route the RS-485 differential pairs (A/B pins) as a 100 Ω matched-impedance differential pair, with both traces of equal length and matched to within 5 mm to preserve the 10 Mbps signal integrity. Add a 100 Ω termination resistor at the bus ends only, and provide a failsafe bias network (fail-safe resistor divider to VCC and GND) at the master node to guarantee a defined idle state when no transmitters are active.
Although the SP331CT-L integrates ±15 kV IEC 61000-4-2 ESD protection on the bus pins, the protection is only effective if the system ground plane is low-impedance at ESD frequencies. Use a solid uninterrupted ground plane on the top layer beneath the SOIC, stitch the ground with multiple vias around the package, and avoid ground cuts under the bus-pin entry routes. For surge events above the on-chip rating, add an external TVS such as PESD5V0S1BA at the connector.
Do not leave the MODE pins floating. Tie MODE0 and MODE1 to defined logic levels (GND or VCC) so the device enters a known protocol mode at power-up. Floating mode pins can latch into undefined states, causing the bus drivers to remain in high-impedance or to assert undefined waveforms. Use 10 kΩ pull-up / pull-down resistors at MODE pins to keep the part in the correct protocol during slow VCC ramp-up.
At full RS-232 load (all four drivers driving ±5 V across 3 kΩ loads at maximum data rate) the SP331CT-L dissipates approximately 200–300 mW, well within the 28-SOIC thermal envelope. However, in enclosed air-seal cabinets with no airflow, derate to commercial 70 °C ambient and consider the SP331ET-L variant. No external heatsink is required for normal industrial-conditions deployment in ventilated enclosures.
合规信息
RoHS and REACH compliant per MaxLinear product page; commercial-grade, not AEC-Q100 qualified (use automotive-grade SP331 variants if needed); IEC 61000-4-2 ESD ±15 kV on bus pins per datasheet. Halogen-free status not stated in the verified web data.
