PI7C9X7954BFDE - PCIe Quad UART Bridge 128-LQFP | Diodes Inc
MPN： PI7C9X7954BFDE ✓ 啟用中PI7C9X7954BFDE 概覽
A PCIe-to-UART bridge is a serial interface controller that converts a PCI Express bus transaction into legacy-style asynchronous serial communication. In the system hierarchy, it sits between the interface controller family and the broader categories of communication ICs and bridge ICs, allowing modern PCIe-only CPU platforms to retain multi-channel RS-232/RS-485 serial ports without a legacy PCI bus.
Key features include four independent UART channels, 128-byte transmit and receive FIFOs per channel for reduced CPU interrupt overhead, a PCI Express x1 upstream interface, and dual 1.8V core / 3.3V I/O operation. The lead-free (Pb-free) construction and reduced 14x14 mm package size address modern system requirements for high performance and compact PCB footprints.
Architecturally, the device bridges PCIe configuration and memory-mapped transactions to the internal UART register set, maintaining 16550 register compatibility so standard OS serial drivers can operate the ports. The deep FIFOs decouple bursty processor access from slower serial line rates, improving throughput in multi-port systems.
Typical applications include remote access servers, industrial automation and process control, instrumentation, point-of-sale (POS) terminals, ATMs, and multi-port RS-232 cards.
Design consideration: verify the PCIe reference clock and reset sequencing against the manufacturer datasheet, and provide adequate decoupling on both 1.8V and 3.3V rails.
This page synthesizes distributor pricing context, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替換替代品，適用於 PI7C9X7954BFDE — 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： PI7C9X7954BFDE （相同外形與佔位） — 差異在於 UART Compatibility, Function.
PI7C9X7954AFDE
✅ 直接替換📋 參考替代品（不在目錄中）
PI7C9X7954BFZE
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
PI7C9X7954BFDE 最大額定值與電氣特性
| 功能 | PCI Express to Quad UART I/O Bridge |
| UART Channels | 4 |
| FIFO Size | 128 byte per UART channel |
| Upstream Interface | PCI Express x1 |
| Supply Voltage (Core) | 1.8 V |
| Supply Voltage (I/O) | 3.3 V |
| 封裝 | 128-LQFP (14x14 mm) |
| 安裝類型 | Surface Mount |
| UART Compatibility | 16550-compatible register set |
| Lead-Free (Pb-Free) | Yes |
| RoHS 狀態 | Compliant |
| Typical Applications | Remote Access Servers, Automation, Process Control, Instrumentation, POS, ATM, Multi-port RS-232 |
PI7C9X7954BFDE 128-lqfp (14x14 mm) 腳位配置指南
PI7C9X7954BFDE（128-lqfp (14x14 mm) 封裝）的腳位配置。 此功率元件具有閘極、汲極與源極端子。對於非極性封裝，請參閱製造商資料表以取得確切的第 1 腳方向與佈局詳細資訊。常見應用包括電源設計、馬達驅動與負載切換。
無詳細腳位定義資料： PI7C9X7954BFDE.
請參閱 資料表 以查看完整腳位配置。
典型應用
PI7C9X7954BFDE 適用於 6 應用s: Remote Access Servers, Industrial Automation and Process Control, Point-of-Sale (POS) Terminals, ATM and Financial Kiosks, Instrumentation and Test Equipment, Multi-port RS-232 Add-in Cards.
Remote Access Servers
Remote access servers concentrate dozens of dial-up, console, and management serial lines behind one host. The PI7C9X7954BFDE fits this role because its PCIe x1 upstream link attaches directly to modern server chipsets that no longer offer legacy PCI or ISA buses, while its four 16550-compatible UARTs with 128-byte FIFOs sustain buffered line rates without flooding the CPU with interrupts. Each channel is driver-compatible with standard operating system serial stacks, so console-management software works unchanged. Placed on a multi-port adapter card, one bridge serves four ports and multiple bridges can be cascaded across PCIe lanes, scaling port density. The main trade-off versus PCIe switch plus discrete UARTs is integration: fewer parts, smaller board area, but port count fixed at four per device.
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Industrial Automation and Process Control
Factory automation and process-control equipment still communicates with PLCs, drives, meters, and sensors over RS-232 and RS-485 serial links. The PI7C9X7954BFDE suits these systems because it bridges a PCI Express host (industrial PC or edge controller) to four legacy UART channels with 16550 register compatibility, letting existing control software run unmodified. The 128-byte FIFOs absorb burst transfers during polling cycles of multiple field devices, and the 3.3 V I/O rail interfaces cleanly to standard RS-485 transceivers. According to the manufacturer product description, automation and process control are explicitly listed target applications. Designers should verify the operating temperature range in the datasheet for cabinet environments and provide isolation between the UART lines and field wiring via the transceiver stage.
推薦
Point-of-Sale (POS) Terminals
Retail POS terminals connect receipt printers, barcode scanners, card readers, and cash drawers that frequently expose RS-232 serial interfaces. The PI7C9X7954BFDE fits because a single PCIe x1 link from the terminal's x86 or ARM host yields four independent COM ports, each with a 16550-compatible register set that standard POS application software addresses without custom drivers. The 128-byte FIFOs smooth bursty printer data streams, and the 14x14 mm 128-LQFP package keeps the adapter area small inside compact terminal enclosures. POS and ATM are named applications in the manufacturer product description. Design considerations include ESD protection on all externally accessible serial lines, since retail environments subject connectors to frequent human contact and cable swaps.
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ATM and Financial Kiosks
ATMs and financial kiosks interface to encrypting PIN pads, receipt printers, currency modules, and modems over serial ports managed by a modern PCIe host. The PI7C9X7954BFDE addresses this need directly: the manufacturer product description names ATM as a target application, and the bridge's 16550 compatibility preserves the legacy serial driver model that kiosk software stacks rely on. Four channels with 128-byte FIFOs handle concurrent peripheral traffic without host intervention between transactions. The dual 1.8 V core and 3.3 V I/O operation supports low-power standby states required by energy regulations for always-on kiosks. Hardware designers should implement the PCIe reset and clock sequencing exactly as specified in the datasheet and protect each external serial port with robust ESD and surge clamping for unattended public environments.
推薦
Instrumentation and Test Equipment
Bench and rack instrumentation frequently retains RS-232 command interfaces defined by legacy SCPI-style protocols. The PI7C9X7954BFDE lets an instrument's PCIe-based controller board drive four such serial devices - or expose four external ports - with guaranteed register-level compatibility, since the four UART channels implement the standard 16550 register set. The 128-byte FIFOs maintain data integrity during long ASCII transaction sequences at moderate baud rates, and the PCIe enumeration presents each port as a standard COM device to host software. Instrumentation is explicitly listed among the manufacturer's target applications. Because measurement timing can be sensitive, designers should validate the UART clock source tolerance specified in the datasheet and budget interrupt latency for simultaneous activity on all four channels in high-throughput test sequences.
推薦
Multi-port RS-232 Add-in Cards
The classic use case for this device is a PCI Express add-in card providing four RS-232 COM ports for servers, thin clients, and embedded PCs. The PI7C9X7954BFDE is purpose-built for this: PCIe x1 upstream, four 16550-compatible UARTs, 128-byte FIFOs per channel, and a 128-LQFP (14x14 mm) package that fits a half-height card layout with room for four line transceivers and DB-9 connectors. Multi-port RS-232 is a named application in the manufacturer product description. Compared to stacking two dual-UART USB bridges, a single bridge IC reduces BOM count and firmware complexity, and enumeration is deterministic at boot - important for port-name stability in server management software. Verify the maximum UART baud rate and clock configuration options in the datasheet against your target line speeds.
推薦
推薦產品摘要
工程參考資料，適用於 PI7C9X7954BFDE — 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 | PI7C9X7954AFDE | PI7C9X7954BFZE |
|---|---|---|---|
| Package | 128-LQFP (14x14 mm) | 128-LQFP (14x14 mm) - same | 128-LQFP (14x14 mm) - same |
| Brand | Diodes Incorporated | Diodes Incorporated | Diodes Incorporated |
| UART Channels | 4 | 4 | 4 |
| FIFO Size per Channel | 128 byte | 128 byte | 128 byte |
| Upstream Interface | PCI Express x1 | PCI Express x1 | PCI Express x1 |
| Supply Voltages | 1.8 V / 3.3 V | 1.8 V / 3.3 V | 1.8 V / 3.3 V |
| UART Register Compatibility | 16550-compatible | 16550-compatible | 16550-compatible |
| Lead-Free / RoHS | Yes / Compliant | Yes / Compliant | Yes / Compliant |
主要差異化特點
- Integrated PCIe bridge + four UARTs in one package (對比PI7C9X7954AFDE)
- 128-byte FIFOs per channel (對比PI7C9X7954AFDE)
- Compact 14x14 mm 128-LQFP lead-free package (對比PI7C9X7954AFDE)
設計說明
The PI7C9X7954BFDE requires dual rails: 1.8 V for core logic and 3.3 V for I/O and the PCIe interface (per distributor listings). Place 100 nF ceramic decoupling capacitors at each supply pin pair plus bulk 10 uF per rail. Verify power-rail sequencing requirements in the manufacturer datasheet - violating core/I/O sequencing order can back-power the device through internal ESD structures and cause reliability issues. Estimated: total power dissipation is low for bridge devices of this class, but confirm the datasheet typical/max current figures for your clock configuration before finalizing the regulator budget.
The PCIe x1 differential pair (PETp/n, PERp/n) should follow standard PCIe layout rules: 100 ohm differential impedance, length matching within 5 mils between the pair, no stubs, and AC coupling capacitors (typically 75-100 nF, per PCIe CEM/base spec values - confirm exact values for your form factor) placed near the transmitter side. Keep the pair away from the UART switching lines to minimize crosstalk. Reference the manufacturer datasheet layout section for the reference clock input requirements, since incorrect clock levels are the most common cause of link-training failures with bridge ICs.
When substituting the same-family PI7C9X7954AFDE for the BFDE, verify the suffix code's silicon revision implications in the manufacturer documentation - revision errata can affect PCIe link training behavior or UART timing edge cases even on pin-compatible parts. Also confirm reset timing: PERST# must be asserted long enough relative to power-good and the 100 MHz reference clock, per the datasheet power-up sequence. Skipping this verification is the most frequent source of field failures when second-sourcing PCIe bridge silicon.
合規資訊
Manufacturer product description states the PI7C9X7954 is designed to meet latest system requirements of high performance and lead (Pb)-free construction. REACH, halogen-free, and conflict-minerals declarations were not found in the provided data.
