PCA9546AD,118 - 4-Ch I2C Bus Switch Reset | NXP | SOIC-16
N.º da peça: PCA9546AD,118 ✗ Fim de vida| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $1.52 | $1,52 |
| 10 | $1.42 | $14,20 |
| 100 | $1.29 | $129,00 |
| 500 | $1.15 | $575,00 |
| 1.000 | $0.98 | $980,00 |
PCA9546AD,118 Visão geral
An I2C multiplexer (bus switch) is an interface IC that solves address-conflict and bus-capacitance problems in I2C systems. In the interface IC hierarchy (I2C switch -> bus multiplexer -> I2C controller peripheral -> interface IC), it sits between a master controller and multiple I2C slave buses, allowing the master to isolate or connect downstream segments on demand. Multiplexing also lets two devices sharing the same slave address coexist on separate channels.
Key features include four bidirectional translating switch channels, I2C and SMBus compatibility, three hardware address pins (A0, A1, A2) allowing up to eight PCA9546A devices on one bus, and an active-LOW RESET input that recovers the switch to the all-channels-deselected state if the bus hangs. On power-up all channels are deselected, guaranteeing a deterministic bus state. Low on-resistance pass-gate switches preserve signal integrity for standard-mode and fast-mode I2C traffic.
Architecturally, the PCA9546A uses a write-only control register addressed at one of eight I2C addresses set by the A0-A2 pins; the register byte directly maps bits D0-D3 to channels 0-3. Because the pass-gate switches are bidirectional and voltage-translating, upstream and downstream segments may run at different logic levels within the 2.3-5.5 V supply envelope. Maximum power dissipation is rated at 400 mW.
Typical applications include multiple sensor or EEPROM buses in industrial automation, camera and display module selection in consumer electronics, and isolating slow or fault-prone slave devices from a shared system management bus (SMBus/PMBus topologies).
Design consideration: place the RESET pin pull-up close to the device and use 1-10 kOhm pull-ups on SDA/SCL per bus segment; note that the control register is write-only and the RESET input is the only hardware recovery path.
This page synthesizes distributor pricing, drop-in alternatives, pinout detail, and practical design notes not consolidated in the manufacturer datasheet. Note: the NXP product page lists PCA9546AD as End of Life (EOL); plan second-source qualification accordingly.
Alternativas drop-in para PCA9546AD,118 — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com PCA9546AD,118 (mesmo formato e footprint) — diferindo em Address Pins, Function, Interface, Package, Reset Input.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
PCA9546AD
✅ Drop-In✓ Em estoque
$0.7 / unidade
Ver ficha técnica →TCA9546AD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
PCA9546AD,118 Classificações máximas e características elétricas
| Função | 4-channel bidirectional I2C/SMBus translating switch with reset |
| Interface | I2C, SMBus |
| Tensão de alimentação | 2.3 V to 5.5 V |
| Canais | 4 downstream SCL/SDA pairs |
| Address Pins | A0, A1, A2 (up to 8 devices per bus) |
| Reset Input | Active-LOW RESET |
| Power-on Default | All switch channels deselected |
| Control Register | Write-only, 1 byte, bits D0-D3 select channels |
| Maximum Power Dissipation | 400 mW |
| Encapsulamento | 16-SOIC (0.154 in, 3.90 mm width) |
| Tipo de montagem | Surface Mount |
| Packaging | Digi-Reel / Tape & Reel |
| Lead Free | Yes |
Configuração de pinos do PCA9546AD,118
| Pino 1 | A0 — Address input 0 |
| Pino 2 | A1 — Address input 1 |
| Pino 3 | A2 — Address input 2 |
| Pino 4 | GND — Ground (supply) |
| Pino 5 | RESET — Active-LOW reset input |
| Pino 6 | SC0 — Serial clock for downstream channel 0 |
| Pino 7 | SD0 — Serial data for downstream channel 0 |
| Pino 8 | SC1 — Serial clock for downstream channel 1 |
| Pino 9 | SD1 — Serial data for downstream channel 1 |
| Pino 10 | SC2 — Serial clock for downstream channel 2 |
| Pino 11 | SD2 — Serial data for downstream channel 2 |
| Pino 12 | SC3 — Serial clock for downstream channel 3 |
| Pino 13 | SD3 — Serial data for downstream channel 3 |
| Pino 14 | NC — Not connected (per datasheet) |
| Pino 15 | SDA — Upstream serial data |
| Pino 16 | VDD — Supply voltage, 2.3 V to 5.5 V |
Aplicações típicas
PCA9546AD,118 é adequado para 6 aplicaçãos: Industrial Sensor Bus Segmentation, Server and Hardware System Management (SMBus), Camera and Display Module Selection, Multi-EEPROM and Memory Board Configuration, Test and Measurement Instrumentation, Automotive Body and Gateway ECU Sub-buses.
Industrial Sensor Bus Segmentation
In factory automation and process-control systems, dozens of I2C sensors (temperature, pressure, humidity) frequently share identical slave addresses. The PCA9546AD,118 resolves this by letting a PLC or MCU master route the bus to one sensor bank at a time through its four SCx/SDx channel pairs. With three address pins supporting up to eight switches per bus, a single controller can address up to 32 isolated sensor segments. The 2.3 V to 5.5 V supply range matches common industrial 3.3 V and 5 V logic rails, and the active-LOW RESET allows a supervisor to restore a hung segment to the all-deselected safe state within one reset pulse. Place 4.7 kOhm pull-ups per segment and keep each downstream bus under its capacitance budget for reliable fast-mode operation.
Recomendado
Server and Hardware System Management (SMBus)
Server platforms use SMBus/PMBus trees to monitor power supplies, hot-swap controllers, EEPROMs and fan controllers. The PCA9546AD,118 isolates each managed device onto its own downstream pair, preventing a single hung slave from locking the entire management bus. Because SMBus timing is compatible with the PCA9546A switch topology, BMC masters can select channels by a single register write. The power-up all-deselected default guarantees a clean bus during hot-plug events, and the RESET input enables BMC-driven recovery without a board power cycle - a documented pattern in system-management reference designs. Low pass-gate on-resistance preserves SMBus rise-time compliance; keep segment pull-ups sized per the relevant SMBus specification to avoid excessive bus loading when channels are combined.
Recomendado
Camera and Display Module Selection
Consumer and surveillance products often carry two to four camera or display modules, each with an I2C configuration port (sensor registers, EEROM, focus drivers). Many modules use identical fixed slave addresses, making direct parallel connection impossible. The PCA9546AD,118 fans the master SCL/SDA pair out to four module ports, selecting exactly the module being configured or streamed. The 400 mW power dissipation rating and small 16-SOIC 3.90 mm footprint suit densely packed board layouts, and deselecting all channels at power-up prevents programming glitches during module hot-insertion. Because the switches are bidirectional, both register writes and interrupt/status reads pass cleanly. Route RESET to the SoC GPIO bank so a failed module can be quarantined without rebooting the host.
Recomendado
Multi-EEPROM and Memory Board Configuration
Backplane and carrier-card designs commonly host multiple serial EEPROMs or FRAMs for board identity, calibration and logging, often with the same fixed address. The PCA9546AD,118 partitions them into four separately addressable banks: the master writes one control-register byte to reach any EEPROM without address straps on the memories themselves, simplifying BOM and layout. With three address pins, up to eight PCA9546A devices coexist on the backplane management bus, scaling to 32 memory segments. The 2.3 V to 5.5 V supply supports both legacy 5 V and modern 3.3 V memory rails, and the write-only control register keeps software overhead to one I2C transaction per switch change. All-deselected power-up ensures no spurious writes during card insertion.
Recomendado
Test and Measurement Instrumentation
Bench instruments and automated test equipment (ATE) frequently must talk to several DUT I2C ports or calibration memories sequentially. The PCA9546AD,118 acts as a software-controlled multiplexer at the instrument's I2C master: each of the four downstream pairs connects to one DUT connector, and the test sequencer writes the control register to step through devices. The active-LOW RESET gives the test controller a deterministic abort path when a DUT stalls the bus, returning all channels to the deselected safe state and protecting other DUTs. The 16-SOIC package solders easily onto test-fixture adapter boards, and the wide 2.3 V to 5.5 V operating range accommodates mixed-voltage DUT rails without additional translation in most cases.
Recomendado
Automotive Body and Gateway ECU Sub-buses
Automotive gateway and body-control modules aggregate multiple I2C device clusters - window/seat controllers, ambient-light drivers, battery-monitor front ends - on a shared low-speed bus. The PCA9546AD,118 topology (4 channel pairs, addressable control register, hardware reset) matches this segmentation need, and its 2.3 V to 5.5 V range covers typical 3.3 V and 5 V ECU rails. The RESET input supports fault containment: if one cluster's transceiver fails and holds SDA low, the ECU resets the switch and continues polling healthy clusters. Note the NXP part is EOL and not AEC-Q100 listed here; for new automotive programs evaluate the TI PCA9546A/TCA9546A equivalents in the same SOIC-16 footprint, or TI automotive-grade switches such as TCA9546A-Q1 variants, and qualify per your OEM process.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para PCA9546AD,118 — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | PCA9546AD (TI) | TCA9546AD |
|---|---|---|---|
| Package | 16-SOIC (0.154 in, 3.90 mm) | 16-SOIC (0.154 in, 3.90 mm) - same | 16-SOIC (0.154 in, 3.90 mm) - same |
| Brand | NXP Semiconductors | Texas Instruments | Texas Instruments |
| Channels | 4 | 4 | 4 |
| Supply Voltage | 2.3 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V |
| Reset Input | Active-LOW RESET | Active-LOW RESET | Active-LOW RESET |
| Address Pins | 3 (up to 8 devices) | 3 (up to 8 devices) | 3 (up to 8 devices) |
| Lifecycle Status | EOL (NXP) | Active | Active |
Principais diferenciais
- Hardware reset pin for bus-hang recovery (vs TCA9546AD)
- Proven multi-vendor second source in identical footprint (vs PCA9546AD (TI))
- Active availability advantage (vs PCA9546AD (TI))
Notas de projeto
Place 1 kOhm to 10 kOhm pull-up resistors on SDA and SCL of each bus segment, sized against total bus capacitance to meet I2C rise-time limits (standard mode target rise time under 1000 ns, fast mode under 300 ns). Because the PCA9546A deselects all channels at power-up, the upstream pull-ups alone define the initial bus; downstream pull-ups only load the bus when that channel is enabled. The RESET pin needs a pull-up (typ. 10 kOhm) to VDD and should be driven from a GPIO or supervisor IC; never leave it floating.
The control register is write-only: reading back channel state is impossible, so software must track the active channel mask locally. Also, NXP has declared PCA9546AD End of Life - designs released today on this MPN face supply risk. Qualify the TI PCA9546A/TCA9546A SOIC-16 equivalents in parallel; they are pin-compatible. Finally, when connecting multiple channels simultaneously, the combined bus capacitance of all enabled segments counts against one I2C bus budget, which is easy to overlook in fan-out designs.
The device dissipates a maximum of 400 mW per specification data; in practice a passive pass-gate switch dissipates far less, so no thermal copper pour is required. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of pin 16, plus optional 4.7 uF bulk. Estimated: quiescent draw of the PCA9546A family is in the microamp-to-milliamp range, so supply design effort should focus on bus pull-up currents (each enabled SCL/SDA line sinks up to 3 mA at VOL = 0.4 V with 3 mA sink current capability), not IC power.
Informações de conformidade
Distributor specification data lists Lead Free for PCA9546AD,118. RoHS/REACH/halogen status not stated in the provided data - confirm on the NXP product page or PCN documentation.
