PCA9544AD - 4-Channel I2C Multiplexer with Interrupt | NXP
부품 번호: PCA9544AD ✗ 단종PCA9544AD 개요
An I2C-bus multiplexer, also called an I2C switch or channel selector, extends the practical reach of a shared two-wire bus by placing independently selectable devices behind one controller port. The PCA9544A belongs to the translating switch interface class, where the upstream SCL and SDA conductors fan out to four downstream conductors. Only the selected channel passes bus traffic, allowing several peripheral addresses to share one microcontroller or processor I2C port without simultaneous contention.
The PCA9544A family includes interrupt logic, allowing downstream devices to request attention without the host repeatedly polling every bus segment. Channel selection and interrupt behavior are handled through the I2C control interface. The verified device information identifies a 2.3 V to 5.5 V operating range, four downstream I2C channels, bidirectional translation, interrupt logic, and a maximum power dissipation of 400 mW for the documented PCA9544APW,112 comparison variant.
Typical uses include sensor aggregation, power-management controllers, EEPROMs, real-time-clock devices, and analog front ends that share one host I2C port. The multiplexer is particularly useful when one bus controller must reach four groups of peripherals, especially when the peripherals do not share a single usable address or require isolation to prevent unintended bus activity.
Because the NXP product page states that PCA9544AD is no longer manufactured, new production designs should confirm availability and lifecycle status before committing to the footprint. Existing boards can generally preserve the SO-20 land pattern when substituting a verified PCA9544A-family device with matching logic, supply voltage, channel configuration, interrupt polarity, and address-selection behavior. A footprint match alone is not sufficient for a safe replacement.
This page consolidates the verified manufacturer description, lifecycle status, distributor references, and documented PCA9544A-family alternatives into an engineering-focused view. It also distinguishes verified electrical facts from parameters that require confirmation against the NXP datasheet, preventing unsupported assumptions during redesign and end-of-life substitution work.
드롭인 대체품: PCA9544AD — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: PCA9544AD (동일 폼 팩터 및 풋프린트) — 차이점: Maximum Power Dissipation, Package.
PCA9544AD,112
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
PCA9544AD,118
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
PCA9544ABS
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
PCA9544ARGYR
✅ 드롭인가격 문의
데이터시트 보기 →PCA9544AD/T
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
PCA9544AD 사양
| Device Type | 4-channel I2C-bus multiplexer |
| Number of Downstream Channels | 4 channels |
| Upstream Bus Pairs | 1 SCL/SDA pair |
| Downstream Bus Pairs | 4 SCx/SDx pairs |
| Bus Interface | I2C-bus |
| Supported Protocol Family | I2C and SMBus-compatible |
| 동작 공급 전압 | 2.3 V to 5.5 V |
| Signal Direction | Bidirectional |
| Channel Selection | One channel selected at a time by programmable control register |
| Interrupt Function | Yes, interrupt logic |
| Maximum Power Dissipation | 400 mW for the documented PCA9544APW,112 comparison variant |
| 패키지 | 20-SO |
| 실장 유형 | Surface Mount |
| 수명 주기 상태 | No Longer Manufactured |
PCA9544AD 20-so 핀 구성 가이드
PCA9544AD(20-so 패키지)의 핀 구성입니다. 핀 번호, 기능, 연결 다이어그램은 제조사 데이터시트에 정의되어 있습니다. 정확한 풋프린트와 솔더링 지침은 해당 문서를 참조하십시오.
다음에 대한 상세 핀아웃 데이터 없음: PCA9544AD.
다음을 참조하십시오: 데이터시트 전체 핀 구성은 다음을 참조하십시오.
일반적인 애플리케이션
PCA9544AD 적합 용도: 6 애플리케이션s: Industrial Sensor Aggregation, Power-Management Controller Isolation, Real-Time Clock and EEPROM Expansion, Battery-Powered Sensor Node, Communication and Network Module Breakout, Consumer Peripheral Hub.
Industrial Sensor Aggregation
The PCA9544AD fits industrial sensor-hub designs that must connect more peripheral groups than the available I2C address space permits. Its one upstream SCL/SDA pair fans out to four downstream SCx/SDx pairs, and the programmable control register activates only one channel at a time. This prevents devices on separate segments from responding simultaneously while the host polls sensors. Interrupt logic can reduce polling traffic when a downstream device has new data. Because the part operates from 2.3 V to 5.5 V, it can support both 3.3 V and 5 V peripherals, subject to each device's voltage and pull-up requirements. The key design check is bus rise time after switching: channel capacitance, pull-up strength, wiring length, and the selected pull-up values must preserve the required I2C timing.
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Power-Management Controller Isolation
The PCA9544AD is useful when a system includes several power-management ICs, load switches, voltage monitors, or configuration controllers that would otherwise share one host I2C port. Four selectable downstream pairs let the processor isolate groups of devices and avoid unintended transactions between similarly addressed parts. The bidirectional translating switch supports mixed bus levels within the documented 2.3 V to 5.5 V range, although each rail still needs appropriate pull-ups and a verified logic-level relationship. Interrupt logic can report a downstream request through the common interrupt path. When choosing the mux, account for the no-longer-manufactured status of PCA9544AD and qualify a current-order-code alternative before new production release.
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Real-Time Clock and EEPROM Expansion
A single I2C host port can reach four separate real-time-clock or EEPROM groups through the PCA9544AD when address conflicts or address-space exhaustion make a direct connection impractical. The controller selects a downstream channel, performs the transfer, and then switches to another segment as required. This arrangement is particularly helpful where independent subsystems each reserve a familiar address range. Because only one downstream channel is active at a time, the host can avoid simultaneous acknowledgment conflicts without manually switching FETs or writing complex arbitration code. Validate the complete datasheet timing values and confirm channel-switch behavior, pull-up placement, and any required reset or power-up delay before applying the part to high-reliability storage systems.
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Battery-Powered Sensor Node
The PCA9544AD can organize four low-power sensor channels in a compact battery-operated node while giving the host a single I2C connection point. Its 2.3 V minimum supply supports lower-voltage operation, and the 20-pin SO package is suitable for space-constrained boards. The multiplexer helps the host access devices with identical or conflicting addresses on separate segments. Standby current should be checked against the complete system power budget because the supplied excerpts do not quantify PCA9544A quiescent current, and external pull-ups can dominate consumption even when the mux is idle. For low-duty-cycle sensing, the host can deselect channels between measurements, but engineers should verify that downstream devices do not require continuous clocking or an always-present bus connection.
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Communication and Network Module Breakout
Network, communication, and data-acquisition modules often expose multiple internal I2C buses with repeated device addresses. The PCA9544AD provides four downstream channel pairs that can place those buses on separate segments behind one host controller. This improves routing flexibility and reduces software address remapping. The interrupt output provides a shared notification path for downstream modules requesting service. In designs where modules operate at different logic voltages, the translating switch function and the device's documented 2.3 V to 5.5 V range must be checked against the complete system voltage plan, including pull-up placement on each bus segment. Signal-integrity verification should include cable or connector capacitance, channel switching transients, and the maximum clock rate permitted by the selected PCA9544A variant.
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Consumer Peripheral Hub
The PCA9544AD can divide consumer peripherals such as touch controllers, audio codecs, configuration devices, and display helpers across four I2C segments. A host processor then reaches the peripherals through one upstream pair while selecting the required channel in firmware. The interrupt logic helps the controller respond to device-generated events without continuously polling every segment. This approach can simplify routing when several devices share similar addresses or when each peripheral group has a different local bus voltage. A practical design review must compare the PCA9544AD against a two-channel switch such as PCA9515AD or PCA9517DR to determine whether four channels are genuinely needed. If only two isolated segments are required, the lower-channel-count device may reduce board area, cost, and lifecycle risk.
추천
추천 제품 요약
엔지니어링 참조 데이터: PCA9544AD — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | PCA9544AD,112 | PCA9544AD,118 | PCA9544ABS | PCA9544ARGYR | PCA9544AD/T |
|---|---|---|---|---|---|---|
| Package | 20-SO | 20-SO | 20-SO | 20-SO | 20-SO | 20-SO |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Number of Downstream Channels | 4 channels | 4 channels | 4 channels | 4 channels | 4 channels | 4 channels |
| Bus Function | 1-of-4 bidirectional translating I2C multiplexer | 1-of-4 bidirectional translating I2C multiplexer | 1-of-4 bidirectional translating I2C multiplexer | 1-of-4 bidirectional translating I2C multiplexer | 1-of-4 bidirectional translating I2C multiplexer | 1-of-4 bidirectional translating I2C multiplexer |
| Mounting Type | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount |
주요 차별점
- Provides four downstream I2C segments rather than the two channels available from the listed site alternatives (vs PCA9515AD)
- Combines channel multiplexing with a shared interrupt notification path (vs PCA9517DR)
- Directly documented order-code variants simplify legacy maintenance without changing the core multiplexer architecture (vs PCA9544AD,118)
설계 노트
Do not use the documented 400 mW maximum power-dissipation figure as a design target. The supplied verification attributes that figure to the PCA9544APW,112 comparison variant rather than directly to PCA9544AD. Base the thermal budget on the exact replacement's datasheet current ratings, supply voltage, ambient temperature, and package thermal resistance. Because the PCA9544AD is no longer manufactured, verify the ordering code, temperature grade, and electrical limits before applying a family member to a new board.
Keep each upstream and downstream SCL/SDA route short, place pull-up resistors at the physical bus endpoints, and route the four downstream pairs away from noisy power converters. I2C rise time depends on the effective bus capacitance, pull-up resistance, and leakage from disabled channels, so changing the selected mux can alter timing on an existing PCB. Validate the worst-case combination of channel capacitance, cable length, connector capacitance, pull-up value, and maximum bus frequency before release.
A matching SO-20 footprint does not by itself prove a safe substitution. Verify upstream SCL/SDA pin mapping, the four SCx/SDx mappings, channel-select logic levels, address pins, reset behavior, interrupt polarity, and supply sequencing. The verified excerpts identify the channel count and interrupt function but do not reproduce complete pin tables. Obtain the manufacturer ordering information and compare every configuration-dependent function before releasing a substitution.
Account for bus rise time immediately after switching between downstream channels. Pull-ups should be sized for the highest intended clock frequency and the total capacitance of the selected segment, not merely the connector capacitance. Leave the unused downstream segments appropriately configured and confirm that the host never addresses more than one channel simultaneously. Where a downstream device supports hot-plug or repeated connect/disconnect operation, verify its requirements against the selected device's channel-switching characteristics.
규정 준수 정보
The verified excerpts mention RoHS and REACH only as comparison attributes and do not provide the actual compliance declarations. No compliance claim has been assumed. The PCA9544AD is an interface IC and is not presented as an AEC-Q100-qualified automotive device because the supplied data does not verify that qualification.
