PCA9534ADW - 8-Bit I2C I/O Expander | Texas Instruments
부품 번호: PCA9534ADW ✓ 활성PCA9534ADW 개요
An I2C I/O expander is a peripheral integrated circuit that extends the number of digital input and output lines available to a system without increasing the host controller pin count. The PCA9534A belongs to the I/O expander, interface IC, and power-management-support semiconductor hierarchy. It is useful in compact embedded products where connectors, indicators, sensors, relays, or control signals exceed the native GPIO capacity of the controller.
Key features include programmable configuration registers, an interrupt output for change detection, three hardware address inputs that allow multiple devices to share one bus, and support for both I2C and SMBus operation. The manufacturer identifies a maximum bus frequency of 400 kHz for the PCA9534ADW. Its low-power design is suited to battery-powered and industrial embedded systems, while the open-drain interrupt output supports wired-OR signaling across multiple expanders.
The PCA9534A uses an 8-bit parallel I/O architecture with separate input and output register organization in the device family. Each port bit can be configured for input or output, allowing a design to mix sensed inputs and driven outputs. The hardware address pins allow up to eight devices to coexist on the same two-wire bus, which simplifies distributed I/O expansion in larger control systems.
Typical applications include reading push buttons, controlling LEDs, monitoring digital sensors, driving discrete logic, interfacing external connector banks, and expanding control lines in industrial controllers, test equipment, appliances, and consumer electronics. The PCA9534ADW is particularly suitable when a controller has limited GPIO pins but already supports I2C.
Designers should verify the I2C pull-up resistor network, ensure the total bus capacitance remains within device limits, and define how interrupt inputs are handled. External devices driving a port pin should be checked against the configured input/output direction. Firmware must also account for the PCA9534A register differences from older parallel-port expanders rather than assuming transparent software compatibility.
This product page combines the exact ordering information, package details, functional limits, drop-in alternatives, and application-oriented design guidance for engineers evaluating the PCA9534ADW. It supports faster component selection while keeping the critical distinction between electrical compatibility and complete software compatibility explicit.
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대체품 요청PCA9534ADW 사양
| Device Type | 8-bit I2C/SMBus I/O expander |
| Number of I/O Lines | 8 lines |
| Supply Voltage Range | 2.3 V to 5.5 V |
| I2C Bus Frequency | 400 kHz maximum |
| Supported Bus | I2C and SMBus |
| 동작 온도 범위 | -40 °C to 85 °C |
| Package Type | 16-pin SOIC |
| Package Width | 7.50 mm |
| Package Length | 0.295 inch |
| Low Standby Current | 1 µA maximum |
| Interrupt Output | Open-drain active-low |
| Address Configuration | 3 hardware address pins |
| Maximum Devices per Bus | 8 devices |
| Configuration Registers | 8-bit configurable port registers |
PCA9534ADW 핀 구성
| 핀 1 | A0 — Hardware address input A0 |
| 핀 2 | A1 — Hardware address input A1 |
| 핀 3 | A2 — Hardware address input A2 |
| 핀 4 | VSS — Ground connection |
| 핀 5 | P0 — Configurable I/O port 0 |
| 핀 6 | P1 — Configurable I/O port 1 |
| 핀 7 | P2 — Configurable I/O port 2 |
| 핀 8 | P3 — Configurable I/O port 3 |
| 핀 9 | VDD — Positive supply connection |
| 핀 10 | P4 — Configurable I/O port 4 |
| 핀 11 | P5 — Configurable I/O port 5 |
| 핀 12 | P6 — Configurable I/O port 6 |
| 핀 13 | P7 — Configurable I/O port 7 |
| 핀 14 | INT — Active-low open-drain interrupt output |
| 핀 15 | SCL — Serial clock input |
| 핀 16 | SDA — Serial data input and output |
일반적인 애플리케이션
PCA9534ADW 적합 용도: 6 애플리케이션s: Microcontroller GPIO Expansion, Industrial Control Panels, LED and Indicator Control, Digital Sensor and Input Aggregation, Test and Measurement Equipment, Appliance and Embedded Control.
Microcontroller GPIO Expansion
The PCA9534ADW is suitable when a microcontroller or processor has exhausted its native general-purpose I/O pins but retains an I2C interface. The eight P0-P7 ports can be configured individually as inputs or outputs, allowing buttons, status indicators, and discrete control signals to share one two-wire bus. Its 2.3 V to 5.5 V operating range supports both 3.3 V and 5 V systems. Compared with adding another dedicated digital interface, the PCA9534ADW provides eight lines with limited additional firmware overhead. The host must assign directions, initialize registers, and monitor the active-low interrupt when input changes matter.
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Industrial Control Panels
Industrial control panels often need more input and output lines than the controller can provide directly. The PCA9534ADW can monitor limit switches, selector positions, and panel status while driving relays or logic gates through suitable interface circuits. The three address inputs permit as many as eight expanders on one bus when each uses a different address, reducing wiring complexity. The 400 kHz maximum bus rate supports routine panel polling, while the open-drain active-low interrupt lets the controller respond to selected input transitions. Industrial designs should add appropriate isolation, surge protection, and isolation barriers where the external wiring leaves the control board.
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LED and Indicator Control
The PCA9534ADW can provide compact control of multiple LEDs, status indicators, or relay-driver enable lines where direct host GPIO pins are limited. Each P0-P7 line has a configurable direction, and the host can update output registers over I2C rather than driving eight dedicated pins. Because the device itself targets digital port expansion rather than constant-current LED regulation, the application should use appropriate series resistors or dedicated constant-current drivers. The 2.3 V to 5.5 V supply range makes the expander adaptable to common embedded logic levels, while the interrupt output can support event-driven status reporting.
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Digital Sensor and Input Aggregation
The PCA9534ADW can aggregate multiple digital sensor outputs, door or presence switches, limit switches, and interlock signals into a common remote I/O bank. Inputs can be monitored through the interrupt output rather than requiring continuous polling of every bit, helping the controller use its processing time more efficiently. The device supports a 400 kHz I2C bus, while the three hardware address inputs allow multiple distributed input banks to share a controller. System designers should configure unused pins appropriately, account for logic-level compatibility, and ensure external signals cannot exceed the device's rated voltage and injection limits.
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Test and Measurement Equipment
In test and measurement products, the PCA9534ADW can expand control and sense points for front-panel buttons, fixture selects, relay controls, and status lamps. The host controller can use the interrupt output to react to operator actions or fixture changes while using the I2C bus for configuration. Its compact 16-pin SOIC package supports dense instrument boards, and its 1 µA maximum standby current is useful in portable instruments. Measurement engineers should keep sensitive analog paths separate from the digital expander and use separate routing or grounding techniques to prevent switching and relay transients from coupling into precision measurement circuitry.
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Appliance and Embedded Control
The PCA9534ADW fits appliances and embedded controllers that need a bank of simple digital interfaces for door switches, program selectors, display enables, heaters, and auxiliary indicators. Using I2C expansion preserves host-controller pins for timing, communications, and safety-related interfaces. The broad 2.3 V to 5.5 V supply range supports mixed-voltage logic systems, although every connected signal must meet the PCA9534ADW electrical limits. The active-low interrupt output supports responsive event handling, while the open-drain architecture allows compatible interrupt sharing. Production firmware should include startup defaults and diagnostic checks for stuck or unexpected port states.
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추천 제품 요약
엔지니어링 참조 데이터: PCA9534ADW — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | PCA9534PWR | PCA9534DBR |
|---|---|---|---|
| Package | SOIC-16 | TSSOP-16 | VSSOP-16 |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| I/O Count | 8 bits | 8 bits | 8 bits |
| Interface | I2C/SMBus | I2C/SMBus | I2C/SMBus |
| Supply Voltage | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V |
| Maximum Bus Frequency | 400 kHz | 400 kHz | 400 kHz |
| Interrupt Output | Open-drain active-low | Open-drain active-low | Open-drain active-low |
| Low Standby Current | 1 µA maximum | 1 µA maximum | 1 µA maximum |
| Operating Temperature | -40 °C to 85 °C | -40 °C to 85 °C | -40 °C to 85 °C |
주요 차별점
- Eight configurable lines in a standard 16-pin SOIC (vs PCA9534PWR)
- Broad 2.3 V to 5.5 V operating range (vs PCA9534DBR)
- Address expansion and event notification (vs PCA9534DBR)
설계 노트
Route SDA and SCL as a compact, continuous pair away from switching nodes and high-current relay traces. Place the bus pull-up resistors near the bus master when practical, use the smallest practical loop area, and avoid routing the pair across a split power-plane boundary. Validate the complete topology with an oscilloscope because rise time and capacitance determine whether the 400 kHz operating limit is met.
Do not treat the PCF8574A hardware compatibility as transparent firmware compatibility. The PCA9534A uses enhanced configuration and interrupt behavior, so a PCF8574A driver generally cannot be reused without review. During migration, verify reset states, port direction defaults, interrupt polarity, address selection, and any bus timeout or repeated-start behavior used by the host controller.
Decouple the 2.3 V to 5.5 V supply with local high-frequency and bulk capacitance placed close to VDD and VSS. Keep the digital return path short and use a quiet ground reference, especially when the I/O pins drive external loads. The PCA9534ADW can support multiple standard-logic loads, but output-current, voltage, and injected-current limits must be checked against the complete application before external signals are connected.
Configure every unused port pin in a defined state before enabling external circuitry. Because the P0-P7 pins can be inputs or outputs, an incorrect direction can cause contention when an external circuit drives the same node. Review the reset configuration, validate the written register value, and add a firmware diagnostic that reads back the direction and output registers during initialization.
규정 준수 정보
The verified product information does not state RoHS, REACH, lead-free, halogen-free, or conflict-minerals status. AEC-Q100 qualification is not applicable to the standard industrial-temperature PCA9534ADW ordering option.