PCAL6524HEAZ - 24-bit I2C Fm+ I/O Expander | NXP | 0.8V Level Translation
Teilenummer: PCAL6524HEAZ ✓ Aktiv| Menge | Stückpreis | Gesamt |
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| 1 | $0 | $0,00 |
| 10 | $0 | $0,00 |
| 100 | $0 | $0,00 |
| 500 | $0 | $0,00 |
| 1.000 | $0 | $0,00 |
PCAL6524HEAZ Übersicht
An I/O expander (also called a GPIO expander or remote I/O port) is an interface IC that extends the number of general-purpose input/output pins of a microcontroller or SoC over a serial bus such as I2C or SMBus. It sits in the broader hierarchy of interface ICs within system logic, offloading GPIO shortages without consuming parallel bus pins, and this device adds bidirectional level translation between the host controller rail and the port-voltage rail.
Key features of the PCAL6524 include its 24 configurable quasi-bidirectional I/O pins, Fm+ (Fast-mode Plus) I2C operation at up to 1 MHz, and an ultra-low-voltage interface that connects directly to microcontrollers operating down to 0.8 V - critical for modern sub-1V SoC and FPGA banks. It also integrates an open-drain interrupt output and an active-low hardware reset pin, plus NXP's Agile I/O enhancements: programmable output drive strength, pull-up/pull-down selection, input latch, and maskable transition detection on individual pins.
Architecturally, the device contains two 12-bit or three 8-bit port register groups accessed through a register-map compatible with the industry-standard PCF/P CIA expander family, extended by configuration, pull-enable, pull-selection, input-latch and drive-strength registers. The level-translating front end isolates the VDD(I2C) bus rail from the VDD(P) port rail, allowing mixed-voltage systems such as a 1.2 V processor talking to 3.3 V sensors or actuators over one bus.
Typical applications include server and baseboard fan and LED control, QWERTY-style keypad and button matrices in mobile devices, industrial module status monitoring, and mixed-voltage sensor aggregation in consumer and communications equipment.
When designing, always connect the interrupt and reset pins appropriately: the RESET pin requires proper assertion during power-up to guarantee register default states, and Agile I/O transition-detection registers must be configured for pins that require edge monitoring.
This page synthesizes distributor availability data, the NXP product data sheet, drop-in alternative options, and practical design notes not consolidated in the manufacturer documentation.
Drop-in-Alternativen für PCAL6524HEAZ – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
PCAL6524HE
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
PCAL6524UEAZ
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
PCAL6524MPAZ
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
PCAL6524HEAZ Technische Daten
| Number of I/O | 24 |
| Schnittstelle | I2C-bus / SMBus (Fast-mode Plus, Fm+) |
| Maximum Bus Frequency | 1 MHz |
| Level Translation | Yes (ultra low-voltage, down to 0.8 V) |
| Interrupt Output | Yes (open-drain, with maskable transition detection) |
| Hardware Reset | Yes (active-low RESET pin) |
| Agile I/O Features | Programmable output drive strength, pull-up/pull-down selection, input latch |
| Gehäuse | 32-HUQFN (5x5 mm) |
| Montageart | Surface Mount |
PCAL6524HEAZ 32-huqfn (5x5 mm) Pinbelegungsleitfaden
Pinbelegung für PCAL6524HEAZ (32-huqfn (5x5 mm)-Gehäuse). Pin-Nummerierung, Funktionen und Anschlussdiagramme sind im Herstellerdatenblatt definiert. Entnehmen Sie diesem den genauen Footprint und Lötrichtlinien.
Keine detaillierten Pinbelegungsdaten verfügbar für PCAL6524HEAZ.
Siehe die Datenblatt für die vollständige Pin-Konfiguration.
Typische Anwendungen
PCAL6524HEAZ ist geeignet für 6 Anwendungs: Server and Baseboard Management Control, Sub-1V SoC GPIO Expansion in Mobile Devices, Mixed-Voltage Industrial I/O Modules, Keypad and Button Matrix Interfaces, Status LED and Indicator Control in Networking Equipment, Test and Measurement Instrument Front Panels.
Server and Baseboard Management Control
The PCAL6524HEAZ is well suited to server baseboard fan, LED, and hot-swap handle monitoring because its 24 GPIOs are driven from a single 1 MHz Fm+ I2C bus, freeing the BMC from parallel GPIO shortage. The maskable Agile I/O transition detection asserts the open-drain INT output on back-panel events, so the BMC does not need to poll status registers, reducing bus traffic in multi-node systems. The active-low RESET pin gives baseboard firmware a deterministic register reset during power sequencing, and the 32-pin HUQFN 5x5 mm footprint fits dense server boards where PCB area is at a premium.
Empfohlen
Sub-1V SoC GPIO Expansion in Mobile Devices
Modern application processors and modems run core rails at 0.8-1.2 V, below the threshold of conventional I2C devices. The PCAL6524's ultra-low-voltage interface connects directly to a microcontroller operating down to 0.8 V, eliminating external discrete level-shifter transistors on SDA/SCL. Its 24 quasi-bidirectional I/O handle keypad matrices, cover-display control, and LED indicators at a separate port rail. Agile I/O programmable drive strength allows weak drive on sensitive lines and strong drive on LED lines from the same device, and the input latch preserves transient button states between host reads - critical in battery-powered handsets where interrupt latency is unpredictable.
Empfohlen
Mixed-Voltage Industrial I/O Modules
Industrial control modules frequently mix a 1.8-3.3 V logic domain with 5 V sensor and actuator lines. The PCAL6524's dual-rail level-translating architecture bridges these domains in one IC: VDD(I2C) matches the host bus rail while VDD(P) powers the port side at the field level. Selectable pull-up/pull-down per pin simplifies interfacing with dry-contact and open-collector sensors, and maskable transition detection flags input changes through the INT pin without polling. In PLC I/O cards, the 24-bit width lets a single expander cover a full 24-point digital input bank, cutting component count and bus addresses compared to three 8-bit expanders.
Empfohlen
Keypad and Button Matrix Interfaces
For keypad and button-panel designs, the PCAL6524HEAZ combines 24 configurable I/O with its Agile I/O input latch and maskable transition detection. Short key presses that would otherwise be missed between host register reads are captured by the input latch, and the open-drain INT output immediately signals the host that a key event occurred - enabling low-power designs where the host sleeps until interrupted. Programmable pull-ups eliminate external resistors for a direct switch matrix, and the active-low RESET guarantees a known key-state register condition after brown-out events, improving reliability in consumer appliance and point-of-sale keypads.
Empfohlen
Status LED and Indicator Control in Networking Equipment
Routers, switches, and optical modules need dozens of status LEDs driven from a management controller with limited GPIO. A single PCAL6524 provides 24 output channels over a 1 MHz Fm+ I2C bus, and the programmable output drive strength lets designers tune LED brightness per pin without series-resistor redesign across LED bin variations. The level-translating interface allows the management MCU (often 1.0-1.8 V) to share the bus with 3.3 V peripheral devices, and multiple expanders coexist on one bus via address pins. The HUQFN32 5x5 mm package suits the dense front-panel PCBs typical of networking faceplate designs.
Empfohlen
Test and Measurement Instrument Front Panels
Bench instruments and modular measurement systems use the PCAL6524HEAZ for front-panel switch sensing, range-indicator LED drive, and interlock monitoring. The interrupt-driven transition detection means the instrument CPU only services the expander when a user presses a button or an interlock changes - no periodic polling of 24 channels over I2C. The input latch guarantees that even brief switch closures are retained until read, and the hardware RESET pin supports the deterministic initialization that safety-related interlock logic requires. Its level translation also lets a 1.2 V FPGA-adjacent controller manage 3.3 V panel hardware over a common bus.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für PCAL6524HEAZ – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | PCAL6524HE | PCAL6524UEAZ | PCAL6524MPAZ |
|---|---|---|---|---|
| Package | 32-HUQFN (5x5 mm) | 32-HUQFN (5x5 mm) - same | 32-HUQFN (5x5 mm) - same family package | 32-HUQFN (5x5 mm) - same family package |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Number of I/O | 24 | 24 | 24 | 24 |
| Bus Interface / Speed | I2C Fm+ / SMBus, 1 MHz | I2C Fm+ / SMBus, 1 MHz | I2C Fm+ / SMBus, 1 MHz | I2C Fm+ / SMBus, 1 MHz |
| Level Translation | Yes, down to 0.8 V host rail | Yes, down to 0.8 V | Yes, down to 0.8 V | Yes, down to 0.8 V |
| Interrupt Output | Yes, open-drain with maskable transition detection | Yes | Yes | Yes |
| Hardware Reset | Yes, active-low RESET | Yes | Yes | Yes |
Wichtigste Unterscheidungsmerkmale
- Ultra-low-voltage host interface down to 0.8 V (vs. PCAL6524HE)
- Agile I/O programmable drive strength and pull selection (vs. PCAL6416A)
- Integrated hardware RESET pin (vs. PCAL6524UEAZ)
Designhinweise
Treat RESET as a controlled signal, not a tie-high strap. The PCAL6524 registers power up to defaults, but a controlled assertion of the active-low RESET pin during host power-up (or after brown-out) guarantees the I/O configuration, pull-select, and transition-mask registers are in a known state before bus traffic begins. If RESET is driven by a supervisor or host GPIO, ensure the host bus controller holds SDA/SCL idle until reset deassertion completes; check the reset pulse-width requirement in the NXP PCAL6524DS datasheet timing tables before finalizing firmware.
The 32-pin HUQFN 5x5 mm package has a small exposed thermal/electrical pad pattern per the NXP datasheet land-pattern recommendation - connect it per the datasheet (typically to ground plane) and use an adequate via fan-out for solder wicking control. Place 100 nF decoupling capacitors within 2 mm of both VDD(I2C) and VDD(P) pins, since the two rails are independent and noise on VDD(P) directly couples into the I/O input comparators. Keep SDA/SCL traces short; at 1 MHz Fm+ the bus is fast enough that stubs above ~10 cm begin to affect rise-time margin.
The dual-rail architecture means total supply current is the sum of VDD(I2C) and VDD(P) consumption; when most pins idle as inputs with internal pull-ups enabled, pull-up current through external loads can dominate. Choose Agile I/O pull resistors intentionally - the programmable pull strength lets you minimize standby drain in battery designs by using weak pulls on stable lines and strong pulls only on switch-matrix lines. Estimated: with 24 lines at a typical weak-pull current and a 3.3 V port rail, bias currents dominate over the device's own quiescent consumption, so per-line pull budgeting is worthwhile before locking the design.
Compliance-Informationen
Compliance status was not stated in the provided web data. The AZ suffix in NXP ordering codes conventionally denotes lead-free/halogen-free finishing options, but this must be confirmed against the NXP PCAL6524DS datasheet and the NXP PCAL6524HE product page before use in regulated products.
