FXL6408UMX - 8-Bit I2C GPIO Expander 400kHz 16-UMLP | onsemi
Teilenummer: FXL6408UMX ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $0.62 | $0,62 |
| 10 | $0.55 | $5,50 |
| 100 | $0.44 | $44,00 |
| 500 | $0.38 | $190,00 |
| 1.000 | $0.33 | $330,00 |
FXL6408UMX Übersicht
A GPIO (General Purpose Input/Output) expander is a type of interface IC in the logic family hierarchy that adds digital input and output pins to a microcontroller or baseband processor through a serial bus. Where the host MCU or SoC lacks enough parallel I/O pins, an I2C GPIO expander converts two bus pins (SDA and SCL) into eight additional configurable I/O lines, making it a core building block of system I/O management and power-management-adjacent designs.
Key features include input transition monitoring with an interrupt output: when configured in Input Mode, the FXL6408 watches the input ports for data transitions and asserts the /INT pin to signal the baseband or host. Default input values can be programmed independently, allowing customized input detection thresholds. All eight inputs can be configured with internal pull-up or pull-down resistors, pre-biasing the inputs for open-drain or push-pull operation without external components.
Technically, the device implements a register-based configuration model in which each pin's direction, polarity, pull resistor, and default state are set through I2C write cycles at up to 400 kHz (Fast-mode). The wide 1.65 V to 4.0 V supply range lets one part interface between low-voltage (1.8 V) processors and legacy 3.3 V peripherals, and the small-footprint UMLP-16 package suits space-constrained portable designs.
Typical applications include smartphone and tablet baseband I/O expansion, keyboard and button matrices, LED and backlight status indication, and sensor or peripheral status monitoring in portable and industrial systems where the host MCU lacks spare GPIO.
Design consideration: keep the I2C bus within 400 kHz Fast-mode timing and use the programmable pull resistors to avoid external resistor networks; account for the /INT open-drain output requiring a pull-up to the host logic rail.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in-Alternativen für FXL6408UMX – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
FT2925P
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
FXL6408UMX Technische Daten
| Funktion | 8-Bit I2C-Controlled GPIO Expander |
| Number of I/O | 8 |
| Schnittstelle | I2C |
| I2C Clock Frequency | 400 kHz |
| Supply Voltage Range | 1.65 V to 4 V |
| Interrupt Output | Yes (/INT, asserts on input data transitions) |
| Pull-up/Pull-down Resistors | Configurable per input |
| Programmable Input Default Values | Yes, per input |
| Voltage Translation | Bidirectional between I2C bus and GPIO pins |
| Montageart | Surface Mount |
| Gehäuse | 16-UMLP (1.8 x 2.6 mm) |
| RoHS-Status | Compliant |
| Package Height | 0.6 mm |
FXL6408UMX 0.6 mm Pinbelegungsleitfaden
Pinbelegung für FXL6408UMX (0.6 mm-Gehäuse). Pin-Nummerierung, Funktionen und Anschlussdiagramme sind im Herstellerdatenblatt definiert. Entnehmen Sie diesem den genauen Footprint und Lötrichtlinien.
Keine detaillierten Pinbelegungsdaten verfügbar für FXL6408UMX.
Siehe die Datenblatt für die vollständige Pin-Konfiguration.
Typische Anwendungen
FXL6408UMX ist geeignet für 6 Anwendungs: Smartphone and Tablet Baseband I/O Expansion, Keyboard and Button Matrix Scanning, LED Status and Backlight Indication, Industrial Control Panel I/O Expansion, Sensor and Peripheral Status Monitoring, Voltage-Level Translation Between Logic Domains.
Smartphone and Tablet Baseband I/O Expansion
The FXL6408UMX is explicitly designed for baseband I/O expansion in mobile devices. Its 1.65 V to 4 V supply range natively matches 1.8 V baseband processor rails, and the bidirectional voltage translation between the I2C bus and GPIO pins lets one small IC bridge logic domains without level-shift circuitry. The datasheet describes the part asserting the /INT pin to signal the baseband when input transitions occur, allowing the processor to sleep instead of polling - directly reducing system power draw. The 1.8 x 2.6 mm 16-UMLP package fits the dense board layouts of smartphones and tablets, and the internal pull-up/pull-down resistors remove external components from button and detect lines, saving both area and BOM cost in high-volume mobile designs.
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Keyboard and Button Matrix Scanning
The FXL6408UMX suits keyboard and button-matrix scanning because each of its eight inputs supports independently programmable default values and configurable internal pull-up or pull-down resistors, per the onsemi FXL6408 datasheet. A designer can pre-bias each key line for open-drain or push-pull operation without any external resistors, and the input transition monitor asserts /INT only when a programmed key state changes, so the host MCU services interrupts rather than continuously scanning at 400 kHz I2C speed. In a typical circuit, key pins pull to ground on press while pull-ups define the idle state; the FXL6408 flags the transition in microseconds, giving responsive human-interface behavior with a single 1.8 x 2.6 mm IC and no extra logic glue.
Empfohlen
LED Status and Backlight Indication
The FXL6408UMX expands a processor's limited GPIO into eight outputs for driving LED status indicators and simple backlight enable lines. Configured in push-pull output mode through its I2C register set at up to 400 kHz, each pin sources or sinks indicator LEDs directly or drives LED-driver enable inputs. The 1.65 V to 4 V operating range means the expander can live on a 1.8 V logic rail while signaling 3.3 V LED-driver ICs, thanks to its bidirectional voltage-translation capability described in the onsemi product documentation. The tiny 16-UMLP (1.8 x 2.6 mm) footprint allows placement directly inside the indicator cluster region of a PCB, shortening LED traces, and the register-based control lets firmware change all eight indicators with a single two-wire bus transaction.
Empfohlen
Industrial Control Panel I/O Expansion
In industrial panels and automation IO racks, the FXL6408UMX provides eight additional monitored inputs or driven outputs over a standard I2C bus when the host PLC-adjacent controller runs short of parallel I/O. The configurable pull-up and pull-down resistors pre-bias sensor and switch inputs for open-drain wiring, and independently programmable input defaults enable customized detection thresholds - for example, treating door-switch closure as an alarm event while ignoring sensor chatter. Per the onsemi datasheet, /INT asserts on input data transitions, so the controller responds to field events in interrupt-driven fashion. The 1.65 V to 4 V range integrates with 3.3 V industrial controllers, though designers should verify the [operating temperature range] against the panel environment before deployment in harsh enclosures.
Empfohlen
Sensor and Peripheral Status Monitoring
The FXL6408UMX monitors the status lines of sensors and peripherals that would otherwise each consume a dedicated MCU pin. Card-detect, fault, sleep, and interrupt outputs from multiple devices can be aggregated onto the expander's eight inputs; with programmable default values per the onsemi FXL6408 datasheet, the designer defines exactly which logical state constitutes an event, and the /INT output flags the baseband or host the moment any monitored line transitions. This converts a polling architecture with eight MCU pins into a two-wire interrupt-driven design. The 400 kHz I2C interface reads all eight states in a single transaction, and internal pull resistors eliminate external biasing networks around the monitored signal sources, simplifying PCB routing in dense mixed-signal boards.
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Voltage-Level Translation Between Logic Domains
The FXL6408UMX serves as a bidirectional voltage translator between an I2C bus operating at one voltage and GPIO signals at another, thanks to its 1.65 V to 4 V operating range and the translation capability described in onsemi's product documentation. A common use case is a 1.8 V processor whose I2C bus must control 3.3 V peripherals: the FXL6408UMX bridges the domains while simultaneously adding eight I/O lines, replacing a dedicated level-shifter IC plus a separate expander. The 16-UMLP (1.8 x 2.6 mm) package keeps the combined function within a footprint smaller than many single level translators. Designers should decouple the VDD pin with 0.1 uF and confirm both domain voltage levels stay within the datasheet's absolute maximum ratings before finalizing the rail architecture.
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Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für FXL6408UMX – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | FT2925P |
|---|---|---|
| Package | 16-UMLP (1.8 x 2.6 mm) | 16-UMLP (1.8 x 2.6 mm) - same |
| Brand | onsemi | onsemi (discontinued) |
| Number of I/O | 8 | 8 |
| Interface | I2C, 400 kHz | I2C, 400 kHz |
| Supply Voltage | 1.65 V to 4 V | 1.65 V to 4 V |
| Interrupt Output | Yes (/INT on input transition) | Yes (/INT) |
| Pull-up/Pull-down Config | Yes, per input | Yes, per input |
| Lifecycle Status | Active | Discontinued - use FXL6408UMX as replacement |
Wichtigste Unterscheidungsmerkmale
- Native 1.8 V operation with voltage translation (vs. PCA9654EDR2G)
- Extreme footprint advantage for portable boards (vs. PCA9654EDR2G)
- Per-pin configurable pull resistors and programmable defaults (vs. FT2925P (discontinued))
Designhinweise
Place a 0.1 uF ceramic decoupling capacitor as close as possible to the FXL6408UMX VDD pin, with a solid low-impedance ground return. The 16-UMLP (1.8 x 2.6 mm) land pattern is small, so follow the onsemi datasheet recommended PCB footprint exactly and verify stencil aperture design for the fine pitch. Because the internal pull-up/pull-down resistors eliminate external biasing networks, keep GPIO traces short to reduce coupling into neighboring high-speed lines in dense portable layouts.
The I2C bus runs at up to 400 kHz Fast-mode, so size SDA and SCL pull-up resistors (typically 2.2 k to 4.7 k at 3.3 V, adjusted for bus capacitance and VDD level) to meet rise-time requirements. The /INT output is asserted open-drain style per the datasheet description and requires a pull-up to the host logic rail - do not drive it push-pull. Route SDA/SCL away from switching regulator nodes to avoid glitching the transition detector into spurious interrupts.
Common pitfall: treating the FXL6408UMX as pin-compatible with onsemi's PCA9654EDR2G. Per onsemi's own community guidance, the two differ in package (UMLP-16 vs SOIC-16), pinout, and electrical parameters - a PCB redesign is mandatory to swap between them. Also confirm the operating supply stays within 1.65 V to 4 V at all times; exceeding 4 V on VDD or GPIO pins risks permanent damage. Finally, program the input default-value registers after power-up before relying on /INT behavior.
Compliance-Informationen
RoHS compliant and lead-free per onsemi/DigiKey product listings. REACH, halogen-free, and conflict-minerals declarations not found in verified data - request material declaration from onsemi for regulated-market use.
