FXMA2102L8X - Dual Supply 2-Bit I2C Level Translator | onsemi
MPN: FXMA2102L8X ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.55 | $5.50 |
| 100 | $0.42 | $42.00 |
| 500 | $0.36 | $180.00 |
| 1,000 | $0.31 | $310.00 |
FXMA2102L8X Overview
A voltage level translator (also called a level shifter) is an interface IC that bridges digital circuits operating at different supply voltages, allowing a 1.8V microcontroller to safely communicate with a 3.3V sensor or a 5V peripheral. Level translators sit within the broader logic IC and interface IC hierarchy and are essential wherever mixed-voltage subsystems must share a bus.
Key features of the FXMA2102 include truly bidirectional operation with automatic direction sensing, so no direction-control pin is required on the I2C data (SDA) and clock (SCL) lines. Its wide dual-supply architecture supports translation over a wide range of input and output voltage levels, and the device functions as a buffer, repeater, and isolator for I2C applications, isolating bus capacitance and extending bus length. The device requires external pull-up resistors on both sides, per the onsemi product page.
Technically, the FXMA2102 uses configurable dual voltage supplies (VCCA and VCCB) with architecture that makes each I/O pin referenced to its own supply rail. The 37 MHz data-rate capability comfortably exceeds the 3.4 MHz High-speed mode of the I2C specification, giving large timing margin. Buffering capability isolates the capacitance of one bus segment from the other, which is critical for heavily loaded or long PCB traces and cable runs.
Typical applications include I2C bus level translation between 1.8V, 2.5V, 3.3V, and 5V domains, SMBus and PMBus interfaces in power systems, sensor hubs mixing voltage domains, and general-purpose 2-bit bidirectional translation in industrial and consumer electronics. Its tiny MicroPak footprint suits space-constrained portable designs.
Design consideration: because the device is intended for open-drain I2C use, external pull-up resistors must be provided on both the A-side and B-side; size them against total bus capacitance and the required rise time to preserve signal integrity at speed.
This page synthesizes distributor pricing, drop-in alternatives, practical design notes, and FAQ content not found in a single manufacturer datasheet, providing information gain over standard distributor listings.
Drop-in alternatives for FXMA2102L8X — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
FXMA2102UMX
✅ Drop-In📋 Reference alternative (not in catalog)
FXMAR2102UMX-F106
✅ Drop-In📋 Reference alternative (not in catalog)
FXMA2102L8X Specifications
| Function | Dual-supply 2-bit bidirectional voltage translator / buffer / repeater / isolator |
| Translator Type | Voltage Level Translator, Bidirectional |
| Number of Circuits | 1 |
| Number of Channels | 2 |
| Bits per Channel | 2 |
| Maximum Data Rate | 37 MHz |
| Direction Control | Automatic direction sensing (no DIR pin required) |
| Application | I2C bus interface (buffer / repeater / isolator) |
| Supply Architecture | Dual supply (VCCA / VCCB) |
| Package | 8-Pin MicroPak (L8X) |
| Mounting Type | Surface Mount |
| MSL Rating | MSL 1 (Unlimited) |
| RoHS Status | ROHS3 Compliant |
| REACH Status | REACH Unaffected |
| External Components | External pull-up resistors required (per onsemi product page) |
FXMA2102L8X 8-pin micropak (l8x) Pin Configuration Guide
Pin configuration for FXMA2102L8X (8-pin micropak (l8x) package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for FXMA2102L8X.
Refer to the datasheet for full pin configuration.
Typical Applications
FXMA2102L8X is suitable for 6 applications: I2C Bus Level Translation, I2C Bus Buffering and Capacitance Isolation, Embedded Systems Mixed-Voltage Interfaces, Sensor Hubs in Mobile and Wearable Devices, Industrial Control and Automation, Consumer Electronics and Set-Top Designs.
I2C Bus Level Translation
The primary application of the FXMA2102L8X is bidirectional level translation of a complete I2C bus between two voltage domains, for example a 1.8V microcontroller communicating with 3.3V sensors. The onsemi product page states the device is intended specifically for I2C bus interfaces, with input and output levels compatible with I2C device specification voltage levels. Its automatic direction sensing handles the bidirectional SDA line without firmware intervention, and its 37 MHz data-rate capability provides roughly ten-fold timing margin over 400 kHz Fast-mode operation. External pull-up resistors on both sides set rise times for each rail independently, allowing optimization of each bus segment.
Recommended
I2C Bus Buffering and Capacitance Isolation
As a bus buffer and repeater, the FXMA2102L8X divides one heavily loaded I2C bus into two electrically separate segments, isolating the bus capacitance of sensors, cables, or connectors on one side from the controller side. This allows long PCB traces or external cable runs to be added without violating the I2C bus capacitance limit on the master segment. Because each segment has its own pull-up rail sized independently, rise-time requirements can be met on both a short, fast master segment and a long, capacitive peripheral segment. The 37 MHz rating ensures repeater propagation delay does not compromise 100 kHz to 400 kHz bus timing budgets.
Recommended
Embedded Systems Mixed-Voltage Interfaces
Modern embedded designs routinely mix a low-voltage MCU core domain (1.8V or 2.5V) with 3.3V peripherals. The FXMA2102L8X bridges two such rails for two-wire interfaces such as I2C, PMBus, or SMBus links between a low-voltage processor and sensors, EEPROMs, or power-management ICs. According to the onsemi datasheet, the device is a configurable dual-voltage-supply translator over a wide range of voltage levels, so it supports the common 1.8V / 3.3V pairing without extra components beyond pull-ups. Its 2-channel layout matches exactly the SDA and SCL pair, keeping board area minimal in the tiny MicroPak footprint.
Recommended
Sensor Hubs in Mobile and Wearable Devices
Smartphone, tablet, and wearable sensor hubs aggregate accelerometers, gyroscopes, and environmental sensors that often run at a lower rail than the application processor. The FXMA2102L8X's 8-pin MicroPak package minimizes board area, and its MSL 1 (Unlimited) rating simplifies high-volume reflow logistics. The dual-supply architecture allows the sensor rail and processor rail to power up independently - an important sequencing advantage in battery-operated systems where subsystems are enabled selectively to save power. With a 37 MHz data-rate ceiling, the device comfortably supports both standard I2C sensor polling and faster burst reads of motion-sensor FIFO data.
Recommended
Industrial Control and Automation
Industrial controllers frequently combine legacy 5V logic with modern 3.3V or 1.8V subsystems. The FXMA2102L8X provides a compact, bidirectional bridge for the I2C or SMBus management bus connecting a modern low-voltage controller to 5V-referenced modules, EEPROM configuration memories, and monitoring devices. Its buffer and isolator role is especially valuable in electrically noisy factory environments: separating long cable-connected peripheral segments from the controller segment contains capacitance and improves signal integrity. The part's ROHS3 compliance and REACH-unaffected status support industrial export requirements, and its active lifecycle status per onsemi supports long-term production designs.
Recommended
Consumer Electronics and Set-Top Designs
Consumer platforms such as smart TVs, set-top boxes, and home-automation hubs use I2C extensively for HDMI-to-I2C control paths, tuner control, LED controllers, and configuration EEPROMs, often across mixed voltage rails. The FXMA2102L8X's low cost (sub-dollar at volume), tiny MicroPak footprint, and simple two-external-pull-up bill of materials make it a natural choice for these cost-sensitive two-wire translation points. Automatic direction sensing removes any need for GPIO-based direction control from the host, reducing firmware complexity, while the 37 MHz capability leaves headroom for faster custom two-wire protocols used in panel and backlight control links.
Recommended
Recommended Products Summary
Engineering reference data for FXMA2102L8X — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | FXMA2102UMX | FXMAR2102UMX-F106 |
|---|---|---|---|
| Package | 8-Pin MicroPak (L8X) | 8-Pin MicroPak (UDFN) | 8-Pin MicroPak (UDFN) |
| Brand | onsemi | onsemi | onsemi |
| Number of Channels | 2 (bidirectional) | 2 (bidirectional) | 2 (bidirectional) |
| Supply Architecture | Dual supply (VCCA / VCCB) | Dual supply (VCCA / VCCB) | Dual supply (VCCA / VCCB) |
| Direction Control | Automatic | Automatic | Automatic |
| Primary Application | I2C translator / buffer / repeater / isolator | I2C translator / buffer / repeater / isolator | I2C translator / buffer / repeater / isolator (automotive grade) |
| Function | Translator / Buffer / Repeater / Isolator | Translator / Buffer / Repeater / Isolator | Translator / Buffer / Repeater / Isolator |
Key Differentiators
- Integrated buffer / repeater / isolator function (vs TXS0102)
- 37 MHz data rate with automatic direction sensing (vs PCA9306)
- Same-die package options within onsemi family (vs FXMA2102UMX)
Design Notes
Size pull-up resistors independently on the A-side and B-side. The FXMA2102L8X isolates the capacitance of the two bus segments, so the low-voltage controller side may use 4.7k pull-ups to 1.8V while the peripheral side uses 2.2k to 3.3V for faster edges on a longer, more capacitive segment. Pull-up current must stay within each slave device's sink specification (typically 3 mA for I2C standard/Fast mode) per the onsemi datasheet application guidance.
VCCA and VCCB can power up in any order because the translator is configured for dual independent supplies, but avoid leaving either rail floating while signals are driven - a floating VCC can cause undefined I/O states. Add 0.1 uF ceramic decoupling capacitors close to both VCC pins, placed within a few millimeters on the MicroPak land pattern. Note the pinout is extremely compact, so verify pad geometry against the datasheet package drawing before layout release.
The L8X (MicroPak) and UMX package suffixes are NOT footprint-identical, even though the die is the same. Ordering or substituting FXMA2102UMX onto an L8X land pattern will fail assembly. Also, do not attempt to drive push-pull outputs through the device without pull-ups when using it in its intended I2C open-drain mode - the architecture expects pull-up termination on both sides, per the onsemi product page. Confirm current onsemi ordering information before BOM release.
Compliance Information
ROHS3 Compliant and REACH Unaffected, MSL 1 (Unlimited), per PartGenie compliance summary. AEC-Q100 status not stated for FXMA2102L8X; the FXMAR2102 automotive variant exists for qualified applications.
